WO2016105012A1

WO2016105012A1 - Member for gas sensor, having a metal oxide semiconductor tube wall with micropores and macropores, gas sensor, and method for manufacturing same

Info

Publication number: WO2016105012A1
Application number: PCT/KR2015/013707
Authority: WO
Inventors: 김일두; 장지수; 김상준; 최선진
Original assignee: 한국과학기술원
Priority date: 2014-12-23
Filing date: 2015-12-15
Publication date: 2016-06-30

Abstract

The present invention relates to a member for a gas sensor, a gas sensor using the same, and a method for manufacturing the same and, specifically, to a member for a gas sensor, using a one-dimensional porous metal oxide nanotube composite material having a double average pore distribution, in which micropores (0.1 nm-50 nm) and macropores (50 nm-300 nm) are simultaneously formed in a surface of nanotubes by decomposition of a spherical polymer sacrifice layer template and continuous crystallization and diffusion of a metal oxide, and a nanoparticle catalyst embedded in apoferritin is uniformly bound to an inside, an outer wall, and an inner wall of one-dimensional metal oxide nanotubes through high-temperature thermal treatment, to a gas sensor, and to a method for manufacturing the same.

Description

[Specifications

[Name of invention]

Member for gas sensor, gas sensor and method for manufacturing microporous and macropore formed on metal oxide semiconductor tube wall

Technical Field

The present invention relates to an optimal sensing material structure in which gas is rapidly diffused and reacted, and a method for manufacturing the same. The present invention relates to metal particles and spherical polymer regeneration surrounded by a protein contained in a metal salt precursor / polymer composite nanofiber prepared by electrospinning. Metal oxide semiconductor nanotubes having a dual mean pore distribution functionalized by catalyst particles containing micropores and macropores simultaneously formed at the same time as the layer template is subjected to high temperature pyrolysis, and for the gas sensor using the same, a member, a gas sensor, and a manufacturing method thereof It is about. Background Art

Recently, as the interest in health care has increased, the development of metal oxide semiconductor-based gas sensors for detecting volatile organic compound gas in the exhalation for detecting diseases and harmful environmental gases for measuring indoor air quality has been actively conducted. The metal oxide semiconductor-based gas sensor detects a gas by measuring a change in electrical resistance during the adsorption and desorption process caused by the interaction of oxygen ions adsorbed on the metal oxide surface with a specific gas to be detected. In particular, since the metal oxide gas sensor has an advantage of easy miniaturization, a recent research has been attempted to mount the gas sensor in a mobile device or a wearable device from the viewpoint of commercialization. In addition, it has the advantage of low price, and has been actively used throughout the society, such as hazardous environmental gas alarm, alcohol breathalyzer, air pollution meter, anti-terror gas sensor. In particular, the detection of volatile organic compounds such as acetone, ammonia, nitrogen monoxide, hydrogen sulfide and toluene, which are related to trace amounts of metabolism released from the body's exhalation, has been used to detect diabetes and kidney disease. The possibility of diagnosing a variety of diseases, including asthma, bad breath, and lung cancer, is being raised. However, in order to diagnose diseases early on using these biomarker gases, very low concentrations of biomarker gases in the range of 10 parts per billion to 10 ppmCpart per million are required to be used within a few seconds. It should be able to detect with high sensitivity. In particular, it is important to develop a highly selective sensing material with a specific target biomarker and a gas to be measured because thousands of species and mixed gases contained in the fly must be reacted with high sensitivity. .

The development of gas sensors based on various nanostructures including nanoparticles, nanofibers, and nanotube structures at work is being studied for metal oxide semiconductor based gas sensors to have high sensitivity and high selectivity. As mentioned above, since the metal oxide base and the gas sensor are caused by the surface reflection between the sensing material surface and the sensor body, the higher the surface area of the sensing material that the sensor molecules can react with, the higher the sensitivity characteristic can be expected. In view of this, nanostructure sensing materials have a larger area of reaction with gases than thick film or thin film materials. Since it is relatively wide, it can have excellent gas sensing characteristics, and because it has a porous structure that can sufficiently diffuse gas molecules into the sensing material, it can induce ultrafast reaction properties. In particular, having micropores and macropores

In the case of 1-dimensional porous metal oxide nanotubes, the surface area can be expected to be increased by 2-10 times or more than the nanofibers of the thin film structure, and thus, high sensing characteristics can be predicted, and pores of various sizes are distributed on the surface of the ribs. Compared with the structure, gas molecules can move freely, maximizing sensor characteristics. In addition, if the catalytic nanoparticles are uniformly bound to the one-dimensional porous nanotubes without any mutual concavity, the catalytic effect can be maximized even with a small amount of catalyst. In addition, a catalyst is a catalyst are functionalized by the exposure forms on the surface of the built-in inside the dense sensing material than the structure in which the reaction of the gas does not easily done, the sensing material in order to maximize the effectiveness of the ^catalyst, of the gas catalytic banung It is ideal to be able to maximize. These catalysts can be broadly classified into two types:-Chemical sensitization, which enhances the gas sensor characteristics by increasing the concentration of gases participating in the surface reaction using metal catalysts such as platinum (Pt) and gold (Au). ), Or electronically, to improve sensitivity using the oxidation number change resulting from the formation of metal oxides such as PdO, NiO, Co203, Ag20, such as palladium (Pd), nickel (Ni), cobalt (Co), silver (Ag), etc. There is an electronic sensitization method.

As described above, despite the development of various nanostructures and researches utilizing the sensing material in which various nanoparticle catalysts are bound, Despite; Metal oxide semiconductor-based sensing materials that can measure extremely small amounts of gas at hundreds of ppb at high speed have not been commercialized, and to detect an extremely small amount of gas, the detection of an extremely small amount of gas is needed. It is important to develop a sensing material that can be used and to clearly recognize the pattern of the detected result by giving selectivity to various gases.

In view of the synthetic viewpoint of the sensing material having a nanostructure, a number of methods for preparing nanostructures through chemical vapor deposition, physical vapor deposition, and chemical growth have been studied. However, these methods include complex and cumbersome processes in synthesizing nanostructures, which makes it difficult to mass produce, expensive process cost, and long process time. It is becoming.

In addition, when viewed from the viewpoint of the nanoparticle catalyst that is bound to the sensing material, the catalysts should be well dispersed in all regions of the sensing material uniformly and well to induce the most effective catalysis. In this respect, it is difficult to optimize the sensor characteristics because it is difficult to avoid agglomeration between the catalyst nanoparticles during the nanoparticle synthesis and the binding process between the sensing material and the catalyst particle using the polyol process method widely used in the conventional sensor field. Situation.

In order to overcome the shortcomings of the existing sensor synthesis, an ideal nanostructure with a wide range of targets and micropores that can induce rapid diffusion and reversal of gas with simple and effective manufacturing method, and nanoscale of nanoscale particle There is a need for a process technology capable of functionalizing the sensor with high dispersion so that the catalysts are not packed together. In addition, by simultaneously satisfying the two aspects described above, the process technology for the development of a sensor that can selectively detect a small amount of biomarker gases contained in the exhalation of the human body and recognize the pattern, ultimately distinguish patients with disease This is necessary.

[Detailed Description of the Invention]

[Technical problem]

Embodiments of the present invention, the spherical polymer colloids that serve as a regenerative layer template to form the macropores are dispersed in the electrospinning solution, and the high temperature heat treatment after the electrospinning, spherical polymer template (> 200 nm ) Macropores (50 nm-300 nm) are formed on the surface of the nanotubes through pyrolysis, and macropore covering and protein templates (12 nm) are sequentially generated through the diffusion of metal oxides generated during the formation of the ribs. Provided is a one-dimensional porous metal oxide nano-leave electrospinning synthesis method to simultaneously form micropores (0.1 nm-50 nm) on the surface of the nanotube through pyrolysis of. In addition, by dispersing a highly dispersed protein-based nanoparticle catalyst in an electrospinning solution, a double average having a macropore (50 nm-300 nm) and micropores (0.1 nm-50 nm) in which the nanoparticle catalyst is uniformly bound Provided is a one-dimensional porous metal oxide nanotube electrospinning method having a pore distribution.

Particularly, macropores are formed (50 nm-300 nm) through decomposition of the sacrificial layer template polymer through high temperature heat treatment using a polymer regenerative layer template having a size of 200 nm or more. It forms on the surface of the fiber, and in order to form the metal oxide nano-lube sequentially, diffusion of the metal oxide occurs in the direction of the macropores formed on the surface to fill a part of the macropores, thereby forming micropores having a size distribution of 0.1 nm-50 nm. It is additionally formed on the surface of the nanotubes, and the catalyst is uniformly distributed on the one-dimensional porous metal oxide nanotubes having high sensitivity and high selectivity by using a protein-based highly dispersible nanoparticle catalyst to help uniform catalyst distribution and micropore formation. We present the gas sensor grand technology using ^■ sensing material synthesis technology. The protein template, apo-ferritin, used in the present invention, is a spherical thickened protein material having an empty space of about 8 nm, and includes a nanoparticle catalyst in the empty inside of the apoferritin protein. It is possible to provide a method for electrospinning a metal oxide nanotube comprising a functionalized nanoparticle catalyst from apoferritin particles including a nanoparticle catalyst.

In particular, despite the inclusion of a metal nanoparticle catalyst after high temperature heat treatment, the Ostwald ripening phenomenon synthesizes a metal oxide nanotube structure having a large surface area, and the nanoparticle catalyst also forms a nanotube. We present the ultra-sensitive nanotube sensing material synthesis technology and gas sensor application technology that can satisfy both the specific surface area increase and the catalytic effect, which are uniformly dispersed in the shell, which are important indicators of gas sensor characteristics. .

This is a solution to the problems of the prior art, in which nanoparticle catalysts of very small (1 nm-3 nm) size are evenly distributed inside and outside the metal oxide without intermingling each other. Metal oxide nanotube structures containing a large number of micropores (0.1 nm-50 nm) and macropores (50 nm-300 nm) can be easily synthesized in a single electrospinning and post-heating process, while being dispersed and bound. It is an object of the present invention to provide a gas sensor member, a gas sensor using the same, and a method of manufacturing the same.

Technical Solution

In one aspect of the present invention for solving the above problem, applying a surface charge characteristic in dispersibility is excellent _i synthesizing nanoparticle catalyst, and the dispersibility is excellent sphericity of polymeric regenerative layer template colloid at the same time, the electrospinning solution The nanoparticle catalyst is easily uniformly bound in a single process, and includes a porous 1-dimensional metal oxide nanotube formed with micropores and macropores at the same time ^{: a} sensing material and a method for manufacturing a gas sensor member using the same. Sensing material according to the present embodiment and a method for manufacturing a gas sensor member using the same step (a) synthesizing a dispersion solution in which the metal nanoparticle catalyst surrounded by a protein contained in the hollow structure of the apoferritin uniformly dispersed ; (b) mixing a dispersion solution in which metal nanoparticle catalysts piled up uniformly by proteins contained in the internal hollow structure of the apoferritin with a spherical polymer sacrificial layer template dispersion solution, and combining these with a metal oxide precursor (metal salt precursor) The solution is mixed with a solution in which the polymer is dissolved. Manufacturing step; (c) The additive electrospinning solution is subjected to electrospinning and has at least one spherical polymer sacrificial layer template and a metal nanoparticle catalyst contained in the inner hollow structure of the apoferritin protein on the inside and the surface of the metal oxide precursor / polymer composite nanofiber. Evenly in plural Forming a distributed composite nanofiber; (d) formation of macropores on the surface of the fiber (50 nm-300 nm) through decomposition of the regenerative layer template polymer through high heat treatment, and the diffusion of the metal oxide on the surface to sequentially form metal oxide nanotubes. It forms in the pore direction and fills a part of the macropores to form micropores having a size distribution of 0.1 nm-50 nm on the surface of the nano-lube, and protein-based nanoparticle catalysts in the composite nanofibers also diffuse outwardly Uniformly binding to the nanotubes; (e) The nanoparticle catalyst having a dividing surface pore distribution is uniformly bound to the inner and inner and outer surfaces of the plepids constituting the nano-leuve, and to disperse the porous metal oxide nanotubes having micropores and macropores. Or by pulverizing, manufacturing a resistance-type semiconductor gas sensor using at least one coating process on the sensor electrode for measuring a semiconductor gas sensor by using drop coating, spin coating, inkjet printing, and dispensing; It includes a method for producing a catalyst-metal oxide nanotube composite sensing material having a binary surface pore distribution for the gas sensor capable of detecting the environmentally harmful gas and biomarker gas for disease diagnosis comprising a.

Here, in the step (a), apoferritin is a protein having a hollow structure (hollow structure) of about 8 nm from the protein called ferritin (ferritin) containing iron components present in the small intestine mucosa cells The total size is 12 nm. Various metal ions were diffused into the apoferritin structure, and various kinds of nanoparticle catalysts could be easily synthesized by reducing them. The types and forms of metal salts that can be substituted inside apoferritin can vary widely. Representative salt type catalysts include copper (II) nitrate, copper (II) chloride, cobalt (II) nitrate, cobalt (II) acetate, lanthanum (III) nitrate, lanthanum (III) acetate, platinum ( IV) chloride, platinum (II) acetate, gold (I, III) chloride, gold (III) acetate, silver chloride, silver acetate, Iron (III) chloride, Iron (III) acetate, nickel (II) chloride, nickel ( II) acetate, ruthenium (III) chloride, ruthenium acetate, iridium (III) chloride, iridium acetate, tantalum (V) chloride, palladium (II) chloride _. And, if the form of a salt containing a metal silver is not limited to the type of special metal salt, when using a single metal salt, a single metal particles are formed in the hollow portion of the apoferritin, the synthesis using two metal salts at the same time In this case, the nanoparticle catalyst formed in the vaporization portion of the apoferritin in the form of a metal alloy (metal alloy) having a strong binding force because it is easy to bond with the heterogeneous type, and the phases can be separated from each other due to the strong homogeneous binding force. can do. In the case of the nanoparticle catalyst embedded in the synthesized apoferritin hollow structure, the surface of the hook is surrounded by a protein having a surface charge, and thus, it is possible to effectively maintain a dispersed state without mutual congestion.

In addition, the step (b) is to prepare an electrospinning solution for the electrospinning process, dissolving the polymer and metal oxide precursor serving as a template for effectively synthesizing the nanofibers during the electrospinning process in a solvent, spinning solution Can be prepared. Representative polymers used here include polymethylmethacrylate (PMMA), polyvinylpyridone (PVP), polyvinylacetate (PVAc),. Polyvinyl alcohol (PVA), Polyacrylonitrile (PAN), polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene oxide co-polymer, polypropylene oxide copolymer, polycarbonate (PC), polyvinyl chloride ( polyvinylchloride (PVC), polycaprolactone, polyvinylidene fluoride and the like. Representative metal salts include acetate, chloride, acetylacetonate, nitrate, methoxide, ethoxide, Subtypes, isopropoxide, sulfide and the like. In addition, the colloidal electrospinning solution was prepared by uniformly dispersing the nanoparticle catalyst solution accumulated in the apoferritin protein synthesized in step (a) and the spherical polymer sacrificial layer template colloid having excellent dispersibility in the electrospinning solution. can do. In the case of the sacrificial layer template of the spherical shape used for the formation of the large pore means a template that can be removed during high temperature heat treatment, there is no particular restriction on the type of template. Specifically, polymethyl methacrylate (ΡΜΜΑ), polyvinylpyridone (PVP), polyvinylacetate (PVAc), polyvinyl alcohol (PVA), polystyrene (PS) and polyacrylonitrile (PAN), polyvinyl It may be one or two or more mixtures selected from among the following: fluoride fluoride (PVDF), polyacrylic acid (PAA), polydiaryldimethylammonium chloride (PDADMAC), polystyrenesulfonate (PSS). In addition, the sacrificial layer template has a size in the range of 50 nm -1 _U m, and preferably, when mixed with an electrospinning solution, is characterized by being dispersed without decomposition, and the regenerative layer colloid is a polymer that is dissolved in a solvent. Even though, colloid Charged silver on the surface Black colloidal polymers that do not dissolve in solvents form anionic or cationic surfactants.

In addition, the step (c) is a metal salt / polymer composite nanosam oil in which metal nanoparticles (a metal nanoparticle catalyst) and a spherical polymer regenerative layer template (polymeric beads) in apoferritin are uniformly bound using an electrospinning technique. Synthesis step. The shape of the composite nanofibers is characterized by having a rugged shape by the built-in polymer regenerative layer template.

In the step (d), the polymer constituting the polymer / metal oxide precursor composite nanofibers is decomposed and removed by high temperature heat treatment, and at the same time, a nanoparticle catalyst. The surrounding apoferritin protein shell and spherical polymeric regenerative layer template are removed. Specifically, the macropores formed on the surface of the nanofibers are produced by decomposing a polymer having a size of 200 nm or more through high temperature heat treatment, while metal oxide crystallizes and diffuses outward in the process of forming metal oxide nanotubes sequentially. The micropores partially cover the plurality of micropores. In addition, apopertin particles, which are aggregated between the plurality of polymer sacrificial layer templates, are decomposed to contribute to the formation of micropores. In particular, the gain rate during the heat treatment process plays a very important role in forming the nanotube structure. When the heat treatment is rapidly performed at a temperature increase rate of 10 ° C / min, the double pore distribution including the metal nanoparticle catalyst obtained in the decomposition of the apoferritin protein formed inside the vaporization structure of the nanoparticle catalyst in the metal oxide nanoflube structure ( Micropore and Giant Machining Simultaneously Co-existing distribution) can be more effectively synthesized one-dimensional porous metal oxide nanotubes. On the other hand, if the heat treatment at a relatively slow 4 ⁰ C / min, nanotube structure may not be formed well.

