阅读说明：本技术 光催化剂结构体、光催化剂结构体组合物、光催化剂包覆材料、光催化剂结构体的制造方法以及醛类的分解方法 (Photocatalyst structure, photocatalyst structure composition, photocatalyst coating material, method for producing photocatalyst structure, and method for decomposing aldehyde ) 是由 增田隆夫 中坂佑太 吉川琢也 加藤祯宏 福岛将行 高桥寻子 马场祐一郎 关根可织 于 2018-05-31 设计创作，主要内容包括：本发明的目的在于提供一种能有效地抑制光催化剂粒子的凝聚,能长期地维持良好的光催化功能的光催化剂结构体。该光催化剂结构体的特征在于,具备：多孔质结构的载体,其由沸石型化合物构成；以及至少一种光催化剂物质,其存在于所述载体内,所述载体具有相互连通的通道,所述光催化剂物质是金属氧化物微粒,且存在于所述载体的至少所述通道。(The purpose of the present invention is to provide a photocatalyst structure that can effectively suppress the aggregation of photocatalyst particles and can maintain a good photocatalytic function for a long period of time. The photocatalyst structure is characterized by comprising: a porous support composed of a zeolite-type compound; and at least one photocatalyst substance present in the carrier, the carrier having channels communicating with each other, the photocatalyst substance being a metal oxide fine particle, and being present in at least the channels of the carrier.)

1. A photocatalyst structure, comprising:

a porous support composed of a zeolite-type compound; and

at least one photocatalyst substance present within the support,

the carrier has channels that are in communication with each other,

the photocatalyst substance is a metal oxide microparticle and is present in at least the channel of the carrier.

2. The photocatalyst structure according to claim 1,

the channel has an expanded diameter portion, and,

the photocatalyst substance is present at least in the diameter-enlarged portion.

3. The photocatalyst structure according to claim 2, wherein,

the diameter expanding portion causes a plurality of holes constituting any one of the one-dimensional hole, the two-dimensional hole, and the three-dimensional hole to communicate with each other.

4. The photocatalyst structure according to any one of claims 1 to 3,

the metal oxide microparticles comprise titanium or an alloy oxide comprising titanium.

5. The photocatalyst structure according to any one of claims 1 to 4,

the metal oxide fine particles have an average particle diameter larger than an average inner diameter of the channel and not larger than an inner diameter of the enlarged diameter portion.

6. The photocatalyst structure according to any one of claims 1 to 5,

the metal element (M) of the metal oxide fine particles is contained in an amount of 0.5 to 2.5 mass% relative to the catalyst structure.

7. The photocatalyst structure according to any one of claims 1 to 6,

the metal oxide fine particles have an average particle diameter of 0.1 to 50 nm.

8. The photocatalyst structure according to claim 7,

the metal oxide fine particles have an average particle diameter of 0.45 to 14.0 nm.

9. The photocatalyst structure according to any one of claims 1 to 8,

the ratio of the average particle diameter of the metal oxide fine particles to the average inner diameter of the channels is 0.06 to 500.

10. The photocatalyst structure according to claim 9,

the ratio of the average particle diameter of the metal oxide fine particles to the average inner diameter of the channels is 0.1 to 45.

11. The photocatalyst structure according to claim 10,

the ratio of the average particle diameter of the metal oxide fine particles to the average inner diameter of the channels is 1.7 to 4.5.

12. The photocatalyst structure according to any one of claims 1 to 11,

the channel has: any one of one-dimensional pores, two-dimensional pores, and three-dimensional pores defined by the framework structure of the zeolite-type compound; and a diameter-expanding portion different from any one of the one-dimensional hole, the two-dimensional hole, and the three-dimensional hole,

the average inner diameter of the channel is 0.1 nm-1.5 nm,

the inner diameter of the diameter-expanded portion is 0.5nm to 50 nm.

13. The photocatalyst structure according to any one of claims 1 to 12,

the photocatalyst material further comprises at least one other photocatalyst substance held on the outer surface of the support.

14. The photocatalyst structure according to claim 13,

the at least one photocatalyst substance is present in the support in an amount greater than the amount of the at least one other photocatalyst substance retained on the outer surface of the support.

15. The photocatalyst structure according to any one of claims 1 to 14,

the zeolite-type compound is a silicate compound.

16. The photocatalyst structure according to any one of claims 1 to 15,

the photocatalyst structure is dispersed in a dispersion medium.

17. A photocatalyst structure composition characterized in that,

comprising the photocatalyst structure of any one of claims 1 to 16, and a binder material.

18. The photocatalyst structure composition according to claim 17,

the binder material is an organic binder.

19. A photocatalyst coating material comprising a base material and a photocatalyst layer formed on the base material,

the photocatalyst layer contains the photocatalyst structure according to any one of claims 1 to 16.

20. The photocatalyst coating material as defined in claim 19,

the base material is a building material.

21. A method for manufacturing a photocatalyst structure, comprising:

a firing step of firing a precursor material (B) obtained by impregnating a precursor material (a) with a metal-containing solution, the precursor material (a) being used for obtaining a support having a porous structure made of a zeolite-type compound; and

a hydrothermal treatment step of subjecting a precursor material (C) obtained by firing the precursor material (B) to hydrothermal treatment.

22. The method of manufacturing a photocatalyst structure according to claim 21,

before the firing step, 50 to 500 mass% of a nonionic surfactant is added to the precursor material (a).

23. The method of manufacturing a photocatalyst structure according to claim 21 or 22,

the metal-containing solution is impregnated into the precursor material (a) by adding the metal-containing solution in the precursor material (a) a plurality of times before the firing step.

24. The method of manufacturing a photocatalyst structure according to any one of claims 21 to 23,

when the precursor material (A) is immersed in the metal-containing solution before the firing step, the amount of the metal-containing solution added to the precursor material (A) is adjusted so that the atomic ratio (Si/M), which is the ratio of silicon (Si) constituting the precursor material (A) to the metal element (M) contained in the metal-containing solution added to the precursor material (A), is 10 to 1000.

25. The method of manufacturing a photocatalyst structure according to claim 21,

in the hydrothermal treatment step, the precursor material (C) is mixed with a structure-directing agent.

26. The method of manufacturing a photocatalyst structure according to claim 21,

the hydrothermal treatment step is performed in an alkaline environment.

27. A method for decomposing aldehydes, characterized in that,

decomposing aldehydes using the photocatalyst structure according to any one of claims 1 to 16.

Technical Field

The present invention relates to a photocatalyst structure, a photocatalyst structure composition, a photocatalyst coating material, a method for producing a photocatalyst structure, and a method for decomposing aldehydes.

Background

Photocatalysts exhibit the action of decomposing organic substances and making surfaces superhydrophilic under light irradiation, and are therefore used for environmental purification, antifouling, antibacterial, antifogging, and the like. As such a photocatalyst, for example, a photocatalyst composed of a metal oxide such as titanium oxide is widely used in the photocatalyst market because of its high photocatalytic activity, low price, high chemical stability, and the like.

In general, the more active surfaces of the catalyst, the more excellent the catalytic activity, and therefore, it is desirable that: the same applies to the photocatalyst in that the particle diameter of the catalyst particles is as small as possible. However, in the case of nanoparticles of metal oxides such as titanium oxide, for example, the particles are liable to aggregate disorderly, and such aggregation (sintering) becomes a cause of deterioration of the photocatalytic function.

