KR100594634B1 - Synthesizing Process for Advanced Photocatalytic Titanium Dioxide Composited Nanopowders - Google Patents

Abstract

The present invention relates to a method for producing a high activity photocatalyst-based titanium dioxide composite powder having 2 to 4 times improved photoactivity than conventional catalysts.

The present invention comprises the steps of preparing a metal compound containing a titanyl chloride aqueous solution in which distilled water is added to the titanium tetrachloride stock solution and a metal element substituted with titanium in the titanyl chloride aqueous solution; Mixing the titanyl chloride aqueous solution with a metal compound to obtain a mixed aqueous solution; Precipitating the mixed aqueous solution to obtain a precipitate; Mixing the neutralizing agent with the precipitate to neutralize the reaction to obtain a titanium dioxide-based composite; The titanium dioxide composite is washed, filtered and dried to obtain a titanium dioxide composite powder.

Titanium dioxide, photoactive, catalyst, transition metal element, bandgap energy

Description

Synthesizing Process for Advanced Photocatalytic Titanium Dioxide Composited Nanopowders

1 is an X-ray diffraction test result of titanium dioxide powder loaded with transition metal element, (a) is pure rutile titanium dioxide powder, (b) is zirconium chloride (+4), (c) is nickel chloride (+2) and (d) are copper chloride (+2), (e) is iron chloride (+3), (f) is aluminum chloride (+3), and (g) is niobium chloride (+5). Titanium dioxide powder, wherein R is the characteristic peak of the rutile phase, and A is the characteristic peak of the anatase phase.

2 is a result of photocatalytic decomposition of 4-chloropenol, wherein P-25 is a commercial powder, HPPLT is a powder prepared by low temperature homogeneous precipitation, HPPLT-Ni, Cu, Fe is nickel chloride (+2), copper chloride ( +2) and titanium dioxide powder carrying iron chloride (+3).

3 is a result showing the change in the crystal phase with the precipitation temperature after supporting nickel chloride, where R is the characteristic peak of the rutile phase, A represents the characteristic peak of the anatase phase.

The present invention relates to a method for producing a high active photocatalyst titanium dioxide composite powder, and more particularly, to a method for preparing a high active photocatalyst titanium dioxide composite powder having 2 to 4 times greater photoactivity than a conventional catalyst.

Recently, a study to change environmental pollutants into harmless carbon dioxide (CO ₂ ) and water vapor (H ₂ O) by decomposing environmentally polluted organic materials by using Advanced Oxidation Process (AOP) using photocatalyst as the driving force. Is actively underway.

Photocatalyst is an auxiliary material that can induce chemical reaction by light energy by absorbing sunlight in the wavelength range required to completely decompose environmental pollutants at room temperature, and has high processing efficiency, relatively simple reaction equipment, excellent economic feasibility, and product is environmental This does not cause serious problems.

Therefore, attention has been focused on the use of photocatalysts for the decomposition and treatment of harmful environmental pollutants and the recovery of metal ions and can be effectively used in various industrial fields such as water purification, hydrogen production by water decomposition, wastewater treatment, various deodorization and sterilization Can be.

In addition, high conversion efficiency of more than 10% is obtained for photosensitive solar cells, which are the next generation energy sources. One of them is based on two main reasons, one that absorbs sunlight effectively and the electron injection rate into the semiconductor is very high. It is a photosensitive phenomenon. The other is because the amount of the photosensitizer adsorbed on the surface of the TiO ₂ electrode is made porous.

The maximum photovoltaic power (ΔV) of the solar cell is determined by the difference between the Fermi level of the TiO ₂ semiconductor and the redox potential of the electrolyte. Therefore, it is necessary to increase the generated voltage of the solar cell. In the case of Si cells, this possibility is hardly possible. However, in the photosensitive cell, when the TiO ₂ material is prepared, a complex metal is supported by adding a third metal element, It is also possible to expect the unit voltage increase effect of the battery by changing the Fermi level in the semiconductor by replacing Ti in the TiO ₂ lattice with another metal element.