In the step (e), a sensor electrode prepared in advance for dispersing the dispersion solution obtained by dispersing the one-dimensional porous metal oxide nano-lever obtained in the step (d) in a solvent (electric conductivity and electrical resistance change can be measured. The coating may be performed on alumina insulator giffin :) in which a parallel electrode is formed, using a coating process such as dram coating, spin coating, inkjet printing, dispensing, and the like. Here, if the method can uniformly coat the one-dimensional porous metal oxide nanotubes including the nanoparticle catalyst and have a double pore distribution, there is no particular limitation on the coating method.

The fabricated one-dimensional porous metal oxide nanotube structure having a dilution pore distribution may be determined in the thickness range of 10 _nm to 50 nm between the inner wall and the outer wall, and the diameter of the nanotube is in the range of 50 nm to 5 μηα length. It can have The length of the nanotubes may have a length ranging from 1 μπι to 100 nm. It also contains a plurality of micropores having a range of 0.1 nm-50 nm on the outside of the tube and macropores having a size range of 5 to 300 nm.

According to another aspect of the present invention for solving the aforementioned ^problems, dispersibility is excellent composite nanoparticles catalyst, uniformly them in and out of the ease of single-step method of the one-dimensional metal oxide nanotubes with Binding material having a large surface area and at the same time uniformly distributed nanoparticle catalyst ^' and Provided are a method for manufacturing a gas sensor member. This method relates to a method for manufacturing a member for a gas sensor, in which a catalyst particle having a high dispersion property is bound to a nanotube alone without mixing the polymer template and catalyst particles described above. Sensing material according to the present embodiment and a method for manufacturing a gas sensor member using the same comprises the steps of: (a) synthesizing a nanoparticle catalyst using apoferritin; (b) preparing a metal oxide precursor / polymer mixed electrospinning solution comprising the nanoparticle catalyst included in the hollow structure of apoferritin; (c) forming a metal oxide precursor / polymer composite nanofiber comprising a nanoparticle catalyst contained in a hollow structure of apoferritin on or inside the metal oxide precursor / polymer composite fiber using an electrospinning technique; 1) Apoptotin and the polymeric material surrounding the nanoparticle catalyst are removed by pyrolysis through a high temperature heat treatment at a high temperature and speed. 1 Forming a dimensional metal oxide nanotube structure; (e) dispersing the metal oxide nanotube material to which the metal nanoparticle catalyst is bound in ethanol, and manufacturing a gas sensor by drop-coating a gas sensor and a measuring electrode; (F) preparing at least two or more kinds of ^ -oxide oxide nanotube sensors to which the nanoparticle catalyst is bound by a combination of different nanoparticle catalysts or different metal oxide sensing materials to construct a sensor array; It may further include. It includes a method for producing a structure comprising a nanoparticle catalyst uniformly dispersed on the surface and inside of the one-dimensional nanotubes through the one-time electrospinning process. Here, the step (a) is the same as the process of synthesizing the nanoparticle catalyst of the process of manufacturing the nanotubes containing the micropores and macropores.

In addition, the step (b) is to prepare a spinning solution for the electrospinning, to dissolve a metal salt acting as a precursor and a metal salt acting as a precursor (template) to easily form nanofibers in a solvent A spinning solution can be prepared. Specifically, the polymer is polymethyl methacrylate (PMMA), polyvinylpyridone (PVP), polyvinylacetate (PVAc), polyvinyl alcohol (PVA), polymirylonitrile (PAN), polyethylene oxide ( polypropylene oxide (PEO), polypropylene oxide (PPO), polyethylene oxide co-polymer, polypropylene oxide copolymer, polycarbonate (PC), polyvinylchloride (PVC), polycaprolactone , Polyvinylidene fluoride, and the like, and representative metal salts include acetates, chlorides, acetylacetonates, nitrates, methoxides, eigensides, side-effects, isopropoxide, and sulfides including metal salts. Include form. In addition, the nanoparticle catalyst prepared in step (a) may be added to the electrospinning solution of the apoferritin protein formed in the hollow structure of the electrospinning solution. When the electrospinning solution is prepared, the concentration of apoferritin protein in which the nanoparticle catalyst is formed inside the hollow structure may be controlled in a range of 0.001 wt%-50 wt%. The content of the nanoparticle catalyst contained in the shell of the metal oxide nanotubes is controlled according to the concentration of apoferritin protein. In addition, the step (C) is a step of synthesizing the metal salt / polymer composite nanofibers using an electrospinning technique, the nanoparticle catalyst synthesized in the step (a) is an excellent powder of the apoferritin protein formed inside the hollow structure Because of the acidity, the apoferritin protein including the nanoparticle catalyst may be distributed evenly inside the metal oxide precursor / polymer composite nanofibers.

Further, in the step (d), the polymer constituting the polymer / metal oxide precursor composite nanofiber is decomposed and removed through high temperature heat treatment, and the metal oxide precursor undergoes an oxidation process and an Ostwald ripening process, The metal oxide nano-lube structure including the nanoparticle catalyst of the one-dimensional structure can be formed, in particular, the temperature increase rate during the heat treatment process plays a very important role in forming the nano-lube structure. When the heat treatment proceeds rapidly ^{at a} temperature increase rate of 10 ^° C / min, nanoparticle catalyst is formed inside the hollow structure of apoferritin protein. Metal oxide nanotubes containing the metal nanoparticle catalyst obtained by decomposition in a quaternary structure can be more effectively synthesized. On the other hand, if the heat treatment at a relatively slow 4 ^° C / min, nanotube structure may not be formed well.

In addition, in the step (e), the dispersion solution in which the polycrystalline metal oxide nanotubes to which the nanoparticle catalyst obtained in the step (d) is bound in a solvent is prepared in advance to measure a change in electrical conductivity and electrical resistance. Alumina insulator substrate having a parallel electrode formed thereon, by using a coating process such as dram coating, spin coating, inkjet printing, dispensing, or the like. Sensor board If the nanoparticle catalyst is able to uniformly coat the polycrystalline metal oxide nanotubes including the metal nanoparticle catalyst obtained by decomposing the apoferritin protein formed inside the vapor deposition structure in the shell structure, the coating method is not particularly limited. Does not. In addition, the step (f), the metal oxide nanotubes having a different one-dimensional structure and different nanoparticle catalyst in the sensor having a metal oxide nano-lube structure containing the nanoparticle catalyst synthesized in the step (e) Combination of two or more composite sensing material array sensor including a plurality of nanoparticle catalyst-metal oxide nanotube composite sensing material can be configured.

The fabricated one-dimensional metal oxide nanotube structure may be sealed in a thickness range of 10 nm to 50 nm between the inner wall and the outer wall, the length of the nano-lube may have a length range of 1 μπι to 500 μπι. In the case of the sensing material, the nanoparticle catalyst is intensively and uniformly included in the ¾ quality constituting the metal oxide nanotubes, thereby maximizing the catalyst's talk and maximizing the sensitivity of the sensing material.

The weight ratio of the nanoparticle catalyst in the nanoparticle catalyst-metal oxide nanotube composite sensing material produced by the above method may be selected in the range of 0.001 wt%-50 wt to the weight of the metal oxide nanoleuubric, and included in a human exhalation. Gas can be detected to monitor the presence of diseases, as well as to detect harmful environmental gases indoors and outdoors.

【Effects of the Invention] Embodiments of the present invention form a nanoparticle catalysts having a size of 1 nm 3 nm using a protein template that has a positive charge on the surface and is dispersible due to the repulsive force between each other, and the formed nanoparticle catalysts are electrospinning solutions. It is characterized in that the spherical template colloid is also mixed with the electrospinning solution and electrospun to distribute the spherical template and the catalyst uniformly on the composite nanofibers. In addition, the nanoparticle catalyst is uniformly bound by using the Ostwald-lifeening phenomenon and the polymer decomposition phenomenon in the high heat treatment process, and the one-dimensional porous metal oxide structure having a double pore distribution on the metal oxide surface is used. It is characterized by forming. It is possible to detect various gases through various material composition change with high sensitivity characteristic that can detect trace amount of gas of about 10 ppb through catalytic effect and shape control to increase reaction surface, which are important factors for gas sensor characteristics. Gas sensor member, gas sensor and its manufacturing method that can be mass-produced by simultaneously performing nanotube shape control process including many catalyst binding and pores by simple process by controlling electrospinning and heat treatment process Has the effect to initiate.

According to embodiments of the present invention, in synthesizing one-dimensional porous metal oxide nanotubes including a plurality of circular to elliptic micropores and macropores, using a spherical polymer regenerative layer template, polymer decomposition Using the time difference between the crystallization and diffusion process of the metal oxide and the metal oxide, one-dimensional porous nanotube structure including micropores and macropores is formed on the surface of the nanotube in a single process, and a plurality of polymers are formed. The protein well template, which is agglomerated in between, forms a porous tube structure having a specific surface area that is several tens of times larger than a general thin film structure and a several times larger specific surface area than a dense tube structure. By smoothing the flow of gas molecules through the pores present on the tube surface, the adsorption and desorption between the gas molecules and the metal oxide nanotube surface are facilitated, thereby improving sensor characteristics. In addition, by including the nanoparticle catalyst contained in the apoferritin in the electrospinning solution, all the proteins surrounding the nanoparticle catalyst by electrothermal heat treatment after electrospinning is removed, nanoparticles having a size in the range of 1 nm to 3 nm It is going to be exposed to the surface 1 ^and the newly formed through the porous nanotube inner and outer walls and pore diffusion through the process of Ostwald life turning process is to maximize the catalyst banung effect. Proteins with an internal vaporization size of 8 nm can additionally form ultra-pores on the surface of the nanoleuve during removal. As mentioned above, by maximizing the sensor characteristics through the shape control and catalytic reaction effect of the gas sensor member, it has a high sensitivity characteristic that can detect a trace amount of gas, and has excellent selectivity to detect a specific gas. A gas sensor member capable of producing, a gas sensor, and a manufacturing method thereof can be disclosed.

According to the embodiments of the present invention, in manufacturing a hollow fiber having a one-dimensional metal oxide nanotube structure, by controlling the heat treatment conditions, by forming a nanotube structure in a single process, the ratio is more than six times larger than the general thin film structure It has a surface area and facilitates the movement of gas into the tube, improving the sensitivity to traces of gas. Have In addition, a gas sensor using a sensing material in which the nanoparticle catalyst contained in the apoferritin is included in the electrospinning solution and the nanoparticle catalyst is bound to the inner and outer walls of the metal oxide nanotubes evenly through the high temperature heat and treatment after electrospinning. To maximize the catalyst reaction. Can be. As mentioned above, by maximizing the surface area and catalytic reaction effect of the gas sensor member, it has a high sensitivity characteristic to detect a trace amount of gas, and has a good selectivity to detect a specific gas, and a mass sensor capable of mass production. It has the effect which can start a metal member, a gas sensor, and its manufacturing method.

[Brief Description of Drawings]

, The accompanying drawings are included as part of a better understanding of the present ^invention, a detailed description is provided for an embodiment of the present invention, it will be described from the invention and together with the description.

1 is a schematic diagram of a member for a one-dimensional porous metal oxide nanotube gas sensor in which the nanoparticle catalyst according to an embodiment of the present invention is uniformly bound and includes a plurality of circular to elliptic micropores and macropores.

2 is a one-dimensional porous metal oxide nanotube structure including a nanoparticle catalyst synthesized using apoferritin according to an embodiment of the present invention and including a plurality of circular to elliptic micropores and macropores. It is a flowchart of the gas sensor manufacturing method.

3 is a nanoparticle using an electrospinning method according to an embodiment of the present invention Figure 1 shows the manufacturing process of a one-dimensional porous metal oxide nanotube structure having a double pore distribution including a catalyst and a plurality of circular to elliptic pores.

4 is a view showing the principle that the micro-pores are generated by the crystal structure and diffusion of the metal oxide crystal sphere template and the sphere on the surface of the nanotube according to an embodiment of the present invention.

Figure 5 is a diagram showing the principle of generating micropores through the protein of the hollow structure according to an embodiment of the present invention.

6 is a scanning electron microscope (SEM) photograph of a spherical polymer regenerative layer template serving as a regenerative layer template according to an embodiment of the present invention.

7 (a) and 7 (b) are transmission electron microscopy (TEM) images of apoferritin particles containing Pt nanoparticle catalyst according to Example 1 of the present invention, Figure 7 (c) is the surface charge of the particles Zeta potential data is analyzed, and FIG. 7 (d) shows the size distribution of Pt nanoparticle catalysts, respectively.

FIG. 8 is a metal oxide precursor / polyvinylpyridone (PVP) comprising a hollow structure of apoqueritin protein comprising a Pt nanoparticle catalyst and including a spherical polymer sacrificial layer template according to an embodiment of the present invention. A scanning electron microscope (SEM) photograph of nanofibers obtained by electrospinning a composite spinning solution.

9 (a) and 9 (b) illustrate ^' Pt nanoparticles and spheres synthesized using tin oxide precursor / polyvinylpyridinone (PVP) and apoferritin according to Example 2 of the present invention. Electrospinning the spinning solution made by adding the colloidal template of the polymer regenerative layer in the form, and heat-treating the silver. Scanning electron microscopy (SEM) photographs of one-dimensional porous metal oxide nanotubes containing Pt nanoparticle catalysts, which contain micropores and macropores.

10 (ac) is a transmission electron microscope (TEM) photograph of a one-dimensional porous metal oxide nanotube including a plurality of micropores and macropores, including a Pt nanoparticle catalyst according to Example 2 of the present invention. 10 (d) shows a SAED (Selected Area Electron Diffraction) pattern and FIG. 10 (e) shows an EDS (Energy Dispersive X-ray Spectrometer) photograph.

11 (a) and 11 (b) are thermogravimetric analysis of one-dimensional porous metal oxide nanotubes containing a Pt nanoparticle catalyst according to Example 2 of the present invention and including a plurality of micropores and macropores. The (TGA) graph and the photoelectron spectrometer (XPS) analysis graph are shown, respectively.

12 is a scanning electron microscope of a metal oxide nanotube obtained by electrospinning a metal oxide precursor / polyvinylpyrrolidone (PVP) composite spinning solution according to Comparative Example 1 of the present invention and subjected to a high silver heat treatment under a fast win speed condition ( SEM) picture. . ^■

Figure 13 (a) and Figure 13 (b) is a fast win speed condition for the metal oxide precursor / pulley vinylpyridone (PVP) composite nanofibers containing the spherical polymer regenerative layer template according to Comparative Example 2 of the present invention Distribution of the porosity Eggplants are scanning electron micrographs of one-dimensional porous metal oxide nanotubes. Figure 14 (a) is a one-dimensional porous metal oxide nanotubes containing a Pt nanoparticle catalyst according to Example 2 of the present invention, including a plurality of micropores and macropores and pure tin oxide according to Comparative Example 1 Nanotube structure, anti-acetone gas (100 ppb-5 ppm) at 350 ° C of a one-dimensional porous tin oxide nanotube structure with a bi-porous distribution with a plurality of circular and elliptic pores according to Comparative Example 2 Male graph. Figure 14 (b) shows the acetone detection limit characteristics of the one-dimensional porous metal oxide nanotubes sensing material containing the R nanoparticle catalyst according to an embodiment 2 of the present invention and includes a plurality of micropores and macropores It is a graph.

FIG. 15 illustrates acetone (CH3COCH3) at 350 ° C of a gas sensor having a Pt nanoparticle catalyst according to Example 2 of the present invention and having a one-dimensional porous metal oxide nanotube structure including a plurality of micropores and macropores. ), A semi-linear graph at 1 ppm for biomarker gases such as toluene (C6H5CH3), hydrogen sulfide (H2S), nitrogen monoxide (NO), carbon monoxide (CO), pentane (C5H12) and ammonia (NH3). 16 is a view showing a process of capturing the exhalation of 10 healthy people according to an embodiment of the present invention, and the process of producing a simulated diabetic exhalation similar to the exhalation of a real diabetic patient.

FIG. 17 shows exhalations using an array of sensor materials prepared above according to an embodiment of the present invention, and analyzes the exhalations through Principal Component Analysis (PCA). The picture shows the exhalation and the exhalation of simulated diabetics.

18 is a schematic view of a gas sensor member in which the nanoparticle catalyst according to the fourth embodiment of the present invention is uniformly bound inside and outside the one-dimensional metal oxide nano-lube.

19 is a flowchart illustrating a method of manufacturing a gas sensor using a metal oxide nanotube structure including a nanoparticle catalyst synthesized using apoferritin according to Example 4 of the present invention.

20 is a view showing a process for producing a one-dimensional metal oxide nano-lube structure including a nanoparticle catalyst using an electrospinning method according to an embodiment 4 of the present invention.

21 is a tin oxide precursor / polyvinylpyridone (PVP) composite spinning comprising apopertin protein containing a Pt nanoparticle catalyst and an Au nanoparticle catalyst respectively in a hollow structure according to an embodiment of the present invention. Scanning electron micrograph of the nanofibers obtained by electrospinning the solution.

22 is a scanning electron micrograph of tin oxide nanofibers obtained by electrospinning a high temperature heat treatment of a tin oxide precursor / polyvinylpyridone (PVP) composite spinning solution according to Comparative Example 3 of the present invention.

