Oxide photocatalytic material using organometallic compound and its application article

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to an oxide photocatalyst material capable of obtaining a particularly highly active photocatalytic function in an oxide photocatalyst, and an applied product thereof.

【0002】

[Conventional technology]

It has been conventionally known that an oxide photocatalyst represented by titanium oxide exhibits a photocatalytic function by photoexcitation when irradiated with light having a wavelength having an energy equal to or higher than the band gap. The mechanism of its expression is that electrons are generated in the conduction band by photoexcitation and holes are generated in the valence band. Due to the strong reducing action of electrons and the strong oxidizing action of holes, organic substances and nitrogen that come into contact with the photocatalyst It decomposes oxides into water, carbon dioxide, etc., and has antifouling, deodorant, antibacterial functions, and the like.

【0003】

Environmental purification methods and devices that utilize such antifouling, deodorant, and antibacterial functions of oxide photocatalysts are currently attracting attention. In other words, it is caused by the recent problems of environmental pollution such as water pollution and air pollution. Under such circumstances, in order to improve the performance and efficiency of the environmental purification method, it is required to highly activate the photocatalytic function of the oxide photocatalyst itself.

【0004】

Conventionally, the oxide photocatalyst material is usually used in the form of powder, which is very difficult to handle and difficult to incorporate into an environmental purification device. In order to immobilize the powdered oxide photocatalyst, it is conceivable to mix the powdered oxide photocatalyst with an organic binder, apply it on the substrate, and fix it at room temperature or by heating. In the method, since the organic substance covers a part or most of the surface of the oxide photocatalyst, the photocatalyst function has a drawback that it is significantly inactivated as compared with the powder itself. Further, since the organic matter is decomposed by the photocatalytic function, the film strength deteriorates and the powder gradually falls off, which is another big problem related to durability. The photocatalyst function is exhibited only when the photocatalyst is exposed on the surface, and when the powdery oxide photocatalyst is immobilized with an inorganic binder, the drawback of powder falling off is overcome, but the oxide photocatalyst Since the binder covers a part of the surface, the area of the surface effective for the photocatalytic function is reduced, and the problem that the photocatalytic function is significantly reduced cannot be improved.

【0005】

As a solution to the above-mentioned problems of the powdered oxide photocatalyst, the vacuum deposition method disclosed in JP-A-8-266910, JP-A-9-192498, etc., JP-A-8-309204, JP-A-8-309204, JP-A. The sputtering method disclosed in JP-A-11-12720, the sol-gel method disclosed in JP-A-7-100378, JP-A-10-180118, etc. have been proposed. Although these prior arts have solved the above-mentioned problems of powdered oxides and obtained good photocatalytic functions, they are not satisfactory in terms of high activation.

【0006】

Further, as described above, the photocatalytic function occurs on the surface of the photocatalyst body irradiated with light. Therefore, a technique for controlling the surface state of the photocatalyst for the purpose of highly activating the photocatalyst function or a technique for controlling the crystals on the surface layer of the photocatalyst has been conventionally known. JP-A-9-57912, JP-A-10-36144, JP-A-10-57817, JP-A-10-231146 and the like are disclosed as techniques for controlling the surface state of the photocatalyst. The basic configuration disclosed in these prior arts is that a titanium oxide layer as a photocatalyst is formed directly on the surface of a glass substrate or via an alkali blocking base film, and silicon oxide is formed on the surface of the titanium oxide layer. Is.

【0007】

These prior arts are devised to enhance the photocatalytic function by forming a silicon oxide film porously or by finely processing a titanium oxide film or a glass substrate to provide irregularities on the surface. That is, by forming fine irregularities on the surface, the area of the surface on which the photocatalyst body is exposed is increased and the photocatalyst function is improved, but the photocatalyst function is not necessarily significantly improved. In addition, there are problems in terms of cost such as substrate processing, film processing, and insertion of a base layer.

【0008】

Japanese Unexamined Patent Publication No. 2000-288403 is disclosed as a technique for controlling crystals constituting the surface layer of a photocatalyst. The basic configuration disclosed in this prior art is that titanium oxide is anatase-type crystals, and 30% or more of the titanium oxide crystal grains present on the surface layer thereof have an elliptical or semi-elliptical shape. It is characterized by being a shape. Then, a highly active photocatalytic function can be obtained by forming elliptical or semi-elliptical titanium oxide crystals. This means that by making the crystal grains elliptical or semi-elliptical, the area of the exposed surface of the photocatalyst body is increased and the photocatalyst function is improved, but the photocatalyst function is not necessarily significantly improved.