In order to solve such a problem of aggregation, patent document 1 discloses a method of using a crystalline nanostructure (titanium oxide mesogen) having an intermediate size (specifically, about 1 to 10 μm) in which titanium oxide nanocrystals are regularly arranged as a photocatalyst.

Such titanium oxide mesocrystals can suppress disordered aggregation of nanoparticles or nanocrystals. However, since the titanium oxide mesogen itself is a large-sized (1 μm or more) crystal in which nanocrystals are regularly arranged, the specific surface area thereof is about 50m as compared with that of a general titanium oxide nanoparticle (titanium oxide nanoparticle P25 as a representative photocatalyst)²Per gram) is relatively small, the catalytic activity is poor compared to that of highly dispersed nanocrystalline particles. In addition, titanium oxide mesocrystals are crystals having a large size and are difficult to aggregate as compared with nanoparticles, but in the case of titanium oxide mesocrystals, the particles do not contact each other, and sometimes aggregate when used for a long time.

Disclosure of Invention

Problems to be solved by the invention

The invention aims to provide a photocatalyst structure, a photocatalyst structure composition, a photocatalyst coating material, a method for producing the photocatalyst structure, and a method for decomposing aldehydes, wherein the aggregation of photocatalyst particles can be effectively inhibited, and a good photocatalytic function can be maintained for a long period of time.

Technical scheme

As a result of intensive studies to achieve the above object, the present inventors have found the following facts, and have completed the present invention based on the findings, and have obtained a photocatalyst structure comprising: a porous support composed of a zeolite-type compound; and at least one photocatalyst substance present in the carrier, the carrier having channels communicating with each other, the photocatalyst substance being a metal oxide fine particle and being present in at least the channels of the carrier, whereby aggregation of photocatalyst particles can be effectively suppressed, and a good photocatalytic function can be maintained for a long period of time.

That is, the gist of the present invention is as follows.

[1] A photocatalyst structure, comprising: a porous support composed of a zeolite-type compound; and at least one photocatalyst substance present in the carrier, the carrier having channels communicating with each other, the photocatalyst substance being a metal oxide fine particle, and being present in at least the channels of the carrier.

[2] The photocatalyst structure according to [1], wherein the channel has an enlarged diameter portion, and the photocatalyst substance is present at least in the enlarged diameter portion.

[3] The photocatalyst structure according to [2], wherein the diameter-expanded portion causes a plurality of holes constituting any one of the one-dimensional holes, the two-dimensional holes, and the three-dimensional holes to communicate with each other.

[4] The photocatalyst structure according to any one of [1] to [3], wherein the metal oxide fine particles contain titanium or an alloy oxide containing titanium.

[5] The photocatalyst structure described in any one of [1] to [4], wherein the metal oxide fine particles have an average particle diameter larger than an average inner diameter of the channels and equal to or smaller than an inner diameter of the enlarged diameter portion.

[6] The photocatalyst structure according to any one of [1] to [5], wherein the metal element (M) of the metal oxide fine particles is contained in an amount of 0.5 to 2.5 mass% relative to the catalyst structure.

[7] The photocatalyst structure according to any one of [1] to [6], wherein the metal oxide fine particles have an average particle diameter of 0.1nm to 50 nm.

[8] The photocatalyst structure according to [7], wherein the metal oxide fine particles have an average particle diameter of 0.45nm to 14.0 nm.

[9] The photocatalyst structure according to any one of [1] to [8], wherein the ratio of the average particle diameter of the metal oxide fine particles to the average inner diameter of the channels is 0.06 to 500.

[10] The photocatalyst structure according to item [9], wherein the ratio of the average particle diameter of the metal oxide fine particles to the average inner diameter of the channels is 0.1 to 45.

[11] The photocatalyst structure according to item [10], wherein the ratio of the average particle diameter of the metal oxide fine particles to the average inner diameter of the channels is 1.7 to 4.5.

[12] The photocatalyst structure body according to any one of [1] to [11], wherein the channel has: any one of one-dimensional pores, two-dimensional pores, and three-dimensional pores defined by the framework structure of the zeolite-type compound; and a diameter-expanding portion different from any one of the one-dimensional hole, the two-dimensional hole, and the three-dimensional hole, wherein an average inner diameter of the channel is 0.1nm to 1.5nm, and an inner diameter of the diameter-expanding portion is 0.5nm to 50 nm.

[13] The photocatalyst structure according to any one of [1] to [12], further comprising at least one other photocatalyst substance held on the outer surface of the support.

[14] The photocatalyst structure according to [13], wherein the content of the at least one photocatalyst substance present in the carrier is larger than the content of the at least one other photocatalyst substance held on the outer surface of the carrier.

[15] The photocatalyst structure according to any one of [1] to [14], wherein the zeolite-type compound is a silicate compound.

[16] The photocatalyst structure according to any one of [1] to [15], wherein the photocatalyst structure is dispersed in a dispersion medium.

[17] A photocatalyst structure composition comprising the photocatalyst structure according to any one of [1] to [16] and a binder material.

[18] The photocatalyst structure composition according to item [17], wherein the binder material is an organic binder.

[19] A photocatalyst coating material comprising a base material and a photocatalyst layer formed on the base material,

the photocatalyst layer contains the photocatalyst structure according to any one of [1] to [16 ].

[20] The photocatalyst coating material as described in [19], wherein the base material is a building material.

[21] A method for manufacturing a photocatalyst structure, comprising:

a firing step of firing a precursor material (B) obtained by impregnating a precursor material (a) with a metal-containing solution, the precursor material (a) being used for obtaining a support having a porous structure made of a zeolite-type compound; and

a hydrothermal treatment step of subjecting a precursor material (C) obtained by firing the precursor material (B) to hydrothermal treatment.

[22] The method of producing a photocatalyst structure according to [21], wherein 50 to 500 mass% of a nonionic surfactant is added to the precursor material (A) before the firing step.

[23] The method of manufacturing a photocatalyst structure according to [21] or [22], wherein the metal-containing solution is impregnated into the precursor material (A) by adding the metal-containing solution to the precursor material (A) a plurality of times before the firing step.

[24] The method for producing a photocatalyst structure according to any one of [21] to [23], wherein when the metal-containing solution is immersed in the precursor material (A) before the firing step, the amount of the metal-containing solution added to the precursor material (A) is adjusted so that the ratio (atomic ratio Si/M) of silicon (Si) constituting the precursor material (A) to a metal element (M) contained in the metal-containing solution added to the precursor material (A) is 10 to 1000 in terms of the ratio.

[25] The method of producing a photocatalyst structure according to [21], wherein the precursor material (C) is mixed with a structure-directing agent in the hydrothermal treatment step.

[26] The method of producing a photocatalyst structure according to [21], wherein the hydrothermal treatment step is performed in an alkaline environment.

[27] A method for decomposing an aldehyde, characterized by decomposing an aldehyde using the photocatalyst structure according to any one of [1] to [16 ].

