KR101420653B1 - The cathode catalyst of polymer electrolyte fuel cell and method for preparing the same - Google Patents

Abstract

The present invention relates to a positive electrode catalyst for a polymer electrolyte fuel cell and a method for producing the same, and more particularly, to a method for producing a positive electrode catalyst for a polymer electrolyte fuel cell, which comprises a catalyst support containing carbon nanotubes and graphene, Preparing an anode catalyst of a fuel cell, and a mixed solution containing a catalyst support by mixing carbon nanotube (CNT) and graphene oxide in a solvent; Mixing a titanium salt with a solvent to prepare a mixed solution containing a catalytically active component; Mixing a mixed solution including the catalyst support and a mixed solution containing the catalytically active component, and adding a nitrogen source to prepare a solution containing a catalyst support bonded with the titanium-nitrogen source complex; And firing nitrogen at a temperature of 750 to 800 ° C to obtain a titanium nitride-supported carbon nanotube-graphene composite (CNT-graphene composite). .
The anode catalyst of the polymer electrolyte fuel cell of the present invention exhibits a high activity including a high onset potential and a high current in an oxygen reduction reaction occurring at the anode of a polymer electrolyte fuel cell, Stable and has a high reduction capability, it can be usefully used as a positive electrode of a polymer electrolyte fuel cell. In addition, since the production process of the catalyst is simple, it is easy to manufacture. The catalyst prepared according to the present invention can be usefully used as a positive electrode catalyst for a polymer electrolyte fuel cell suitable for transportation such as automobiles and domestic power sources.

Description

TECHNICAL FIELD The present invention relates to a positive electrode catalyst for a polymer electrolyte fuel cell and a method for preparing the same,

The present invention relates to a positive electrode catalyst for a polymer electrolyte fuel cell and a method for preparing the same, and more particularly, to a positive electrode catalyst for a polymer electrolyte fuel cell comprising a carbon nanotube-graphene composite on which titanium nitride (TiN) And a method for producing the same.

The need for renewable energy is emerging for economic and environmental reasons, such as recent high oil prices and the greenhouse effect due to carbon dioxide.

Fuel cell is a device that generates electrical energy by electrochemically reacting fuel and oxidizer. Examples of the fuel cell include a direct ethanol fuel cell (DEFC), a direct methanol fuel cell (DMFC), a polymer electrolyte fuel cell (PEMFC), an alkaline fuel cell (AFC), Phosphoric Acid Fuel Cell (PAFC), Molten Carbonate Fuel Cell (MCFC), and Solid Oxide Fuel Cell (SOFC).

Polymer electrolyte fuel cells, which generate electricity by using hydrogen as a fuel, are attracting much attention as a power source for transporting and household power such as next-generation automobiles because they do not emit any pollutants during the reaction process.

On the other hand, the electrode reaction of the fuel cell is composed of a hydrogen oxidation reaction at the anode which is the fuel electrode and an oxygen reduction reaction at the cathode which is the oxygen electrode. However, since these oxidation and reduction reactions proceed very slowly, it is necessary to use a catalyst that increases the reaction rate when it is used for practical purposes.

The cathode and anode of a fuel cell generally use a platinum catalyst, but expensive platinum catalysts are a problem. In particular, in the case of the oxygen reduction reaction occurring at the anode, platinum is used more than the cathode because the reaction rate is slower than the hydrogen oxidation reaction occurring at the cathode.

The reactions occurring in the anode and the cathode of the polymer electrolyte fuel cell are as follows.

(1) Hydrogen oxidation of the anode

H ₂ ^- & gt ^; 2H ⁺ + 2e ^-

(2) Oxygen reduction reaction of cathode

1 / 2O ₂ + 2H ⁺ + 2e ^- → H ₂ O

Furthermore, as described above, the positive electrode catalyst for a polymer electrolyte fuel cell includes a platinum-based catalyst such as platinum or a platinum alloy, a chalcogenide-based catalyst such as ruthenium sulfide, a macrocycle which is a complex of iron and a conductive polymer containing nitrogen (macrocycle) are mainly studied. However, platinum-based catalysts are inexpensive because of their high cost, and the non-platinum catalysts, such as chalcogenide and macrocycle catalysts, are limited in stability as a cathode catalyst for polymer electrolytes.