Accordingly, the present invention has been made in view of the problems of the prior art, and its object is to include zirconium chloride (+4), nickel chloride (+2), copper chloride (+2) and iron chloride (+ 3), titanium chloride nanopowder supported or complexed with a transition metal element by mixing a metal chloride such as aluminum chloride (+3) and niobium chloride (+5) with an aqueous solution of titanyl chloride, and photoactive through the powder The present invention provides a method for producing a highly active photocatalyst-titanium dioxide-based composite powder capable of producing a titanium dioxide-based photocatalyst powder having a rutile phase, a rutile or anatase mixed phase, or an anatase phase improved two to four times more than a conventional powder.

In order to achieve the above object, the present invention comprises the steps of: (a) preparing a metal compound comprising a titanyl chloride aqueous solution in which distilled water is added to the titanium tetrachloride stock solution and a metal element substituted with titanium of the titanyl chloride aqueous solution; (b) mixing the titanyl chloride solution and a metal compound to obtain a mixed solution; (c) precipitating the mixed aqueous solution to obtain a precipitate; (d) neutralizing the mixture by mixing the neutralizing agent with the precipitate to obtain a titanium dioxide-based composite; (e) providing a method for producing a high activity photocatalyst-based titanium dioxide composite powder comprising the step of obtaining a titanium dioxide composite powder by washing and drying the titanium dioxide composite after filtration.

The metal element of the metal compound is a transition metal element and is mixed in the state of chloride, nitride, hydrate, etc. For example, AlCl ₃ , NiCl ₂ , FeCl ₃ , NbCl ₂ , ZrCl ₄ , CuCl _2, and the like are used.

The content of the metal element contained in the titanium dioxide-based composite powder is 0.01 to 2 mol%, and when the content of the metal element is included as described above, the volume ratio of the anatase phase and the rutile phase of the titanium dioxide-based powder is 10/90 to 40 /. It is composed of 60.

When the metal element, that is, the transition metal element is not added, a rutile phase of 100% having a needle-like primary particle is formed at low temperature when prepared by low temperature homogeneous precipitation. The reason for this is that the capillary pressure between the particles is generated during the synthesis process. When the transition metal is added, the phenomenon is suppressed, and spherical anatase phase is formed instead of the rutile acicular particles.

Therefore, when the content of the metal element is increased, the growth of the particles is suppressed due to the influence of heterogeneous metal elements in the nucleation process and the growth process, and as a result, the deformation of the particle shape or the change of the crystal phase may occur.

And, when the content of the metal element exceeds 2 mol%, the form of the synthesized titanium dioxide-based powder is not TiO ₂ -M _x O _x substituted state of Ti _1-x M _x O ₂ (wherein M is a substituted metal ) To form a composite of less than 0.01 mol%, the amount of change in the crystal phase according to the influence of the substituted metal element, that is, the amount that cannot change the phase change characteristics such as anatase or rutile or rutile-anatase mixed phase The ratio was limited to 0.01 to 2 mol%.

In addition, when the content of the added metal element is increased, the formation of the anatase phase is increased, and the overall phase change rate is increased. However, if the content of the additive element continues to increase, and the ratio of the anatase phase to the rutile phase exceeds 40/60, the rutile phase particles having a specific surface area larger than the spherical particles decrease, and the spherical anatase phase particles increase. Therefore, the catalytic activity, which is mainly the surface reaction, is reduced, resulting in a decrease in the photocatalytic efficiency.

The step (c) is preferably treated in an autoclave of Teflon material, it is uniformly precipitated for 2 to 20 hours at a constant temperature within the range of 15 ~ 150 ℃.

At this time, when doping other transition metals except Al, Zr, and Ni in the relatively low temperature range of 50 to 100 ° C, a rutile phase of 100% can be obtained. In this range, the free phase of the anatase and rutile phases is obtained. The change in phase can be controlled by controlling the amount of transition metal.