Effects of the invention

According to the present invention, there can be obtained a photocatalyst structure, a photocatalyst structure composition, a photocatalyst coating material, a method for producing a photocatalyst structure, and a method for decomposing aldehydes, wherein the photocatalyst structure comprises: a porous support composed of a zeolite-type compound; and at least one photocatalyst substance present in the carrier, the carrier having channels communicating with each other, the photocatalyst substance being fine metal oxide particles and being present in at least the channels of the carrier, whereby aggregation of photocatalyst particles can be effectively suppressed, and a good photocatalytic function can be maintained for a long period of time.

Drawings

Fig. 1 is a schematic view showing an internal structure of a photocatalyst structure according to an embodiment of the present invention, in which fig. 1 (a) is a perspective view (partially shown in cross section) and fig. 1 (b) is a partially enlarged sectional view.

Fig. 2 is a partially enlarged cross-sectional view for explaining an example of the catalytic function of the photocatalyst structure of fig. 1.

Fig. 3 is a flowchart showing an example of a method for manufacturing the photocatalyst structure of fig. 1.

Fig. 4 is a schematic view showing a modification of the photocatalyst structure of fig. 1.

Fig. 5 is a schematic cross-sectional view showing an example of the photocatalyst coating material of the present invention.

Detailed Description

Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.

[ constitution of photocatalyst Structure ]

Fig. 1 is a view schematically showing the structure of a photocatalyst structure according to an embodiment of the present invention, in which fig. 1 (a) is a perspective view (partially shown in cross section), and fig. 1 (b) is a partially enlarged sectional view. The photocatalyst structure shown in fig. 1 is an example thereof, and the shape, size, and the like of each component of the present invention are not limited to fig. 1.

As shown in fig. 1 (a), the photocatalyst structure 1 includes: a porous support 10 made of a zeolite-type compound; and at least one photocatalyst substance 20 present within the support 10.

In the photocatalyst structure 1, the plurality of photocatalyst substances 20 and 20 … … are included in the porous structure of the support 10. The photocatalyst substance 20 may be any substance having a photocatalytic function (photocatalytic activity), and specifically is a metal oxide fine particle. The metal oxide fine particles will be described in detail later.

The carrier 10 has a porous structure, and preferably has channels 11 communicating with each other by forming a plurality of holes 11a and 11a … …, as shown in fig. 1 (b). Here, the photocatalyst substance 20 is present in at least the channels 11 of the support 10, and preferably, is held in at least the channels 11 of the skeleton body 10.

With such a configuration, the movement of the photocatalytic material 20 in the carrier 10 is restricted, and the aggregation of the photocatalytic materials 20 and 20 is effectively prevented. As a result, the decrease in the effective surface area of the photocatalytic material 20 can be effectively suppressed, and the photocatalytic activity of the photocatalytic material 20 can be maintained for a long period of time. That is, according to the photocatalyst structure 1, it is possible to suppress a decrease in photocatalytic activity due to aggregation of the photocatalyst substance 20, and it is possible to extend the life of the photocatalyst structure 1. Furthermore, by extending the life of the photocatalyst structure 1, the frequency of replacing the photocatalyst structure 1 can be reduced, the amount of waste of the used photocatalyst structure 1 can be greatly reduced, and resources can be saved.

In general, in the case where a photocatalyst structure is used in a fluid (for example, air, water, or the like), an external force may be received from the fluid. In this case, if the photocatalyst substance is held only in an attached state on the outer surface of the carrier 10, there is a problem that the photocatalyst substance is easily detached from the outer surface of the carrier 10 under the influence of an external force from the fluid. In contrast, in the photocatalyst structure 1, since the photocatalyst substance 20 is present in at least the channels 11 of the support 10, the photocatalyst substance 20 is less likely to be detached from the support 10 even when it is affected by an external force from a fluid. Namely, it is considered that: when the photocatalyst structure 1 is in a fluid, the fluid flows into the channels 11 from the holes 11a of the support 10, and therefore the velocity of the fluid flowing through the channels 11 is lower than the velocity of the fluid flowing through the outer surface of the support 10 due to flow path resistance (frictional force). Due to the influence of the flow path resistance, the pressure that the photocatalyst substance 20 existing in the channel 11 receives from the fluid is lower than the pressure that the photocatalyst substance receives from the fluid on the outside (outer surface) of the carrier 10. Therefore, the photocatalyst substance 20 existing in the carrier 11 can be effectively inhibited from being detached, and the photocatalytic activity of the photocatalyst substance 20 can be stably maintained for a long period of time. It should be noted that: the more the channels 11 of the carrier 10 have bends and branches, the more the interior of the carrier 10 has a complicated three-dimensional structure, and the greater the flow path resistance as described above.

Further, it is preferable that the passage 11 has: any one of one-dimensional pores, two-dimensional pores, and three-dimensional pores defined by the framework structure of the zeolite-type compound; and an expanded diameter portion 12 different from any of the one-dimensional hole, the two-dimensional hole, and the three-dimensional hole, in this case, the photocatalyst substance 20 is preferably present at least in the expanded diameter portion 12, and more preferably included at least in the expanded diameter portion 12. The one-dimensional hole referred to herein is a tunnel-type or cage-type hole in which one-dimensional channels (channels) are formed, or a plurality of tunnel-type or cage-type holes (a plurality of one-dimensional channels) in which a plurality of one-dimensional channels are formed. In addition, the two-dimensional hole refers to a two-dimensional hole formed by two-dimensionally connecting a plurality of one-dimensional holes, and the three-dimensional hole refers to a three-dimensional hole formed by three-dimensionally connecting a plurality of one-dimensional holes.

This can further restrict the movement of the photocatalytic material 20 within the carrier 10, and can further effectively prevent the photocatalytic material 20 from being detached and the photocatalytic materials 20 and 20 from being aggregated. Here, inclusion means a state in which the photocatalyst substance 20 is contained in the carrier 10. In this case, the photocatalyst substance 20 and the carrier 10 do not necessarily need to be in direct contact with each other, and the photocatalyst substance 20 may be indirectly held on the carrier 10 in a state where another substance (for example, a surfactant or the like) is interposed between the photocatalyst substance 20 and the carrier 10.

Fig. 1 (b) shows a case where the photocatalyst substance 20 is enclosed in the enlarged diameter portion 12, but the configuration is not limited to this, and the photocatalyst substance 20 may be held in the channel 11 in a state where a part thereof protrudes to the outside of the enlarged diameter portion 12. The photocatalyst substance 20 may be partially embedded in or held by adhesion or the like in a portion of the channel 11 other than the enlarged diameter portion 12 (for example, an inner wall portion of the channel 11).

Further, the enlarged diameter portion 12 preferably causes a plurality of holes 11a, 11a constituting any one of the one-dimensional hole, the two-dimensional hole, and the three-dimensional hole to communicate with each other. Thus, since another channel different from the one-dimensional hole, the two-dimensional hole, or the three-dimensional hole is provided in the carrier 10, the function of the catalyst material 20 can be further exerted.

Further, it is preferable that the channel 11 is three-dimensionally formed inside the carrier 10 so as to include a branching portion or a merging portion, and the diameter-expanding portion 12 is provided in the branching portion or the merging portion of the channel 11.