Therefore, when it is possible to obtain a new low-cost catalyst that does not contain platinum, which is conventionally used as a non-whitening anode catalyst for a polymer electrolyte fuel cell, it is expected to be usefully used in related fields.

Accordingly, one aspect of the present invention is to provide a catalyst for a positive electrode of an electrolyte fuel cell which is economical and stable by using a transition metal nitride and a carbon nanotube-graphene composite.

Another aspect of the present invention is to provide a method for producing a catalyst for a positive electrode of an electrolyte fuel cell in which a transition metal nitride is supported on a carbon nanotube-graphene composite.

According to one aspect of the present invention, there is provided a positive electrode catalyst for a polymer electrolyte fuel cell, comprising a catalytically active component containing titanium nitride (TiN) supported on a catalyst support comprising carbon nanotubes and graphene.

The catalyst support is preferably a carbon nanotube-graphene composite.

The catalyst support preferably contains carbon nanotubes and graphene in a weight ratio of 2: 1 to 1: 2.

The titanium nitride (TiN) is preferably included in an amount of 70 to 80 parts by weight per 100 parts by weight of the total catalyst.

The titanium nitride (TiN) is preferably in the form of particles having a particle diameter of 8 nm or less.

According to another aspect of the present invention, there is provided a method of manufacturing a carbon nanotube, comprising: preparing a mixed solution containing a catalyst support by mixing carbon nanotube (CNT) and graphene oxide in a solvent; Mixing a titanium salt with a solvent to prepare a mixed solution containing a catalytically active component; Mixing a mixed solution including the catalyst support and a mixed solution containing the catalytically active component, and adding a nitrogen source to prepare a solution containing a catalyst support bonded with the titanium-nitrogen source complex; And nitrogen firing at a temperature of 750 to 800 DEG C to obtain a titanium nitride-loaded carbon nanotube-graphene composite (CNT-graphene composite). .

The solvent is preferably ethanol.

It is preferable to further include a step of drying at a temperature of 80 to 120 DEG C for 1 to 4 hours before the nitrogen firing step.

The step of preparing the mixed solution containing the catalyst support preferably involves sonication.

The nitrogen source is preferably urea.

The nitrogen firing is preferably performed for 3 to 5 hours.

The carbon nanotube and the graphene oxide are preferably contained in a weight ratio of 2: 1 to 1: 2.

The titanium nitride (TiN) is preferably included in an amount of 70 to 80 parts by weight per 100 parts by weight of the total catalyst.

The titanium nitride (TiN) is preferably in the form of particles having a particle diameter of 8 nm or less.

The titanium salt preferably contains 50 to 70 parts by weight of the final titanium per 100 parts by weight of the total catalyst.

The nitrogen source is preferably contained in an amount of 4 to 6 times the number of titanium moles.

The titanium salt is preferably selected from the group consisting of TiCl ₄ and TiCl _3.

The anode catalyst of the polymer electrolyte fuel cell of the present invention exhibits a high activity including a high onset potential and a high current in an oxygen reduction reaction occurring at the anode of a polymer electrolyte fuel cell, Stable and has a high reduction capability, it can be usefully used as a positive electrode of a polymer electrolyte fuel cell. In addition, since the production process of the catalyst is simple, it is easy to manufacture. The catalyst prepared according to the present invention can be usefully used as a positive electrode catalyst for a polymer electrolyte fuel cell suitable for transportation such as automobiles and domestic power sources.