In the relatively high temperature range of 100 to 150 ° C., even when no transition metal is added, an anatase phase is formed, so that a rutile phase of 100% cannot be obtained, but the amount of the anatase phase and the rutile phase can be adjusted.

The neutralizing agent may be any one of an aqueous ammonia solution or an aqueous sodium hydroxide solution. If the neutralizing agent is 0.1 M or less, a smooth neutralization reaction may not be performed. Preference is given to using neutralizing agents.

The titanyl chloride aqueous solution is prepared by first adding distilled water to titanium tetrachloride to prepare a high concentration titanyl chloride aqueous solution having a concentration of Ti ⁴⁺ ions 1.5 mol or more, and then adding distilled water to the high concentration titanyl chloride aqueous solution to form Ti ⁴⁺ ions. A low concentration of titanyl chloride aqueous solution diluted to 0.2 to 1.2 mol is used.

The washing and filtration steps of step (e) are for removing Cl ⁻ ions and Na ⁺ ions contained in the neutralized precipitate, and it is preferable to use distilled water.

In addition, the drying treatment of the step (e) is preferably dried for 10 to 40 hours at 30 ~ 150 ℃ or less. That is, there is a disadvantage in that the drying takes a lot of time at 30 ℃, there is a problem in that agglomeration is severe at 150 ℃ or more or the phase changes from the anatase phase to the rutile phase. Of course, when evaporated under reduced pressure it is possible to dry even at 30 ℃.

In more detail, the first step is to prepare a stable aqueous solution of titanyl chloride of 1.5M or more by adding ice or ice water frozen in distilled water to titanium tetrachloride stock solution, this step is the applicant's patent No. 277164, 2852105 Already specified in heading 350.226. To explain this in detail, first, distilled iced ice or ice water was added to a high purity titanium tetrachloride solution to prepare titanium tetrachloride yellow and hard as an intermediate step, and then water was further added and dissolved to give a titanium ion concentration of 1.5M or more. Prepared as a stable, transparent aqueous solution of titanylchloride, and stored at room temperature as starting material for the reaction for precipitation thereof.

The titanyl chloride produced by the reaction is considerably more stable with respect to water than titanium tetrachloride, and may be present as a stable storage solution at room temperature if it is stabilized after the reaction is completed and the concentration is 1.5M or more. If the amount of water and titanium tetrachloride is used as the volume fraction (%) to prepare the starting material of the reaction, the vapor pressure increases during the preparation of the aqueous solution of titanyl chloride having a concentration of titanium ions of 1.5 M or more, resulting in a large loss of titanium tetrachloride. Therefore, it is difficult to accurately predict the yield of the final product because the amount of reactant cannot be precisely controlled and the reproducibility of the preparation is poor. Therefore, in the present invention, the amount of water added is less than the quantitative amount to proceed with the reaction to prepare a stable titanyl chloride aqueous solution first, and then by quantitatively analyzing the concentration of titanium ions in the aqueous solution to obtain an accurate starting concentration The calculations were made easy to maintain the reproducibility of the invention.

Distilled water is added to the titanyl chloride solution again to dilute the concentration of the aqueous solution in the range of 0.2 to 1.2 M. Even when the dilution method according to the present invention is used, if the concentration of titanium ions in the aqueous titanyl chloride solution is higher than 1.2 M, it is 100 ° C. or less. Crystallization does not occur at all when reacted for 10 days or more, and if the concentration of titanium ions is less than 0.2M, many nuclei of titanium dioxide precipitates are produced, but the nucleus growth does not proceed within the same reaction time. Since the reaction solution becomes cloudy at 0.05 탆 or less and does not grow larger, the yield obtained through commercial filter paper and centrifuge is 30% or lower, and the yield is lowered.