FIG. 23 is a scanning electron microscope photograph of tin oxide nanotubes obtained by electrospinning a tin oxide precursor / polyvinylpyrrolidone (PVP) composite spinning solution according to Comparative Example 4 of the present invention and subjected to a high temperature heat treatment at a fast temperature increase rate condition to be. FIG. 24 is a transmission electron microscope photograph of apoferritin particles including Pt nanoparticle catalyst and apoferritin particles including Au nanoparticle catalyst according to Example 3 of the present invention.

FIG. 25 shows the electrospinning of a spinning solution prepared by adding Pt nanoparticles and Au nanoparticles, respectively, synthesized using tin oxide precursor / polyvinylpyridin (PVP) and apoferritin according to Example 4 of the present invention. Scanning electron micrographs of tin oxide nano-levers containing Pt nanoparticle catalysts and tin oxide nanotubes containing Au nanoparticle catalysts obtained by high temperature heat treatment at elevated temperature conditions.

FIG. 26 is a transmission electron microscope photograph and an energy dispersive x-ray spectrometer (EDS) photograph of a tin oxide nanotube structure including a Pt nanoparticle catalyst according to Example 4 of the present invention.

27 is a transmission electron micrograph and an EDS (Energy Dispersive X-ray Spectrometer) photograph of a tin oxide nanotube structure including an Au nanoparticle catalyst according to Example 4 of the present invention.

28 is a tin oxide nanotube structure including a Pt nanoparticle catalyst according to Example 4 of the present invention and a pure tin oxide nanotube structure according to Comparative Example 4 at 350 ⁰ C of the tin oxide nanofiber structure according to Comparative Example 3 It is a semi-linear graph for acetone gas (1-5 ppm).

29 is a pure oxide oxide nanotube structure according to Comparative Example 4 and the main oxide nano-lube containing a Pt nanoparticle catalyst according to Example 4 of the present invention, Comparative Example 3 The semi-ungular graph for hydrogen sulfide gas (1-5 ppm) at 350 ° C of tin oxide nanofiber structure according to.

30 is a tin oxide nanotube comprising a Pt nanoparticle catalyst according to Example 4 of the present invention and a pure tin oxide nanotube structure according to Comparative Example 4, at 350 ° C of the tin oxide nanofiber structure according to Comparative Example 3 Semi-finished graph for toluene gas (1-5 ppm).

31 shows acetone (CH 3 COCH 3), toluene (C 6 H 5 CH 3), hydrogen sulfide (H 2 S) at 350 ° C. of a gas sensor using tin oxide having a one-dimensional nanotube structure to which a Pt nanoparticle catalyst is bound according to Example 4 of the present invention. Graph of reactivity at 1 ppm for biomarker gases such as nitrogen monoxide (NO), carbon monoxide (CO), pentane (C5H12) and ammonia (NH3).

32 is a tin oxide nanotube comprising an Au nanoparticle catalyst according to Example 4 of the present invention and a pure tin oxide nanotube structure according to Comparative Example 4, at 300 ° C of the tin oxide nanofiber structure according to Comparative Example 3 A semi-ungular graph for hydrogen sulfide gas (1-5 ppm).

33 shows acetone (CH 3 COCH 3), toluene (C 6 H 5 CH 3), hydrogen sulfide (H 2 S) at 300 ° C. of a gas sensor using tin oxide of 1-dimensional nanotube structure to which Au nanoparticle catalyst is bound in Example 4 of the present invention. Ethanol is a semi-finished graph at 1 ppm against biomarker gases such as (C2H50H) and ammonia (NH3).

[Best form for implementation of the invention] The present invention can be applied to various changes and may have a number of embodiments, hereinafter, specific embodiments will be described in detail with reference to the accompanying drawings.

In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

First and may be used for the term of the second, etc., in describing various elements, the elements are not limited to the above terms, the ^"terms are only to distinguish one element from the other Used.

Hereinafter, by using the time difference between the decomposition process of the regenerative layer polymer and the diffusion process time of the metal oxide, a sensing material in which a protein-based highly dispersible nanoparticle catalyst is functionalized on a one-dimensional porous metal oxide nanotube having both micropores and macropores is present. A gas sensor member, a gas sensor, and a method of manufacturing the same will be described in detail with reference to the accompanying drawings.

Embodiments of the present invention include a nanoparticle catalyst synthesized with apoferritin, and the polystyrene polymer is decomposed during the high temperature heat treatment process of the metal oxide precursor / polymer composite nanofiber containing the spherical polystyrene colloid used as a sacrificial layer template Micropores (0.1 nm-50 nm) and macropores (50 nm-300 nm) are generated in the metal oxide nanotubes by using the sequential processes of crystallization and diffusion of metal oxides. At the same time, the contents of the one-dimensional porous nanotube gas sensor member in which the nanoparticle catalyst is uniformly distributed. In case of gas sensor research using metal oxide, specific surface area is used to improve sensor characteristics of metal oxide sensing material. Research has been conducted to improve the detection characteristics by making a structure capable of reacting with a large amount of gas by widening, and in addition, studies to activate a catalytic reaction by binding a metal or metal oxide catalyst to a sensing material. In other words, it can be seen that two important factors for improving the sensor characteristics are the shape of the sensing material and the role of catalyst activation. However, studies to date require a process to increase the specific surface area and a process to bind the catalyst to the sensing material, and each process is quite complicated. Specifically, the process of uniformly synthesizing nanoparticle catalysts of several nm size requires several pretreatment processes, and it is relatively complicated and time-consuming and expensive to synthesize metal oxide nanotubes or pore-containing metal oxide nanolyuves. It has the disadvantage of being able to. In order to design an optimal sensing material to overcome these disadvantages, the present invention easily synthesizes nanoparticle catalysts having a uniform size distribution of about 1 nm-3 nm size using a protein template called apoferritin, and 200 nm. The nanoparticle catalyst and the spherical polystyrene regenerative layer template were mixed with a metal oxide precursor / polymer mixed electrospinning solution together with a spherical polystyrene colloid with various size distributions between -1000 nm and then electrospinning. The oxide precursor / polymer composite nanofibers were allowed to bind uniformly on and inside. In addition, micropore (0.1 nm-50 nm) and macropore (50) of the synthesized composite nanofibers are formed by sequentially decomposing the regenerative layer polymer and 'crystallizing and diffusing the metal oxide in the high temperature heat treatment process. nm-300 nm) and uniformly bound nanoparticle catalyst By forming a porous metal oxide nanotube structure, it is possible to synthesize a large amount of one-dimensional porous nanotube sensing material having a double pore distribution in which a specific surface area is large and nanoparticle catalysts are uniformly bound without a hole and maximize catalyst activity in a single process. It has features. Here, micropores with a size range of 0,1 nm-50 nm and macropores with a range of 50 nm-300 nm in the inner and outer walls of the nanotubes not only widen the specific surface area of the nanotubes but also serve as sensing materials. Maximize gas flow to improve detection. In particular, the number of ^"having, sensing material the developed micropores (0.1 nm-50 nm) that plays an important role the fine pores having a 0.1 nm-50 nm in size and range to detect VOCs gas effectively macropores ( Compared to 50 nm-300 nm), it has more than several times the distribution number, and it has excellent condition as a sensing material. In addition, the uniformly distributed nanoparticle catalysts on the inner and outer surfaces of the nano-lube and the surface exposed to the pores can maximize the effect of the catalyst when the gases react with the sensing material with a minimum amount of catalyst. Can be. A synergistic effect can be expected with the morphological concept of the nanotube structure including a large number of pores and the catalytic activity distributed evenly without aggregation, and it is the highest sensitivity gas sensor sensing material compared to the existing sensing materials. Characterized in that can be produced. In particular, despite the use of a regenerative layer polymer template of several hundred nanometers (nm) in size, the natural phenomena of the material can be used to produce micropores in the 0.1 nm-50 nm range and macropores in the 50 nm-300 nm size. Can be formed on. Efficient and easy to manufacture a gas sensor member having the above characteristics A process for implementing a gas sensor member, a gas sensor, and a manufacturing method thereof.

1 is a nanoparticle catalyst 110 and a plurality of micropores 121 and a macropores 131 according to an embodiment 2 of the present invention. Gas sensor member using a one-dimensional porous nanotube 100 The schematic diagram of this is shown. Spherical sacrificial layer template and apoferritin by electrospinning the electrospinning solution prepared by adding nanoparticle catalyst and spherical regenerative layer template colloid to a metal oxide precursor / polymer mixed spinning solution A metal oxide precursor / polymer composite nanofiber in which the core nanoparticle catalyst is uniformly bound is synthesized. The composite nanofiber formed by the above method is subjected to a solid heat treatment to remove the regenerative layer template and the apoferritin protein shell and form micropores in the range of 0.1 nm-50 nm and macropores having a size of 50 nm-300 nm. As the metal oxide particles gather on the fiber surface, the metal oxide particles fill the micropores to form micropores, and the nanoparticle catalysts also gather on the surface to uniformly attach the nanoparticle catalyst inside and outside the tube structure. Characterized in that it can form a one-dimensional porous nanotubes including phosphorus micropores and macropores.

Herein, metals that can be synthesized inside the hollow structure of apoferritin are not particularly limited as long as they exist in ionic form. Specifically, copper (II) nitrate, copper (II) chloride, cobalt (II) nitrate, cobalt (II) acetate, lanthanum (III) nitrate, lanthanum (III) acetate, platinum (IV) chloride, platinum (II) acetate , gold (I, III) chloride, gold (III) acetate, silver chloride, silver acetate, iron (III) chloride, iron (III) acetate, nickel (II) chloride, nickel (II) acetate, ruthenium (III) chloride, ruthenium acetate, iridium (III ) chloride, iridium acetate, tantalum (V) chloride, palladium (II) chloride, and Pt, Pd, Rh, Ru, Ni, Co, Cr, Ir, Au, Ag, Zn, W, Sn Nanoparticle catalyst composed of one or two or more of particles such as Sr, In, Pb, Fe, Cu, V, Ta, Sb, Sc, Ti, Mn, Ga, and Ge may be synthesized in an alloy form. Can be. In the case of the alloy nanoparticle catalyst, one heterogeneous nanoparticle catalyst selected from the metal-metal, metal-metal oxide, or metal oxide-metal oxide type group may be used. Representative metal-metal oxide nanocatalysts include Pt / Ir02, Pt / Ru02, Pt / Rh203, Pt / NiO, Pt / Co304, Pt / CuO, Pt / Ag20, Pt / Fe203, Au / Ir02, Au / Ru02, Au / Rh203, Au / NiO, Au / Co304, Au / CuO, Au / Ag20, etc., and metal-metal nanocatalysts include Pt-Au, and n-type for metal oxide-metal oxide catalysts. Metal oxides Ti02, ZnO, W03, Sn02, Ir02, In203, V203, Mo03 and p-type metal oxides Ag20, PdO, Ru02, Rh203, NiO, Co304, CuO, Fe203, Fe304, V205, Cr203, ^ It can be a metal-carbide catalyst consisting of two species. In the case of synthesizing the nanoparticle catalyst using the apoferritin template of the vaporization structure, the nanoparticles can be synthesized to have a uniform size distribution, and the size of the nanoparticle catalyst can be controlled by controlling the amount of the metal precursor. have. In addition, nanoparticle catalysts are surrounded by a protein shell called apoferritin. The surface of apoferritin is positively charged around pH 7-8.5, so it does not clump together in the electrospinning solution. It has the advantage of being distributed. Looking at the role of nanoparticle catalysts in gas sensor sensing materials in detail, the chemical sensitization effect increases the concentration of oxygen ions participating in the surface reaction by promoting the decomposition reaction of oxygen molecules between the surface of the metal oxide and the air layer. Nanoparticle catalysts such as noble metals such as platinum (Pt) and gold (Au) may be used, and PdO, Co304, NiO, Cr203, CuO, Fe203, Fe304, Ti02, ZnO, Sn02, There may be a nanoparticle catalyst that exhibits an electronic sensitizing effect that causes a catalytic reaction through oxidation such as V205, V203, and the like.

As described above, in the case of a spherical regenerative layer template used for synthesizing a one-dimensional porous metal oxide having a double pore distribution, it means a template that can be removed during heat treatment, and the type of template is not particularly limited. Specifically, polymethyl methacrylate (PMMA), polyvinylpyridone (PVP), polyvinylacetate (PVAc), polyvinyl alcohol (PVA), polystyrene (PS) and polyacrylonitrile (PAN), polyvinyl It may be one, or two or more mixed balls selected from lithium denfluoride (PVDF), polyacrylic acid (PAA), polydianyldimethylammonium chloride (PDADMAC), polystyrenesulfonate (PSS). In addition, the regenerative layer template has a size in the range of 50 nm-1 μιη, and when mixed with the electrospinning solution, is characterized in that it does not decompose and is dispersed, even if the regenerative layer colloid is a polymer that is dissolved in a solvent, the colloid surface To form chargeable or charged ionic surfactants (anionic or cationic surfactants) Polymeric colloids that do not dissolve in solvents may be used.

When the nanoparticle catalyst synthesized using the apoferritin described above and the spherical regenerative layer template are dispersed in the electrospinning solution and the electrospinning technique is used, the nanoparticle catalyst in the regenerative layer template and the apoferritin vapor deposition structure are uniformly distributed. And a metal oxide precursor / polymer composite nanofiber having a rugged structure can be prepared. The composite nanofibers thus formed form micropores and macropores by sequentially decomposing the regenerative layer polymer, crystallizing and diffusing the metal oxide through high temperature heat treatment, and diffusing phenomenon of the nanoparticle catalyst during tube formation. Through the nanoparticle catalyst it is possible to synthesize a uniform one-dimensional porous nanotubes. In the case of 1-dimensional porous nanotubes having micropores and macropores, and including nanoparticle catalysts, the diameters of the nanotube structures range from 50 nm to 5 μηι (with an outer diameter of 50 nm to 2 nm). Included, the inner diameter may be in the size range of 40 nm to 1.95 iim), the thickness between the inner wall and the outer wall (shell thickness) ranges from 10 nm to 50 nm, the length ranges from 1 nm to 100 urn Characterized in having a.

The one-dimensional porous nanotube having the metal oxide semiconductor double pore distribution constituting the nanostructure is not limited to a special material as long as the values of electrical resistance and conductivity can be changed by adsorption and desorption of gas. Specifically, ZnO, Sn02, W03, Fe203, Fe304, NiO, Ti02, CuO, In203, Zn2Sn04, Co304, PdO, LaCo03, NiCo204, Ca2Mn308, V205, Cr203, Nd203, Sm203, Eu203, Gd203, Tb407, Dy203, Ho203, Er203, Yb203, Lu203, Ag2V4011, Ag20, Li0.3La0.57TiO3, LiV308, InTa04, CaCu3Ti4012, Ag3P04, BaTi03, NiTi03, SrTi03, Sr2Nb207, Sr2Ta207, Ba0.5Sr0.5Co0.8Fe0.2 It may be a one-dimensional porous nanotube having a double pore distribution consisting of one or more composite materials selected from 7 and the like.

Human exhalation using a gas sensor member using the one-dimensional porous metal oxide nanotubes 100 having a double pore distribution including the prepared nanoparticle catalyst 110, micropores 121 and macropores 131 By selectively detecting specific sanche indicator gas that acts as a biomarker in the body, it is possible to diagnose human diseases early and make an ultra-sensitivity / high selectivity sensor that can be applied as an environmental sensor that can monitor harmful environmental gases in real time. can do. In particular, by maximizing the gas flow to the sensing material by forming pores on the surface of the nanotube, the sensing material of all zones formed an optimal structure that can effectively react to the gas. In addition, by making a porous tube structure with a thin surface and increasing surface area, it has a great advantage of maximizing sensor characteristics of a sensing material even with a small amount of catalyst, and it is possible to easily and quickly make various gas sensor members. It has the advantage of mass production at low price.

Figure 2 is a method of manufacturing a member for a gas sensor using a one-dimensional porous metal oxide semiconductor nanotubes having a double pore distribution comprising a nanoparticle catalyst and a plurality of pores through an electrospinning method according to an embodiment of the present invention Flowchart Is showing. According to the flow chart of Figure 2, the gas sensor member manufacturing method, using the apoferritin template having a hollow structure synthesizing a nano-indentation catalyst (S210 the synthesized nanoparticle catalyst and the spherical sacrificial layer template metal oxide Step (S220) to prepare a mixed electrospinning solution by stirring in the precursor / polymer electrospinning solution, the metal oxide precursor / polymer composite nanofibers in which the spherical sacrificial layer template and the nanoparticle catalyst is uniformly distributed through electrospinning Step (S230), by decomposing the spherical polymer regenerative layer template through the high temperature heat treatment to form a macropores (50 nm-300 nm), the polymer decomposition time and the metal oxide diffusion process is generated by using a fine Through the formation of pores (0.1 nm-50 nm) (S240) and continuous high temperature heat treatment, the nanoparticle catalyst is uniformly functionalized It is composed of the step (S250) of synthesizing the metal oxide nanotubes having micropores and macropores, each of the above steps will be described in more detail.

