JP2003190810A - Photocatalytic material and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an oxide photocatalytic material having a high activity photocatalytic function. <P>SOLUTION: In the photocatalytic material 10, in the basic constitution of a columnar hollow crystal comprising a base 2 for fixation on the surface of a photocatalytic material carrier 1 and a photocatalyst crystal body 3 which elongates from the base 2 and has a hollow columnar structure, an internal exposure structure 8 is disposed which runs to the hollow interior 5 of the photocatalyst crystal body 3 and has a function to expose an aggregate structure of photocatalyst particles 6 present in the hollow interior 5 because a part of a surface of 4 the crystal body 3 is removed or an outer wall part 4 is formed at low density. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocatalyst material and a method for producing the same, and more particularly to an oxide photocatalyst having an unusual crystal shape and capable of obtaining a highly active photocatalytic function and the production thereof. Regarding the method.

[0002]

2. Description of the Related Art It is conventionally known that an oxide photocatalyst typified by titanium oxide exhibits a photocatalytic function by photoexcitation when irradiated with light having a wavelength having an energy larger than its band gap. The expression mechanism of the photocatalytic function is
This is because photoexcitation produces electrons in the conduction band and holes in the valence band. Due to the strong reducing power of electrons and the strong oxidizing power of holes, it decomposes organic substances and nitrogen oxides that come into contact with the photocatalyst into water and carbon dioxide, and has antifouling, deodorizing, and antibacterial functions. There is.

At present, an environmental purification method and apparatus utilizing the antifouling, deodorizing, and antibacterial functions of such oxide photocatalysts are drawing attention. That is, it is caused by recent environmental pollution problems such as water pollution and air pollution. In this situation,
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.

Since the oxide photocatalyst material is usually used in the form of powder, it is very difficult to handle, and it has been difficult to incorporate it into an environmental purification device. In order to fix the powdery oxide photocatalyst, there is a method in which the powdery oxide photocatalyst is mixed with an organic binder and applied onto a base material, and the mixture is fixed at room temperature or by heating. However, this method has a drawback that the photocatalytic function is significantly inactivated as compared with the powder itself because the organic material covers a part or most of the surface of the oxide photocatalyst. Furthermore, since the organic binder, which is an organic substance, is decomposed by the photocatalytic function,
There is another major problem related to durability, in which the film strength deteriorates and the powder gradually falls off. The photocatalytic function exhibits its function only when the photocatalyst is exposed on the surface. When the powdered oxide photocatalyst was fixed with an inorganic binder, the disadvantage of powder falling off was overcome,
Since the binder covers a part of the oxide photocatalyst, the surface area effective for manifesting the photocatalytic function is reduced, and the problem that the photocatalytic function is significantly deteriorated cannot be solved.

In order to solve the above problems of the powdery oxide photocatalyst, many techniques for producing an oxide photocatalyst have been proposed so far. As its manufacturing technique, Japanese Patent Application Laid-Open No. 8-26
6910, vacuum deposition methods disclosed in JP-A-9-192498, JP-A-8-309204, JP-A-11-127.
20 etc., the sputtering method disclosed in JP-A-7-10
0378, and the sol-gel method disclosed in JP-A-10-180118. Attempts have been made to solve the problems of the above-mentioned powdery oxides by these prior arts, and the photocatalytic function has been improved, but from the viewpoint of high activation,
We haven't been able to get anything satisfactory yet.

As described above, the photocatalytic function occurs on the surface of the photocatalyst which is irradiated with light. Therefore, a technique for controlling the surface state of the photocatalyst body or a technique for controlling the crystal of the surface layer of the photocatalyst body has been proposed in order to highly activate the photocatalyst function. As a technique for controlling the surface condition of the photocatalyst body, JP-A-9-57912 and JP-A-10-
JP-A-36144, JP-A-10-57817 and JP-A-10-231146 are disclosed.
The basic configuration disclosed in these prior arts is one in which a titanium oxide layer as a photocatalyst is formed directly on the surface of a glass substrate or through an alkali blocking base film, and silicon oxide is formed on the surface of this titanium oxide layer. Is.

Each of the above-mentioned prior arts is devised to enhance the photocatalytic function by forming a silicon oxide film in a porous manner or by finely processing a titanium oxide film or a glass substrate to form irregularities on the surface. ing.

That is, the photocatalytic function is improved by increasing the area of the surface where the photocatalyst is exposed by forming fine irregularities on the surface, but not necessarily a remarkable improvement. In addition, substrate processing, film processing,
There is also a problem in terms of cost, such as insertion of a base layer.

Japanese Unexamined Patent Publication No. 2000-288403 has been disclosed as a technique for controlling crystals constituting the surface layer of the 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 in the surface layer have an elliptical or semi-elliptical shape. It is characterized by being a shape. By forming an elliptic or semi-elliptical titanium oxide crystal, a highly active photocatalytic function can be obtained. This is because the area of the exposed surface of the photocatalyst increases and the photocatalytic function is improved by making the crystal grains elliptical or semi-elliptical, but the marked improvement is not necessarily seen.

[0010]

In the above-mentioned prior art, the oxide photocatalyst formed by various manufacturing methods,
The oxide photocatalyst formed by controlling the surface state of the photocatalyst and controlling the crystals that make up the surface layer of the photocatalyst has a certain level of improvement in the photocatalytic function, but a more highly active photocatalytic function. There is a need for oxide photocatalysts having

With respect to the above-mentioned problems, the inventors of the present application focus on the high activation of the oxide photocatalyst by controlling the crystal shape, and use the CVD method (chemical vapor deposition method) and the PVD method (physical vapor deposition method). Etc., and the preparation of an oxide photocatalyst by a sol-gel method using an organic metal compound or an inorganic metal compound. As a result, the crystal nuclei produced by various manufacturing methods such as the CVD method or the PVD method are put in a sol solution composed of an organometallic compound or an inorganic metal compound, or the sol solution is applied to the crystal nuclei, solidified, and heat-treated, A method of growing a titanium oxide crystal from the crystal nucleus was found. The crystal shape of the titanium oxide crystal grown from the crystal nuclei forms a columnar crystal, and the inside of the crystal forms a hollow structure to form a columnar hollow structure crystal (hereinafter, also referred to as “columnar hollow crystal”). Therefore, it was found that a highly active photocatalytic function can be obtained. Based on this discovery, a new photocatalyst material was invented and developed, and unknown patent applications (Japanese Patent Application Nos. 2001-058917 and 2001-0).
58918).

FIG. 10 is a schematic view showing the appearance of a photocatalyst material made of titanium oxide crystals having such a columnar hollow structure already developed. In the figure, a photocatalyst material 60 already developed has a base 52 for being fixed on the surface of the photocatalyst material carrier 51.
And a photocatalyst crystal body 53 having a columnar hollow structure which is a hollow columnar structure extending from the base 52, and is mainly composed of, for example, various kinds of glass, metal, ceramics or fibers having a mesh structure. It has a structure in which a columnar hollow titanium oxide crystal 53 is grown from a base 52 such as a crystal nucleus, which is carried on a photocatalyst material carrier 51 such as a substrate. Here, the columnar crystal is a general term including all crystal shapes such as a prism and a column, a branched dendritic crystal shape, and a shape in which a plurality of columnar crystals are fused during the growth.