Therefore, a small amount of a powder or solution in the form of chloride, nitride, or hydroxide, which can supply metal ions, to the titanyl chloride solution diluted in the range of 0.2 to 1.2 M, is sufficiently stirred on a magnetic stirrer.

The metal ions contained in the chloride or nitride, hydroxide, or powder form of the material supplying the metal ions are transition metal elements, and the reason for using the transition metal elements will be described as follows.

TiO ₂ photocatalyst is a semiconducting material, and because band-gap energy is ~ 3.0eV, photo-oxidation, photo-reduction and hydrophilization can be achieved by irradiating light with wavelength below 380nm. Causes a Hydrophilic reaction.

This photocatalytic reaction is an environmentally-friendly purification technology that prevents harmful effects of organic matter (VOCs), removes environmental hormonal decomposition, removes heavy metals in aqueous solutions, removes NO _x , SO _x from air, antibacterial and sterilization, and deodorizes. It is used for functional parts such as function and self-cleaning.

(1) Oxidation and Reduction

Mechanisms of oxidation and reduction reactions caused by photocatalysts form holes (h ⁺ ) and excitation electrons (e ⁻ ) in VB (Valence band) and CB (Conduction band) by light irradiation, respectively. Water and oxygen react to form radicals (OH) and free radicals (O ^2- ), and radicals cause strong oxidation reactions due to their high reactivity, and free radicals cause reduction reactions.

(2) hydrophilization reaction

The mechanism of the surface hydrophilic reaction by light irradiation is that the oxygen deficiency (oxygen vacancy) sites generated by light irradiation, or the water is adsorbed on the surface removed by the photocatalytic decomposition of the adsorbed organic matter appears hydrophilicity.

(3) decomposition of organic pollutants

The strong oxidizing power of the photocatalyst is suitable for decomposing and harming organic pollutants that are difficult to treat by conventional combustion oxidation, ozone oxidation, and fenton oxidation. It can also be used to remove odors.

Organochlorine compounds and phenols (such as trichloroethylene)

Environmental hormones (dioxin, bisphenol, nonylphenol, estradiol, etc.)

Hazardous VOCs (Acetaldehyde, Formaldehyde, Toluene, etc.)

Odor gas (hydrogen sulfide, thiols, amines, etc.)

Other smells that require deodorization (tobacco smell, etc.)

(4) decomposition of air pollutants

Nitrogen oxides (NO _x ) and sulfur oxides (SO _x ), which are emitted from automobile exhaust gas, incinerators and power plants and cause air pollution, are easily recovered and processed in the form of acid through a photooxidation reaction.

(5) Self-Cleaning

Its function is to maintain the clean surface by removing the contamination by itself, and the effect is shown by the decomposition of the pollutants by the floating and photooxidation reactions by the surface hydrophilic reaction of the photocatalyst.

Applicable field: Building exterior materials, road materials, tunnel lighting, outdoor lighting, signage, etc.

(6) antibacterial and antiseptic function

Bacteria and bacteria on the surface can be killed by the strong oxidizing power of the radicals formed by the photocatalytic reaction. This strong oxidizing power decomposes not only antibacterial and sterilization but also debris and toxins of bacteria, and thus shows various and excellent characteristics that other antibacterial agents such as silver (Ag) and copper (Cu) do not have.

Application area: hospital, kitchen and various sanitary equipment

Titanium dioxide (TiO ₂ ) having the photoactive characteristics as described above has a bandgap energy of 3.0 to 3.2 eV, and thus ultraviolet light having a wavelength of 400 nm or less must be irradiated to express photoactive activity.

By the way, sunlight or artificial light contains remarkably many visible rays with a longer wavelength than ultraviolet rays. Therefore, it is necessary to lower the bandgap energy of TiO ₂ in order to utilize light in the visible light wavelength band.

Therefore, a material having a low bandgap energy is required to absorb light in a visible light region having a wavelength longer than that of ultraviolet light and to express photoactivity.