Fig. 1 shows the results of LSV (linear sweep voltammetry) for the catalyst prepared in Example 1 and Comparative Examples 1 to 3. Fig.
FIG. 2 shows the morphology of the catalysts prepared in Example 1 and Comparative Examples 1 to 3 observed using a TEM (transmission electron microscope, JEOL Corp., JEM-2100F).
FIG. 3 shows the X-ray diffraction pattern (XRD) results for the catalyst prepared in Example 1 and Comparative Examples 1 to 3. FIG. In the graph of FIG. 3, each numeral indicates a crystal plane of synthesized TiN particles, that is, (111) indicates that the crystal is grown on the (111) plane, and (200) indicates that the crystal is grown on the (200) plane.
FIG. 4 shows the morphology of the catalyst prepared in Example 1 and Comparative Examples 1 to 3, observed using a scanning electron microscope (JEOL Corp., JSM-7410F).

Hereinafter, preferred embodiments of the present invention will be described. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below.

According to the present invention, there is provided a positive electrode catalyst for a polymer electrolyte fuel cell in which a catalytically active component containing titanium nitride (TiN) is supported on a catalyst support comprising carbon nanotubes and graphene.

Carbon nanotubes and graphenes which can be used in the present invention may be any carbon nanotubes and graphenes widely used in the art, and are not particularly limited. For example, in the case of carbon nanotubes, conventional commercial multi-wall carbon nanotubes (MWCNTs) and single-wall carbon nanotubes (SWCNTs) can be used.

Particularly, in the present invention, the catalyst support is a carbon nanotube-graphene composite wherein carbon nanotubes are present between graphene layers to reduce stacking of graphene, It is possible to alleviate bundling. They prevent the aggregation of each other and expand the area that can react. With this structure, the catalyst support has a large surface area and high electrical conductivity, and titanium nitride (TiN) is evenly distributed in the carbon nanotube-graphene composite, and thus the catalyst support exhibits high activity in the oxygen reduction reaction.

The catalyst support preferably contains carbon nanotubes and graphene in a weight ratio of 2: 1 to 1: 2, more preferably about 1: 1.

When the catalyst support contains carbon nanotubes in excess of the above ratio, the bundling of the carbon nanotubes is not effectively reduced. When the catalyst support contains the graphene in an amount exceeding the above ratio, There is a problem that the stacking is not effectively reduced.

The titanium nitride (TiN) is preferably contained in an amount of 70 to 80 parts by weight, more preferably 75 to 80 parts by weight, and most preferably, about 77.5 parts by weight, based on 100 parts by weight of the total catalyst.

When the titanium nitride (TiN) is contained in an amount exceeding 80 parts by weight, there is a problem that the active point (TiN) is not uniformly dispersed. When the titanium nitride is contained in an amount less than 70 parts by weight, have.

The catalyst of the present invention minimizes the phenomenon that the carbon nanotube particles are bundled with each other or the stacking of graphene sheets by using the carbon nanotube-graphene composite as the catalyst support, Titanium nitride (TiN) particles are exposed to the electrolyte, thereby providing a high conductivity to increase the activity of the titanium nitride (TiN) particles.

The titanium nitride (TiN) is preferably in the form of particles having a particle diameter of 8 nm or less, more preferably 5 nm or less, and more preferably 3 to 5 nm. The lower limit is not particularly limited, but when the size is excessively small, it may be difficult to synthesize TiN of the corresponding particle size.

In the catalyst according to the present invention, titanium nitride (TiN), which is a catalytically active component, exhibits a smaller particle size and lower particle aggregation phenomenon than titanium nitride (TiN) not supported on the catalyst support, And exhibit excellent metal-support interaction due to the absence of titanium nitride (TiN) particles.

Accordingly, the catalyst prepared according to the present invention can be used as a preferred anode catalyst for a polymer electrolyte fuel cell suitable for transportation and domestic power sources.

According to the present invention, there is provided a method of preparing a catalyst capable of synthesizing titanium nitride (TiN) and supporting it on a catalyst support in connection with the production of the catalyst of the present invention.