Since the obtained photocatalytic material is fixed to the base material which is a carrier, it has the characteristics that it does not have the problem of scattering unlike powdered photocatalysts and that it is extremely highly active. Therefore, its practical application is very effective for applications such as incorporation in an air purification system. However, in order to further enhance the photocatalyst technology and further expand and develop its application field, it is extremely effective and fundamentally necessary to further activate the photocatalyst function.

[Means for Solving the Problems]

In view of such a situation, the inventors of the present application have made earnest studies on the enhancement of the photocatalytic function by controlling the structure of the columnar hollow crystals for the purpose of further enhancing the photocatalytic function of the columnar hollow titanium oxide crystals. As a result, by exposing the inside of the hollow structure to the outside by a method such as partially removing the outer wall of the columnar hollow crystal, the surface area contributing to the photocatalytic function is increased, and the highly active photocatalytic function is improved. They have found that they can be obtained and have completed the present invention. That is, the invention claimed in the present application is as follows.

(1) A base for fixing on the surface of the photocatalyst material carrier, or a base for fixing on the surface of the photocatalyst material carrier, and a photocatalyst crystal body having a hollow columnar structure extending from the base. A photocatalytic material consisting of
Exposing the structure inside the crystal to the photocatalyst crystal,
A photocatalytic material characterized by the presence of an internally exposed structure.

(2) The photocatalyst is titanium oxide, the base is a crystal nucleus, and a structure composed of photocatalyst particles is present inside the photocatalyst crystal.
The photocatalytic material of (1).

(3) A photocatalyst body comprising a photocatalyst material carrier and the photocatalyst material (1) or (2) carried on the photocatalyst material carrier.

(4) The crystal nucleus for forming the base of the photocatalyst material is placed in a sol solution containing an organometallic compound or an inorganic metal compound, or the crystal nucleus for forming the base of the photocatalyst material contains an organometallic compound or an inorganic metal. A sol solution containing a compound was applied, and a gelling step for obtaining a prototype of a photocatalytic material by gelation, a solidification step for drying and solidifying the prototype obtained by the gelling step, and solidification were performed. In the photocatalyst material manufacturing method, which comprises a heat treatment step for heat-treating the prototype to obtain a photocatalyst material having a photocatalyst crystal body having a hollow columnar structure, the photocatalyst material obtained in the heat treatment step is subjected to a dry etching method. And an internal exposed structure forming step for forming an internal exposed structure for exposing a structure inside the crystal on the surface of the photocatalyst crystal. Medium material manufacturing method.

(5) The method for producing a photocatalytic material according to (4), wherein the step of forming the exposed internal structure uses a wet etching method instead of a dry etching method.

(6) The method for producing a photocatalyst material according to (4), wherein the step of forming the exposed internal structure uses a mechanical method instead of the dry etching method.

(7) In the method for producing a photocatalyst material, which comprises the gelling step, the solidifying step, and the heat treatment step, an internal exposed structure for exposing the structure inside the crystal body is formed on the surface of the photocatalyst crystal body. In order to do so, in the heat treatment step, the heat treatment is performed at a temperature rising rate of 15 ° C./min to 105 ° C./min.

(8) A photocatalyst material application product using the photocatalyst material of (1) or (2) or the photocatalyst body of (3).

That is, a typical oxide photocatalyst material according to the present invention is a titanium oxide crystal having a columnar hollow structure grown from crystal nuclei as described in the claims, and the titanium oxide crystal The gist is that a highly active photocatalytic function is obtained by exposing the inside of the hollow to the outside.

In the present invention, the columnar shape of the photocatalyst crystal includes all prismatic, columnar, rod-shaped, and other columnar three-dimensional structures, and the columnar crystals extend straight in the vertical direction and have a slant. It includes those extending in a shape, those extending while curving, those branching and branching, those in which a plurality of columnar crystals grow and are fused in the middle, and the like.

The crystal nuclei are not only crystal nuclei produced by a PVD method such as a sputtering method or a vacuum deposition method, or a CVD method, but the kinds thereof are single crystals, polycrystals, powders, ceramics, metal thermal oxide films, Any anodized film may be used. Also, as crystal nuclei, those that are not clearly recognized as nuclei as seen in normal chemical reactions, such as scratches on the substrate and protrusions of foreign matter, are on the substrate and are different from the substrate. It is also possible to use a portion having a state of being a substitute for the nucleus. The columnar crystal structure means that one or more columnar crystals are grown on the crystal nucleus, the crystal nucleus and the columnar crystal grown thereon grow in the same direction, and the inside of the columnar crystal has a hollow structure. Characterize. A photocatalyst having a columnar crystal structure has a better contact efficiency with an object to be decomposed than a conventional one having another crystal shape, and the decomposition performance is dramatically improved.

The specific means for solving the present invention will be described below.

According to the present invention, a photocatalyst material having higher activity can be obtained by controlling the structure of the titanium oxide photocatalyst crystal having the columnar hollow structure, which has been already developed by the present inventors and disclosed in an unknown patent application. It is a thing. The titanium oxide crystal is characterized in that crystal nuclei are placed in a sol solution of an organic metal compound or an inorganic metal compound, or the sol solution is applied to the crystal nuclei, solidified and heat-treated to grow from the crystal nuclei. The titanium oxide crystal itself having a columnar hollow structure is already very active, but its activity is further improved by partially removing the outer wall portion of the columnar hollow crystal and exposing the hollow inner structure to the outside.

As a method of exposing the hollow internal structure of the columnar hollow crystal to the outside, a dry etching method, a wet etching method and a mechanical method are effective. The dry etching method includes a physical etching method and a chemical etching method. The physical etching method includes an ion etching method and a plasma etching method, and the chemical etching method includes a gas etching method.
The wet etching method uses an etching solution containing a strong inorganic acid, a strong oxidant, a fluoride, etc. as a basic composition. Further, the mechanical method is a method of exposing the hollow internal structure on the surface by polishing the columnar hollow crystals. By these methods, the outer wall portion of the columnar hollow crystal is partially removed, the hollow internal structure is exposed to the outside,
A highly active photocatalytic function can be obtained.