First, looks at the step (S210) of synthesizing the nanoparticle catalyst using apoferritin. The apoferritin used in the step (S210) includes ferritin extracted from the equine spleen, and iron contained in the interior using ferritin obtained regardless of the extraction site such as liver or spleen of human or pig. Apoferritin having been removed may be used. In the case of the storage method of apoferritin having a hollow structure, sodium chloride (NaCl) solution of various concentrations, including saline solution, can be used as a solution for storing apoferritin, and storage at 4 ° C or less is required. Shall be. In addition, in order to embed the metal salt inside the apoferritin acidic state of pH 2-3 or pH 7.5-8.5 A basic solution in the range (or pH 7.5-9) is preferred and the apoferritin is immersed in a solution in which the metal salt is dissolved for 1 hour to 24 hours, allowing the metal salt to diffuse deeply into the apoferritin. The concentration of the saline solution containing apoferritin should be in the range of 0.1-200 mg / ml. In preparing the metal salt solution, the solvent used is ethanol, water, chloroform, Ν, Ν'—dimethylformamide, dimethylsulfoxide Compatible solvents such as N, N'-dimethylacetamide, N-methylpyrrolidone, etc. Do not put The types of nanoparticle catalysts embedded in apoferritin are Pt, Pd, Rh, Ru, Ni, Co, Cr, Ir, Au, Ag, Zn, W, Sn, Sr, In, Pb, Fe, Cu, V, Ta , Sb, Sc, Ti, Mn, Ga, Ge and the like, one or more of these nanoparticle catalysts composed of two or more can be synthesized in the alloy (alloy) form. In the case of the alloy nanoparticle catalyst, one heterogeneous nanoparticle catalyst selected from the metal-metal, metal-metal oxide, or metal oxide-metal oxide type group may be used. Representative metal-metal oxide nanocatalysts include Pt / Ir02, Pt / Ru02, Pt / Rh203, Pt / NiO, Pt / Co304, Pt / CuO, Pt / Ag20, Pt / Fe203, Au / Ir02, Au / Ru02, Au / Rh203, Au / NiO, Au / Co304, Au / CuO, Au / Ag20, with rounds. Metal-metal nanocatalysts include Pt-Au, and metal oxide-metal oxide catalysts are n-type metals. Two selected from oxides Ti02, ZnO, W03, Sn02, Ir02, In203, V203, Mo03 and p-type metal oxides Ag20, PdO, Ru02, Rh203, NiO, Co304, CuO, Fe203, Fe304, V205, Cr203 It may be a metal oxide catalyst composed of species. Examples of the reducing agent which serves that by the reduction of the metal salt contained in the interior of the Apo ferritin Zeng Gong structures sodium borohydride (Sodium borohydride, NaBH4) and formic acid (formic acid, HCOOH), oxalic acid include (oxalic _acid: C2H204), lithium A commonly used reducing agent such as aluminum aluminum hydride (LiAlH4) may be used, and any reducing agent capable of reducing a metal salt to form a metal nanoparticle catalyst may be used without particular limitation. The solution which reduced the metal salt in apoferritin using a reducing agent filters out the apoferritin protein including the nanoparticle catalyst through centrifugation, and the electrolysis rate of the centrifuge used here is preferably about 10,000 rpm-13,000 rpm.

Next, the step (S220) of preparing a metal oxide precursor / polymer mixed spinning solution including the nanoparticle catalyst embedded in the synthesized apoferritin hollow structure and a spherical regenerative layer template will be described. In the step (S220), the nanoparticle catalyst and the sacrificial layer template colloid are added to the metal oxide precursor / polymer mixed spinning solution, and the nanoparticle catalyst and the sacrificial layer template colloid are uniformly dispersed in the spinning solution. Stir to disperse to prepare a mixed spinning solution. Herein, the solvents used in the preparation of the spinning solution include Ν, Ν'-dimethylformamide (N, N'-dimethyIformamide), dimethylsulfoxide, Ν, Ν'-dimethylacetamide (N, Compatible solvents such as N'-dimethylacetamide), N-methylpyrrolidone, DI water and Ethanol can be used, but they can dissolve metal oxide precursors and polymers at the same time. Solvent You must choose. In addition, the polymer and regenerative layer templates used herein do not have any particular limitations as long as they are removed during high heat treatment, and typically, polymethylmethacrylate (PMMA), polyvinylpyridone (PVP), and polyvinylacetate ( PVAc), polyvinyl alcohol (PVA), polyacrylonitrile (PAN), polypropylene oxide (PEO), polypropylene oxide (PPO), polyethylene oxide copolymer, polypropylene oxide copolymer, poly Polymers such as carbonate (PC), polyvinylchloride (PVC), polycaprolactone, polyvinylidene fluoride and the like.

In addition, the metal oxide precursor used in this step must be dissolved in a solvent and upon high temperature heat treatment, Sn02, W03, CuO, NiO, ZnO, Zn2Sn04, Co304, Cr203, LaCo03, V205, Ir02, Ti02, Er203, Tb203, Lu203, If the precursor contains a metal salt capable of forming a semiconductor metal oxide nanofibers or nanotubes that may change resistance when adsorption and desorption of gases such as Ag20, SrTi03, Sr2Ta207, BaTi03, Ba0.5Sr0.5Co0.8Fe0.2O3-7, etc. There is no restriction on specific metal salts. The weight ratio of the metal oxide precursor to the polymer for forming the spinning solution is preferably 1: 1 ᅳ 2, and the ratio of the polymer and the nanoparticle catalyst synthesized using apoferritin is about 1: 0.00001-0.1. Preferred and may be included in the range of 1: 0.000001-1. In addition, the sacrificial layer template of the spherical form used in step (S220) is preferably a weight ratio of 1: 1 to about 1-2, and included in the range of 0.wt% -50 wt%. Can be. In addition, the weight ratio of the metal nanoparticle catalyst surrounded by the protein may be included in the concentration range of 0.001 wt to 50 ^% of the metal oxide precursor constituting the metal oxide precursor / polymer composite nanofibers. The size of the spherical regenerative layer template having a size in the range of 50 nm-1 μπι is preferably selected in consideration of the size of the pore to be made. By doing so, it is possible to manufacture a gas sensor member having various characteristics.

In the step (S220), the process of preparing the mixed electrospinning solution first dissolves the metal oxide precursor in a solvent, and then disperses the apoferritin and the spherical regenerative layer template including the pre-made nanoparticle catalyst in the solution. As a method of dispersing here, there is a method of stirring for 1 hour or more at a rotational speed of 500 rpm. In order to give a constant viscosity to facilitate the electrospinning of the solution thus prepared, the polymer is added at an appropriate ratio and stirred until the polymer is completely dissolved in the solution. Stirring conditions are preferably stirred at 50 ° C or less at room temperature, agitated in 5 hours to 48 hours and then apoptotin and the regenerative layer template colloid containing a nanoparticle catalyst in the metal oxide precursor and polymer solution Ensure uniform mixing.

Electrospinning the prepared electrospinning mixed solution to uniformly distribute the spherical regenerative layer template and the nanoparticle catalyst in the apoferritin and produce a rugged type metal oxide precursor / polymer composite nanofiber (S230) ) Perform. .

In performing the electrospinning to perform the step (S230), the syringe (syringe) to the metal oxide precursor / polymer mixed spinning solution containing the prepared nanoparticle catalyst and the spherical regenerative layer template _. After filling in, it pushes the syringe at a constant speed using a syringe pump to discharge a certain amount of spinning solution. The electrospinning system may include a high voltage device, a grounded conductive substrate, a syringe, and a syringe nozzle, and a high voltage is applied between 5 kV and 30 kV between the solution filled in the syringe and the conductive substrate to form an electric field. Due to the electric field formed, the spinning solution discharged through the syringe nozzle is elongated in the form of nanofibers. The spinning solution in the form of a long spout is obtained by evaporating and volatilizing the solvent contained in the spinning solution to obtain a solid polymer fiber, and at the same time, a metal oxide precursor, a nanoparticle catalyst in apoferritin, and a spherical regenerative layer. A composite fiber comprising a template is produced. The discharge rate can be adjusted to within 0.01 ml / min or 0.5 ml / min, and the metal oxide precursor / polymer / nanoparticle catalyst composite nanofibers having a desired diameter and an unstructured structure can be manufactured by controlling voltage and discharge amount. Can be.

Through the step (S240) to form a metal oxide nanotube structure through the high-temperature heat treatment of the produced composite nanofibers, at the same time micropores and macropores are distributed on the surface of the metal oxide nanotubes and these nanotube structure nanoparticle catalysts are uniform One-dimensional porous metal oxide nanotubes can be prepared ^' . 500- The high-temperature heat treatment in the range of 800 ° C removes both spherical polymer and apoferritin used as a regenerative layer template, forming macropores (50 nm-300 nm) and micropores (0.1 nm-50 nm). Through the process of crystallization and diffusion of metal oxide that occurs after polymer decomposition, some micropores are filled to form a plurality of micropores (0.1 nm ᅳ 50 nm) on the surface of the nanotube.

In addition, in step S250, the nanoparticle catalyst in the apoferritin is uniformly bound to the inner and outer walls of the porous nanotubes and the inner wall during the heat treatment process while the aperitin is removed. The structure finally formed through the step (S250) is a nanoparticle catalyst is uniformly bound to the inner wall and outer wall and the inside of the tube, a one-dimensional porous metal oxide nanotube structure having a plurality of micropores and macropores.

3 schematically a manufacturing process flow according to the production method of the present invention an exemplary member for a gas sensor for example comprises a nanoparticle catalyst using the electrospinning process in accordance with and using the one-dimensional porous metal oxide nanotubes, a double pore distribution ^"has the The first step (S310) is a process showing an intermediate process of high-temperature heat treatment of the metal oxide precursor / polymer composite nanofibers in which the spherical regenerative layer template and the nanoparticle catalyst in apoferritin are uniformly bound. As a result, the spherical regenerative layer template and apoferritin are removed to form pores of various sizes, and at the same time, an intermediate process of forming a metal oxide tube through Ost Wald life phenomenon is shown.

Step S320, which is the second process, removes the polymer matrix from all the spherical regenerative layer templates, the apoferritin and the composite fiber after the final silver heat treatment, As crystallization and diffusion occur, finally, a large number of micropores and macropores exist in the inner and outer walls of the nanotubes, and the nanoparticle catalysts all diffuse, resulting in a one-dimensional porosity having a double pore distribution uniformly bound to the nanotubes. Metal oxide nanotubes are synthesized.

4 illustrates a mechanism of forming a plurality of micropores and macropores formed on a surface of a nanotube during a high temperature heat treatment process. Specifically, during the high temperature heat treatment process, the regenerative layer polystyrene template is decomposed and forms macropores, after which the metal oxide crystallizes and diffuses to fill the micropores, thereby forming micropores. ^,

Figure 5 and a polystyrene-protein ^"system pulrit of 12 nm size, which together between templates distributed on nanofibers are concentrated, while the protein templates dense decomposition at a high temperature heat treatment with respect to the process of the contribution in forming the fine pores Explaining. Here, the protein template with excellent dispersion may be concentrated in a narrow space between the polystyrene templates.

Like a mall, a one-dimensional porous metal oxide nano including a plurality of micropores and macropores including a nanoparticle catalyst using a regenerative layer template electrospinning technique and a decomposition time difference between a metal oxide and a polymer template according to embodiments of the present invention. The method of manufacturing a gas sensor member using a tube forms a one-dimensional nanotube structure with a large reaction surface area with gas and simultaneously forms pores to maximize gas flow in the sensing material, thereby improving gas sensing effect. Unlike the catalyst of the protein properties By binding a catalyst having a uniformly dispersed chemical / electronic sensitization effect, the reaction sensor's reaction velocity, sensitivity, and selectivity can be greatly improved.

Hereinafter, the present invention will be described in detail through Examples and Comparative Examples. The examples and comparative examples are only for illustrating the present invention, and the present invention is not limited to the following examples.

Example 1 Preparation of Pt Nanoparticle Catalyst Using Apoferritin as Template

In order to synthesize Pt nanoparticle catalyst of 3 nm or less inside apoferritin having a hollow structure, the following synthesis process is carried out.

Apoferritin solution (Sigma Aldrich) is dispersed in 0.15 M NaCl aqueous solution at a concentration of 35 mg / ml. By adding a basic aqueous solution such as NaOH to the apoferritin solution as described above, the pH is adjusted to about 8.5 to make optimum conditions for Pt metal ions to diffuse into the apoferritin. The basic solution used herein is not particularly limited as long as it is an aqueous solution having basicity in addition to NaOH. The precursor of Pt metal ion entering apoferritin is H2PtC16'H20, and 16 mg of H2PtC16 * H20 is dissolved in 1 g of DI water to prepare an aqueous solution. The aqueous metal salt precursor solution prepared here is slowly dropped drop by drop using a dropper to the pH-controlled apoferritin solution. The mixed solution is stirred for 1 hour to allow the Pt metal silvers to diffuse into the hollow apoferritin. As mentioned above, the stirring condition means to proceed at room temperature for about 1 hour at 100 rpm. After sufficient stirring,

r The reducing agent is used to reduce the metal ions present in the apoferritin so that Pt nanoparticle catalysts can be synthesized inside the apoferritin. Reducing agents used herein typically include aqueous NaBH 4 solution. At this time, the reducing agent used NaBH4 in the form of an aqueous solution at 40 mM dong and add 0.5 ml.

Since the aqueous solution in which the Pt nanoparticle catalysts present in the apoferritin hollow structure synthesized as described above contains many reducing agents and ligands of metal salts, only the Pt nanoparticle catalyst synthesized through the centrifuge should be extracted. . At this time, the condition of the centrifuge is preferably about 12,000 rpm and preferably centrifuged for at least 10 minutes. If the Pt nanoparticle catalysts in apoferritin extracted by centrifugation are dispersed in DI water, an aqueous solution in which Pt nanoparticles are dispersed in apoferritin can be prepared. _.

7 (a) and 7 (b) are transmission electron microscopy (TEM) photographs of apoferritin containing Pt nanoparticle catalyst synthesized through the above process, and FIG. 7 (c) is a surface charge state and FIG. 7 ( d) shows the size distribution. Transmission electron micrographs confirm that the Pt nanoparticles are well dispersed, which can be explained by the positive effect of the surface of the protein shell on the surface of the protein shell. In addition, it can be seen that the nanoparticle catalysts have a diameter distribution of 1 to 3 nm.

Example 2 Fabrication of 1-D Porous Tin Oxide (Sn02) Nanotubes 100 with Pt Nanoparticle Catalyst Uniformly Bonded to the Inner and Outer Walls of the Tube and with Micropore and Macropore Distributions First of all, 0.25 g of metal chloride precursor tin chloride dehydrate is added to 1.35 g of DMF and 1.35 g of a mixed solvent to dissolve at room temperature. ' Next, 0.3 g of a spherical polystyrene (diameter 200 nm) colloid serving as a sacrificial layer template as shown in FIG. 6 is added to the solution in which the metal salt precursor is dissolved, and is dispersed. The polystyrene colloid used in Example 2 has an anionic surfactant formed on the surface, has excellent dispersibility, and is insoluble in DMF, which is a solvent, and is subsequently removed during heat treatment to form large pores. . In Example 2, a polystyrene polymer bead having a size of 200 nm was used as a colloidal template, but the type of the polymer template is not particularly limited. Specifically, polymethyl methacrylate (PMMA), polyvinylpyridone (PVP), polyvinylacetate (PVAc), polyvinyl alcohol (PVA), polystyrene (PS) and polyacrylonitrile (PAN), poly One or two or more mixtures selected from vinylidene fluoride (PVDF), polyacrylic acid (PAA), polydianyldimethylammonium chloride (PDADMAC), polystyrenesulfonate (PSS). In addition, the sacrificial layer template has a size in the range of 50 nm-1 μπι, and when mixed with an electrospinning solution, has a characteristic of being dispersed without disassembly, even if the regenerative layer colloid is a polymer that is soluble in a solvent, the colloid surface Polymeric colloids that do not dissolve in solvents can form anionic or cationic surfactants that charge on them. Dispersion condition of the polystyrene colloidal template means to stir about 10 hun at 500 rpm rpm, The diameter of the polystyrene used above is not limited to 200 nm, it is possible to use a polystyrene colloidal solution having a variety of diameters. In addition, 200 mg of the Pt nanoparticle catalyst aqueous solution synthesized in Example 1 was added to a mixed solution (polystyrene colloid + metal salt + mixed solvent) and mixed. 0.35 g of polyvinylpyrrolidone (PVP) polymer having a molecular weight of 1,300,000 g / mol was added to increase the viscosity in a homogeneously mixed solution of the spherical polystyrene polymer and the nanoparticle catalysts in the apoferritin thus synthesized. A spinning solution is prepared by stirring at a rotational speed of 500 rpm for 24 hours at room temperature. The prepared electrospinning solution is placed in a syringe (Henke-Sass Wolf, 10 mL) RM— JECT®), connected to a silage pump, pushes out the electrospinning solution at a 0.1-ml / min discharge rate, and is used in the spinning process. Electrospinning is carried out with a voltage of 14 kV between the nozzle (needle, 25 gauge) and the current collector where the nanofibers collect. At this time, a stainless steel plate was used as the current collector plate of the nanofiber, and the distance between the nozzle and the current collector was set to 26 cm.