【0009】

[Problems to be Solved by the Invention]

In the above-mentioned prior art, the oxide photocatalyst formed by various production methods and the oxide photocatalyst formed by controlling the surface state of the photocatalyst and the crystals constituting the surface layer portion of the photocatalyst are good. Although it shows a photocatalytic function, an oxide photocatalyst having a more highly active photocatalytic function is required.

【0010】

In view of such conventional circumstances, the inventors of the present application have focused on high activation of the oxide photocatalyst by controlling the crystal shape, various production methods such as CVD method and PVD method, and a sol-gel method using an organometallic compound. The preparation of the oxide photocatalyst was studied diligently. As a result, the crystal nuclei prepared by various manufacturing methods such as the CVD method or the PVD method are put into a sol solution composed of an organic metal compound, or the sol solution is applied to the crystal nuclei and solidified and heat-treated to obtain the titanium oxide crystal. It has been found that a highly active photocatalytic function can be obtained by forming a columnar crystal in the crystal shape of the titanium oxide crystal grown from the crystal nuclei by growing from the crystal nuclei, and completed the present invention.

【0011】

[Means for solving problems]

That is, as described in claim 1, the shape of the titanium oxide crystal grown from the crystal nuclei on the substrate forms a columnar shape, and at least one or more of the columnar crystals are grown from the crystal nuclei to form a photocatalytic thin film. The gist is that.

【0012】

Hereinafter, the present invention will be specifically described. The oxide photocatalyst material of the present invention is prepared by producing an oxide photocatalyst by various manufacturing methods such as a CVD method and a PVD method, and a sol-gel method using an organic metal compound, and a CVD method is used in a sol solution of the organic metal compound. , PVD method and other manufacturing methods are used to insert the produced crystal nuclei, or a sol solution of an organic metal compound is applied to the crystal nuclei, and the titanium oxide crystals are grown from the crystal nuclei by solidification and heat treatment. To do. Here, the solidification may be simply heat-dried, other heat components may be added, or water may be added to gel.

【0013】

In the oxide photocatalyst of the present invention, the crystal nuclei to be put into the sol solution or the crystal nuclei to which the sol solution is applied are powder, single crystal, polycrystal, ceramics, crystallized glass, thermal oxide film of metal, and anodization. Any of the membranes may be used. Further, as the crystal nucleus, a crystal film prepared by the CVD method or the PVD method may be used. Further, the crystal nuclei for growing these titanium oxide crystals are preferably 1 nm to 350 nm in size regardless of the type of the crystal nucleation material.

【0014】

As described above, the present invention is characterized in that titanium oxide crystals are grown from crystal nuclei by solidifying and heat-treating a sol solution composed of an organometallic compound. The shape of the titanium oxide crystal grown from the crystal nuclei is columnar, and at least one or more columnar crystals are grown on the crystal nuclei, and the crystal nuclei and the columnar crystals grown on the crystal nuclei grow in the same direction. It is characterized by that. In the present invention, the shape of the titanium oxide crystal is columnar, including prismatic, columnar, rod-shaped, etc., and the columnar crystal extends straight in the vertical direction, extends in an inclined manner, or extends while curving. Includes those that branch into branches and extend, those in which a plurality of columnar crystals are fused during growth, and the like.

【0015】

In the oxide photocatalyst, the crystal nuclei prepared by various manufacturing methods such as CVD method and PVD method are put in the above crystal shape, that is, the sol solution of the organic metal compound, or the sol solution is applied to the crystal nuclei to solidify and heat-treat. By growing the titanium oxide crystal forming a columnar crystal from the crystal nucleus, the photocatalytic function can be highly activated.

【0016】

Further, various applied products exhibiting a cleaning function, an antibacterial function, a deodorizing function, an antifouling function and the like can be provided by using the oxide photocatalyst material according to the present invention. Specific examples of the applied products include various products such as various air-conditioning devices such as air purifiers, deodorizers and air conditioners, and environmental purification devices such as water purifiers and water purification devices.