Further, in the columnar hollow titanium oxide crystal production process, heat treatment is performed at a temperature rising rate of 15 ° C./min to 105 ° C./min, or 20 ° C./min to 100 ° C./min, which greatly contributes to crystal formation. The heat conduction rate is increased and the crystal density of the crystals forming the outer wall of the columnar structure is lowered, so that the hollow internal structure of the columnar hollow crystal is exposed, and the photocatalytic function is highly activated.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in more detail with reference to the drawings. FIG. 1 is a schematic diagram showing a vertical cross-sectional structure of the photocatalytic material of the present invention. In the figure, a photocatalyst material 10 of the present invention has a base 2 for being fixed on the surface of a photocatalyst material carrier 1, and a hollow columnar structure extending from the base 2 (hereinafter, also referred to as "columnar hollow structure"). And a photocatalyst crystal body 3 having
It is formed by removing a part of the outer wall portion 4 in a basic structure including an outer wall portion 4 and a hollow interior (hereinafter referred to as “hollow interior”) 5 of the photocatalyst crystal body 3. Alternatively, there is an internally exposed structure 8 having a function of exposing a structure existing in the hollow interior 5, which is formed by configuring the outer wall portion 4 to have a low density.

The outer wall portion 4 is the outer shell structure of the photocatalyst crystal body 3 having a columnar hollow structure, and corresponds to the outer shell structure of the portion corresponding to the side surface portion of the columnar body. However, not only that, the outer wall portion 4 also includes the outer shell structure of the portion corresponding to the bottom surface portion on the extension (growth) direction side. Therefore, the internal exposed structure 8 is present on at least one of the outer wall portion corresponding to the side surface portion and the outer wall portion corresponding to the bottom surface portion, and may be present on both. In the present invention, the internal exposed structure 8
Can be present at least in the outer wall portion 4 corresponding to the side surface portion.

The inner exposed structure 8 is a structure formed by removing a part of the outer wall portion 4 or by forming the outer wall portion 4 to have a low density. By exposing the internal structure having a photocatalytic function existing in No. 5, it has a function of expressing the photocatalytic function in the internal structure. The internal exposed structure 8
Is a hole, a crack, a notch-like portion, a notched portion, or any other internal structure having a photocatalytic function in the hollow interior 5, the internal structure may exhibit a photocatalytic function. Including all structures to expose.

Titanium oxide can be used for the photocatalyst crystal body 3, and crystal nuclei for growing the photocatalyst crystal body 3 can be used for the base 2. Further, the hollow interior 5 may have a structure in which photocatalyst particles 6 (hereinafter, also referred to as “crystal particles”) are present.

[0034]

In FIG. 1, a photocatalyst material 10 having a columnar hollow structure according to the present invention comprises a photocatalyst material carrier 1 on a base 2.
Is fixed to the surface of the photocatalyst crystal body 3 extending from the base portion 2 and the inner exposed structure 8 on the outer wall portion 4 of the photocatalyst crystal body 3 is partially removed, or the outer wall portion 4 is removed. The portion 4 is configured to have a low density, and the internal structure existing in the hollow interior 5 is exposed to the outside. That is, when the hollow interior 5 has an internal structure having a photocatalytic function, the internal structure is in a state capable of exhibiting the photocatalytic function. Therefore, this photocatalyst material 10
Has an increased surface area, and the photocatalytic function becomes highly active. In addition, since the hollow interior 5 can have a structure in which the photocatalyst particles 6 are present, the surface area of the photocatalyst material 10 is further increased, and the photocatalytic function becomes even more active.

FIG. 2 is a schematic view showing the external constitution of the photocatalyst material of the present invention. In the figure, various substrates such as glass, metal, ceramics or fibers having a mesh structure can be used as the photocatalyst material carrier 1.

In the figure, a photocatalyst body 20 according to the invention described in claim 3 comprises a photocatalyst material carrier 1 and the photocatalyst material 10 carried on the photocatalyst material carrier 1 in the base 2. Composed.

FIG. 3 is a schematic view showing an example of the internal structure 5 of the photocatalyst crystal body 3 constituting the photocatalyst material of the present invention. In the figure, the internal structure of the photocatalyst crystal body 3 has a hollow interior 5 surrounded by an outer wall portion 4 in which crystals are bonded in a high density state, in which an internal exposed structure 8 having a function of exposing the photocatalyst crystal body 3 to the outside exists. 2), which is a structure in which a plurality of photocatalyst particles 6 having various particle sizes of large and small form a crystal aggregate in a low density state.

In the outer wall portion 4 in which the crystals are bonded in a high density state, the size of the crystal grains is about 2 nm.
50 nm and the width of the outer wall is about 20 nm to 100
nm. In the inside 5 of the columnar hollow crystal surrounded by the outer wall portion 4, the crystal particles 6 form a crystal aggregate in a low density state. Since the crystal grains 6 are present in a low density state, the columnar crystal interior (hollow interior) 5 has a hollow structure. Columnar hollow crystals without the crystal grains 6 are rarely observed, but their proportion in the whole is very small. The more the crystal particles 6 are present, the higher the photocatalytic activity. The diameter of the crystal particles 6 present in the hollow interior 5 is approximately 5 nm to 50 nm, and is generally larger than the crystal particles forming the outer wall portion 4.

FIG. 4 is a flow chart showing the construction of the method for producing a photocatalyst material according to the invention described in claim 4. In the figure, in the manufacturing method of the present invention, a crystal nucleus S1 for forming the base 1 of the photocatalytic material P6 (the same as 10 in FIG. 1 and the like).
Is dipped in a sol solution S2 containing an organic metal compound or an inorganic metal compound, or a sol solution S2 containing an organic metal compound or an inorganic metal compound is applied to the crystal nucleus S1 for forming the base 1 of the photocatalyst material 10, A gelling step 31 for obtaining a prototype M3 of the photocatalytic material by gelling, and a solidification step 32 for drying and solidifying the prototype M3 obtained by the gelling step 31 to obtain a solidified prototype M4. A heat treatment step 33 for heat-treating the solidified prototype M4 to obtain a photocatalyst material M5 having a photocatalyst crystal body 3 having a columnar hollow structure but having no internally exposed structure 8, and the heat treatment step 3
The photocatalyst material M5 having no internal exposed structure obtained in 3 is subjected to a dry etching method to form an internal exposed structure 8 exposing the structure of the crystalline inside 5 on the surface of the photocatalytic crystalline body 3, And an inner exposed structure forming step 35 for forming the photocatalyst material P6 (10) of the invention.

In the figure, a crystal nucleus S1 for forming the base portion 1 of the photocatalytic material P6 (10) by the gelling step 31.
Is immersed in a sol solution S2 containing an organometallic compound or an inorganic metal compound, or a sol solution S2 containing an organometallic compound or an inorganic metal compound is applied to the crystal nucleus S1 for forming the base 1 of the photocatalytic material P6 (10). To obtain a prototype M3 of the photocatalytic material by gelling, and then by the solidification step 32, the prototype M obtained by the gelling step 31.
3 is dried and solidified to obtain a solidified prototype M4, and the solidified prototype M4 is then heat-treated in a heat treatment step 33 to have a photocatalyst crystal body 3 having a columnar hollow structure but no internal exposed structure 8. The photocatalyst material M5 is obtained, and then, in the internal exposed structure forming step 35, the photocatalyst material M5 having no internal exposed structure is subjected to a dry etching method to form the structure of the crystal interior 5 on the surface of the photocatalyst crystal body 3. The internal exposed structure 8 to be exposed is formed, and the photocatalytic material P6 (10) of the present invention is obtained.