8 is a metal oxide precursor obtained after the electrospinning process, polyvinylpyridone polymer ,. Scanning electron micrographs of complex nanofibers comprising a spherical polystyrene regenerative layer template and a Pt nanoparticle catalyst in apoferritin hollow structure. It can be confirmed that one-dimensional nanofibers are formed, and the structure of the nanofibers has a rugged structure by including polystyrene in the form of a sphere. The diameter of the synthesized nanofibers has a value between 200 nm and 300 nm. The composite nanofibers including the metal oxide precursor prepared by the same method, the polyvinylpyridone polymer, the spherical polystyrene regenerative layer template, and the Pt nanoparticle catalyst in the apoferritin hollow structure were used at 600 ° C for 1 hour. It was maintained and cooled down to room temperature at a rate of temperature drop of 40 ° C / min. The heat treatment was performed in an air atmosphere using Ney's Vulcan 3-550 small electric furnace. The heat treatment process decomposes the apoferritin protein and the polymer that surrounds the nanoparticle catalyst. In addition, because the metal oxide metal salt precursor on the surface of the nanofiber is first oxidized through nucleation and particle growth process through the process of heat treatment in the air atmosphere, the metal salt precursors inside the nanofiber through the Ostwald life phenomenon. As it is oxidized, it diffuses to the surface of the nanofibers to form nanotubes, and at the same time, the polystyrene template is removed by heat treatment, and the metal oxide is partially filled with the macropores through the diffusion process, so that the micropores and macropores on the surface of the nano-leave are large. It will form pores. The Pt nanoparticle catalyst also has a very small size, which ensures that the tin oxide particles with the tin oxide surface are uniformly bound to the inner and outer walls of the tin oxide nanotubes. As a result, a large number of pores are distributed on the surface of the tin oxide nanotube structure and a one-dimensional porous nanotube structure in which the R nanoparticle catalysts are uniformly distributed is formed.

9 (a) and 9 (b) show scanning electron micrographs of the one-dimensional porous tin oxide nanotubes including the Pt nanoparticle catalyst synthesized in Example 1 and having a double surface pore distribution. The diameter of the formed nanotube is about 50 nm-5 μπι And the thickness between the outer and inner walls of the tube has a thickness in the range of 10-50 nm. In addition, the size of the micropores formed on the surface of the nanotubes has a range of 0.1-50 nm and the macropores have a size of 5 to 300 nm.

Figure 10 (a-c) shows a transmission electron micrograph of the one-dimensional porous tin oxide nanotubes containing the R nanoparticle catalyst synthesized in Example 1 and having a double surface pore distribution. High-throughput transmission electron microscopy analysis showed that Pt nanoparticle catalysts exist in one-dimensional porous tin oxide nanotubes, and Pt particles were selected in one-dimensional porosity through the SAED (Selected Area Electron Diffraction) pattern of FIG. It can be seen that the tin oxide nanotubes have crystallinity. In addition, it can be seen from the transmission electron micrograph that various pores having a size of between 5-150 nm are distributed on the surface of the tin oxide nanotubes. In addition, it can be seen that Pt nanoparticle catalysts are uniformly distributed in the tin oxide nanotube structure formed through the TEM analysis (EDS) photograph of FIG. 10 (e).

11 (a) and 11 (b) are thermogravimetric (TGA) and photoelectron spectroscopic (XPS) analyzes of one-dimensional porous tin oxide nanolevers containing synthesized Pt nanoparticle catalysts and having large and microporous distributions. Are shown respectively. Through thermogravimetric analysis (TGA), it was confirmed that the sacrificial layer template polymer was removed at around 300 ° C, forming the macropores (5 to 300 nm). As diffusion occurs, it can be seen that the micropores (0.1-50 nm) are formed by blocking the macropores. Photon spectroscopy (XPS) showed that R nanoparticles were oxidized It was confirmed that PtO and Pt metal form coexist.

Comparative Example 1 Preparation of Pure Tin Oxide Nanotubes Without Nanoparticle Catalyst Comparative Example 1 compared with Example 2 is pure tin that does not contain Pt nanoparticles catalyst and does not contain pores in the form of circle or ellipse. Relates to oxide nanotube synthesis. Specifically, 0.25 g of tin chloride dehydrate, a tin oxide precursor, is dissolved in a mixed solvent (1.35 g of DMF + 1.35 g of ethane) and has a weight average of 1,300,000 g / mol to add the viscosity of the mixed solution. Add 0.35 g of polyvinylpyrrolidone (PVP) and stir thoroughly. The stirring condition mentioned here means stirring at least 5 hours at a rotational speed of 500 rpm. The tin oxide precursor / polymer mixed electrospinning solution thus formed is filled with an electrospinning syringe (Henke-Sass Wolf, 10 mL NORM-JECT®) ^], connected to a syringe pump, and the spinning solution is discharged at a discharge rate of 0.1 ml / min. It pushes and electrospinning.

The needle used for electrospinning is a tin oxide precursor / polymer composite nanofiber by applying a high voltage of about 14 kV while maintaining the distance between the nozzle and the current collector collecting nanofibers at 26 cm while using 25 gauge. Was produced. The synthesized tin oxide precursor / polymer composite nanofiber is to remove the polymer through high temperature heat treatment and to form tin oxide through the oxidation process of the tin oxide ^' precursor. The high temperature heat treatment condition was performed at 600 ⁰ C for 1 hour, and the temperature increase rate was kept constant at 10 ⁰ C / min. The rate of descent was kept constant at 40 ⁰ C / min. Here, the relatively high temperature rising rate of 10 ° C / min is characterized in that it plays an important role in forming the nanotube structure.

12 is a pure tin oxide nanotube produced through Comparative Example 1 ^. The scanning electron micrograph of the structure is shown. The synthesized tin oxide nanotubes had a diameter in the range of 50 nm-5 iim, and the thickness between the inner and outer walls of the nanotubes was between 1 and 50 nm.

Comparative Example ^· 2. Fabrication of pure tin oxide one-dimensional porous nanotubes without nanoparticle catalyst

Comparative Example 2 compared with Example 2 does not add the Pt nanoparticle catalyst embedded in the apoferritin, the pure tin oxide 1-dimensional having the pores in the form of circles and ellipses by adding ¾ of the spherical polystyrene sacrificial layer It relates to porous nanotube synthesis. Specifically, 0.25 g of tin chloride dehydrate, a tin oxide precursor, is dissolved in a mixed solvent (1.35 g of DMF 1.35 g + ethane). In addition, 0.3 g of polystyrene colloid serving as a spherical regenerative layer template having a size of 200 nm was added and dispersed. Dispersion condition as used herein means to stir at least 1 hour at a rotational speed of 500 rpm. In order to impart viscosity to the prepared tin oxide precursor / polystyrene composite solution, 0.35 g of polyvinylpyrrolidone (PVP) having an average increase of 1,300,000 g / mol is added thereto, and the mixture is sufficiently stirred. Stirring condition here is 500 rpm It means to stir at least 10 hours under the conditions. The thoroughly stirred metal precursor / polystyrene regenerated layer template / polymer electrospinning solution is placed in an electrospinning syringe (Henke-Sass Wolf, 10 mL N-M-JECT®) and connected to a syringe pump, The spinning solution pushes the spinning solution at the discharge speed. The needle used for electrospinning uses 25 gauge and maintains the distance between the nozzle and the collector for collecting nanofibers at 26 cm while applying a high voltage of about 14 kV. Given tin oxide precursor / polystyrene regenerative layer template / polymer composite nanofibers were prepared. The tin oxide precursor / polymer regenerative layer template / polymer composite nanofibers synthesized in the above form high-temperature heat treatment to remove macromolecules and decompose spherical polystyrene sacrificial layers to form macropores in a circle or ellipse shape, and then tin oxide. The micropores are formed by partially filling the macropores through crystallization and diffusion process to form the one-dimensional porous tin oxide nanotubes. The high temperature heat treatment conditions here were made at 600 ° C for 1 hour.

Figure 13 (a) and Figure 13 (b) shows a scanning electron micrograph of a pure tin oxide nanotube structure including pores in the form of circle to ellipse prepared through Comparative Example 2. The fabricated one-dimensional porous tin oxide nanotubes have a diameter of 50 nm-5 μιη and the thickness between the inner and outer walls of the nanotubes has a value ranging from 1 to 50 nm. Here, the size of the micropores has a value between 0.1-50 nm, the macropores have a size of 5 to 300 nm. Since it has no role in inhibiting the growth of tin oxide particles of a protein template called apoferritin, it is relatively large unlike Example 2. It can be seen that it has a pore size.

Experimental Example 1. One-dimensional porous tin oxide nanotubes in which Pt nanoparticle catalyst was uniformly bound to the inner and outer walls of the tube and contained a large number of circular and elliptic pores, tin oxide one-dimensional porous nanotubes with pores, and pure Fabrication and Characterization of Gas Sensors Using Tin Oxide Nanotubes

In order to prepare a sensing material for a gas sensor manufactured in Examples 1 and 2 and Comparative Examples 1 and 2 as an exhalation sensor, one-dimensional porous tin oxide including Pt nanoparticle catalysts and a plurality of micropores and macropores. After dispersing 6 mg of nano-lube, one-dimensional porous tin oxide nanotube, and tin oxide nanotube in 100 μl of ethane, respectively, the mixture is pulverized by ultrasonic cleaning for 1 hour. During the grinding process, the porous nanotube structure synthesized above may exhibit a shorter porous nanotube structure in the longitudinal direction.

Two parallel one-dimensional porous tin oxide nanotubes, one-dimensional porous tin oxide nanotubes, and tin oxide nanotubes spaced at intervals of 150 μπι, bound by a Pt nanoparticle catalyst and containing a large number of circular to elliptic pores. A 3 mm x 3 mm alumina substrate on which gold (Au) electrodes were formed was coated using a drop coating method. The coating process was performed by using a micropipette on alumina substrate with sensor electrode for mixing 1-D porous nanotube, 1-D porous tin oxide nanotube, and tin oxide nanotube mixed solution bound with 3 μΐ Pt nano-pressure catalyst dispersed in ethanol. 60 ^° C hotplate after application on After drying the process, the process was repeated 4-6 times so that a sufficient amount of sensing material was applied on the alumina sensor substrate.

In addition, the gas sensor system designed for evaluating simulation characteristics as an exhalation sensor is acetone, which is an indicator gas for diagnosing diabetes, bad breath, and lung cancer at RH 85-95% relative humidity, similar to the humidity of gas from human breath. (CH3COCH3), hydrogen sulfide (H2S), and toluene (C6H5CH3) gas concentrations were changed to 5 ᅳ 4, 3, 2, 1, 0.6, 0.4, 0.2, 0.1 ppm and the operating temperature of the sensor was 350 ° C. Maintaining and evaluating the reaction properties for each gas. In Experimental Example 1, as well as acetone (CH3COCH3), hydrogen sulfide (H2S), toluene (C6H5CH3) gas which is a representative example of volatile organic compound gas, asthma, chronic obstructive pulmonary disease, kidney disease. In addition, the selective gas detection characteristics were identified by evaluating the detection characteristics of nitric oxide (NO), carbon monoxide (CO), ammonia (NH 3), and pentane (C 5 H 12) gases.

In addition, to evaluate the ability to detect actual exhalation and diabetic patients, we simulated exhalation of simulated diabetic patients with 10 healthy exhalations and similar expirations with diabetics. The fabricated exhalation was directly detected by the sensor array, and the measured sensor results were compared and analyzed by exhalation of diabetic patients and healthy persons using PCA.

14 (a) shows the reaction rate when the acetone gas concentration decreases to 5, 4, 3, 2, 1, 0.6, 0.4, 0.2 and 0.1 ppm at 350 ° C (Rair / Rgas, where Rair is The resistance value of the metal oxide material when injected, Rgas is the metal oxide when acetone gas is injected It means the resistance value of the material). In addition, Figure 14 (b) also shows a graph showing the detection limit of the one-dimensional porous nanotubes to which the Pt nanoparticle catalyst is bound using a linear approximation equation.

As shown in FIG. 14, the one-dimensional porous tin oxide nanotube sensing material to which the Pt nanoparticle catalyst is bound while the Pt nanoparticle catalyst embedded in the apoferritin hollow structure is thermally treated includes a catalyst for 5 ppm acetone gas. It shows 21.1 times higher detection characteristics than unused one-dimensional porous tin oxide nanotubes and 38 times higher than pure tin oxide nanotubes. In addition, one-dimensional porous tin oxide nanotubes bound with Pt nanoparticle catalysts obtained by linear approximation based on sensor results measured at acetone concentrations of 5, 4, 3, 2, 1, 0.6, 0.4, 0.2, and 0.1 ppm. The detection limit of can be seen that the sensitivity (Rair / Rgas) is 2,1 when the acetone concentration is 10 ppb.

FIG. 15 is a one-dimensional porous tin oxide nanoleuve including a large number of circular and elliptical pores, including a Pt nanoparticle catalyst bound by heat treatment of a platinum (Pt) nanoparticle catalyst embedded in apoferritin at 350 ° C. The sensor was used to show the reactivity values at concentrations of 1 ppm against the acetone gas known as a biomarker gas for diabetes and body lipolysis, compared to hydrogen sulfide, toluene, nitrogen monoxide, carbon monoxide, ammonia and pentane gas.

As shown in FIG. 15, a sensor made of a one-dimensional porous tin oxide nanotube sensing material having a double pore distribution and having a Pt nanoparticle catalyst bound is used for other diseases. Compared to the biomarker gases hydrogen sulfide, toluene, pentane, carbon monoxide, ammonia, and nitrogen monoxide gas, it can be seen that it shows excellent selective detection characteristics for acetone, which is a biomarker gas for diabetes and body fat decomposition.

FIG. 16 shows the exhalation of 10 healthy subjects in a Tedler bag, the quantitative injection of concentrated acetone gas, and the exhalation of 10 simulated diabetic patients so that acetone concentration is present in the exhalation of humans. It is showing the process of making. Using a diaphragm pump to quantitatively inhale and discharge the gas as shown in Figure 16, it was possible to produce acetone concentration of about 2 ppm in the exhalation. FIG. 17 shows porous tin oxide nanotubes in which micropores and macropores in which platinum nanoinjector catalysts are bound, tin oxide nanotubes in which platinum nanoparticles are bound, and exhalation of 10 healthy humans exhaled and simulated diabetic patients are actually collected. The result of sensing is obtained by injecting into the sensor array composed of tin oxide nanotube sensing material in which micropores and macropores are distributed. As shown in FIG. 17, it can be seen that 10 healthy people's exhalation and simulated diabetic patients' gas zones are clearly distinguished from each other, and through this, the possibility of diagnosing diabetic patients through exhalation is confirmed. It was.

In the above experimental example, the biomarker gas was shown as an example, and the sensor characteristics of the gas sensor sensing material were shown. However, excellent sensor detection characteristics can be expected for hazardous environment gases such as H2, NOx, SOx, HCHO, and C02, and Au, Pd, Rh, Cr, which are widely used as catalysts for Pt nanoparticle catalysts embedded in apoferritin. , Co, Ni etc. By synthesizing different types of catalysts by synthesizing the catalyst particles in the form, it is expected that a gas sensor having excellent selectivity for other harmful gases besides acetone may be manufactured. In addition, by varying the type of metal oxide serving as a sensing material matrix, the multi-catalyst particles contain a large number of circular to elliptical pores, and use one-dimensional porous multi-metal oxide nanotubes having a dilution pore distribution, thereby providing super high sensitivity. And a nanosensor array having high selectivity can be manufactured. The one-dimensional porous metal oxide nanotube sensing material having a double pore distribution in which the nanoparticle catalyst obtained from the apoferritin template is bound is an excellent hazardous gas sensor and a gas sensor for healthcare for analysis and diagnosis of volatile organic compound gas in the exhalation. Can be used for

Hereinafter, a member for a gas sensor using a metal oxide semiconductor nanotube structure including a nanoparticle catalyst synthesized using apoferritin, a gas sensor, and a method of manufacturing the same will be described in detail with reference to the accompanying drawings.

The present invention provides a nanotube structure in which nanoparticle catalysts are uniformly distributed on the surface and inside of a nanotube shell by controlling the temperature increase rate of a tin oxide precursor / polymer composite nanofiber including a nanoparticle catalyst synthesized with apoferritin during heat treatment. It characterized in that the synthesis. In order to improve the detection characteristics of gas sensors using metal oxides, researches have been carried out to improve the detection characteristics by increasing the specific surface area and improving the porosity so that a larger amount of gas reacts with the metal or -metal oxide catalyst. Studies that activate catalytic reaction by binding to a sensing material It has been going on. However, these studies have disadvantages in that a process for forming pores or widening specific targets and a process for binding a catalyst to nanofibers are required separately. In particular, the process of synthesizing metal or metal oxide nanoparticle catalysts uniformly to nanofibers and synthesizing nanoparticle catalysts of several nm size are quite complicated. Forming process also has the disadvantage that it can be relatively complicated and time-consuming and expensive. In order to overcome this disadvantage, in the present invention, by using apoferritin-easily synthesized nanoparticle catalyst of the size of 0.1 nm to 8 nm and mixed with a metal oxide precursor / polymer mixed spinning solution and then carrying out full-spinning, The nanoparticle catalyst was allowed to bind uniformly to the inside and inside of the metal oxide precursor / polymer composite nanofiber. In addition, by controlling the speed of Seung-eun, 'metal heat-treatment process removes the protein template surrounding the nanoparticle catalyst and removes the polymer, while forming the metal oxide nanotube structure including the nanoparticle catalyst through the Ostwald ripening phenomenon. As a result, in a single process, nanoparticle catalysts can be easily synthesized in a large-surface specific nanotube structure without the uniform formation of a large number of sensing materials. Here, the metal oxide semiconductor nanotubes in which the nanoparticle catalysts are uniformly distributed inside and outside the nanotubes can maximize the effect of the catalyst when the gases react with the sensing material by uniformly distributing the catalysts. The nanotube structure formed through the membrane facilitates the invasion of the gas inside the tube. It is possible to produce a highly sensitive gas sensor sensing material by inducing surface reaction. In particular, it is possible to synthesize a variety of metal or metal oxide nanoparticles in the apoferritin protein has a feature that can be produced gas sensor having a specific gas selectivity. In order to manufacture a gas sensor member having the above characteristics, it is characterized by implementing the gas sensor member, the gas sensor and a manufacturing method thereof in an efficient and easy process.