More specifically, according to the present invention, there is provided a method for producing a carbon nanotube, comprising: preparing a mixed solution containing a catalyst support by mixing carbon nanotube (CNT) and graphene oxide in a solvent; Mixing a titanium salt with a solvent to prepare a mixed solution containing a catalytically active component; Mixing a mixed solution including the catalyst support and a mixed solution containing the catalytically active component, and adding a nitrogen source to prepare a solution containing a catalyst support bonded with the titanium-nitrogen source complex; And nitrogen firing at a temperature of 750 to 800 DEG C to obtain a titanium nitride-loaded carbon nanotube-graphene composite (CNT-graphene composite). .

The solvent is preferably ethanol, and it is preferable that ethanol is used in both the first and second steps.

Although the amount of the solvent used in the step of preparing the mixed solution containing the catalyst support is not particularly limited, it is preferable that CNT-graphene oxide is sufficiently wetted and not too much, and therefore, it is preferable to use 10-20 ml of ethanol , And more preferably about 15 ml of ethanol is preferably used.

On the other hand, it is preferable that the amount of the solvent in the step of mixing the titanium salt into the solvent to prepare the mixed solution containing the catalytically active component is 2 to 3 ml, more preferably about 2.53 ml per 1 g of the titanium salt.

It is preferable to further include a step of drying at a temperature of 80 to 120 ° C. for 1 to 4 hours before the nitrogen firing. As a result of performing the drying step, the catalyst support, ie, carbon nanotube-graphene An oxide-supported solid can be obtained.

Furthermore, the step of preparing the mixed solution including the catalyst support preferably involves sonication, and the sonication may be carried out by any device known in the art for generating sonication, , And is not particularly limited. In the case of performing sonication, mixing of carbon nanotubes and graphene oxide is more smoothly performed.

The sonication is preferably performed for 5 to 10 minutes, and when the sonication is insufficiently performed, there is a problem that the carbon nanotube and the graphene oxide are not mixed well, and when the sonication is performed excessively, Pin oxide can clump.

The step of preparing the mixed solution containing the catalyst support may further be carried out for one minute to one hour of stirring to prepare a homogeneous mixed solution. Furthermore, the step of preparing the mixed solution containing the catalytically active component may involve stirring to produce a uniform mixed solution.

In the step of preparing the solution containing the catalyst support bonded with the titanium-nitrogen source complex, the nitrogen source is preferably urea, and when the urea is used, the nitrogen source is low in toxicity.

The firing performed in the step of obtaining a titanium nitride-supported carbon nanotube-graphene composite is preferably performed at a temperature of 750 to 800 ° C. If the calcination temperature is lower than 750 캜, there is a problem that crystal formation of TiN is not smoothly performed. If it exceeds 800 캜, the particle size of TiN becomes large and impurities such as TiO ₂ and Ti are produced. It is most preferable to suppress the sintering of the active metal when firing is carried out within the temperature range of the present invention.

The nitrogen calcination is preferably carried out for 3 to 5 hours, and when the calcination is carried out at less than 5 hours, the calcination is insufficiently performed, and when the calcination is performed for more than 5 hours, the grain size is increased.

The carbon nanotube-graphene oxide is transformed into a carbon nanotube-graphene composite to convert the titanium nitride-supported carbon nanotube-graphene composite (CNT- graphene composite can be obtained. More specifically, graphene oxide is converted into graphene during firing.

The carbon nanotubes and the graphene oxide are mixed at a weight ratio of 1: 2 to 2: 1, more preferably at a weight ratio of about 1: 1.

When the carbon nanotubes are contained in an amount exceeding the above weight ratio range, there is a problem that the bundling of the carbon nanotubes is not effectively reduced. When the graphene oxide is contained in an amount exceeding the above weight ratio range, there is a problem that stacking is not effectively reduced.

The titanium nitride (TiN) is preferably contained in an amount of 70 to 80 parts by weight, more preferably 75 to 80 parts by weight, and most preferably, about 77.5 parts by weight, based on 100 parts by weight of the total catalyst.