【0017】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in more detail with reference to the drawings. FIGS. 1 (a) and 1 (b) show schematic views of an example of an embodiment of the oxide photocatalyst material according to the present invention. FIG. 1 (a) shows a titanium oxide crystal (columnar column) when a crystal film prepared by the CVD method or the PVD method is used as the crystal nuclei 2 on various substrates 1 such as glass, metal, or fibers having a network structure. Crystal) 3 growth schematic, FIG. 1 (b) is a growth schematic of titanium oxide crystal (columnar crystal) 3 when a powder is used as the crystal nucleus 2'. FIG. 2 shows an electron micrograph of an example of the embodiment of the oxide photocatalyst according to the present invention. As described above, the oxide photocatalyst material according to the present invention focuses on high activation of the oxide photocatalyst by controlling the crystal shape in order to solve the technical problem of producing an oxide photocatalyst exhibiting a highly active photocatalyst function. Then, we focused on the production of oxide photocatalysts by various manufacturing methods such as CVD method and PVD method and sol-gel method using organic metal compounds, and as a result, put crystal nuclei in the sol solution of organic metal compounds, or crystal nuclei. A sol solution is applied to the photocatalyst, solidified, and heat-treated to grow titanium oxide crystals having columnar crystal shapes from the crystal nuclei, thereby achieving high activation of the photocatalytic function.

【0018】

As shown in FIGS. 1 (a) and 1 (b), the oxide photocatalyst of the present invention grows at least one or more columnar titanium oxide crystals (columnar crystals) 3 from the crystal nuclei 2 on the substrate 1. It is a feature. In addition, it can be clearly confirmed from the electron micrograph of FIG. 2 that columnar titanium oxide crystals are formed. As can be seen here, the columnar crystal includes a crystal shape such as a prism or a columnar crystal shape, a branched dendritic crystal shape, and a shape in which a plurality of columnar crystals are fused during growth.

【0019】

The titanium oxide crystal 3 grown from the crystal nucleus 2 is prepared by a sol solution composed of an organometallic compound. Normally, when a sol solution composed of an organometallic compound is applied onto a substrate and solidified and heat-treated in the absence of a substance to be a crystal nucleus, the titanium oxide crystals formed are granular. On the other hand, the oxide photocatalyst of the present invention forms a peculiar crystal shape, that is, a columnar crystal, which grows in the longitudinal direction with respect to the substrate 1. When crystallized in the solidification process of the sol solution in the titanium oxide crystal preparation method, columnar crystals are already formed at that time, and the residual organic matter evaporates in the subsequent heat treatment process and the crystal shape resembles that before the heat treatment. It has been confirmed that columnar titanium oxide crystals 3 are formed. In addition, columnar titanium oxide crystals are also formed when the sol solution is gelled in the solidification process, heat-treated, and dissipated from organic substances, but its photocatalytic function is not very good. Therefore, it is desirable to crystallize the sol solution during the solidification process. It is not clear why the crystal shape that grows from the crystal nucleus is columnar, but in the process of growing a titanium oxide crystal, a seed crystal that promotes crystal growth, that is, a titanium oxide crystal in which the presence or absence of a core crystal is formed. It is clear that it has a great effect on the shape. From this, it is also observed that the titanium oxide crystal 3 formed on the crystal nuclei 2 grows in almost the same direction as the orientation of the crystal nuclei 2. However, it has been confirmed that some of them grow in a direction different from that of the crystal nuclei, although the frequency is low.

【0020】

As described above, the photocatalytic function occurs on the surface of the photocatalyst. The columnar crystals 3 obtained in the present invention are present innumerably on the surface of the oxide photocatalyst material A, and most of them are formed in the longitudinal direction with respect to the substrate 1 as shown in FIG. 1 (a), so that they are granular crystals. It is clear that the exposed area of the photocatalyst surface, which contributes to the photocatalytic function, increases. For this reason, it is considered that the photocatalytic function is highly activated. It is also known that if a large number of columnar crystals grown in the lateral direction are present in the substrate 1 for the same reason, the photocatalytic function is reduced at that rate.

【0021】

As described above, the crystal nuclei 2 for growing the titanium oxide crystal 3 have a great influence on forming a peculiar crystal shape. The type of the crystal nuclei 2 may be a single crystal, a polycrystal, a powder, a ceramic, a thermal oxide film of a metal, or an anodized film. Even when the crystal nuclei listed here are placed in a sol solution of an organometallic compound, or a sol solution of an organometallic compound is applied to the crystal nuclei and solidified or heat-treated, titanium oxide crystals forming columnar crystals can be obtained from the crystal nuclei. It has been proven that it can be done.