The average inner diameter D of the channel 11 formed in the carrier 10_FThe average value of the minor axis and major axis of the pores 11a constituting any one of the one-dimensional pores, two-dimensional pores, and three-dimensional pores is, for example, 0.1nm to 1.5nm, preferably 0.5nm to 0.8 nm. Further, the inner diameter D of the enlarged diameter portion 12_EFor example, 0.5nm to 50nm, preferably 1.1nm to 40nm, and more preferably 1.1nm to 3.3 nm. Inner diameter D of enlarged diameter portion 12_EFor example, the pore diameter of the precursor (A) described later and the average particle diameter D of the photocatalyst substance 20 to be included_C. Inner diameter D of enlarged diameter portion 12_EIs of a size capable of enclosing the photocatalyst substance 20.

The support 10 is composed of a zeolite-type compound. Examples of the zeolite-type compound include: silicate compounds such as zeolite (aluminosilicate), cation-exchanged zeolite, and silicalite; zeolite-like compounds such as aluminoborate, aluminoarsenate, germanate and the like; and phosphate-based zeolite-like substances such as molybdenum phosphate. Among them, the zeolite-type compound is preferably a silicate compound.

The framework structure of the zeolite-type compound is selected from FAU-type (Y-type or X-type), MTW-type, MFI-type (ZSM-5), FER-type (ferrierite), LTA-type (A-type), MWW-type (MCM-22), MOR-type (mordenite), LTL-type (L-type), BEA-type (beta-type), etc., preferably MFI-type, more preferably ZSM-5. In the zeolite-type compound, a plurality of pores having pore diameters corresponding to respective framework structures are formed, and for example, the maximum pore diameter of MFI type is 0.636nm

Average pore diameter of 0.560nm

The photocatalyst substance 20 will be described in detail below.

The photocatalyst substance 20 is a metal oxide fine particle. There are: the metal oxide fine particles 20 are primary particles, and secondary particles formed by aggregation of the primary particlesParticles, but the average particle diameter D of the fine metal oxide particles 20_CPreferably greater than the average internal diameter D of the channel 11_FAnd is not more than the inner diameter D of the diameter-expanding portion 12_E(D_F<D_C≤D_E). The metal oxide fine particles 20 are preferably included in the diameter-enlarged part 12 in the channel 11, and the movement of the metal oxide fine particles 20 in the carrier 10 is restricted. Thus, even when the metal oxide fine particles 20 are subjected to an external force from a fluid, the movement of the metal oxide fine particles 20 in the carrier 10 can be suppressed, and the metal oxide fine particles 20, 20 … … included in the respective diameter-enlarged portions 12, 12 … … dispersedly arranged in the channels 11 of the carrier 10 can be effectively prevented from contacting each other.

The metal oxide fine particles 20 have an average particle diameter D of either primary particles or secondary particles_CEach of these is preferably 0.1 to 50nm, more preferably 0.1nm or more and less than 30nm, still more preferably 0.45 to 14.0nm, and particularly preferably 1.0 to 3.3 nm. Further, the average particle diameter D of the metal oxide fine particles 20_CRelative to the mean internal diameter D of the channel 11_FRatio (D)_C/D_F) Preferably 0.06 to 500, more preferably 0.1 to 45, further preferably 1.1 to 45, and particularly preferably 1.7 to 4.5.

In addition, when the photocatalyst substance 20 is a metal oxide fine particle, it is preferable to contain the metal element (M) of the metal oxide fine particle in an amount of 0.5 to 2.5 mass% with respect to the photocatalyst structure 1, and more preferable to contain the metal element (M) of the metal oxide fine particle in an amount of 0.5 to 1.5 mass% with respect to the photocatalyst structure 1. For example, in the case where the metal element (M) is Co, the content (mass%) of the Co element is represented by (mass of the Co element)/(mass of all elements of the catalyst structure 1) × 100.

The metal oxide fine particles may be composed of a metal oxide, and may be composed of a single metal oxide or a mixture of two or more metal oxides. In the present specification, the term "metal oxide" (as a material) constituting the metal oxide fine particles means an oxide containing one metal element (M) and a composite oxide containing two or more metal elements (M), and is a generic term for an oxide containing one or more metal elements (M).

Examples of such metal oxides include: cobalt oxide (CoO)_x) Nickel oxide (NiO)_x) Iron oxide (FeO)_x) Copper oxide (CuO)_x) Zirconium oxide (ZrO)_x) Cerium oxide (CeO)_x) Aluminum oxide (AlO)_x) Niobium oxide (NbO)_x) Titanium oxide (TiO)_x) Bismuth oxide (BiO)_x) Molybdenum oxide (MoO)_x) Vanadium Oxide (VO)_x) Chromium oxide (CrO)_x) Tungsten oxide (WO)_x) Cerium oxide (CeO)_x) And the like, preferably any one or more of the above as a main component. Among these, titanium oxide and an alloy oxide containing titanium oxide are more preferable, and titanium oxide is more preferable. In addition, in the case where the metal oxide fine particles contain a metal oxide composed of two or more of the above metal species, the metal oxide may be referred to as a composite metal oxide.

The ratio (atomic ratio Si/M) of silicon (Si) constituting the carrier 10 to the metal element (M) constituting the metal oxide fine particles 20 is preferably 10 to 1000, and more preferably 50 to 200. When the above ratio is more than 1000, the activity may be low, and the function as a photocatalyst substance may not be sufficiently obtained. On the other hand, when the ratio is less than 10, the ratio of the metal oxide fine particles 20 is too large, and the strength of the carrier 10 tends to be lowered. The metal oxide fine particles 20 referred to herein are metal oxide fine particles held or supported in the carrier 10, and do not include metal oxide fine particles adhering to the outer surface of the carrier 10.

[ photocatalytic Activity of photocatalyst Structure ]

Fig. 2 is a partially enlarged cross-sectional view for explaining an example of the catalytic function of the photocatalyst structure 1. As shown in fig. 2, the metal oxide fine particles 20 as the photocatalyst substance are held in the channels 11 (particularly, the diameter-enlarged portions 12) of the carrier 10. Thus, for example, (H) contained in the atmosphere₂O), oxygen (O)₂) Flows into the passage from the hole 11a11 in contact with the metal oxide particles 20 held within the channels 11. Further, a part of the light (particularly, ultraviolet rays) irradiated on the outer surface of the photocatalyst structure 1 passes through the support 10 or enters from the channels 11, and reaches the metal oxide fine particles 20 held in the channels 11 while being reflected inside the channels 11. Then, the water (H) flowing into the passage 11₂O), oxygen (O)₂) When brought into contact with the metal oxide fine particles 20, OH is generated by the photocatalytic function of the metal oxide fine particles 20 activated by irradiation with light (particularly, ultraviolet rays) for a certain period of time^-、O^2-And the like. These oxidizing agents decompose bacteria, odor components, dirt components, and the like, thereby exerting antifouling properties (e.g., decomposition power).

Further, the photocatalyst structure 1 can restrict the movement of the metal oxide fine particles 20 in the support 10, and can effectively prevent the aggregation between the metal oxide fine particles 20, 20. As a result, the reduction of the effective surface area as a photocatalyst can be effectively suppressed, and the photocatalytic function of the metal oxide fine particles 20 can be maintained for a long period of time. That is, according to the photocatalyst structure 1, it is possible to suppress the decrease in the photocatalytic function due to the aggregation of the photocatalyst particles, and it is possible to extend the life of the photocatalyst structure 1. Furthermore, by extending the life of the photocatalyst structure 1, the frequency of replacing the photocatalyst structure 1 can be reduced, the amount of waste of the used photocatalyst structure 1 can be greatly reduced, and resources can be saved.