When the titanium nitride (TiN) is contained in an amount exceeding 80 parts by weight, there is a problem that the active point (TiN) is not uniformly dispersed. When the titanium nitride is contained in an amount less than 70 parts by weight, have.

The titanium nitride (TiN) is preferably in the form of particles having a particle diameter of 8 nm or less, more preferably 5 nm or less, and more preferably 3 to 5 nm. The lower limit is not particularly limited, but when the size is excessively small, it may be difficult to synthesize TiN of the corresponding particle size.

Preferably, the titanium salt includes 50 to 70 parts by weight of the final titanium per 100 parts by weight of the total catalyst, and the nitrogen source is included in an amount of 4 to 6 times the number of titanium moles Do.

When the nitrogen source contains more than 6 times the number of moles of titanium, titanium carbide (TiC) may be produced together with TiN as an impurity, and if it is contained in an amount of less than 4 times the number of moles of titanium there is a problem that the titanium oxide (TiO ₂₎ can be produced as an impurity with TiN.

The titanium salt is preferably selected from the group consisting of TiCl ₄ and TiCl _3.

According to the catalyst preparation method of the present invention, the synthesis of titanium nitride (TiN) and the step of supporting it on the catalyst support are not separated and are simultaneously performed.

According to the present invention, since the carbon nanotube-graphene oxide complex is formed first and then the graphene oxide is transformed into graphene at the high temperature, the carbon nanotube-graphene complex is formed, A synthetic method can be obtained.

Hereinafter, the present invention will be described more specifically by way of specific examples. The following examples are provided to aid understanding of the present invention, and the scope of the present invention is not limited thereto.

Example

1. Preparation of Catalyst

Example  One

In order to prepare the catalyst of the present invention, 47.5 mg of carbon nanotube (CNT) and 47.5 mg of graphene oxide were sonicated in 15 ml of ethanol solution for about 10 minutes and stirred for 30 minutes to prepare a carbon nanotube and a graphene catalyst The CNT-GO solution containing the support . CMP-310F carbon nanotubes (CNT) of Hanwha Nanotech were used as the carbon nanotubes. The graphene oxide was obtained from graphite using the Hummer's method (Journal of Americal Chemical Society 80 (1958) 1339) graphite.

Next, 1 g of a titanium salt (TiCl ₄ ) was added to 2.53 ml of ethanol and stirred for 30 minutes or longer to prepare titanium oxide (Ti (Ti)) as a process for synthesizing titanium nitride ethoxide solution was prepared, and the solution was added to a CNT-GO solution containing the carbon nanotubes and the graphene catalyst support prepared above, and 1583 mg of urea was added to the nitrogen source, followed by stirring for 30 minutes. To prepare a solution containing a catalyst support bonded with a titanium-urea complex (Ti-urea complex).

The solution thus obtained was dried in an oven at 100 ° C. for 1 hour, transferred to an alumina vessel, and calcined at 750 ° C. for 3 hours. During the firing process, the Ti-urea complex is converted to titanium nitride (TiN) while the catalyst support in the CNT-GO solution containing the catalyst support is a carbon nanotube-graphene complex (CNT -graphene composite) to finally synthesize a CNT-graphene composite catalyst having titanium nitride supported thereon.

Comparative Example  One

1 g of a titanium salt (TiCl ₄ ) as a catalytically active ingredient was added to 2.53 ml of ethanol and stirred for 30 minutes or longer to prepare a titanium ethoxide solution. To this solution, 1583 mg of urea used as a nitrogen source was added And then stirred for another 30 minutes to prepare a solution containing a titanium-urea complex (Ti-urea complex).

The solution was dried in an oven at 100 ° C. for 1 hour, transferred to an alumina vessel, and calcined at 750 ° C. for 3 hours. During the firing process, the Ti-urea complex is converted to titanium nitride (TiN), and finally a TiN catalyst that is not supported on the support is synthesized.