That is, in order to expose the hollow interior 5 of the columnar hollow crystal on the surface, it is necessary to remove a part of the outer wall portion 4. The dry etching method is one of the effective methods for removing a part of the outer wall portion 4. As a dry etching method, a method of physically removing a part of the outer wall portion 4 by bombarding an inert gas ion such as Ar (argon), Kr (krypton), Xe (xenon), and He (helium), so-called ion etching Method, ion milling method, etc. can be applied. By such a method, a part of the outer wall portion 4 of the columnar hollow crystal is physically removed, and the hollow interior 5
The structure of is exposed to the outside as a surface, and high activation of the photocatalytic function is achieved.

Further, as another dry etching method, a gas etching method of performing etching by using plasma, photolysis or thermal decomposition in an active gas may be used to remove a part of the outer wall portion 4, The photocatalytic function is highly activated. This has been confirmed by experiments.

FIG. 5 is an electron micrograph showing an example of a state in which the structure of the hollow interior 5 of the columnar hollow crystal of the photocatalyst material obtained by the method for producing a photocatalyst material of the present invention including the dry etching method is exposed to the outside. . In the figure, the outer wall portion of the photocatalyst crystal body forming a columnar hollow crystal is partially removed,
It can be confirmed that the structure inside the hollow is exposed to the outside, and the crystal grains inside form a crystal aggregate in a low density state.

FIG. 6 is a flow chart showing the constitution of the method for producing a photocatalyst material according to the invention described in claim 5. In the figure, in the production method of the present invention, the crystal nucleus S1 for forming the base portion 1 of the photocatalytic material P6 (10) is immersed in a sol solution S2 containing an organometallic compound or an inorganic metal compound, or the crystal nucleus S1 is Gelation process 31 for applying the sol solution S2 to obtain the photocatalytic material prototype M3 by gelation
And a solidification step 3 for obtaining a solidified prototype M4 by drying and solidifying the prototype M3 obtained in the gelling step 31.
2, a heat treatment step 33 for heat-treating the solidified prototype M4 to obtain a photocatalyst material M5 having a photocatalyst crystal body 3 having a columnar hollow structure but no internal exposed structure 8, and the heat treatment step 33 obtained in the heat treatment step 33. By subjecting the photocatalytic material M5 having no internal exposed structure to a wet etching technique, an internal exposed structure 8 for exposing the structure inside the crystalline body 5 is formed on the surface of the photocatalytic crystalline body 3, and the photocatalytic material of the present invention is formed. P6
(10) to form an internal exposed structure 36.

In the figure, a crystal nucleus S1 for forming the base portion 1 of the photocatalytic material P6 (10) by the gelling step 31.
Is immersed in a sol solution S2 containing an organic metal compound or an inorganic metal compound, or the sol solution S is added to the crystal nucleus S1.
2 is applied to obtain a prototype M3 of the photocatalytic material by gelling, and then the solidifying step 32 is followed by the gelling step 31.
The prototype M3 obtained by the above is dried and solidified to obtain a solidified prototype M4. Then, in the heat treatment step 33, the solidified prototype M4 is heat-treated to have a photocatalyst crystal body 3 having a columnar hollow structure. The photocatalyst material M5 without the internal exposed structure 8 is obtained, and then the photocatalyst material M5 without the internal exposed structure is subjected to a wet etching method in the internal exposed structure forming step 36 so that the crystal is formed on the surface of the photocatalytic crystal body 3. The internal exposed structure 8 that exposes the structure inside the body 5 is formed, and the photocatalytic material P6 (10) of the present invention is obtained.

That is, in order to expose the hollow interior 5 of the columnar hollow crystal on the surface, it is necessary to remove a part of the outer wall portion 4. The wet etching method is one of the effective methods for removing a part of the outer wall portion 4. The wet etching method uses an etching solution prepared on the basis of a strong inorganic acid, a strong oxidant, a fluoride, etc., and a columnar hollow titanium oxide crystal is immersed in an etching solution which is soluble in titanium oxide. By
Alternatively, by applying the etching solution to columnar hollow titanium oxide crystals, a part of the outer wall portion 4 is dissolved and removed,
The structure of the hollow interior 5 is exposed to the outside as a surface, and high activation of the photocatalytic function is achieved.

FIG. 7 is a flow chart showing the structure of the method for producing a photocatalyst material according to the invention described in claim 6. In the figure, in the production method of the present invention, the crystal nucleus S1 for forming the base portion 1 of the photocatalytic material P6 (10) is immersed in a sol solution S2 containing an organometallic compound or an inorganic metal compound, or the crystal nucleus S1 is Gelation process 31 for applying the sol solution S2 to obtain the photocatalytic material prototype M3 by gelation
And a solidification step 3 for obtaining a solidified prototype M4 by drying and solidifying the prototype M3 obtained in the gelling step 31.
2, a heat treatment step 33 for heat-treating the solidified prototype M4 to obtain a photocatalyst material M5 having a photocatalyst crystal body 3 having a columnar hollow structure but no internal exposed structure 8, and the heat treatment step 33 obtained in the heat treatment step 33. By subjecting the photocatalyst material M5 having no internal exposed structure to a mechanical method, an internal exposed structure 8 for exposing the structure of the crystal interior 5 is formed on the surface of the photocatalytic crystalline body 3, and the photocatalyst material of the present invention is formed. And an internal exposed structure forming step 38 for setting P6 (10).

In the figure, a crystal nucleus S1 for forming the base portion 1 of the photocatalytic material P6 (10) by the gelling step 31.
Is immersed in a sol solution S2 containing an organic metal compound or an inorganic metal compound, or the sol solution S is added to the crystal nucleus S1.
2 is applied to obtain a prototype M3 of the photocatalytic material by gelling, and then the solidifying step 32 is followed by the gelling step 31.
The prototype M3 obtained by the above is dried and solidified to obtain a solidified prototype M4. Then, in the heat treatment step 33, the solidified prototype M4 is heat-treated to have a photocatalyst crystal body 3 having a columnar hollow structure. The photocatalytic material M5 without the internal exposed structure 8 is obtained, and then the photocatalytic material M5 without the internal exposed structure is subjected to a mechanical method by the internal exposed structure forming step 38 to form the crystal on the surface of the photocatalytic crystal body 3. The internal exposed structure 8 that exposes the structure inside the body 5 is formed, and the photocatalytic material P6 (10) of the present invention is obtained.

That is, in order to expose the hollow interior 5 of the columnar hollow crystal on the surface, it is necessary to remove a part of the outer wall portion 4. A mechanical method is one of effective methods for removing a part of the outer wall portion 4. What is a mechanical method?
For example, the outer wall portion 4 of the columnar hollow crystal is mechanically polished, and a part of the outer wall portion 4 is removed by polishing the outer wall portion 4, whereby the structure of the hollow interior 5 is exposed to the outside as a surface, and the photocatalytic function is obtained. High activation of is achieved.