In the present invention, when the Ti site in the lattice in which the cation exists in the structure of the titanium dioxide-based powder is replaced with another metal element, the basic property of the titanium dioxide is changed to transfer the band gap energy to a material that can lower the band gap energy than the band gap of the titanium dioxide. A metal element is used.

Precipitation reaction in the state in which the aqueous titanyl chloride solution and the metal compound containing the transition metal element are mixed as described above results in lowering the bandgap energy because the titanium dioxide is crystallized and the transition metal element is replaced and crystallized at a part of the titanium. Giving results, which has the effect of enhancing photoactivity.

For reference, the powder was synthesized experimentally by the addition of precious metal elements such as Pt or Ag, but the characteristics evaluation resulted in a worse result than the addition of the transition metal element.

In the embodiment of the present invention, chloride was used as a compound capable of supplying a transition metal. In addition, other compounds capable of supplying metal ions capable of substituting a lattice of Ti, ie, nitrides, hydrates, and the like, may be used. Can be.

A metal compound containing a transition metal element having the above characteristics and a titanyl chloride aqueous solution are mixed and maintained at a predetermined temperature within a range of 15 to 150 ° C. for 2 to 20 hours to perform a precipitation reaction.

At this time, it takes some time for the precipitation to occur, which means that there is an activation barrier in the precipitation reaction. Thus, the addition of water provides a source of OH ⁻ ions and maintains at the precipitation temperature, causing precipitation with increasing acidity by crystallization coinciding with hydrolysis while crossing the activation barrier. At this time, the titanium dioxide secondary particles formed by agglomerating the primary particles uniformly according to the difference of the metal elements added are rutile phase having a uniform size distribution as a monodispersion sphere having a size of 0.005 to 0.5 μm as the precipitation reaction temperature is increased. Or a superfine titanium dioxide powder of anatase-rutile mixed phase or anatase phase is produced.

Next, neutralize the precipitate by using an aqueous sodium hydroxide solution or ammonia water.

After neutralization it is filtered and washed with a reduced pressure filter for effective removal of Cl ⁻ and Na ⁺ ions present in the precipitate, followed by drying at a temperature below 150 ° C. At this time, when the drying temperature is high, since photoactivity decreases, a low drying temperature is required.

In order to explain the features of the present invention made as described above, the experiments were performed for each embodiment as described below, and the features thereof were described.

1. First embodiment

The titanium tetrachloride stock solution and distilled water were mixed to obtain an aqueous titanyl chloride solution. In order to lower the heat of reaction resulting from this reaction, an appropriate amount of distilled water is slowly added at a temperature of 0 ° C. or lower so that the titanium concentration is 1.5M or more (preferably 4.7M), followed by stirring to maintain a stable state at room temperature. A titanyl chloride aqueous solution was obtained. Distilled water is added to the high concentration of titanyl chloride solution and diluted with a low concentration of titanyl chloride solution having a concentration of titanium ions of 0.67M.

Then, copper chloride (+2), iron chloride (+3), and niobium chloride (+5), which are metal chlorides having a cation radius similar to that of titanium, were added to 0.01 M, stirred for about 20 minutes, and then stirred at 100 ° C. The reaction vessel was placed in a maintained bath, followed by precipitation for 4 hours, and then neutralized with a neutralizing agent to obtain titanium dioxide powder to which metal ions were added.

At this time, the concentration of the metal element present on the composite titanium dioxide powder was analyzed by inductively coupled plasma, and 0.05 mol% of copper chloride (+2) was supported, 1.33 mol% of iron chloride (+3), When niobium chloride (+5) was loaded, the metal element content of 0.23 mol% was shown.

Monodisperse spheres of the obtained titanium dioxide were observed by transmission electron microscopy, and non-spherical chestnut-shaped particles composed of primary particles of 10 nm or less were observed. As a result of the scanning electron microscopy, the total particle size ranged from 0.2 to 0.4 μm. As a result of X-ray diffraction, rutile crystal phases were obtained ((d), (e), and (g) of FIG. 1).