Further, as shown in FIG. 2, the average particle diameter D of the metal oxide fine particles 20_CGreater than the average internal diameter D of the channel 11_FAnd is smaller than the inner diameter D of the diameter-enlarged part 12_EIn the case of (D)_F<D_C<D_E) Small channels 13 (arrows in the figure) are formed between the metal oxide fine particles 20 and the enlarged diameter portion 12, and water (H) flowing into the small channels 13₂O), oxygen (O)₂) In contact with the metal oxide particles 20. At this time, the metal oxide microparticles 20 are confined in the enlarged diameter portion 12 and can maintain and contain the water (H) flowing into the channel 11₂O), oxygen (O)₂) A large contact area of the fluid (e.g., the atmosphere).

[ modification of photocatalyst Structure 1]

Fig. 4 is a schematic diagram showing a modification of the photocatalyst structure 1 of fig. 1.

The photocatalyst structure 1 of fig. 1 is shown to include the support 10 and the photocatalyst substance 20 present in the support 10, but the structure is not limited to this, and for example, as shown in fig. 4, the photocatalyst structure 2 may further include at least one other photocatalyst substance 30 held on the outer surface 10a of the support 10.

The photocatalyst substance 30 is a substance that exerts a photocatalytic function. The material of the other photocatalyst substance 30 may be the same as or different from that of the photocatalyst substance 20. According to this configuration, the content of the photocatalytic material held in the photocatalytic structure 2 can be increased, and the photocatalytic activity of the photocatalytic material can be further promoted.

In this case, it is preferable that the content of the photocatalyst substance 20 present in the support 10 is larger than the content of the at least one other photocatalyst substance 30 held on the outer surface 10a of the support 10.

Thus, the photocatalytic function of the photocatalytic material 20 held in the carrier 10 becomes dominant, and the photocatalytic function of the photocatalytic material is stably exhibited.

[ method for producing photocatalyst Structure ]

Fig. 3 is a flowchart showing an example of the method for manufacturing the photocatalyst structure 1 of fig. 1. An example of a method for producing a photocatalyst structure is described below.

(step S1: preparation Process)

As shown in fig. 3, first, a precursor material (a) for obtaining a support having a porous structure made of a zeolite-type compound is prepared. The precursor material (a) is preferably a regular mesoporous substance, and may be appropriately selected depending on the type (composition) of the zeolite-type compound constituting the support of the photocatalyst structure.

Here, when the zeolite-type compound constituting the carrier of the photocatalyst structure is a silicate compound, the regular mesoporous material is preferably a compound composed of an Si — O skeleton in which pores having a pore diameter of 1nm to 50nm are uniformly and regularly developed in one-dimensional, two-dimensional or three-dimensional size. Such a regular mesoporous material is obtained as various compositions according to synthesis conditions, and specific examples of the compositions include: SBA-1, SBA-15, SBA-16, KIT-6, FSM-16, MCM-41, etc., wherein MCM-41 is preferred. The pore diameter of SBA-1 is 10nm to 30nm, the pore diameter of SBA-15 is 6nm to 10nm, the pore diameter of SBA-16 is 6nm, the pore diameter of KIT-6 is 9nm, the pore diameter of FSM-16 is 3nm to 5nm, and the pore diameter of MCM-41 is 1nm to 10 nm. Examples of such a regular mesoporous material include: mesoporous silica, mesoporous aluminosilicates, mesoporous metallosilicates, and the like.

The precursor (a) may be any of commercially available products and synthetic products. In the case of synthesizing the precursor material (a), it can be carried out by a known method for synthesizing a mesoporous substance having a regularity. For example, a mixed solution containing a raw material containing a constituent element of the precursor material (a) and a template agent for specifying the structure of the precursor material (a) is prepared, and hydrothermal treatment (hydrothermal synthesis) is performed by adjusting the pH as necessary. Then, the precipitate (product) obtained by the hydrothermal treatment is recovered (e.g., filtered), washed and dried as necessary, and further fired, whereby the precursor material (a) as a powdery regular mesoporous substance can be obtained. Here, as the solvent of the mixed solution, for example, an organic solvent such as water or alcohol, or a mixed solvent thereof can be used. The raw material may be selected depending on the kind of the carrier, and examples thereof include: silicon agents (silica agents) such as Tetraethoxysilane (TEOS), fumed silica (fumed silica), quartz sand, and the like. Further, as the template agent, various surfactants, block copolymers and the like can be used, and it is preferably selected according to the kind of the composition of the ordered mesoporous substance, and for example, in the case of producing MCM-41, a surfactant such as cetyltrimethylammonium bromide is preferred. The hydrothermal treatment may be carried out, for example, in a closed vessel under treatment conditions of 80 to 800 ℃ for 5 to 240 hours and 0 to 2000 kPa. The firing treatment may be carried out, for example, in air under the treatment conditions of 350 to 850 ℃ for 2 to 30 hours.

(step S2: impregnation step)

Next, the prepared precursor material (a) is immersed in a metal-containing solution to obtain a precursor material (B).

The metal-containing solution may be a solution containing a metal component (for example, metal ion) corresponding to the metal element (M) constituting the metal oxide fine particles of the photocatalyst structure, and can be prepared, for example, by dissolving a metal salt containing the metal element (M) in a solvent. Examples of such metal salts include: chlorides, hydroxides, oxides, sulfates, nitrates, etc., among which nitrates are preferred. As the solvent, for example, an organic solvent such as water or alcohol, or a mixed solvent thereof can be used.

The method for immersing the metal-containing solution in the precursor material (a) is not particularly limited, and for example, it is preferable to add the metal-containing solution in small amounts at a time in a plurality of times while stirring the powdery precursor material (a) before the firing step described later. Further, from the viewpoint that the metal-containing solution more easily penetrates into the inside of the pores of the precursor material (a), it is preferable to add a surfactant as an additive in advance before adding the metal-containing solution to the precursor material (a). Consider that: such an additive has an effect of covering the outer surface of the precursor material (a), and suppresses the metal-containing solution added later from adhering to the outer surface of the precursor material (a), so that the metal-containing solution more easily penetrates into the pores of the precursor material (a).

Examples of such additives include polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether and nonionic surfactants such as polyoxyethylene alkylphenyl ether. Consider that: these surfactants have large molecular sizes and cannot penetrate into the pores of the precursor material (a), and therefore do not adhere to the inside of the pores and do not inhibit the metal-containing solution from penetrating into the pores. As a method of adding the nonionic surfactant, for example, it is preferable to add 50 to 500 mass% of the nonionic surfactant to the precursor material (a) before a firing step described later. If the amount of the nonionic surfactant added to the precursor material (a) is less than 50 mass%, the above-described inhibiting effect is hardly exhibited, and if the amount of the nonionic surfactant added to the precursor material (a) is more than 500 mass%, the viscosity is excessively increased, which is not preferable. Thus, the amount of the nonionic surfactant added to the precursor material (a) is set to a value within the above range.