【0022】

Further, even if a crystal film, that is, a crystal nucleus is formed on the substrate 1 by a CVD method or a PVD method and a titanium oxide crystal is grown by the same method as described above, a titanium oxide crystal forming a columnar crystal can be obtained from the crystal nucleus. Has been proven.

【0023】

The size of the crystal nuclei 2 for growing the titanium oxide crystal 3 should be limited to 1 nm to 350 nm for the following reasons. That is, if the crystal nuclei are smaller than 1 nm, it is considered that the titanium oxide crystal that grows on the crystal nuclei grows without being affected by the miniaturization of the crystal nuclei. Even if the crystal nuclei become larger than 350 nm, the same thing can be considered due to the coarsening of the crystal nuclei. That is, it can be said that the size of the crystal nucleus effective for the titanium oxide crystal to form a columnar crystal is 1 nm to 350 nm.

【0024】

By solidifying and heat-treating the crystal shape as described above, that is, the sol solution of the organometallic compound to form columnar crystals from the crystal nuclei, an oxide photocatalyst exhibiting a highly active photocatalytic function can be obtained. It has been confirmed that the oxide photocatalyst material of the present invention can decompose odorous components and harmful components by incorporating it into a housing together with an ultraviolet light source and circulating air, and can efficiently purify the air. In addition, it has been confirmed by experiments that it can be applied to environmental purification equipment for the purpose of water purification, deodorization, antibacterial, and sterilization.

【0025】

[Example]

Hereinafter, examples will be described. Non-alkali glass that has been washed with a neutral detergent, isopropyl alcohol, or pure water is used as the substrate 1, and on the surface of the substrate 1, crystal nuclei are placed in a sol solution composed of an organic metal compound, or organic metals are placed in the crystal nuclei. A titanium oxide crystal 3 was formed on the crystal nuclei 2 by applying a sol solution composed of a compound, solidifying and heat-treating.

【0026】

As a method for preparing a sol solution composed of an organometallic compound, butanediol: 45 g, H₂O: 0.6 g and nitric acid: 0.4 g were mixed, and 5 g of titanium tetraisopropoxide (hereinafter referred to as TTIP) was added dropwise to this solution with stirring, and then the mixture was stirred at room temperature for 4 hours.

【0027】

The crystal nuclei prepared by various preparation methods are put into the sol solution thus obtained, or the sol solution obtained as described above is applied to the crystal nuclei prepared by various preparation methods, and solidified and heat-treated. As a result, titanium oxide crystals were formed on the crystal nuclei. The solidification was carried out in a dryer under the conditions of reaching temperature of 150 ° C. and holding time of 2 hours. The heat treatment was performed in an electric furnace under the conditions of a heating rate of 10 ° C / min, an ultimate temperature of 550 ° C, and a holding time of 2 hours.

【0028】

Using the oxide photocatalyst material thus obtained as a sample, a decomposition test of acetaldehyde, which is a harmful substance, was carried out as an evaluation of the photocatalytic function. In the test method, the prepared oxide photocatalyst material is first placed in a 20-liter glass container, the inside of the container is replaced with artificial air, and then acetaldehyde gas is injected into the container so as to be 20 ppm. Next, the oxide photocatalyst was irradiated with black light, and the time until the acetaldehyde concentration became 1 ppm or less was measured with a gas monitor.

【0029】

In addition, the crystal structure analysis of the oxide photocatalyst in the above sample was performed by X-ray diffraction. The surface of the oxide photocatalyst was observed with a scanning electron microscope (SEM). Table 1 shows the experimental conditions in Examples and Comparative Examples.

【0030】

[table 1]

<img file="JP2002253975A_D0001.tif" />【0031】

In Example 1, titanium oxide powder was used as the crystal nuclei. The crystal nuclei were placed in the sol solution prepared as described above, or the sol solution was applied to the crystal nuclei to grow titanium oxide crystals as described above. As a method for adjusting the titanium oxide powder, a solution of TTIP: 7 g (0.025 mol) in 50 ml of 1-propanol is slowly added dropwise to distilled water at room temperature while stirring, and after the addition, the mixture is stirred for 1 hour and suction filtered. It was dried at 110 ° C for a whole day and night. The dried product was crushed in a mortar and heat-treated in an electric furnace at 600 ° C. for 2 hours.