FIG. 8 is a flow chart showing the construction of the method for producing a photocatalyst material according to the invention described in claim 7. In the figure, in the production method of the present invention, the crystal nucleus S1 for forming the base portion 1 of the photocatalytic material P6 (10) is immersed in a sol solution S2 containing an organometallic compound or an inorganic metal compound, or the crystal nucleus S1 is Gelation process 31 for applying the sol solution S2 to obtain the photocatalytic material prototype M3 by gelation
And a solidification step 3 for obtaining a solidified prototype M4 by drying and solidifying the prototype M3 obtained in the gelling step 31.
2 and a heat treatment step 34 for heat-treating the solidified prototype M4 to obtain a photocatalyst material having a photocatalyst crystal body 3 having a columnar hollow structure. The conditions are 15 [deg.] C./min to 105 [deg.] C./min in order to form the internal exposed structure 8 that exposes the structure of the inside 5 of the crystal on the surface of the photocatalyst crystal 3.
The photocatalyst material P6 of the present invention
(10) is obtained. That is, it is characterized in that the heat treatment step 34 also serves as an internal exposed structure forming step.

In the figure, a crystal nucleus S1 for forming the base portion 1 of the photocatalytic material P6 (10) by the gelling step 31.
Is immersed in a sol solution S2 containing an organic metal compound or an inorganic metal compound, or the sol solution S is added to the crystal nucleus S1.
2 is applied to obtain a prototype M3 of the photocatalytic material by gelling, and then the solidifying step 32 is followed by the gelling step 31.
The prototype M3 thus obtained is dried and solidified to obtain a solidified prototype M4.

After the solidifying step 32, the temperature rising rate condition is set to 1
Heat treatment step 34 at 5 ° C / min to 105 ° C / min
As a result, the solidified prototype M4 is heat-treated, and at the same time, an inner exposed structure 8 exposing the structure of the inner portion 5 of the crystal is formed on the surface of the photocatalyst crystal 3 to form a columnar hollow structure having the inner exposed structure 8. The photocatalytic material P6 (1 of the present invention
0) is obtained.

More preferably, following the solidification step 32,
In the heat treatment step 34, the temperature rising rate condition is 20 ° C./min
By setting the temperature to ˜100 ° C./min, the solidified prototype M4 is heat-treated, and at the same time, the inner exposed structure 8 exposing the structure of the inside of the crystalline body 5 is formed on the surface of the photocatalytic crystalline body 3 to form the internally exposed structure. The photocatalyst material P6 (10) of the present invention having a columnar hollow structure having 8 is obtained.

The exposure of the structure of the hollow interior 5 to the outside by the dry etching, the wet etching, or the mechanical method is obtained by performing a post-treatment after producing the titanium oxide crystal having the columnar hollow structure. However, by controlling the manufacturing process of columnar hollow titanium oxide crystals,
Exposing the structure of the hollow interior 5 to the outside is realized. That is, the control in the heat treatment step in which the thermal energy, which is one of the important factors for forming the crystal shape, contributes,
This is a feature of the method for producing a photocatalyst material according to the described invention.

The columnar hollow-structured titanium oxide crystal is produced by the sol-gel method using an organic metal compound or an inorganic metal compound as described above, and contains the solvent and the residue derived from the treatment in the previous step in the heat treatment step. By controlling the evaporation mode of the organic substance, the structure of the hollow interior 5 is exposed to the outside. Specifically, it is realized by setting the rate of temperature rise in the heat treatment step in the range of 15 ° C / min to 105 ° C / min. More desirably, the temperature rising rate is 20 ° C /
It is realized by setting the range from min to 100 ° C / min.

Usually, the heat treatment step of the columnar hollow titanium oxide crystals is carried out at a temperature rising rate of about 10 ° C./min, and the outer wall portion 4 having a high crystal density is formed at this temperature rising rate. Therefore, in order to expose the structure of the hollow interior 5 to the outside as described above, the etching process is necessary.

However, in the step of producing the columnar hollow titanium oxide crystals, it is more preferable that the temperature rising rate is 15 ° C./min to 105 ° C./min, more preferably 20 ° C./min to 100 ° C./m.
By performing the heat treatment at the temperature rising rate of in, the solvent and the residual organic substances derived from the treatment in the previous step are rapidly evaporated, and the outer wall portion 4 is formed in a state where the crystal density is low. By forming the outer wall portion 4 with a low crystal density, the outer wall portion 4
Is opened, that is, the internal exposed structure 8 is formed, and the structure of the hollow interior 5 is exposed to the outside.

Even when the temperature rising rate of the heat treatment is higher than the upper limit of the above range, the outer wall portion 4 is formed with a low crystal density and the structure of the hollow interior 5 is exposed. But,
In this case, due to the rapid heat conduction, the rutile-type crystal structure that causes the decrease of the photocatalytic function is mixed into the anatase-type crystal structure that is effective for the expression of the photocatalytic function, so the effect of highly activating the photocatalytic function is reduced. To do.

FIG. 9 is an electron micrograph showing an example of a state in which the structure of the hollow interior 5 of the columnar hollow crystal of the photocatalyst material obtained by the method for producing a photocatalyst material of the present invention in which the heat treatment step is controlled is exposed to the outside. . In the figure, the crystal density of the outer wall portion of the photocatalyst crystal body forming a columnar hollow crystal is low, and therefore the structure of the hollow interior is exposed to the outside, and the crystal grains inside form a crystal aggregate in a low density state. You can check the situation.

As described above, the present invention is to obtain a photocatalytic material having higher activity by controlling the structure of the titanium oxide crystal having the columnar hollow structure which has been developed.
The titanium oxide crystal is characterized in that crystal nuclei are placed in a sol solution of an organic metal compound or an inorganic metal compound, or the sol solution is applied to the crystal nuclei, dried and heat-treated to grow from the crystal nuclei. Although the titanium oxide crystal itself having a columnar hollow structure is also very highly active, a part of the outer wall portion 4 of the columnar hollow crystal is removed by the dry etching method, the wet etching method, or the mechanical method, and the hollow interior 5 is removed.
The activity is further improved by exposing the structure of (3) to the outside. In addition, in the heat treatment step of producing the columnar hollow titanium oxide crystal, the temperature rising rate is 15 ° C / min to 105 ° C /
min, more preferably 20 ° C / min to 100 ° C /
By controlling to min, the outer wall portion 4 is formed with a low crystal density, the structure of the hollow interior 5 is exposed to the outside, and high activity of the photocatalytic function is realized. Then, the oxide photocatalytic material of the present invention is incorporated into a housing together with an ultraviolet light source and circulates air to decompose odorous components and harmful components and efficiently purify the air. This has been confirmed. In addition, it can be applied to an environmental purifying device for purifying water, deodorizing, antibacterial and sterilizing. This has also been confirmed by experiments.