FIG. 18 shows a schematic diagram of a gas sensor member 1800 using a metal oxide semiconductor nanotube structure 1810 including a nanoparticle catalyst 1821 according to an embodiment of the present invention. The nanoparticle catalyst is electrospun with the apoferritin protein formed inside the vaporization structure together with the metal oxide precursor / polymer mixed spinning solution to increase the temperature of the composite nanofibers. It is characterized in that the nanotubes 1810 of the aggregated and hollow structure can be formed and the nanoparticle catalysts 1821 can be uniformly bound inside and outside the tube structure.

The metals that can be synthesized inside the hollow structure of apoferritin here are not restricted if the ionic form S is present. Specifically, copper (II) nitrate, copper (II) chloride, Cobalt (II) nitrate, Cobalt (II) acetate, ^' Lanthanum (III) nitrate, Lanthanum (III) acetate, platinum (IV) chloride, platinum (II) acetate, gold (I, III) chloride, gold (III) acetate, silver chloride, silver acetate, Iron (III) chloride, Iron (III) acetate, Nickel (II) chloride, Nickel (II) acetate, Ruthenium (III) chloride, Ruthenium Acetate, Iridium (III) chloride, iridium acetate, Tantalum (V) chloride, Palladium (II) chloride, and these precursors are used to make Pt, Pd, Rh, Ru, Ni, Co, Cr, Ir, Au, Ag Nanoparticle catalysts such as, Zn, W, Sn, Sr, In, Pb, Fe, Cu, V, Ta, Sb, Sc, Ti, Mn, Ga, Ge can be synthesized. Thus, using the apoferritin as a template to control the size of the nanoparticle catalyst by controlling the amount of precursor in the size range of 0.1 nm to 8 nm, the nanoparticle catalysts are surrounded by apoferritin protein shells having a hollow structure Because it is stacked, it has a great advantage of being well dispersed in the electrospinning solution. Looking at the role of nanoparticle catalysts in gas sensor sensing materials in detail, it acts as a chemical sensitizing effect that increases the concentration of adsorbed oxygen ions participating in the surface reaction by promoting the decomposition reaction of oxygen molecules between the surface of the metal oxide and the air layer. PdO, Co304, NiO, Cr203, CuO, Fe203, Fe304, Ti02, ZnO, Sn02, which may have nanoparticle catalysts of precious metals such as platinum (Pt), gold (Au) There may be a nanoparticle catalyst that exhibits an electronic sensitizing effect that causes a catalyst reaction through oxidation such as V205, V203, and the like.

When the nanoparticle catalyst 1821 synthesized using the apoferritin described above is bound to the inside and the outside of the nanotube structure, the nanoparticle catalyst surrounded by the protein shell is used. Compared with this, there is no uneven phenomenon and dispersion can be performed well. With this feature, the nanocatalyst particles may be used to prepare a metal oxide precursor / polymer mixed spinning solution. When added together and spun together, the nanoparticle catalysts can bind evenly to the outside and inside of the metal oxide precursor / polymer nanofibers. Here, a metal oxide nanotube structure including a nanoparticle catalyst may be formed through nucleation, particle growth, and Ostwald ripening through high temperature heat treatment having a temperature rising rate of 10 ° C / min. The diameter of the metal oxide nanotube structure containing the nanoparticle catalyst has a diameter ranging from 50 nm to 5 μπι, the thickness between the inner and outer walls ranges from 10 nm to 50 nm, and the length ranges from 1 μπι to 100 μπι. It is characterized by having a range.

The metal oxide semiconductor nanotube constituting the nanostructure is not limited to a special material as long as the values of electrical resistance and conductivity can be changed by adsorption and desorption of gas. Specifically, ZnO, Sn02, W03, Fe203, Fe304, NiO, Ti02, CuO, In203, Zn2Sn04, Co304, PdO, LaCo03, NiCo204, Ca2Mn308, V205, Cr203, Nd203, Sm203, Eu203, Gd203, Tb407, Dy203, Ho203 , Er203, Yb203, Lu203, Ag2V4011, Ag20, Li0.3La0.57TiO3, LiV308, InTa04, CaCu3Ti4012, Ag3P04, BaTi03, NiTi03, SrTi03, Sr2Nb207, Sr2Ta207, BaO.5SrO.5CoO.8FeO. It may be a nanotube composed of two or more composite materials.

Using a gas sensor member 1800 using the metal oxide semiconductor nanotube 1810 including the nanoparticle catalyst 1821, a specific gas acting as a biomarker in the exhalation of the human body can be detected early. To diagnose And it may also be capable of ongyong second configuration the sensor sensitivity to the environmental sensor capable of monitoring hazardous gas _{environments.} In addition, it is possible to quantitatively control the amount of binding of the nanoparticle catalyst bound to the nanotubes while controlling the amount of the nanoparticle catalyst quantitatively, thereby effectively controlling the catalyst properties and controlling the temperature increase rate during the heat treatment. From the full structure to the nanotube structure, the surface area of the fiber can be effectively controlled, which makes it possible to quickly and easily manufacture various gas sensor members.

19 is a flowchart illustrating a method of manufacturing a gas sensor member using a metal oxide semiconductor nanotube including a nanoparticle catalyst through an electrospinning method according to an embodiment of the present invention. As shown in the flowchart of FIG. 19, the method for manufacturing a gas sensor member includes synthesizing a nanoparticle catalyst using apoferritin (S1910), and synthesizing the synthesized nanoparticle catalyst with a metal oxide residue / polymer electrospinning solution. Preparing a complex electrospinning solution by adding to the (S1920), preparing a metal oxide precursor / polymer composite nanofiber including a nanoparticle catalyst made of apoferritin using the complex electrospinning solution using an electrospinning apparatus; (S1930) And it can be configured to include a step (S1940) to produce a metal oxide nanotubes in which the nanoparticle catalyst is uniformly bound through a high temperature heat treatment by increasing the temperature increase rate to 10 ° C / min relatively. In the following it will be described in more detail for each of the above steps.

First, look at the step (S1910) of synthesizing the nanoparticle catalyst using apoferritin. Apoferritin used in this step (S1910) includes ferritin extracted from the equine spleen, and apoferritin from which iron ions have been removed from the internal space using ferritin obtained regardless of the extraction site such as human liver or spleen. This can be used. The removal of iron and silver from the ferritin, which has a protein-enclosed structure, can be a chemical method or an electrical method. The solution for maintaining apoferritin in the hollow structure having an empty space therein can be used in various concentrations of sodium chloride (NaCl) solution, including saline solution, and it needs to be stored below 4 ⁰ C. do. In addition, in order to embed the metal salt in the apoferritin, a basic solution in the pH range of 8.0 to 9.5 is preferable, and in a solution where the metal salt is dissolved for about 1 to 24 hours so that the metal salt can diffuse into the apoferritin. Soak apoferritin. The concentration of the storage solution, such as a saline solution containing apoferritin, should be in the range of 0.1-200 mg / ml. In preparing the metal salt solution, solvents used are ethanol, water, chloroform, Ν, Ν'-dimethylf ormamide and dimethylsulfoxide. Compatible solvents such as N, N'-dimethylacetamide and N-methylpyrrolidone can be used. If the metal salt is soluble, it is limited to a specific solvent. Do not put As described above, the type and form of the metal salt generated inside the apopperitan is not particularly limited as long as it is in the form of an ionic precursor. Metal salts are Pt, Pd, Rh, Ru, Ni, Co, Cr, Ir, Au, Ag, Zn, W, Sn, Sr, In, Pb, Fe, Cu, V, Ta, Sb, Sc, Ti, Mn, Ga, Ge and apoferritin Salt precursors that can be included therein are preferred, and proteins are removed after high temperature heat treatment, and nanoparticle catalysts have the property of converting to metal or metal oxide catalyst particles. In this case, the metal particles which are well oxidized are easily converted into metal oxide particles. Such metal oxide particles may have n-type or p-type semiconductor properties. Reducing agents that play a role in reducing the metal salts contained in the hollow structure of apoferritin include sodium borohydride (Sodium borohydride,

Commonly used reducing agents such as formic acid (HCOOH), oxalic acid (C2H204), and lithium aluminum hydride (LiAlH4), including NaBH4), can be used. Any reducing agent capable of forming a particle catalyst can be used without particular limitation. The solution that reduced the metal apoferritin metal using a reducing agent through the centrifugation to filter out the apoferritin protein including the nanoparticle catalyst, the rotation speed of the centrifuge is preferably about 10,000 rpm-13,000 rpm.

Subsequently, the step of preparing the metal oxide precursor / polymer mixed spinning solution including the metal nanoparticle catalyst synthesized using the synthesized apoculitine is examined (S1920). In this step (S1920) by adding the apoferritin protein containing the nanoparticle catalyst prepared above to the metal oxide precursor / polymer mixed spinning solution to form a mixed spinning solution of nanoparticle catalyst particles uniformly dispersed in the spinning solution Manufacture. Here, the solvent is Ν, Ν'-dimethylformamide (N, N'-dimethylformamid 6), Compatible solvents such as dimethylsulfoxide, 1 ^ -dimethylacetamide, N-methylpyrrodon, pure water (DI water) and ethanol However, a solvent that can dissolve the metal oxide precursor and the polymer at the same time should be selected. In addition, the polymer that can be used here is not limited to a specific polymer as long as it can be dissolved with a solvent and can be removed through high temperature heat treatment. Specifically, the polymer that can be used in the present step (S1920) is polymethyl methacrylate (PMMA), polyvinylpyridone (PVP), polyvinylacetate (PVAc), polyvinyl alcohol (PVA), polymicrylo Nitrile (PAN), polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene oxide copolymer, polypropylene oxide copolymer, polycarbonate, PC, polyvinylchloride, PVC ), Polycaprolactone, polyvinylidene fluoride and the like.

The metal oxide precursor used in this step is dissolved in a solvent and subjected to high temperature heat treatment, such as Sn02, W03, CuO, NiO, ZnO, Zn2Sn04, Co304, Cr203, LaCo03, V205, Ir02, Ti02, Er203, Tb203, Lu203, Ag20, SrTi03, A precursor containing a metal salt capable of forming semiconductor metal oxide nanofibers or nanotubes having gas sensor characteristics such as Sr2Ta207, BaTi03, Ba0.5Sr0.5Co0.8Fe0.2O3-7 is not limited to a specific metal salt.

The ratio of the polymer and the metal oxide precursor to form the spinning solution is 1: Q.5 ~ 2 It is preferable to have a degree, and the ratio of the polymer and the nanoparticle catalyst synthesized using apoferritin is preferably in the range of 1: 0.00001 to 1: 0.1. The type of metal salt contained in the apoqueritin should be selected in consideration of the sensing characteristics and selectivity of the gas to be detected, and it is possible to manufacture a gas sensor member having various characteristics while changing the metal salt.

The process of preparing the electrospinning solution in step (S1920) first dissolves the metal oxide precursor in a solvent and adds the apoferritin solution containing the pre-made nanoparticle catalyst to uniformly disperse the apoferritin containing the nanoparticle catalyst Mix the solution so that After thorough mixing, the polymer is added at an appropriate ratio and stirred until all of the polymer is dissolved in the solution. Stirring conditions are preferably stirred at 50 ° C or less at room temperature, and stirred for 5 hours to 48 hours to ensure that the apoferritin containing the nanoparticle catalyst, the metal oxide precursor and the polymer are uniformly mixed in the solution. do. Electrospinning the synthesized electrospun solution, and performs a step (S1930) to produce a metal oxide precursor / polymer composite nanofibers containing the apoferritin protein including a nanoparticle catalyst by electrospinning.

In performing the electrospinning technique to perform the step (S1930), to a syringe (syringe) that can fill the spinning solution containing a metal oxide precursor / polymer containing the apoferritin protein containing the nanoparticle catalyst prepared above After filling, press the syringe at a constant speed using a syringe pump Allow the spinning solution to be discharged. The electrospinning system may include a high voltage device, a grounded conductive substrate, a syringe, and a syringe nozzle, and a high voltage is applied between 5 kV and 30 kV between the solution filled in the syringe and the conductive substrate to form an electric field. Due to the electric field formed, the spinning solution discharged through the syringe nozzle is elongated in the form of nanofibers. The spinning solution in the form of a long spout is obtained by evaporation and volatilization of the solvent contained in the spinning solution to obtain a solid polymer fiber, and at the same time contains the apoferritin protein including a metal oxide precursor and a nanoparticle catalyst therein. Composite fibers are produced. The discharge rate can be adjusted to about 0.01 ml / min to 0.5 ml / min and can be prepared metal oxide precursor / polymer / nanoparticles catalyst composite nanofibers having a desired diameter by controlling the voltage and the discharge amount.

Finally, in the step (S1940) of fabricating a metal oxide nanotube structure in which nanoparticle catalysts are uniformly contained without high temperature through high temperature heat treatment of the manufactured composite nanofibers, the metal oxide nano is controlled by controlling the temperature increase rate during the heat treatment process. It is possible to form a tube structure. Through the heat treatment in the silver range of 400-800 ° C, all the proteins surrounding the polymer and the nanoparticle catalyst are decomposed and removed, and the metal oxide precursor and the nano-oxide inside the nanofiber are processed through the Ostwald ripening process. Particle catalysts can diffuse toward the surface of the nanofibers to achieve metal oxide nanotube structures after the final heat treatment. In this process, the temperature increase rate is relatively high, such as 10 V, so that the nanoparticle catalysts Metal oxide nanotube structures (1810) can be fabricated that are concentrated on the quaternary structure of metal oxide nanotubes.

FIG. 20 schematically illustrates a manufacturing process sequence according to a method for manufacturing a gas sensor member using a metal oxide semiconductor nanotube including a nanoparticle catalyst using an electrospinning method according to an embodiment of the present invention.

The first step ( ^' S2010) is to perform nanosumming using a complex spinning solution (2010) containing a metal oxide precursor (tin precursor) / polymer and a nanoparticle catalyst embedded in the apoferritin using an electrospinning technique. The example to produce is shown. The nanofibers 2030 shown in FIG. 20 produced through the above process are shown to have an even distribution of the apoferritin 2020 including the nanoparticle catalyst.

Step S2020, which is a second process, represents a process of high temperature heat treatment of the composite nanofibers synthesized in step S2010. In the process of heat treatment, the temperature increase rate is 10 ° C / min, which heats up to 600 ° C at a relatively high rate to remove all of the proteins surrounding the polymer and the nanoparticle catalyst, and the metal oxide and nanoparticle catalysts are all diffused into the nanofiber hook. As a result, the metal oxide semiconductor nanotubes 2040 that contain the metal nanoparticle catalyst uniformly are synthesized.

In the embodiment of FIG. 20, an example of manufacturing a tin oxide nanotube structure using a tin oxide precursor has been described, but in the case of a metal oxide precursor, as long as it includes one of the metal salts as described above, no significant restriction is imposed. . As described above, the manufacturing method of the gas sensor member 1800 using the metal oxide semiconductor nanotubes 1810 including the nanoparticle catalyst 1821 using the electrospinning technique and the heat treatment temperature control rate according to the embodiments of the present invention The reaction properties of the gas sensor are formed by forming a one-dimensional nano-hub structure with a large reaction surface area with gas and binding a catalyst having a uniformly dispersed chemical / electronic sensitization effect using protein properties unlike conventional catalysts. The sensitivity, sensitivity, and selectivity can be greatly improved.

Hereinafter, the present invention will be described in detail through Examples and Comparative Examples. The examples and comparative examples are only for illustrating the present invention, and the present invention is not limited to the following examples. ^{^:} Example 3: synthesis procedure as described below to the apo-ferritin synthesis of Pt and Au nanoparticle catalyst made increased tool crude platinum (Pt), gold (Au) inside Apo ferritin, which have a nanoparticle catalyst using as a template Go through

In a solution of apoferritin (Sigma Aldrich) NaOH-dispersed in 0.15M aqueous solution of NaCl at a concentration of 35 mg / ml, NaOH-was used to adjust the pH to 8.6 to allow diffusion of metal salts into the aperitin. Make it. The material used to adjust the pH here is not a big limitation as long as the solution is basic. Next, H2PtC16-H20 was used as a Pt precursor and H2AuC16'H20 was used as an Au precursor to synthesize Pt and Au nanoparticle catalysts. 16 mg of H2PtC16'H20 and 16 mg of H2AuC16-H20 were dissolved in DI water, respectively. Produced in the form. When the two aqueous metal salt precursor solutions made as described above are stirred slowly dropping into the pH-controlled apoferritin solution, Pt and Au salts are respectively diffused into the hollow of the apoferritin and embedded therein. The stirring condition here means to proceed at about 100 hrs at 100 rpm. After the metal salt is sufficiently embedded in the apoferritin, the use of a NaBH4 reducing agent causes the metal silver (Pt4 + / Au4 +) metals (Pt4 + / Au4 +) to be reduced to (Pt4 + / Au4 +) metal to form a nanoparticle catalyst. The reducing agent NaBH4 used at this time is made into an aqueous solution at a concentration of 40 mM and 0.5 ml is added thereto.