2. Second Embodiment

To titanium titanate chloride having a concentration of 0.67M prepared in Example 1, 0.01M of zirconium chloride (+4), a metal chloride having a cation radius that is much larger than the titanium ion radius, was stirred for about 20 minutes, and then stirred. The reaction vessel was placed in a bath kept at 0 ° C., followed by precipitation for 4 hours, and then neutralized with a neutralizing agent to obtain titanium dioxide powder to which metal chloride was added.

As in the first embodiment, the concentration of the metal element present on the composite titanium dioxide powder was analyzed by inductively coupled plasma, and the content of 1.47 mol% was indicated when zirconium chloride (+4) was supported. As a result of observing the obtained titanium dioxide by transmission electron microscopy, it had a spherical particle shape of 5 nm or less, and by scanning electron microscopy, it was observed that a large number of spherical particles were agglomerated, X-ray diffraction test, anatase The crystal phase of was obtained (FIG. 1 (b)).

As a result of comparative analysis of the particle shape and the crystal form of the powder obtained and the powder without metal chloride, when the cation radius is much larger than the titanium ion radius, the particle shape and the crystal phase are from the spherical chestnut-shaped rutile to the spherical anatase phase. A phase change occurred.

3. Third embodiment

To the titanyl chloride having a concentration of 0.67M of titanium ions prepared in Example 1, 0.01M of aluminum chloride (+3) and nickel chloride (+2), which are metal chlorides having a cation radius very smaller than that of titanium ions, were added After stirring for about 20 minutes, the reaction vessel was placed in a bath kept at 100 ° C., followed by precipitation for 4 hours, and then neutralized with a neutralizing agent to obtain a titanium dioxide powder to which metal chloride was added.

At this time, the concentration of the metal element present on the composite titanium dioxide powder was analyzed by inductively coupled plasma. As a result, 0.17 mol% when aluminum chloride (+3) was supported and 0.12 mol% when nickel chloride (+2) was supported. The content of is shown. As a result of observing the obtained titanium dioxide with a transmission electron microscope, it was observed that spherical particles were enclosed around the needle shape, and when observed with a scanning electron microscope, the spherical chestnut was slightly distorted. As a result of the X-ray diffraction test, crystals in which the main phase was the anatase phase were obtained (Figs. 1 (c) and (f)).

As a result of comparative analysis of the obtained powder, powder without metal chloride, particle shape and crystalline phase, when the cation radius is very small than the titanium ion radius, the particle shape and crystal phase are non-spherical chestnut-shaped rutile and spherical anatase phase. As a result, the phase change from the rutile phase to the anatase phase was observed.

4. Fourth embodiment

1 mM 4-chloropenol degradation experiment was conducted using the samples prepared in Example 1, 2, and 3. At this time, for uniform surface reaction on the surface of TiO ₂ particles, it is dispersed using ultrasonic waves for about 5 minutes in the dark or dark. It is also stirred using a magnetic bar to maintain dispersibility. In order to measure the concentration of 4-chlorophenol adsorbed just before the photoreaction, the TiO ₂ particles were filtered using a 0.2 μm filter, and the resulting solution was sampled.

Samples were photoreacted using a lamp having a wavelength of 250-400 nm as a light source. At this time, sampling was performed every 30 minutes, and finally, TOC (total organic carbon) measurement was performed. The analyzed TOC results are shown in FIG. 2. As shown in FIG. 2, the nickel-supported powder increased photodegradation efficiency by four times compared to commercial powder P-25.