【0032】

In Example 2, a titanium oxide crystal film produced by a sputtering method was used as a crystal nucleus, and a sol solution was applied onto the crystal film to grow titanium oxide crystals. The conditions for producing a crystal film by the sputtering method are metallic titanium with a target purity of 99.995% or more, applied power of 1500 W, sputtering pressure of 10.0 Pa, argon and oxygen flow rate ratio of 20 sccm to 20 sccm, substrate temperature of 200 to 300 ° C, and film formation. The time is 3 hours. It was confirmed by surface observation that the crystal film obtained by such a sputtering method was composed of crystals having a size of 10 nm to 60 nm.

【0033】

In Example 3, a titanium oxide crystal film prepared by a spray pyrolysis method was used as a crystal nucleus, and a sol solution was applied on the crystal film to grow titanium oxide crystals. As a method for producing a titanium oxide crystal film by the spray pyrolysis method, the raw material solution is prepared by adding acetylacetone (Hacac) to titanium tetraisopropoxide (TTIP) at a mol ratio (Hacac / TTIP) of 1.0 and diluting with isopropyl alcohol. Stirred. The film forming conditions were a spray pressure of 0.3 Mpa, a spray amount of 1.0 ml / sec, a spray time of 0.5 min / time, a substrate temperature of 450 ° C, and a spray count of 200 times. It was confirmed by surface observation that the titanium oxide crystal film produced by the spray pyrolysis method was composed of crystals having a size of 30 nm to 100 nm.

【0034】

In Comparative Example 1, a sol solution was applied onto a glass substrate without crystal nuclei to prepare titanium oxide crystals.

【0035】

In Comparative Example 2, a titanium oxide crystal film was produced by a sputtering method, and a sol solution was not supported after the production. The conditions for producing a crystal film by the sputtering method are metallic titanium with a target purity of 99.995% or more, applied power of 1500 W, sputtering pressure of 10.0 Pa, argon and oxygen flow rate ratio of 20 sccm to 20 sccm, substrate temperature of 200 to 300 ° C, and film formation. The time is 3 hours.

【0036】

In Comparative Example 3, a titanium oxide crystal film was prepared by a spray pyrolysis method, and a sol solution was not supported after the preparation. As a method for producing a titanium oxide crystal film by the spray pyrolysis method, the raw material solution is prepared by adding acetylacetone (Hacac) to titanium tetraisopropoxide (TTIP) at a mol ratio (Hacac / TTIP) of 1.0 and diluting with isopropyl alcohol. Stirred. The film forming conditions were a spray pressure of 0.3 Mpa, a spray amount of 1.0 ml / sec, a spray time of 0.5 min / time, a substrate temperature of 450 ° C, and a spray count of 200 times.

【0037】

Table 2 shows the experimental results in these examples and comparative examples.

【0038】

[Table 2]

<img file="JP2002253975A_D0002.tif" />【0039】

The following can be seen from the results in Table 2. In Comparative Example 1 in which a sol solution was applied onto a glass substrate without crystal nuclei to prepare a titanium oxide crystal, the crystal structure had an anatase type effective for photocatalytic function, and the decomposition time of acetaldehyde was 60 min. It showed relatively good photocatalytic function.

【0040】

In Comparative Example 2 in which a titanium oxide crystal film is prepared by a sputtering method and a sol solution is not supported after the preparation, the crystal structure has an anatase type effective for photocatalytic function, and the decomposition time of acetaldehyde is relatively good at 45 min. It showed a photocatalytic function.

【0041】

In Comparative Example 3 in which the titanium oxide crystal film was prepared by the spray pyrolysis method and the sol solution was not supported after the preparation, the crystal structure had an anatase type effective for the photocatalytic function, but the decomposition time of acetaldehyde was 180 min. It cannot be said that the photocatalytic function is good.

【0042】

On the other hand, in Examples 1 to 3, a sol solution was supported by using titanium oxide powder, a crystal film by a sputtering method, and a crystal film by a spray pyrolysis method as crystal nuclei, respectively. In Examples 1 to 3, columnar crystals are formed from the crystal nuclei, and the photocatalytic function also shows a remarkable improvement as compared with Comparative Examples 1 to 3. The details of the experimental results of Examples 1 to 3 are described below.