The two aqueous solutions in which the Pt nanoparticle catalyst and Au nanoparticle catalyst are dispersed using apoferritin as described above contain a large amount of ligands together with a reducing agent and a metal salt. Only apoferritin containing nanoparticle catalysts will be extracted. The condition of the centrifuge is preferably about 10,000 rpm to about 12,000 rpm, and preferably centrifuged for at least 10 minutes. If apoferritin containing the R and Au nanoparticle catalyst extracted through a centrifuge is dispersed in water again, an aqueous solution in which Pt and Au nanoparticle catalysts are dispersed in the apoferritin can be finally prepared.

FIG. 24 shows a transmission electron microscope photograph of apoferritin containing Pt nanoparticle catalyst and Au nanoparticle catalyst prepared by the above procedure. It can be seen that the apoferritin including the synthesized Pt and Au nanoparticle catalysts has a diameter of about 2-5 nm and has a spherical shape. Example 4 Fabrication of Tin Oxide (Sn02) Nanotubes 2040 Including Pt and Au Nanoparticle Catalysts

First, 0.25 g of tin chloride dihydrate, a tin oxide precursor, is added to a mixed solvent containing 1.35 g of DMF and 1.35 g of ethanol, and dissolved at room temperature. Next, 200 mg of the apoferritin (2020) aqueous solution containing the Pt nanoparticle catalyst and the Au nanoparticle catalyst prepared in Example 3 were added to the two tin oxide precursor / mixed solvent electrospinning solutions, respectively, and mixed. A polyvinylpyrrolidone (PVP) polymer having a molecular weight of 1,300,000 g / mol was used to increase the viscosity of a homogeneous solution in which apoferritin particles and tin precursors including Pt nanoparticle catalyst and Au nanoparticle catalyst were mixed. Each of g is added and stirred at a rotational speed of 500 rpm for 24 hours at room temperature to prepare a spinning solution. The electrospinning solution thus prepared is placed in a syringe (Henke-Sass Wolf, 10 mL NORM-JECT®) and connected to a syringe pump to push and spin the electrospinning solution at a discharge rate of 0.1 ml / min. Electrospinning is carried out with a voltage of 14 kV between the nozzle (needle, 27 gauge) and the current collector where the nanofibers collect. A stainless steel plate was used as the current collector plate of the nanofibers, and the distance between the nozzle and the current collector was set to 15 cm.

FIG. 21 shows a tin oxide precursor / polyvinylpyridone composite nanofiber including Pt nanoparticle catalyst obtained after electrospinning and a tin oxide precursor / polyvinylpyridone composite nanofiber scanning electron microscope including Au nanoparticle catalyst. All. It can be seen that one-dimensional nanofibers are synthesized, and the diameter has a value between 200 nm and 300 nm.

The Pt nanoparticle catalyst-bound metal oxide precursor / polymer composite fiber and Au nanoparticle catalyst-bound metal oxide precursor / polymer composite fiber prepared by the method described above were heated at 600 ° C. at a temperature of 10 ° C / min, respectively ^. Hold at C for one hour, then cooled to room temperature at a rate of 40 ° C./mi drop. Heat treatment was performed in an air atmosphere using Ney's Vulcan 3-550 small electric furnace. Through the high temperature heat treatment process, the apoferritin protein and the polymer surrounding the nanoparticle catalyst are decomposed and removed. Also ^{preferentially,} tin salt precursor is a tin salt precursor was within the nanofiber is oxidized while passing through the nucleation and particle growth process by tin oxide particles through Ostwald life turning phenomenon from the surface of the nanofibers because the heat treatment in an air atmosphere As the oxides are oxidized, they diffuse to the surface of the nanofibers to form tin oxide nanotubes, and the Pt nanoparticle catalyst and Au nanoparticle catalysts included in the nanofibers also diffuse to the nanotube surface. Tin oxide nanotubes in which nanoparticle catalysts are uniformly bound and tin oxide nanotube structures in which Au nanoparticle catalysts are uniformly bound are formed.

FIG. 25 shows scanning electron micrographs of tin oxide nanotubes bound with Pt nanoparticle catalysts obtained after the heat treatment prepared in Example 4 and tin oxide nanotubes bound with Au nanoparticle catalysts. The outer diameter of the formed nanotube structure is about 50 nm-2 μπι and the inside diameter is about 40 nm-1.9 μπι. Tube The thickness is about 10-100 nm.

FIG. 26 shows a transmission electron micrograph of a tin oxide nanolyve including a Pt nanoparticle catalyst prepared in Example 4. FIG. Transmission electron microscopic lattice analysis shows that Pt nanoparticle catalysts are present in tin oxide nanotubes, and the SAEDCSelected Area Electron Diffraction pattern shows that Pt nanoparticle catalysts crystallize in tin oxide nanotubes. . In addition, Pt nanoparticle catalysts are uniformly distributed in the tin oxide nanotube structure formed through the TEM analysis (EDS).

FIG. 27 shows a transmission electron micrograph of a tin oxide nanotube including an Au nanoparticle catalyst synthesized in Example 4. FIG. Transmission electron microscopic lattice analysis shows that Au nanoparticle catalysts are present in tin oxide nanotubes, and SAEDCSelected Area Electron Diffraction (SAEDC) pattern shows that Au nanoparticle catalysts are crystallized in tin oxide nanolevers. have. In addition, it can be seen that Au nanoparticle catalysts are uniformly distributed in the tin oxide nanotube structure formed through the TEM analysis (EDS).

Comparative Example 3 Preparation of Pure Tin Oxide Nanofibers without Nanoparticle Catalyst In Comparative Example 2, pure tin oxide nanofibers without addition of the nanoparticle catalyst embedded in apoferritin were formed. will be. Specifically, 0.35 g of polyvinylpyrrolidone (PVP) having a weight average molecular weight of 1,300,000 g / m and tin oxide precursor ^' tin ^' 0.25 g of tin chloride dihydrate is dissolved in 1.35 g of DMF and 1.35 g of ethane in a mixed solvent at 500 rpm for 24 hours at normal silver conditions. After all the agitation, the tin oxide precursor / polymer mixed spinning solution was added to an electrospinning syringe (Henke-Sass Wolf, 10 mL N0RM-JECT®), connected to a syringe pump, and discharged at a discharge rate of 0.1 ml / min. Push up the liquid. The nozzle used for electrospinning uses 27 gauge. The distance between the needle and the current collector to obtain the non-fiber is about 15 cm and the voltage of 14 kV is applied to the tin oxide precursor / polymer composite nanofiber web. To prepare. The prepared tin oxide precursor / polymer composite nanofibers are removed through the high temperature heat treatment process, the tin oxide precursor is formed through the oxidation process to form a tin oxide. The high temperature heat treatment process was performed at 600 ° C for 1 hour, the temperature rising rate was kept constant at 4 ° C / min and the temperature falling rate was kept constant at 40 ° C / min.

FIG. 22 shows a scanning electron micrograph of pure tin oxide nanofibers to which no nanoparticle catalyst prepared through Comparative Example 3 was added. The fabricated tin oxide nanofibers have a diameter of about 50 nm-2 iim and have a cylindrical nanofiber structure.

The prepared pure tin oxide nanofibers were compared with the tin oxide nanotubes bound with the Pt nanoparticle catalyst prepared in Example 4 and the tin oxide nanotubes bound with the Au nanoparticle catalyst. Used. Comparative Example 4 Fabrication of Pure Tin Oxide Nano-Lube without Nanoparticle Catalyst Comparative Example 4 compared with Example 4 relates to the synthesis of pure tin oxide nanotubes without the addition of the R and Au nanoparticle catalyst embedded in the apoferritin. Specifically, 0.35 g of polyvinylpyrrolidone (PVP) having a weight average molecular weight of 1,300,000 g / mol and 0,25 g of tin chloride dihydrate (tin chloride dihydrate) were prepared using DMF 1.35 g and ethane 1.35 g. It is dissolved in g of a mixed solvent at 500 rpm for 24 hours at room temperature. After the agitation is complete, the tin oxide—precursor / polymer mixed spinning solution is filled with an electrospinning syringe (Henke-Sass Wolf, 10 mL NORM-JECT®) ^ and connected to a syringe pump, discharging rate of 0.1 ml / min. The needle used for electrospinning the spinning solution with a high pressure of about 14 kV while keeping the distance between the nozzle and the current collector collecting nanofibers is 15 cm. A precursor / polymer composite nanofiber was produced.

Synthesized above. Tin oxide precursor / polymer composite nanofibers remove polymer through high temperature heat treatment and form tin oxide through oxidation process of tin oxide precursor. The high temperature heat treatment condition was performed for 1 hour at 600 ° C. The temperature increase rate was kept constant at 10 ° C min and the temperature falling rate was kept constant at 40 ° C / min. Here, the temperature increase rate to 10 ⁰ Cmin is a feature that increases the temperature at a rate faster than the temperature increase rate of 4 ° C / min of Comparative Example 3 has a feature that plays an important role in forming nanotube structure.

23 is a pure oxide tin oxide nanotube produced through Comparative Example 4 The scanning electron micrograph of the structure is shown. ， The fabricated pure tin oxide nanotubes have an outer diameter of 50 nm-2 μπι and an inner diameter of 40 nm-1.9 μπι. The thickness of the tube was about 10-100 nm. Experimental Example 2. Preparation of a gas sensor using tin oxide nanotubes bound with platinum (Pt) nanoparticle catalysts, tin oxide nanotubes bound with gold (Au) nanoparticle catalysts, pure tin oxide nanolevers and pure tin oxide nanofibers And characterization

In order to manufacture the sensing material for the gas sensor manufactured in Examples 3 and 4 and Comparative Examples 3 and 4 as an exhalation sensor, tin oxide nanotubes to which Pt nanoparticle catalysts which are partially oxidized through high heat treatment are bound. ， 5 mg of tin oxide nanotubes, pure tin oxide nanotubes and pure tin oxide nanofibers bound with Au nanoparticle catalyst partially oxidized by high heat treatment were dispersed in 100 μΐ of ethane, and then for 1 hour. The ultrasonic cleaning is broken and then crushed. During the grinding process, the nanotube structure or nanofiber structure synthesized above may exhibit a nanorod structure in which the shorter lengthwise direction is obtained.

2 parallel gold (Au) electrodes separated by 300 μπι of tin oxide nanotubes (1810), pure tin oxide nanofibers, and pure tin oxide nanofibers bound with a Pt nanoparticle catalyst or Au nanoparticle catalyst. The size of mm x 3 mm and the alumina substrate were coated using a drop coating method. The coating process was performed by using a micropipette, tin oxide nanotubes bound with 2 μΐ Pt nanoparticle catalyst dispersed in ethanol prepared above, and Au ^' nanoparticle catalyst bound. Tin oxide nanotubes, pure tin oxide nanotubes and pure tin oxide nanofibers ^{: The} mixed solution was applied onto an alumina substrate with a sensor electrode section, respectively, and then dried on a 60 ° C. hotplate. This process was repeated 4 to 6 times, and the tin oxide nanotubes with Pt nanoparticle catalyst bound, the tin oxide nanolyuves bound with Au nanoparticle catalyst, pure tin oxide nanolevers, and pure tin oxide nanofibers were alumina sensor. 'Coated on top of the substrate.

In addition, the gas sensor manufactured for evaluating the characteristics of the exhalation sensor is acetone, which is an indicator gas for diagnosing diabetes, bad breath, and lung cancer at a relative humidity of 85 to 95 RH%, which is similar to the humidity of gas from human mip (CH3 ⁽ X ⁾ CH3), hydrogen sulfide (H2S), and toluene (C6H5CH3) gas concentrations are changed to 5, 4, 3, 2, 1 ppm and at the same time the sensor's operating temperature is maintained at 350 ° C. The response of the reaction was evaluated. In addition, in Experimental Example 2, ^' . Acetone (CH3COCH3), hydrogen sulfide (H2S) and toluene (C6H5CH3) gases, which are representative examples of volatile organic compound gases, as well as nitrogen monoxide (NO) and carbon monoxide (CO), which are biomarkers of asthma, chronic obstructive pulmonary disease, kidney disease and heart disease Selective gas detection characteristics were evaluated by evaluating the detection characteristics for the gas, ammonia (NH3) and pentane (C5H12) gas.

28 is a reaction degree when the concentration of aceron gas decreases to 5, 4, 3, 2, and 1 ppm at 350 ° C. (Rair / Rgas, where Rair is a resistance value of a metal oxide material when air is injected. Rgas is the resistance value of metal oxide material when acetone gas is injected). As shown in FIG. 28, a tin oxide nanotube (1810) sensor including a Pt nanoparticle catalyst bound as the platinum (Pt) nanoparticle catalyst embedded in the apoferritin is heat treated is pure tin oxide nanotubes with respect to acetone gas. It can be seen that the reaction properties are 8.27 times higher than that of the pure tin oxide, and 18.95 times higher than the reaction of pure tin oxide.

29 is a sensor test result showing the reactivity value with time when the concentration of hydrogen sulfide gas is reduced to 5, 4, 3, 2, 1 ppm at 350 ⁰ C.

As shown in FIG. 29, a sensor made of tin oxide nano-levers 1810 containing Pt nanoparticle catalysts bound by heat treatment of a platinum (Pt) nanoparticle catalyst embedded in apoferritin was pure tin with respect to hydrogen sulfide gas. It can be seen that the reaction characteristics are 4.23 times higher than that of the oxide nanotubes, and 11.03 times higher than those of the pure tin oxide nanofibers.

FIG. 30 is a sensor test result showing a time response of the semi-arithmetic value when the concentration of toluene gas is reduced to 5, 4, 3, 2, and 1 ppm at -350 ⁰ C. FIG.

As shown in FIG. 30, the tin oxide nanotube 1810 sensor including the Pt nanoparticle catalyst bound by the heat treatment of the platinum (Pt) nanoparticle catalyst embedded in the apoferritin is pure tin oxide nanotubes with respect to hydrogen sulfide gas. It can be seen that the reaction properties are 1.12 times higher than that, and that they are 1.76 times higher than pure tin oxide nanofibers.

31 shows a platinum (Pt) nanoparticle catalyst embedded inside apoferritin at 350 ⁰ C. Hydrogen sulfide, toluene, nitrogen monoxide, carbon monoxide, which are biomarker gases of other diseases, compared to acetone gas, which is known as a biomarker gas for diabetes and body fat decomposition, using a tin oxide nanotube sensor containing Pt nanoparticle catalysts bound by heat treatment , Shows the reactivity values appearing at a concentration of 1 ppm with respect to ammonia pentane gas.

As shown in FIG. 31, the sensor made of tin oxide nanotubes 1810 to which Pt nanoparticle catalysts are bound is prepared in comparison with other biomarker gases such as nitrogen monoxide, hydrogen sulfide, carbon monoxide, ammonia, toluene, and pentane gas. Characteristically, it was confirmed that the selective detection characteristics were excellent for acetone, which is a biomarker gas for diabetes and body fat decomposition.

FIG. 32 shows hydrogen sulfide gas concentration changes (1-5 ppm) of a tin oxide nanotube sensor including Au nanoparticle catalysts bound by the heat treatment of the gold (Au) nanoparticles embedded in apoferritin obtained from Example 3. It is a graph showing a change in sensor sensitivity.

FIG. 33 is a hydrogen sulfide gas known as a biomarker gas of bad breath using a tin oxide nanotube sensor including Au nanoparticle catalysts bound by heat treatment of gold (Au) nanoparticle catalysts embedded in apoferritin at 300 ° C. The hemispheric values at 1 ppm of the abundance of biomarker gases such as toluene, acetone, ammonia and ethanol are shown.

In the above experimental example, the sensor characteristics of the gas sensor sensing material were shown by using the volatile organic compound gas as an example. In addition, harmful gases such as H2, NOx, CO, SOx It can be expected to excellent sensor detection characteristics, such as tin oxide nano-lube including Pt nanoparticle catalyst or Au nanoparticle catalyst is bound by the heat treatment of the platinum (Pt) or gold (Au) nanoparticle catalyst embedded in the apoferritin It was confirmed that the gas sensor having excellent selectivity for acetone and hydrogen sulfide was manufactured by changing the 'type of catalyst' in the sensor manufactured using the sensing material. In addition, by changing the type of metal oxide material, it is possible to expect additional selectivity change characteristics, it is possible to manufacture a nanosensor array having a high sensitivity and high selectivity using the multi-metal oxide nanotubes in which the multi-catalyst particles are bound. The metal oxide nanotube sensing material to which the nanoparticle catalyst obtained from the apoferritin template is bound may be used in an excellent hazardous gas sensor and a gas sensor for healthcare for analyzing and diagnosing volatile organic compound gas in an exhalation.

[Description of the code]

100: member for the one-dimensional porous metal oxide nanotube gas sensor having a nanoporous catalyst and having a double pore distribution including a plurality of circular to elliptic pores

110: nanoparticle catalyst in which apoferritin shell is removed and partially oxidized after high temperature heat treatment

121: After the high temperature heat treatment, the spherical polystyrene regenerated layer template is decomposed, and the microporous circular to elliptic shape is formed by partially filling the macropores by crystallization and diffusion of the metal oxide. 131: macropore generated by spherical polystyrene regenerative layer template after solid silver heat treatment

1800: Metal oxide nanotube containing a nanoparticle catalyst. Gas sensor member 1810: Metal oxide nanotube containing a nanoparticle catalyst.