[0061]

EXAMPLES The test results of the examples and comparative examples will be described below. In the following description, the “substrate” is the same symbol “1” as the photocatalyst material carrier 1, the “crystal nucleus” is the same symbol “2” as the base 2, and the “columnar hollow structure oxidation” is used. The same reference numeral “3” as that of the photocatalyst crystal body 3 is attached to each “titanium crystal” for description.

Alkali-free glass that has been washed with a neutral detergent, isopropyl alcohol, and pure water is used as the substrate 1, and crystal nuclei are put on the surface of the substrate 1 in a sol solution containing an organometallic compound, or crystal nuclei are added. By applying a sol solution to the above, solidifying and heat-treating, a titanium oxide crystal 3 having a columnar hollow structure was formed on the crystal nucleus 2.

As a method of preparing a sol solution containing an organometallic compound, butanediol: 35 g, H 2 O: 0.4
g, nitric acid: 0.5 g to prepare a solution, and titanium tetraisopropoxide (hereinafter, referred to as “TTIP”) was added to the solution.
Is written. ) 5 g was added dropwise with stirring, and then the mixture was stirred for 4 hours at room temperature to obtain a sol solution.

The crystal nuclei prepared by various preparation methods are dipped in 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 dried. Titanium oxide crystals were formed on the crystal nuclei by solidification and heat treatment. The solidification was carried out in a dryer under the conditions that the ultimate temperature was 150 ° C to 200 ° C and the holding time was 2 hours. The heat treatment was performed in an electric furnace under the conditions of a temperature rising rate of 10 ° C./min, an ultimate temperature of 500 ° C. to 600 ° C., and a holding time of 2 hours.

Among the crystal nuclei produced by various production methods, the method for producing a titanium oxide crystal film by the spray pyrolysis method (SPD method) is not known to the inventors of the present application (Patent application 2).
001-181969 etc.),
Prepared as follows. That is, the raw material liquid was prepared by adding acetylacetone (hereinafter referred to as “Hacac”) to TTIP at a molar ratio (Hacac / TTIP) of 1.0, diluting this with isopropyl alcohol, and stirring. The film formation conditions using a spray pyrolysis (SPD) device (YKII manufactured by Make Co., Ltd.) are as follows: spray pressure 0.3MP
a, spray amount 1.0 ml / sec, spray time 0.5 ml /
The substrate temperature was 450 ° C. and the number of spraying was 200 times.
The titanium oxide crystal film produced by the SPD method was confirmed to be composed of crystals having a size of 30 nm to 100 nm by surface observation with a scanning electron microscope (hereinafter referred to as “SEM”).

In the photocatalyst carrying the titanium oxide photocatalyst material having the columnar hollow structure thus obtained, a part of the outer wall portion 4 of the titanium oxide photocatalyst material having the columnar hollow structure carried is partly ion-etched and It was removed by a wet etching method to expose the structure of the hollow inside 5 to the outside. Further, the exposure of the structure of the hollow interior 5 to the outside by controlling the heat treatment process for producing the columnar hollow titanium oxide crystal is performed at a temperature rising rate of 20 ° C./min to 1 under the above producing conditions.
It was carried out at 00 ° C./min.

As an evaluation of the photocatalytic function, a decomposition test of acetaldehyde which is a harmful substance was carried out. The test method is
First, the produced titanium oxide photocatalyst was placed in a 20-liter glass container, the interior of the container was replaced with artificial air, and then acetaldehyde gas was injected into the container at 20 ppm. Next, the titanium oxide photocatalyst was irradiated with black light so that the acetaldehyde concentration in the container was 1 p
The time required to reach pm or less was measured with a gas monitor. The surface of the produced titanium oxide photocatalyst was observed by S
It was performed by EM.

Table 1 shows the experimental conditions in each Example and Comparative Example.

[0069]

[Table 1]

In Example 1, a titanium oxide photocatalyst material having a columnar hollow structure was subjected to an ion etching treatment as a dry etching treatment. The ion etching process is
Batch type sputtering equipment (manufactured by Nippon Vacuum Technology Co., Ltd.)
It was performed using an etching mechanism of model name: SH-350EL-T06). The etching procedure is shown below. A substrate on which a titanium oxide crystal having a columnar hollow structure was formed was placed in an etching chamber (deposition chamber). Then, the etching chamber was evacuated to 10 Pa by an oil rotary pump. Then, the interior of the etching chamber was evacuated by a turbo molecular pump to a predetermined vacuum degree of 8 × 10 −4 Pa or less. Argon gas was introduced into the etching chamber to create an argon atmosphere. At this time, the argon gas pressure (sputtering pressure) is 0.5 Pa.
The flow rate of the introduced gas and the degree of opening / closing of the main valve were adjusted so as to be ˜10.0 Pa. Then, a high frequency power supply was used to perform discharge in the etching chamber for etching (the introduced argon atoms are ionized and accelerated by the discharge. The accelerated ionized argon atoms are columnar hollow structure titanium oxide crystals serving as an etching target. The outer wall portion 4 is destroyed by the collision with the). The etching process was performed for 1 to 30 minutes. It was confirmed by surface observation using an SEM that the photocatalyst material thus obtained had a structure in which a part of the outer wall portion 4 of the columnar hollow crystal was removed as shown in FIG.

In Example 2, a titanium oxide photocatalyst material having a columnar hollow structure was subjected to an ion etching treatment as a dry etching treatment. The ion etching process is
It was performed using the etching mechanism of the sputtering device.
The etching procedure is shown below. A substrate on which a titanium oxide crystal having a columnar hollow structure was formed was placed in an etching chamber (deposition chamber). First, the etching chamber was evacuated to 10 Pa by an oil rotary pump. Then, a turbo molecular pump was evacuated to 10-4 Pa or less, and the inside of the etching chamber was set to a predetermined vacuum degree. Argon gas was introduced into the etching chamber to create an argon atmosphere. At this time, the flow rate of the introduced gas and the degree of opening / closing of the main valve were adjusted so that the argon gas pressure (sputtering pressure) was 0.5 Pa to 10.0 Pa. Then, a high frequency power source was used to discharge in the etching chamber to perform etching. When the introduced argon atoms are ionized and accelerated by the discharge, they collide with titanium oxide crystals having a columnar hollow structure as an etching target, and a part of the outer wall portion 4 is destroyed. This etching treatment was performed for 30 to 120 minutes. It was confirmed by surface observation using an SEM that the photocatalyst material thus obtained had a structure in which the outer wall portion 4 of the columnar hollow crystal as shown in FIG. 5 was removed.

In Example 3, a titanium oxide photocatalyst material having a columnar hollow structure was wet-etched. The wet etching treatment was performed using sulfuric acid having solubility in titanium oxide (hereinafter referred to as “H2SO4”). The etching procedure is shown below. Concentration 1
A 20% H2SO4 solution was prepared, and a photocatalyst body in which a photocatalyst material having columnar hollow structure titanium oxide crystals was supported on a substrate was immersed in the solution. After soaking for 1 to 24 hours, ultrasonic cleaning with pure water is applied for 30 minutes, and then 1
It was dried at 50 ° C. for 2 hours. It was confirmed by surface observation using an SEM that the photocatalyst body thus obtained had a structure in which a part of the outer wall portion 4 of the columnar hollow crystal was removed.