Comparative Example  2

95 mg of graphene oxide was subjected to sonication in 15 ml of ethanol for about 10 minutes and then stirred for 30 minutes to prepare a GO solution containing a graphene oxide catalyst support.

Next, 1 g of titanium salt (TiCl ₄ ) was added to 2.53 ml of ethanol and stirred for 30 minutes or longer to synthesize titanium nitride (TiN), which is a catalytically active component, and to carry it on the catalyst support. Titanium ethoxide ethoxide solution was prepared, and 1583 mg of urea was added as a nitrogen source to the solution. Then, the solution was stirred for 30 minutes to prepare a catalyst support bonded with a titanium-urea complex ≪ / RTI >

The solution was dried in an oven at 100 ° C. for 1 hour, transferred to an alumina vessel, and calcined at 750 ° C. for 3 hours. During the firing process, the titanium-urea complex is converted to titanium nitride (TiN), and at the same time the catalyst support is converted to graphene, and finally a graphene catalyst bearing titanium nitride is synthesized.

Comparative Example  3

95 mg of carbon nanotubes (CNT) were sonicated in 15 ml of ethanol solution for about 10 minutes and stirred for 30 minutes to prepare a CNT solution containing a carbon nanotube catalyst support.

Next, 1 g of titanium salt (TiCl ₄ ) was added to 2.53 ml of ethanol and stirred for 30 minutes or longer to synthesize titanium nitride (TiN), which is a catalytically active component, and to carry it on the catalyst support. Titanium ethoxide ethoxide solution was prepared, and 1583 mg of urea was added as a nitrogen source to the solution. Then, the solution was stirred for 30 minutes to prepare a catalyst support bonded with a titanium-urea complex ≪ / RTI >

The solution was dried in an oven at 100 ° C. for 1 hour, transferred to an alumina vessel, and calcined at 750 ° C. for 3 hours. During the firing process, the Ti-urea complex is converted to titanium nitride (TiN), and the carbon nanotubes are retained to finally synthesize a carbon nanotube catalyst carrying titanium nitride.

2. Oxygen reduction using catalyst

An oxygen reduction reaction was carried out as described below using the catalyst prepared in the above 1.

The oxygen reduction reaction was carried out by forming a 3-electrode electrode in a 0.5 M sulfuric acid solution saturated with high purity oxygen and measuring the working electrode at 1600 rpm in the range of 0.9 V to 0.0 V by LSV (linear sweep voltammetry) Respectively. A platinum wire was used as a counter electrode and an Ag / AgCl electrode was used as a reference electrode. As a working electrode, a glassy carbon electrode having a width of about 0.19635 cm ² coated with a catalyst slurry was used.

A method of producing a catalyst slurry for forming a working electrode is as follows. 20 mg of the prepared catalyst was subjected to sonication in a 15 ml vial for about 30 minutes with 2 ml of distilled water and 40 ul of a 5% Nafion solution to prepare a catalyst slurry. 15 [mu] l of catalyst slurry was dropped on the glass carbon electrode and dried in an oven at 100 [deg.] C. 10 [mu] l of 5% NaCl solution was dropped on the dried catalyst layer, and dried in an oven at 100 [deg.] C to complete the working electrode.

In order to measure the activity of oxygen reduction reaction using LSV (linear sweep voltammetry), a voltage of -0.2V ~ 1.0V was applied 20 times (cyclic voltammetry, CV) to remove impurities adsorbed on the working electrode and to stabilize the activity of the catalyst.

Then, a voltage of 0.9 V to 0.0 V was applied to the same working electrode in a 0.5 M sulfuric acid solution saturated with nitrogen to measure the LSV. The measured current is the background current, and the actual oxygen reduction current (J _ORR ) can be obtained by subtracting the background current from the oxygen reduction current measured in the 0.5M sulfuric acid solution saturated with oxygen.