【0043】

In Example 1, a crystal nuclei made of titanium oxide powder was placed in a sol solution, coated on a substrate, solidified, and heat-treated to grow titanium oxide crystals from the crystal nuclei. The crystal structure has an anatase type that is effective for the photocatalytic function, and from the surface observation results, it was confirmed that columnar crystals were growing from the crystal nuclei. The decomposition time of acetaldehyde was 16 min, and it showed a very high photocatalytic function.

【0044】

In Example 2, a titanium oxide crystal film produced by a sputtering method was used as the crystal nuclei, and a sol solution was applied to the crystal film, and the crystal nuclei were solidified and heat-treated to grow titanium oxide crystals from the crystal nuclei. It is a sol. The crystal structure has an anatase type that is effective for photocatalytic function, and it was confirmed from the surface observation results that columnar crystals were growing from the crystal nuclei. The decomposition time of acetaldehyde was 15 min, and it showed a very high photocatalytic function.

【0045】

In Example 3, a titanium oxide crystal film produced by a spray pyrolysis method was used as the crystal nuclei, and a sol solution was applied to the crystal film, and the crystal nuclei were solidified and heat-treated to obtain titanium oxide crystals from the crystal nuclei. It is a grown product. The crystal structure has an anatase type that is effective for the photocatalytic function, and from the surface observation results, it was confirmed that columnar crystals were growing from the crystal nuclei. The decomposition time of acetaldehyde was 16 min, and it showed a very high photocatalytic function.

【0046】

From the above Examples 1 to 3, it was confirmed that it is effective that the oxide photocatalyst crystal is composed of columnar crystals in order to exhibit the highly active photocatalyst function. It was also confirmed that the columnar crystals were formed by supporting a sol solution of an organometallic compound on the crystal nuclei, solidifying and heat-treating. In Examples 1 to 3, titanium oxide powder, a crystal film by a sputtering method, and a crystal film by a spray thermal decomposition method are given as examples as crystal nuclei, but other crystal nuclei include single crystals and polycrystals. It has been confirmed by experiments that columnar crystals are formed from the crystal nuclei and exhibit a highly active photocatalytic function even when ceramics, a thermal oxide film of metal, an anodized film, or crystallized glass is used. Further, in Examples 1 to 3 above, non-alkali glass was given as an example as a substrate used for forming crystal nuclei and supporting a sol solution, but other substrates include woven cloth, sponge-like object, or chemical. It has been confirmed by experiments that the same result can be obtained even when an object made porous by corrosion, machining, etc. is used as a substrate.

【0047】

[Effect of the invention]

As described above, the oxide photocatalyst of the present invention is characterized in that the crystal shape of the titanium oxide crystal grown from the crystal nucleus forms a columnar shape, and the oxide photocatalyst thin film is formed of the columnar crystal to form a highly active oxide photocatalyst. A photocatalytic function can be obtained. Further, according to the oxide photocatalyst of the present invention, the odorous component and the harmful component can be decomposed and the air can be efficiently purified by incorporating it into the housing together with the ultraviolet light source and circulating the air. Further, since the oxide photocatalyst of the present invention is an aggregate of columnar crystals, it has a great effect of capturing fine particles and bacteria. Further, in the oxide photocatalyst material according to the present invention, the above-mentioned large-scale allergy is obtained by forming holes and grooves having the same size as those of a large-scale allergen such as pollen on a substrate serving as a base material for forming crystal nuclei. It has many effects, such as being able to improve the effect of capturing substances. Further, the oxide photocatalyst material according to the present invention has remarkable effects in cleaning function, antibacterial function, deodorizing function, antifouling function and the like as described above, and various air conditioning devices such as air purifiers, deodorizers and air conditioners. Alternatively, it can be applied to environmental purification devices such as water purifiers and water purification equipment.

[Simple explanation of drawings]

[Figure 1]

In the schematic diagram of the oxide photocatalyst material according to the present invention, (a) is an example in which a crystal film prepared by a CVD method or a PVD method is used as a crystal nucleus, and (b) is an example in which powder is used as a crystal nucleus. Shown.

[Figure 2]

An electron micrograph of an example of an oxide photocatalytic material according to the present invention.

[Explanation of symbols]

A: Oxide photocatalytic material 1: Board 2: Crystal nuclei 3: Titanium oxide crystal (columnar crystal)