Further, the amount of the metal-containing solution added to the precursor material (a) is preferably adjusted as appropriate in consideration of the amount of the metal element (M) contained in the metal-containing solution to be impregnated into the precursor material (a) (that is, the amount of the metal element (M) to be present in the precursor material (B)). For example, before the firing step described later, the amount of the metal-containing solution added to the precursor material (a) is preferably adjusted so that the ratio (atomic ratio Si/M) of silicon (Si) constituting the precursor material (a) to the metal element (M) contained in the metal-containing solution added to the precursor material (a) is 10 to 1000, more preferably 50 to 200. For example, when a surfactant is added as an additive to the precursor material (a) before the metal-containing solution is added to the precursor material (a), the metal element (M) of the metal oxide fine particles can be contained in an amount of 0.5 to 2.5 mass% with respect to the photocatalyst structure by setting the amount of the metal-containing solution added to the precursor material (a) to 50 to 200 in terms of an atomic ratio Si/M. In the state of the precursor material (B), if the metal concentration of the metal-containing solution, the presence or absence of the additive, and other conditions such as temperature and pressure are the same, the amount of the metal element (M) present in the pores thereof is substantially proportional to the amount of the metal-containing solution added to the precursor material (a). Further, the presence and amount of the metal element (M) in the precursor material (B) are in proportional relation to the amount of the metal element constituting the metal oxide fine particles present in the carrier of the photocatalyst structure. Therefore, by controlling the amount of the metal-containing solution added to the precursor material (a) within the above range, the interior of the pores of the precursor material (a) can be sufficiently impregnated with the metal-containing solution, and the amount of the metal oxide fine particles present in the carrier of the photocatalyst structure can be adjusted.

After the metal-containing solution is impregnated in the precursor material (a), a cleaning treatment may be performed as needed. As the cleaning solution, water, an organic solvent such as alcohol, or a mixed solvent thereof can be used. Further, it is preferable that the metal-containing solution is immersed in the precursor material (a) and, after a cleaning treatment is performed as necessary, a drying treatment is further performed. Examples of the drying treatment include natural drying at about evening and high-temperature drying at 150 ℃. When the firing treatment described later is performed in a state where a large amount of moisture contained in the metal-containing solution and moisture in the cleaning solution remain in the precursor (a), the skeleton structure of the ordered mesoporous material as the precursor (a) may be broken, and therefore, it is preferable to sufficiently dry the precursor (a).

(step S3: firing Process)

Next, a precursor material (B) obtained by impregnating a precursor material (a) for obtaining a support having a porous structure made of a zeolite-type compound with a metal-containing solution is fired to obtain a precursor material (C).

The firing treatment is preferably carried out in air under the treatment conditions of 350 to 850 ℃ for 2 to 30 hours, for example. By the firing treatment, the metal component impregnated into the pores of the ordered mesoporous material is subjected to crystal growth to form metal oxide fine particles in the pores.

(step S4: hydrothermal treatment Process)

Next, a mixed solution in which the precursor material (C) and the structure directing agent are mixed is prepared, and the precursor material (C) obtained by firing the precursor material (B) is subjected to hydrothermal treatment to obtain the photocatalyst structure.

The structure directing agent is a template agent for specifying the framework structure of the support of the photocatalyst structure, and a surfactant, for example, can be used. The structure directing agent is preferably selected according to the skeletal structure of the support of the photocatalyst structure, and is preferably a surfactant such as tetramethylammonium bromide (TMABr), tetraethylammonium bromide (TEABr), tetrapropylammonium bromide (TPABr), or the like.

The mixing of the precursor material (C) and the structure directing agent may be performed during the hydrothermal treatment step or may be performed before the hydrothermal treatment step. The method for preparing the mixed solution is not particularly limited, and the precursor material (C), the structure-directing agent, and the solvent may be mixed at the same time, or the precursor material (C) and the structure-directing agent may be dispersed in the solvent in the form of separate solutions, and then the respective dispersed solutions may be mixed. As the solvent, for example, an organic solvent such as water or alcohol, or a mixed solvent thereof can be used. The mixed solution is preferably adjusted in pH by using an acid or an alkali in advance before the hydrothermal treatment.

The hydrothermal treatment can be carried out by a known method, and is preferably carried out in a closed vessel under treatment conditions of 80 to 800 ℃ for 5 to 240 hours and 0 to 2000kPa, for example. Further, the hydrothermal treatment is preferably performed in an alkaline environment. Although the reaction mechanism is not necessarily clear here, when the precursor material (C) is used as a raw material and subjected to hydrothermal treatment, the framework structure of the fine pore substance is gradually broken in the regularity as the precursor material (C), but the position of the metal oxide fine particles inside the fine pores of the precursor material (C) is maintained substantially unchanged, and a new framework structure (porous structure) serving as a support of the photocatalyst structure is formed by the action of the structure-directing agent. In this way, the obtained photocatalyst structure includes a carrier having a porous structure and metal oxide fine particles present in the carrier, and the carrier further has channels in which the plurality of pores are interconnected due to the porous structure thereof, and at least a part of the metal oxide fine particles are held in the channels of the carrier.

In the present embodiment, in the hydrothermal treatment step, a mixed solution in which the precursor material (C) and the structure-directing agent are mixed is prepared, and the hydrothermal treatment is performed on the precursor material (C), but the hydrothermal treatment is not limited to this, and the hydrothermal treatment may be performed on the precursor material (C) without mixing the precursor material (C) and the structure-directing agent.

It is preferable that the precipitate (photocatalyst structure) obtained after the hydrothermal treatment is recovered (e.g., filtered), and then washed, dried, and fired as necessary. As the cleaning solution, for example, water, an organic solvent such as alcohol, or a mixed solution thereof can be used. Examples of the drying treatment include natural drying at about evening and high-temperature drying at 150 ℃. When the calcination treatment is performed in a state where a large amount of water remains in the precipitate, the skeleton structure of the support serving as the photocatalyst structure may be broken, and therefore, it is preferable to sufficiently dry the precipitate. The firing treatment may be performed, for example, in air under the treatment conditions of 350 to 850 ℃ for 2 to 30 hours. By the firing treatment, the structure directing agent adhering to the photocatalyst structure is burned off. Further, the photocatalyst structure can be used as it is without firing the collected precipitate depending on the purpose of use. For example, when the environment in which the photocatalyst structure is used is a high-temperature environment such as an oxidizing environment, the structure-directing agent is burned off by exposure to the use environment for a certain period of time, and the same photocatalyst structure as that obtained when the firing treatment is performed is obtained, and therefore, the photocatalyst structure can be used as it is. For example, in the case where a photocatalyst structure is mixed with a binder material to form a coating material, and then the coating material is applied to a substrate and then baked to form a photocatalyst layer, a photocatalyst structure composition and a photocatalyst coating material are produced, which will be described later, the structure-directing agent is burned off during baking at the time of forming the photocatalyst layer, and the same photocatalyst structure as that obtained in the case where the baking treatment is performed can be obtained, and therefore, these can be used as they are.