The results of the LSV measured by the above procedure are shown in FIG. 1. As shown in FIG. 1, in the case of Example 1, the onset potential was as high as about 0.63 V (vs Ag / AgCl) , It can be confirmed that the oxygen reduction current is the highest in all potential regions. Particularly, in the case of a polymer electrolyte fuel cell anode, it is desirable to produce a large current at a high potential. The catalyst of Example 1 produced by the present invention is particularly effective in Comparative Examples 1 to 3 at a high potential region (0.6 V to 0.4 V) Of the catalysts. In FIG. 1, the reduction current has a minus sign, and the larger the magnitude of the absolute value, the higher the reduction current.

On the other hand, in Comparative Example 1 in which no support was used and in Comparative Example 2 in which only graphene was used as a support, the activity of the catalyst was drastically reduced in all the potential regions. In Comparative Example 2 using only carbon nanotubes (CNTs) 3 showed high current in the low potential region but very low current in the high potential region.

The catalyst of the present invention supports titanium nitride (TiN), which is excellent in catalytic activity and stability, on a carbon nanotube-graphene composite support having a wide electrical conductivity and surface area, so that more titanium nitride (TiN) particles are exposed to the electrolyte. Can be used as a positive electrode for a fuel cell capable of exhibiting excellent performance because electron transfer to nitride (TiN) is improved.

3. TEM Lt; RTI ID = 0.0 > ( morphology ) Confirmation of

Each of the catalysts prepared in Example 1 and Comparative Examples 1 to 3 was analyzed by using a transmission electron microscope (TEM) (JEOL Corp., JEM-2100F) to confirm the morphology of the catalysts. 5 mg was mixed with 10 ml of ethanol solution and sonicated for 10 minutes to prepare a solution in which the catalyst was dispersed. The solution was dropped twice on a holy carbon grid (10 μl each) to prepare a specimen for TEM analysis. To obtain images, and the results are shown in Fig.

As can be seen from FIG. 2, it can be seen that the TiN particles are strongly adhered to each other in Comparative Example 1 in which the support is not used. However, in Example 1, Comparative Example 2 and Comparative Example 3 using the support, . In particular, it can be seen that CNT particles are present on the graphene layer in the first embodiment.

4. X-ray of catalyst of the invention Diffraction pattern (XRD)  Confirm

The X-ray diffraction pattern (XRD) of the catalyst prepared in Example 1 and Comparative Examples 1 to 3 was confirmed using an X-ray diffractometer (PANalytical, pw 3040/60 X'pert diffractometer) The synthesized catalyst powder was applied to an XRD analysis glass and mounted on an XRD apparatus and analyzed. The results are shown in FIG.

In Fig. 3, five lines drawn perpendicular to the x-axis represent data of titanium nitride (TiN) (JCPDS No. 38-1420) as reference data.

In relation to the graph of FIG. 3, the X-ray diffraction patterns of existing materials were databaseed and numbered by each substance. The database was compared with the X-ray diffraction pattern of the presently synthesized substance to determine whether the synthesis was performed properly I can judge, JCPDS No. 38-1420 is the number of TiN, and its X-ray diffraction pattern is five lines drawn perpendicular to the x-axis.

As can be seen from FIG. 3, the catalysts of Example 1 and Comparative Examples 1 and 3 coincide well with the reference TiN data, and TiN is well synthesized even if the support is used. In addition, since there is no peak due to other impurities, TiN of high purity can be said to be synthesized.

5. SEM Lt; RTI ID = 0.0 > ( morphology ) Confirmation of

To confirm the morphology of the catalyst and the catalyst support using the SEM (scanning electron microscope) apparatus (JEOL, JSM-7410F) for the catalyst prepared in Example 1 and Comparative Examples 1 to 3, One side of the tape was fixed to the holder for the SEM, and the synthesized catalysts were uniformly spread on the other side, and images were obtained using an SEM apparatus. The results are shown in FIG.