In Example 4, a titanium oxide photocatalyst material having a columnar hollow structure was wet-etched. The wet etching treatment was performed using sodium hydroxide having a solubility in titanium oxide (hereinafter referred to as “NaOH”). The etching procedure is shown below. A NaOH solution having a concentration of 1 to 20% was prepared, and a photocatalyst body in which a photocatalyst material having a columnar hollow structure titanium oxide crystal was carried on a substrate was immersed in the solution. 1-2
After soaking for 4 hours, ultrasonic cleaning with pure water was performed for 30 minutes, and then dried at 150 ° C. for 2 hours. It was confirmed by surface observation using SEM that the photocatalyst material thus obtained had a structure in which a part of the outer wall portion 4 of the columnar hollow crystal was removed.

In Example 5, in the heat treatment step for producing a titanium oxide crystal having a columnar hollow structure, various heat treatment conditions were set at a treatment temperature of 500 ° C. to 600 ° C. and a heating rate of 20 ° C./min to 1
It was produced by setting the temperature to 00 ° C./min and the holding time to 2 hours. The photocatalyst material thus obtained may have a structure in which the outer wall portion 4 is formed with a low crystal density and the structure of the hollow interior 5 is exposed to the outside, as shown in FIG. It was confirmed by surface observation using SEM.

In Comparative Example 1, the columnar hollow structure was not oxidized by the above-described dry etching technique or the like to expose the internal structure of the columnar hollow crystal (hereinafter, also referred to as "hollow inside exposure process"). Titanium crystal photocatalyst material.
Since the inside of the hollow was not exposed, the surface of the columnar hollow crystal was not exposed to the outside in the surface observation using SEM.

Comparative Example 2 is a commercially available powdery photocatalytic material (ST-01 manufactured by Ishihara Sangyo Co., Ltd.). According to surface observation using SEM, it was composed of titanium oxide particles having a particle size of about 5 nm to 30 nm.

Table 2 shows the experimental results of these Examples and Comparative Examples.

[0078]

[Table 2]

The following can be seen from the results in Table 2. The titanium oxide crystal photocatalyst material having a columnar hollow structure, which is not subjected to the hollow interior exposure treatment, has a height of 3000 to
An aggregate composed of photocatalyst crystals, which were columnar hollow crystals with a width of 5000 nm and a width of 300 to 500 nm, was formed. It was also confirmed by SEM observation that the structure inside the hollow of the columnar hollow crystal was not exposed to the outside because the hollow inside exposure treatment was not performed. The decomposition time of acetaldehyde was 15 min, and the decomposition performance was higher than that of Comparative Example 2 described later, which showed a highly active photocatalytic function.

It was confirmed by SEM observation that Comparative Example 2 which is a powdery photocatalyst material has a large number of titanium oxide particles having a particle size of 5 to 30 nm. The decomposition time of acetaldehyde was 28 min.

In contrast to Comparative Examples 1 and 2 above, Examples 1 to 1
Reference numeral 5 is a titanium oxide crystal photocatalyst material having a columnar hollow structure, and the structure inside the hollow is exposed to the outside by the above various kinds of hollow inside exposure treatment. The results of each example will be described in detail below.

In Example 1, a titanium oxide photocatalyst material having a columnar hollow structure was subjected to an ion etching treatment as a dry etching treatment. The ion etching process is
Argon gas pressure (sputtering pressure) is 0.5 Pa to 1
It was performed under the conditions of 0.0 Pa and an etching treatment time of 1 to 30 minutes. The photocatalyst material thus obtained has a structure in which a part of the outer wall portion of the columnar hollow crystal is removed and the hollow inner structure is exposed to the outside as shown in FIG. It was confirmed by surface observation. The decomposition time of acetaldehyde was 9 min, which showed a very high decomposition performance and a highly active photocatalytic function.

In Example 2, a titanium oxide photocatalyst material having a columnar hollow structure was subjected to an ion etching treatment as a dry etching treatment. The ion etching process is
Argon gas pressure (sputtering pressure) is 0.5 Pa to 1
It was performed under the conditions of 0.0 Pa and an etching treatment time of 30 to 120 min. The photocatalytic material thus obtained has a part of the outer wall portion of the columnar hollow crystal removed,
It was confirmed by surface observation using SEM that the structure inside the hollow was exposed to the outside. The decomposition time of acetaldehyde was 8 min, and the decomposition performance was very high, and it showed a highly active photocatalytic function.

In Example 3, a titanium oxide photocatalyst material having a columnar hollow structure was wet-etched. The wet etching treatment was performed using H2SO4 (solution concentration 1 to 20%, immersion time 1 to 24 hours) having solubility in titanium oxide. The photocatalyst material thus obtained has a form in which a part of the outer wall of the columnar hollow crystal is removed and the structure of the hollow interior is exposed to the outside, which is confirmed by surface observation using SEM. It was
The decomposition time of acetaldehyde was 10 min, the decomposition performance was very high, and a highly active photocatalytic function was exhibited.

In Example 4, a titanium oxide photocatalyst material having a columnar hollow structure was wet-etched. The wet etching treatment was performed using NaOH (solution concentration 1 to 20%, immersion time 1 to 24 hours) having solubility in titanium oxide. The photocatalyst material thus obtained has a form in which a part of the outer wall of the columnar hollow crystal is removed and the structure of the hollow interior is exposed to the outside, which is confirmed by surface observation using SEM. It was The decomposition time of acetaldehyde was 11 min, the decomposition performance was very high, and it showed a highly active photocatalytic function.

In Example 5, in the heat treatment step for producing a hollow titanium oxide photocatalyst material, various conditions of the heat treatment were: a treatment temperature of 500 ° C. to 600 ° C. and a heating rate of 20 ° C./min.
It was produced by setting the temperature to 100 ° C./min and the holding time to 2 hours. In the photocatalyst material obtained in this manner, a part of the outer wall portion is formed in a state where the crystal density is low, and the structure of the hollow interior 5 is exposed to the outside.
It was confirmed by surface observation using EM. The decomposition time of acetaldehyde was 8 min, and the decomposition performance was very high, and it showed a highly active photocatalytic function.

From the above Examples 1 to 5, it was confirmed that it is effective to expose the hollow interior of the titanium oxide crystal having a columnar hollow structure to the outside in order to exhibit a highly active photocatalytic function. . This is 5nm to 50nm in size
It is presumed that the crystal grains 6 of No. 2 form a crystal aggregate in a low density state and are present in the hollow interior 5. That is,
By exposing the crystal particles 6 existing as a crystal aggregate in a low density state to the outside, the surface area contributing to the photocatalytic function is increased, and high activation is achieved.