5. Fifth Embodiment

To prepare a highly active photocatalyst powder, 0.01M of nickel chloride (+2) was added in the same manner as in the first to third embodiments, and the precipitation temperature was changed to 65 ° C, 75 ° C, 85 ° C, 95 ° C and 100 ° C. After observing the crystal properties with the temperature change (Fig. 3). Only the rutile phase crystal phase was observed at a low temperature of 85 ° C. or lower, whereas a mixed phase of the rutile phase and anatase was formed at a temperature of 95 ° C. or higher. This may be explained by the formation of a spherical anatase phase around the rut-shaped bald form particles. The degree of formation of the anatase phase according to the temperature change has a volume ratio of 0 to 40% depending on the integral strength of the main peak of each phase. In addition, as a result of analyzing the content of nickel element using inductively coupled plasma, the content of nickel element increased with increasing precipitation temperature, because the solubility of nickel ion in titanium dioxide increased with temperature.

Table 1 shows the results of the phase change characteristics and the content of metal elements analyzed by inductively coupled plasma according to the kinds of supported elements having different ionic radii and valences.

element Phase Ion radius at balance state (pm) Doping Source (1.47mol%) Crystal phase ICP measurement result (mol%) +2 +3 +4 +5 Ti Rutile 61, 68 none Aspheric - Zr Anatase 72, 79 ZrCl ₂ rectangle 1.47 Ni Rutile 69 NiCl ₂ Aspheric 0.12 Cu Rutile 72 CuCl ₂ Aspheric 0.05 Fe Rutile 64 FeCl ₃ Aspheric 1.33 Al Anatase 51, 53 AlCl ₃ rectangle 0.17 Nb Rutile 64, 69 NbCl ₅ Aspheric 0.23

The present invention made as described above can easily prepare a composite powder of rutile phase or anatase-rutile mixture phase or anatase phase, and can produce high quality photocatalyst powder having high photoactivity due to the metal element used as the composite raw material. .

In the above, the present invention has been illustrated and described with reference to specific preferred embodiments, but the present invention is not limited to the above-described embodiments and the general knowledge in the technical field to which the present invention pertains without departing from the spirit of the present invention. Various changes and modifications will be made by those who possess.

Claims (8)

(a) a titanyl chloride solution in which distilled water is added to the titanium tetrachloride stock solution, and at least one chloride, nitride, or hydrate selected from Ni, Cu, Fe, Nb, Zr, and Al substituted with titanium in the titanyl chloride solution; Preparing a metal compound comprising; (b1) a metal compound containing at least one chloride, nitride, or hydrate selected from Cu, Fe, and Nb having a relatively small ionic radius difference with titanium to obtain a rutile and anatase mixed phase titanium dioxide powder mainly composed of a rutile phase; Mixing the titanyl chloride aqueous solution, (b2) a metal compound containing at least one chloride, nitride, or hydrate selected from Zr, Al, and Ni having a relatively large difference in ionic radius from titanium, in order to obtain a titanium dioxide powder of rutile and anatase mixed phase mainly composed of an anatase phase; Obtaining a mixed aqueous solution through any one of mixing the aqueous titanyl chloride solution; (c) precipitating the mixed aqueous solution to obtain a precipitate; (d) neutralizing the mixture by mixing a neutralizing agent with the precipitate to obtain a titanium dioxide-based composite; (e) washing the titanium dioxide-based composite and drying it after filtration to obtain a titanium dioxide-based composite powder; Method for producing a high activity photocatalyst titanium dioxide composite powder comprising a. delete delete The method of claim 1, wherein the metal compound is at least one selected from AlCl ₃ , NiCl ₂ , FeCl ₃ , NbCl ₂ , ZrCl ₄ , and CuCl ₂ . The method of producing a high active photocatalyst titanium dioxide composite powder according to claim 1, wherein the content of the metal element contained in the titanium dioxide composite powder is 0.01 to 2 mol%. The method of claim 1, wherein the step (c) is performed at a temperature in the range of 15 to 150 ° C. The method according to claim 1, wherein the neutralizing agent is any one of 0.1 to 0.7 M aqueous ammonia or sodium hydroxide solution. The method of claim 1, wherein the washing of the step (e) is performed using distilled water.

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