[ photocatalyst Structure composition ]

However, when a photocatalyst is actually used, a photocatalyst layer is generally formed on the surface of a substrate (for example, wall material, tile, glass (mirror), circulation filter, sanitary ware, or the like) and used. Examples of a method for forming such a photocatalyst layer include: a method of mixing an organic binder and a photocatalyst to form a coating and applying the coating to the surface of a substrate (Japanese patent laid-open Nos. 2007 and 519799 and 2012 and 210557), a method of fixing a photocatalyst to a binder layer formed in advance on the surface of a substrate (Japanese patent laid-open No. 2006 and 021994), and the like.

However, in the conventional method for forming a photocatalyst layer as described above, since the photocatalyst particles are directly contacted with the binder material for fixation, the organic binder may be decomposed due to the high catalytic activity of the photocatalyst. Such decomposition of the binder material is one of the causes of deterioration of the coating material (photocatalyst composition) and detachment of the photocatalyst layer formed on the substrate surface from the substrate surface.

As a result of intensive studies to achieve the above object, the present inventors have found that a photocatalyst structure composition comprising a photocatalyst structure and a binder material, which is stable for a long period of time, can be obtained, the photocatalyst structure comprising: a porous support composed of a zeolite-type compound; and at least one photocatalyst substance present in the carrier, the carrier having mutually communicating channels, the photocatalyst substance being a metal oxide fine particle, and being present in at least the channels of the carrier, whereby direct contact of the binder material with the photocatalyst substance is prevented, and decomposition of the binder material by the photocatalyst substance is suppressed. The photocatalyst structure composition of the present embodiment will be described in detail below.

The photocatalyst structure composition of the present embodiment mainly contains the photocatalyst structure of the above embodiment and a binder material. If necessary, various additives such as a solvent may be further contained.

With such a configuration, the photocatalyst substance is contained in a carrier having a porous structure made of a zeolite-type compound, and mixed as a photocatalyst structure with a binder material described later. Therefore, in the photocatalyst structure composition, the binder material can be effectively prevented from coming into direct contact with the photocatalyst substance, and the decomposition of the binder material by the photocatalyst substance can be suppressed. As a result, the binder material does not deteriorate over a long period of time, the stability as a coating material is improved, and the binder material does not detach from the substrate surface after the photocatalyst layer is formed on the substrate surface, and thus excellent catalytic activity can be maintained.

In addition, in the photocatalyst structure 1, the movement of the photocatalyst substance 20 in the carrier 10 is restricted, and the aggregation of the photocatalyst substances 20 and 20 is effectively prevented. Therefore, the decrease in the effective surface area of the photocatalytic material 20 can be effectively suppressed, and the photocatalytic activity of the photocatalytic material 20 can be maintained for a long period of time. That is, according to the photocatalyst structure 1, it is possible to suppress a decrease in photocatalytic activity due to aggregation of the photocatalyst substance 20, and it is possible to extend the life of the photocatalyst structure 1. Furthermore, by extending the life of the photocatalyst structure 1, the frequency of replacing the photocatalyst structure 1 can be reduced, the amount of waste of the used photocatalyst structure 1 can be greatly reduced, and resources can be saved.

In the photocatalyst structure composition, the other photocatalyst substance 30 shown in fig. 4 is present on the outer surface 10a of the support 10, and therefore is in direct contact with the binder material. Therefore, there is a fear that the binder material is decomposed by the photocatalyst substance 30. Therefore, it is preferable that the content of the at least one other photocatalyst substance 30 held on the outer surface 10a of the carrier 10 is smaller than the content of the photocatalyst substance 20 present in the carrier 10.

[ method for producing photocatalyst Structure composition ]

The photocatalyst structure composition can be produced by mixing the above photocatalyst structure with a binder material and adding various additives as necessary.

The mixing method is not particularly limited, and can be performed by a known method, for example, by stirring and mixing, or by kneading with a three-roll mill or a high-pressure homogenizer. Since the photocatalyst structure has a support having a porous structure, it is preferable to mix the photocatalyst structure by a method such as stirring and mixing without applying a physically large pressure in order to maintain the structure satisfactorily.

The form of the photocatalyst structure composition is not particularly limited, and may be a coating material or a film. When the photocatalyst composition is, for example, a coating material, it is preferable to appropriately adjust the viscosity according to the use mode (spraying, brushing, dipping, printing, etc.).

1. Photocatalyst structure

The photocatalyst structure produced by the above production method is used as a photocatalyst structure.

2. Adhesive material

The binder material may be any of an organic binder and an inorganic binder.

In the conventional photocatalyst composition, in order to avoid decomposition of the binder material by the photocatalyst substance, it is preferable to use an inorganic binder as the binder material. However, according to the photocatalyst structure composition of the present embodiment, since the photocatalyst substance is contained in the inside of the carrier to form the photocatalyst structure, direct contact with the binder material can be effectively prevented, and decomposition of the binder material by the photocatalyst substance can be suppressed. Therefore, an organic binder can be suitably used also in the photocatalyst structure composition of the present embodiment.

As the organic binder, for example, the following can be used: and resin binders such as polyurethane, poly (meth) acrylate, polystyrene, polyester, polyamide, polyimide, polyurea, and the like.

3. Various additives

If necessary, various additives such as a solvent may be further contained.

As the solvent, known materials can be used, and examples thereof include an aqueous solvent such as water, an organic solvent such as alcohol, and a mixed solvent thereof. The photocatalyst structure composition can be adjusted to a viscosity suitable for use by adding a solvent.

[ photocatalyst-coated Material ]

However, when a photocatalyst is actually used, a photocatalyst layer is generally formed on the surface of a substrate (for example, wall material, tile, glass (mirror), circulation filter, sanitary ware, or the like) and used. As a method for forming such a photocatalyst layer, for example, there are known: a method of mixing a binder material and a photocatalyst substance to form a coating material and applying the coating material to the surface of a substrate.

In the photocatalyst coating material including the photocatalyst layer formed on the conventional substrate as described above, the photocatalyst substance is directly in contact with the substrate, and therefore, the substrate substance may be decomposed due to the high catalytic activity of the photocatalyst substance. Such decomposition of the base material causes deterioration of the base material, and the photocatalyst material of the photocatalyst layer formed on the surface of the base material is separated from the surface of the base material.

In order to solve such a problem, a method of using a silane coupling agent as a binder material has been proposed (international publication No. 2016/181622). However, even in such a method, the structure in which the photocatalyst substance is in direct contact with the substrate is not changed, and deterioration of the substrate cannot be sufficiently suppressed.

As a result of intensive studies to achieve the above object, the present inventors have found that a photocatalyst coating material comprising a base material and a photocatalyst layer formed on the base material, wherein the photocatalyst layer contains a photocatalyst structure, and the photocatalyst coating material has: a porous support composed of a zeolite-type compound; and at least one photocatalyst substance present in the carrier, the carrier having channels communicating with each other, the photocatalyst substance being a metal oxide fine particle, and being present in at least the channels of the carrier, the photocatalyst substance being capable of preventing direct contact between the substrate and the photocatalyst substance, capable of suppressing decomposition of the substrate substance by the photocatalyst substance, and capable of maintaining stable quality over a long period of time. The photocatalyst structure of the present embodiment will be described in detail below.

The photocatalyst coating material of the present embodiment has a base material, and a photocatalyst layer containing the photocatalyst structure of the above embodiment formed on the base material.