As can be seen from FIG. 4, it can be seen that in Comparative Example 1 in which the support is not used, the TiN grains are strongly adhered to each other. In Comparative Example 2 using the graphene support, graphenes are stacked with each other TiN particles are present. On the other hand, in Comparative Example 3 using the carbon nanotube support, it was confirmed that the carbon nanotubes were bundled together and the TiN particles were dispersed around the carbon nanotubes.

That is, in Comparative Example 2 and Comparative Example 3, the TiN grains exhibited a more even dispersion than the TiN grains of Comparative Example 1, but the grains or carbon nanotubes were aggregated, so that the surface area was not well utilized.

In contrast, in Example 1 according to the present invention, the carbon nanotubes are present between the graphene layers to reduce the aggregation of graphene, and graphene also alleviates the multiplication of carbon nanotubes. As a result, more TiN particles are expected to participate in the oxygen reduction reaction because TiN particles are present between relatively wider areas. To better understand the shape of these catalysts, a schematic of the catalyst was inserted on each image of FIG.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be obvious to those of ordinary skill in the art.

Claims (17)

A catalyst supported on a catalytic support comprising titanium nitride (TiN) on a catalyst support comprising carbon nanotubes and graphene.
The anode catalyst of claim 1, wherein the catalyst support is a carbon nanotube-graphene composite.
The anode catalyst of a polymer electrolyte fuel cell according to claim 1, wherein the catalyst support comprises carbon nanotubes and graphene in a weight ratio of 2: 1 to 1: 2.
The positive electrode catalyst for a polymer electrolyte fuel cell according to claim 1, wherein the titanium nitride (TiN) is contained in an amount of 70 to 80 parts by weight per 100 parts by weight of the total catalyst.
The positive electrode catalyst of a polymer electrolyte fuel cell according to claim 1, wherein the titanium nitride (TiN) is in the form of particles having a particle diameter of 8 nm or less.
Mixing a carbon nanotube (CNT) and graphene oxide in a solvent to prepare a mixed solution including a catalyst support;
Mixing a titanium salt with a solvent to prepare a mixed solution containing a catalytically active component;
Mixing a mixed solution including the catalyst support and a mixed solution containing the catalytically active component, and adding a nitrogen source to prepare a solution containing a catalyst support bonded with the titanium-nitrogen source complex; And
Nitriding at 750 to 800 ° C. to obtain a titanium nitride-loaded carbon nanotube-graphene composite (CNT-graphene composite)
Wherein the polymer electrolyte fuel cell comprises a polymer electrolyte membrane.
The method for producing a positive electrode catalyst of a polymer electrolyte fuel cell according to claim 6, wherein the solvent is ethanol.
7. The method of claim 6, further comprising the step of drying at a temperature of 80 to 120 DEG C for 1 to 4 hours before the step of nitrogen calcining.
7. The method of claim 6, wherein the step of preparing the mixed solution containing the catalyst support comprises sonication.
The method for producing a positive electrode catalyst of a polymer electrolyte fuel cell according to claim 6, wherein the nitrogen source is urea.
7. The method of claim 6, wherein the nitrogen firing is performed for 3 to 5 hours.
The method of claim 6, wherein the carbon nanotubes and the graphene oxide are contained in a weight ratio of 2: 1 to 1: 2.
7. The method of claim 6, wherein the titanium nitride (TiN) is included in an amount of 70 to 80 parts by weight per 100 parts by weight of the total catalyst.
The method of claim 6, wherein the titanium nitride (TiN) is in the form of particles having a particle diameter of 8 nm or less.
7. The method of claim 6, wherein the titanium salt comprises 50 to 70 parts by weight of the final titanium per 100 parts by weight of the total catalyst.
7. The method of claim 6, wherein the nitrogen source is contained in an amount of 4 to 6 times the number of titanium moles.
7. The method of claim 6 wherein the titanium salt is a method for manufacturing a cathode catalyst for a polymer electrolyte fuel cell, which is selected from the group consisting of TiCl ₄ and TiCl _3.

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