1821: Nanoparticle catalyst with apoferritin shell removed and partially oxidized after high temperature heat treatment

2010: Pt nanoparticle catalysts or Au nanoparticles Apo ferritin built tin containing catalyst oxide precursor / polymer electrospinning for ^'liquid-

2020: Pt nanoparticle catalyst synthesized using apoferritin

2030: Tin precursor / polymer nanofibers containing apopritein particles containing Pt nanoparticle catalyst or Au nanoparticle catalyst

2040: Tin oxide nanoleubes comprising partially oxidized Pt nanoparticle catalysts or Au nanoparticle catalysts

2050: Partially oxidized Pt nanoparticle catalyst or Au nanoparticle catalyst after the apoferritin shell was removed after high temperature heat treatment

[Form for implementation of the invention] 一

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may various modifications and changes without departing from the essential characteristics of the present invention. . Therefore, the embodiments described in the present invention are intended to limit the technical idea of the present invention. It is for illustrative purposes only and is not intended to be limiting. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

Claims

[Range of request]

[Claim 1]

During the heat treatment process of the metal oxide precursor / polymer composite nanofibers in which a plurality of metal nanoparticle catalysts contained in the spherical polymer regenerative layer template and the internal vaporization structure of the apoferritin and surrounded by protein are dispersed inside and on the surface thereof, the metal nanoparticles A one-dimensional porous metal oxide nanotube composite sensor material, characterized in that the catalyst is uniformly distributed in the metal oxide nanotubes and at the same time, macropores and micropores are formed on the surface of the metal oxide nanotubes to have a double average surface pore distribution.

[Claim 2]

The method of claim 1,

The one-dimensional porous metal oxide nanotube composite sensor material, characterized in that uniform binding to the inner and inner and outer surfaces of ¾ quality constituting the metal nanoparticle catalyst difference metal oxide nanotubes.

[Claim 3]

The method of claim 1,

The diameter of the macropores is included in the range of 50 nm to 300 nm,

The diameter of the micropores is a one-dimensional porous metal oxide nanotube composite sensor material, characterized in that included in the range of 0.1 nm to 50 nm.

[Claim 4]

The method of claim 1, The spherical polymer regenerative layer template used to form the macropores may be polymethyl methacrylate (PMMA), polyvinylpyridone (PVP), polyvinylacetate (PVAc), polyvinyl alcohol (PVA), polystyrene (PS ) And one or two selected from polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), polyacrylic acid (PAA), polydianyldimethylammonium chloride (PDADMAC), polystyrenesulfonate (PSS) A one-dimensional porous metal oxide nanotube composite sensor material, characterized in that the above-mentioned mixture is contained and dispersed without being decomposed when mixed with an electrospinning solution.

[Claim 5]

The method of claim 1,

The spherical polymer regenerative template used to form the macropores forms an ionic or chargeable ionic surfactant (anionic or cationic surfactants) on the surface of the colloid, even though the sacrificial layer colloid is a polymer soluble in a solvent. It comprises a polymer colloid insoluble in the solvent, the size of the polymer sacrificial layer template is a one-dimensional porous metal oxide nanotube composite sensor material, characterized in that selected in the range of 50 nm-1 μπι.

.

[Claim 6]

The method of claim 1,

During the heat treatment process, there is a time difference between the decomposition process of the spherical polymer regenerative layer template and the crystallization and diffusion process of the metal oxide. 1D porous metal oxide nanotube composite sensor material, characterized in that the macropores generated on the surface of the metal oxide nanotubes by the decomposition process of the regenerative layer template is partially filled through the crystallization and diffusion of the metal oxide.

[Claim 7]

The method of claim 1,

Weight ratio between the spherical polymer sacrificial layer template and the metal nano-catalyst contained within the inner hollow structure of apoferritin and surrounded by a protein _. Rate (wt%) is in the range of 1: 0.000001-1, the one-dimensional porous metal oxide nanotube composite sensor material

[Claim 8]

The method of claim 1,

Porous metal oxide nanotubes are Sn02, W03, Co304, ZnO, Fe203, NiO, In203, Mn203, V203, Mo03, Fe304, V205, Zn2Sn04, LaCo03, Ce02, Eu203, Gd203, Ho03, Er203, Yb203, Lu203, LiV308, A one-dimensional porous metal oxide nanotube composite sensor material comprising a metal oxide constituting a single material or two or more kinds of a single material selected from SrTi03, Zr02, CuO, InTa04, Nd203, and Sm203.

[Claim 9]

The method of claim 1,

The increase ratio of the spherical polymer regenerative layer template is a polymer constituting the nanofibers A one-dimensional porous metal oxide nanotube composite sensor material, characterized in that contained in the concentration range of 0.1 wt% to 50 wt% relative to the matrix.

[Claim 10]

The method of claim 1,

The weight ratio of the metal nanoparticle catalyst contained in the internal hollow structure of the apoferritin and surrounded by the protein is in the concentration range of αοοι wt to 50 \% of the metal oxide precursor constituting the metal oxide precursor / polymer composite nanofiber. 1D porous metal oxide nanotube composite sensor material, characterized in that.

[Claim 11]

The method of claim 1,

The protein comprises apoferritin having a hollow structure having an outer diameter of 12 nm and an inner diameter of 8 nm, and dense between the spherical polymer sacrificial layer templates in a metal oxide precursor / polymer composite nanofiber including the spherical polymer regenerative layer template. Become,

Double average surface pore distribution of the macropores and the micropores formed by the spherical polymer regenerative layer template by forming micropores as the shell of the protein constituting the hollow structure is thermally decomposed and removed through the heat treatment process. A one-dimensional porous metal oxide nanotube composite sensor material having a.

[Claim 12] The method of claim 1,

The metal nanoparticle catalyst and the spherical polymer regenerative layer template have a charge surface, and thus, the inside of the metal oxide precursor / polymer composite nanofiber without the spacing between the metal nanoparticle catalysts and the spherical polymer regenerative layer template. And a one-dimensional porous metal oxide nano-leucom composite sensor material, characterized in that uniformly dispersed on the surface. _.

[Claim 13]

The method of claim 1,

Nanotubes included in the one-dimensional porous metal oxide nanotube composite sensor material, the outer diameter is included in the size range of 50 nm to 2 μπι, the inner diameter is included in the size range of 40 nm to 1.95 iim, the thickness of ¾ quality It is included in the size range of 10 nm to 50 nm, the micropores (diameter in the range of 0.1 nm to 50 nm) and the macropores (diameter 50) on the outer surface in all directions at an average interval of 5 nm to 1 iim It is included in the range of nm to 300 nm) one-dimensional porous metal oxide nanotubes composite sensor material comprising a.

[Claim 14]

The method of claim 1,

The metal nanoparticle catalyst is Pt, Pd, Rh, Ru, Ni, Co, Cr, Ir, Au, Ag, Zn, W, Sn, Sr, In, Pb, Fe, Cu, V, Ta, Sb, Sc 1-D porous metal oxide comprising one or two or more nanoparticle catalysts selected from among Ti, Mn, Ga and Ge Nanotube composite sensor material.

[Claim 15]

Proteins and polymers are removed by pyrolyzing metal oxide precursor / polymer composite nanofibers in which a single phase nanoparticle or heterogeneous nanoparticle catalyst surrounded by a protein contained in the internal hollow structure of apoferritin is plurally uniformly dispersed. And the nanoparticle catalyst thus obtained is uniformly bound to the surface and the inside of the nanotube structure, wherein the polycrystalline metal oxide nanotube composite sensor material comprising the nanoparticle catalyst.

[Claim 16]

The method of claim 15,

The nanotube structure is characterized in that the metal oxide precursor is formed by crystallization through the Oswald Ripening process in the process of pyrolysis, polycrystalline metal oxide nanotube composite sensor material comprising a nanoparticle catalyst.

[Claim 17]

The method of claim 15,

Types of metal salts that can be substituted in the apoferritin include Pt, Pd, Rh, Ru, Ni, Co, Cr, Ir, Au, Ag, Zn, W, Sn, Sr, In, Pb, Fe, Cu, V ， Characterized by one or more metal salts that can be produced in the form of rapid or metal oxides such as Ta, Sb, Sc, Ti, Mn, Ga, Ge, etc., typically copper (II) nitrate, copper (II) chloride, cobalt (II) nitrate, cobalt (II) acetate, lanthanum (III) nitrate, lanthanum (III) acetate, platinum (IV) chloride, platinum (II) acetate, goldQ, III) chloride, gold (III) acetate, silver chloride, silver acetate, iron (III) chloride, iron (III) acetate, nickeldl) chloride, nickel (II) acetate, ruthenium (III) chloride, ruthenium acetate, iridium (III) chloride, iridium acetate, tantalum (V) A polycrystalline metal oxide nanotube composite sensor material comprising a nanoparticle catalyst synthesized including chloride, palladium (II) chloride and the like.

[Claim 18]

The method of claim 15,

Heterogeneous nanoparticle catalysts contained in the vaporization structure of apoferritin are Pt / Ir02, Pt / Ru02, Pt / Rh203, Pt / NiO, Pt / Co304, Pt / CuO, Pt / Ag20, Pt / Fe203, Au / Ir02 , Metal-metal oxide forms including Au / Ru02, Au / Rh203, Au / NiO, Au / Co304, Au / CuO, Au / Ag20, etc., or p _t , Au, Ag, Fe, Ni, Ti, Sn Combination of metal-metal heterogeneous selected from among Si, Al, Cu, Mg, Sc, V, Cr, Mn, Co, Zn, Sr, W, Ru, Rh, Ir, Ta, Sb, In, Pb, Pd Nanoparticle catalyst consisting of Ti02, ZnO, W03, Sn02, Ir02, In203, V203, Mo03 and p20 type metal oxides Ag20, PdO, Ru02, Rh203, NiO, Co304, CuO, A polycrystalline metal oxide nanotube composite sensor material comprising one heterogeneous nanoparticle catalyst selected from the group consisting of two kinds selected from Fe203, Fe304, V205 and Cr203.

【Old Port 19】 The method of claim 15,

In the metal oxide precursor / polymer composite nanofibers in which the nanoparticle catalyst is uniformly dispersed in a plurality, the ratio between the polymer and the apoferritin containing the nanoparticle catalyst is in the range of 1: 0.000001 to 1: 0.1. , Polycrystalline metal oxide nanotube composite sensor material comprising a nanoparticle catalyst.

[Claim 20]

The method of claim 15,

The apoferritin is a material consisting of a protein having a hollow structure, and is capable of substituting one or more metal ions, and comprises a nanoparticle catalyst having a diameter size of 0.1 nm to 8 nm through a reduction process. ， Polycrystalline metal oxide nanotube composite sensor material comprising a nanoparticle catalyst.

[Claim 21]

The method of claim 15

The nanoparticle catalyst contained in the hollow structure of the apoferritin is composed of a protein shell having a charge on the surface of the apoferritin, and is uniform on the inside and the surface of the metal oxide precursor / polymer composite nanofiber without interspersing between the nanoparticle catalysts. A polycrystalline metal oxide nanotube composite sensor material comprising a nanoparticle catalyst, which is characterized in that it is dispersed.

[Claim 22]

The method of claim 15, The nanotube structure has an outer diameter ranging from 50 nm to 2 iim in length and an inner diameter ranging from 40 nm to 1.9 μπι,

The thickness of the shell constituting the nanotube structure has a range of 10 nm ~ 100 nm, comprising a nanoparticle catalyst having a length range of 1 μηι to 300 um polycrystalline metal oxide nanotube composite sensor material.

[Claim 23]

The method of claim 15,

The polycrystalline metal oxide nanotubes comprising a nanoparticle catalyst, characterized in that the size of the crystal grain mips constituting the polycrystalline metal oxide nanotubes included in the composite polycrystalline metal oxide nanotube composite sensor material has a range of 0.2 nm to 100 nm. Composite sensor material.

[Claim 24]

The method of claim 15,

Nanoparticle catalyst, characterized in that it further comprises a two-dimensional metal oxide crushing surface comprising a nanoparticle catalyst formed by crushing the tube and the tube shorter in the longitudinal direction through the dispersion and grinding process Polycrystalline metal oxide nanotube composite sensor material.

[Claim 25].

A polycrystalline metal oxide nanotube composite sensor material comprising the nanoparticle catalyst of claim 15 comprising one or two or more kinds of sensing materials for an array gas sensor. Gas sensor.

[Claim 26]

(a) synthesizing the first dispersion solution in which the metal nanoparticle catalyst surrounded by the protein contained in the internal hollow structure of the apoferritin is uniformly dispersed; .

(b) mixing the first dispersion solution with the second dispersion solution in which the spherical polymer regenerative layer template is dispersed, and mixing the mixed dispersion solution with a metal oxide precursor and a solvent in which the polymer is dissolved to prepare an electrospinning solution. step;

(c) The metal nanoparticles of the electrospinning solution surrounded by the protein contained in the spherical polymer regenerative layer template and the internal hollow structure of the apoferritin on the inside and the surface of the metal oxide precursor / polymer composite nanofiber using the electrospinning method. Forming a composite nanofiber having a plurality of particle catalysts distributed therein; And

(d) During the heat treatment process of the composite nanofibers, the polymer matrix constituting the nanofibers and the organic material including the protein surrounding the spherical polymer regenerative layer template and the metal nanoparticle catalyst are simultaneously removed, thereby forming double-surface pores of round or oval shape. A binary mean, wherein the metal nanoparticle catalyst comprises forming one-dimensional porous metal oxide nanotubes uniformly bound to the inner and inner and outer surfaces of the shell constituting the nanotubes; A method for producing a metal oxide nanotube composite sensing material to which a catalyst having a surface pore distribution is bound.

[Claim 27] The method of claim 26,

(e) Resistance change type by coating on the sensor electrode for semiconductor gas sensor measurement by dispersing or pulverizing the one-dimensional porous metal oxide nanotube using at least one coating process among drop coating, spin coating, and inkjet printing dispensing. Further comprising the step of manufacturing a semiconductor gas sensor,

A method of manufacturing a metal oxide nanotube composite sensing material with a catalyst having a double average surface pore distribution, characterized in that detection of environmentally harmful gases and biomarker gases for disease diagnosis is possible through the resistance-change semiconductor gas sensor.

[Claim 28]

The method of claim 26,

In step (a),

As a process in which the metal nanoparticle catalyst is produced inside the apoferritin by substituting a metal salt inside the apoferritin and reducing the substituted metal salt using a reducing agent.

The solution containing apoferritin is included in the range of pH 2-3 and pH 7.5-9, and has a salinity ratio in the range of 0.1 mg / ml to 150 mg / ml. Method for producing a metal oxide nanotube composite sensing material to which a catalyst having a binder.

-

[Claim 29]

The method of claim 26, In step (d),

Using the phenomenon that carbon dioxide and steam gas are generated when the polymer is decomposed through the heat treatment, the polymer is rapidly decomposed through a heat treatment process having a rate of 10 ^° C / min to 50 ^° C / min. By increasing the amount of carbon dioxide and water vapor released per hour, the metal nanoparticle catalysts are uniformly bound to the inside and outside of the nanotube, and the catalyst-bound metal oxide nanotube composite sensing material having a double average surface pore distribution is detected. Manufacturing method.

[Claim 30]

In the gas sensor catalyst-metal oxide nanotube composite sensing material manufacturing method using a polycrystalline metal oxide nanotube containing a nanoparticle catalyst,

(a) synthesizing a nanoparticle catalyst inside the hollow structure of apoferritin;

(b) preparing an electrospinning solution in which an aperitine, a metal oxide precursor, and a polymer containing a nanoparticle catalyst inside the vaporization structure are mixed in a solvent;

(c) forming the composite nanofibers in which the nanoparticle catalyst embedded in the apoferritin is uniformly distributed on the surface and inside of the metal oxide precursor / polymer nanofiber using the electrospinning method; And

(d) forming a polycrystalline metal oxide nanotube in which the nanoparticle catalyst is uniformly bound on the inner surface of the metal oxide nanotube and on the inner surface of the metal oxide nanotube through the heat treatment process. Catalysts for Sensors Metal oxide nanotube composite sensing material manufacturing method.

[Claim 31]

The method of claim 30

(e) dividing or pulverizing the polycrystalline metal oxide nanotubes, and coating the at least one coating process among drop coating, spin coating, inkjet printing, and dispensing on the sensor electrode for measuring a semiconductor gas sensor. Including,

Method for producing a catalyst-metal oxide nanotube composite sensing material for a gas sensor, characterized in that for detecting environmentally harmful gas and biomarker gas for disease diagnosis.

[Claim 32]

The method of claim 30

In step (a),

Substituting the metal salt in the apoferritin to embed the nanoparticle catalyst in the apoferritin '

The solution containing apoferritin has a basic range of pH 8.0-9.0, and has a salinity range of 0.1 mg / ml-150 mg / ml, catalyst-metal oxide nanotube complex sensing for a gas sensor. Material manufacturing method.

[Claim 33]

The method of claim 30,

In step (d),

The surface of the polymer and the apoferritin through the heat treatment process The surrounding protein is removed, the metal oxide precursor is oxidized, and the increase in the heat treatment process is controlled by controlling the speed, so that the nanoparticle catalyst is bound by the nanoparticle catalyst through the Ostwald ripening phenomenon. A method for producing a catalyst-metal oxide nano-lube composite sensing material for a gas sensor, characterized in that to form a nano-lube.

[Claim 34]

Article 30

In step (d),

In order to fabricate the nanotubes in which the nano-indenter catalyst is uniformly bound, the rising speed is adjusted between 10 ^° C. per minute and 50 ^° C. per minute. Manufacturing method.

[Claim 35]

The method of claim 30,

In step (a),

When a specific metal ion is substituted in the interior of the apoferritin, the specific metal ion is waited for a time range of 1 hour or more and 24 hours or less so that the specific metal ion diffuses inside the apoferritin, a catalyst for a gas sensor Oxide nanotube composite sensing material manufacturing method. ,