In Examples 1 to 5, the titanium oxide photocatalyst material having a columnar hollow structure to be subjected to the hollow interior exposure treatment was prepared using a sol solution containing an organic metal compound. However, a sol solution containing an inorganic metal compound was used. Even if it is produced by the above method, a titanium oxide crystal having a columnar hollow structure is produced, and by performing the hollow inside exposure treatment, high activation of the photocatalytic function is achieved. This has been confirmed by experiments.

As an example of the hollow interior exposing process, dry etching, wet etching, and heating rate control in the heat treatment process were mentioned. However, by mechanically polishing the outer wall part 4 of the columnar hollow crystal, a part of the process is performed. Even by removing the, the structure of the hollow inside 5 is exposed to the outside,
The photocatalytic function can be highly activated. This has been confirmed by experiments.

[0090]

According to the photocatalyst material of the present invention, since it is constituted as described above, it is possible to achieve a photocatalytic function having an extremely high activity.

Further, the photocatalyst material of the present invention is incorporated into a housing together with an ultraviolet light source into a device, and air is circulated using the device to decompose odorous components and harmful components,
The air can be efficiently cleaned.

In addition, the photocatalyst material of the present invention is provided with an internal exposed structure to expose the structure inside the hollow of the titanium oxide crystal having a columnar hollow structure to increase the surface area contributing to the photocatalytic function. Therefore, the fine particles,
The effect of capturing bacteria is great.

Further, the photocatalyst material of the present invention has a remarkable effect in cleaning function, antibacterial function, deodorizing function, antifouling function, etc. due to the extremely high activity of the photocatalyst function, and is used in air purifiers, deodorizers, air conditioners, etc. It can be widely applied to various air conditioners or environmental purification devices such as water purifiers and water purification devices.

[Brief description of drawings]

FIG. 1 is a schematic view showing a vertical cross section of a photocatalyst material of the present invention.

FIG. 2 is a schematic diagram showing the appearance of the photocatalytic material of the present invention.

FIG. 3 is a schematic view showing a vertical cross section of the internal structure of the photocatalytic material of the present invention.

FIG. 4 is a flow chart showing a method for producing a photocatalyst material of the present invention using a dry etching method.

FIG. 5 is an electron micrograph showing an example of an embodiment of the present invention. Internal structure of columnar hollow crystals by dry etching method.

FIG. 6 is a flowchart showing a method for producing a photocatalyst material of the present invention using a wet etching method.

FIG. 7 is a flow chart showing a method for producing a photocatalyst material of the present invention using a mechanical method.

FIG. 8 is a flow chart showing a method for producing a photocatalyst material of the present invention by controlling a heat treatment process.

FIG. 9 is an electron micrograph showing an example of an embodiment of the present invention. Internal structure of columnar hollow crystals by controlling the heat treatment process.

FIG. 10 is a schematic diagram showing an external configuration of a photocatalyst material by a manufacturing method that does not include a hole forming step.

[Explanation of symbols]

1, 51 ... Photocatalyst material support (substrate), 2, 52 ... Base (crystal nucleus), 3, 53 ... Photocatalyst crystal (columnar hollow structure titanium oxide crystal), 4 ... Outer wall, 5 ... Hollow interior, 6 ... Internal crystal particles (photocatalyst particles), 8 ... Internal exposed structure, 10,60 ... Photocatalyst material, 20,70 ...
Photocatalyst body, 31 ... Gelation step, 32 ... Solidification step, 3
3, 34 ... Heat treatment step, 35 ... Internal exposed structure forming step (dry etching method), 36 ... Internal exposed structure forming step (wet etching method), 38 ... Internal exposed structure forming step (mechanical method), S1 ... Crystal nucleus , S2 ... Sol solution, M3 ... Prototype of photocatalytic material, M4 ... Prototype solidified, M5 ... Photocatalytic material without internal exposed structure, P6
… Photocatalytic material

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B01J 37/00 C01G 23/053 C01G 23/053 B01D 53/36 J G (72) Inventor Fumie Kawanami Aomori No. 2 672 Nagachitanachi, Ichikawa-cho, Hachinohe City Andes Electric Co., Ltd. (72) Inventor Kudo, No. 2 672, Nagachitanachi, Ichikawa-cho, Hachinohe City, Aomori Prefecture (72) Inventor No. 2 No. 672 Nagachitanachi, Ichikawa-machi, Hachinohe, Higashiomori, Higashi-Aomori Prefecture, Andes Electric Co., Ltd. (72) Inventor, Akira Ikegami No. 2, 672, Nagachiya, Ichikawa, Hachinohe, Aomori Prefecture Term (reference) 4D048 AA19 AB03 BA07X BA41X BB17 EA01 4G047 CA02 CB06 CC03 CD04 4G069 AA03 AA08 BA04A BA04B BA37 BA38 BA48A CA01 CA11 CA17 CD10 DA05 DA07 EA06 EB14X EB14Y EC30 FA01 FB08 FB29 FB48 FC07

Claims (8)

[Claims] 1. A base to be fixed on the surface of a photocatalyst material carrier, or a base fixed to the surface of the photocatalyst material carrier, and a photocatalyst crystal body extending from the base and having a hollow columnar structure. A photocatalyst material comprising: a photocatalyst material, wherein the photocatalyst crystal body has an internally exposed structure for exposing a structure inside the crystal body. 2. The photocatalyst material according to claim 1, wherein the photocatalyst is titanium oxide, the base is a crystal nucleus, and a structure composed of photocatalyst particles is present inside the photocatalyst crystal body. . 3. A photocatalyst body comprising a photocatalyst material carrier and the photocatalyst material according to claim 1 carried on the photocatalyst material carrier. 4. A crystal nucleus for forming a base of a photocatalyst material is placed in a sol solution containing an organometallic compound or an inorganic metal compound, or a crystal nucleus for forming a base of a photocatalyst material contains an organometallic compound or an inorganic metal compound. And a solidification step for drying and solidifying the master obtained by the gelling step, and a solidified master. A heat treatment step for obtaining a photocatalyst material having a photocatalyst crystal body having a hollow columnar structure, and a photocatalyst material manufacturing method consisting of: performing a dry etching technique on the photocatalyst material obtained in the heat treatment step, A photocatalyst material, characterized by comprising an internal exposed structure forming step for forming an internal exposed structure for exposing a structure inside the crystal on the surface of the photocatalytic crystal. Manufacturing method. 5. The method for producing a photocatalyst material according to claim 4, wherein the internal exposed structure forming step uses a wet etching method instead of a dry etching method. 6. The method for producing a photocatalyst material according to claim 4, wherein the internal exposed structure forming step uses a mechanical method instead of a dry etching method. 7. A method for producing a photocatalyst material, which comprises the gelling step, the solidifying step, and the heat treatment step,
In order to form an internal exposed structure that exposes a structure inside the photocatalyst crystal on the surface of the photocatalyst crystal, heat treatment is performed at a heating rate of 15 ° C./min to 105 ° C./min in the heat treatment step. A method for manufacturing a photocatalytic material. 8. A photocatalyst material application product using the photocatalyst material according to claim 1 or 2, or the photocatalyst body according to claim 3.