Fig. 5 is a schematic cross-sectional view schematically showing a cross section of the photocatalyst coating material according to the present embodiment. As shown in fig. 5, the photocatalyst coating material 100 of the present embodiment includes a base material 101 and a photocatalyst layer 102 formed on the base material 101.

Fig. 5 shows a case where the photocatalyst layer 102 is directly formed on the surface of the substrate 101, but the present invention is not limited to this configuration, and the photocatalyst layer 102 may be formed on the surface of the substrate 101 indirectly as long as it is formed on the substrate 101. The case where the photocatalyst layer 102 is indirectly formed on the substrate 101 (not shown) is, for example, a case where an adhesive layer for fixing the photocatalyst layer 102 is provided between the substrate 101 and the photocatalyst layer 102.

The photocatalyst layer is a coating film formed on the substrate, containing the photocatalyst structure of the above embodiment. In the photocatalyst coating material 100, a photocatalytic reaction occurs on the photocatalyst layer 102.

The photocatalyst layer 102 may contain at least a photocatalyst structure, and may further contain other components. Examples of the other components include a binder and a metal oxide suitable for the photocatalyst other than the above.

With such a configuration, the photocatalyst substance is contained in a carrier having a porous structure made of a zeolite-type compound, and is formed on a substrate as a photocatalyst structure, which will be described later. Therefore, the substrate can be effectively prevented from coming into direct contact with the photocatalytic substance, and the decomposition of the substrate substance by the photocatalytic substance can be suppressed. As a result, the base material does not deteriorate over a long period of time, and the quality can be maintained, and the photocatalyst structure does not separate from the surface of the base material, and excellent catalytic activity can be maintained.

In addition, in such a photocatalyst structure, the movement of the photocatalyst substance 20 within the carrier 10 is restricted, and the aggregation between the photocatalyst substances 20, 20 is effectively prevented. Therefore, the decrease in the effective surface area of the photocatalytic material 20 can be effectively suppressed, and the photocatalytic activity of the photocatalytic material 20 can be maintained for a long period of time. That is, according to the photocatalyst structure 1, it is possible to suppress a decrease in photocatalytic activity due to aggregation of the photocatalyst substance 20, and it is possible to extend the life of the photocatalyst structure 1. Furthermore, by extending the life of the photocatalyst structure 1, the frequency of replacing the photocatalyst structure 1 can be reduced, the amount of waste of the used photocatalyst structure 1 can be greatly reduced, and resources can be saved.

In the photocatalyst coating material, the other photocatalyst substance 30 shown in fig. 4 is held on the outer surface 10a of the support 10 and is therefore in direct contact with the base material. Therefore, there is a fear that the base material is decomposed by the photocatalyst substance 30. Therefore, it is preferable that the content of the at least one other photocatalyst substance 30 held on the outer surface 10a of the carrier 10 is smaller than the content of the photocatalyst substance 20 present in the carrier 10.

[ method for producing photocatalyst-coated Material ]

The photocatalyst coating material 100 can be produced by forming a photocatalyst layer 102 on a base material 101.

The method for forming the photocatalyst layer 102 is not particularly limited, and can be performed by a known method. Examples thereof include: a method of forming the photocatalyst structure into a paint and forming the paint on the surface of the base material 101 by coating, spraying, dipping, or the like.

1. Photocatalyst structure

The photocatalyst structure produced by the above production method is used as a photocatalyst structure.

2. Base material

The substrate 101 is not particularly limited, and examples thereof include: building materials, interior materials, appliances, packaging materials, and the like. In particular, the photocatalyst layer of the present invention is preferably formed on a building material as a base material. Here, the building material is a member used as an exterior member or an outdoor member on the outer periphery of a building such as a house. The exterior member is a building material for finishing an outer peripheral surface facing the outside of a building. The outdoor member is a building material used for various outdoor structures located on the outer periphery of a building such as a house. Examples of the outdoor structure include: fences, doors, fences, railings, shutters, fences, courtyard walls, garages, car houses, mud floors, door footprints, decorative walls, canopy frames, wooden platforms, paving materials, various posts, placing objects, and the like.

In the conventional photocatalyst coating material, it is preferable to use an inorganic base material as the base material in order to avoid decomposition of the base material by the photocatalyst substance. However, according to the photocatalyst coating material 100 of the present embodiment, since the photocatalyst substance is contained in the inside of the carrier as the photocatalyst structure, direct contact with the substrate 101 can be effectively prevented, and decomposition of the substrate substance by the photocatalyst substance can be suppressed. Further, it is also effective for removing dirt on the surface of the structure. In the photocatalyst coating material 100 of the present embodiment, an organic base material can be suitably used.

The substrate 101 may be made of an organic material or an inorganic material, and examples of these materials include: glass, concrete, acrylic resin, acrylic urethane resin, tetrafluoro resin, and the like.

3. Other layers

The photocatalyst coating material 100 may further include another layer (not shown) between the base material 101 and the photocatalyst layer 102. Examples of other layers include: adhesive layers, uv inhibiting layers, and the like.

Examples of the adhesive layer include: a layer made of an organic binder such as polyimide, and the like.

According to the photocatalyst coating material 100 of the embodiment, since the photocatalyst substance is contained in the inside of the carrier as the photocatalyst structure, it is possible to effectively prevent the photocatalyst substance from directly contacting the other layer as described above, and it is possible to suppress the decomposition of the constituent substance of the other layer by the photocatalyst substance.

Hereinafter, a case where the photocatalyst structure is formed into a coating material will be described as an example.

The coating material containing the photocatalyst structure can be prepared by mixing the photocatalyst structure with a binder material and adding various additives as necessary.

The mixing method is not particularly limited, and can be performed by a known method, for example, by stirring and mixing, or by kneading with a three-roll mill or a high-pressure homogenizer. Since the photocatalyst structure has a support having a porous structure, it is preferable to mix the photocatalyst structure by a method such as stirring and mixing without applying a physically large pressure in order to maintain the structure satisfactorily. Further, it is preferable to appropriately adjust the viscosity as necessary.

The obtained coating material is applied to the substrate 101, and if necessary, a drying treatment and a baking treatment are performed, whereby the photocatalyst layer 102 having a desired thickness can be formed. Examples of the drying treatment include natural drying and high-temperature drying.

The obtained coating material may be molded into a sheet shape as described above, and attached to the base material 101 via an adhesive layer to form the photocatalyst layer 102.

Although the photocatalyst structure is used as a coating material in the above description, for example, the photocatalyst layer 102 may be formed by forming a binder layer on the surface of the substrate 101 in advance, adhering a powdery photocatalyst structure to the binder layer, and fixing the photocatalyst structure to the substrate 101.

The photocatalyst structure, the photocatalyst structure composition, and the photocatalyst coating according to the embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments, and various modifications and changes can be made based on the technical idea of the present invention.

For example, in the above embodiment, the photocatalyst dispersion liquid may be used in which the photocatalyst structure is dispersed in a dispersion medium. As the dispersion times, for example,: water such as purified water, distilled water, and ion-exchanged water; and hydrophilic dispersion media such as alcohols including methanol, ethanol, and isopropyl alcohol, or mixtures thereof. Among them, water and a mixture of water and alcohol are preferable, and water is more preferable. In addition, among water, purified water, distilled water and ion-exchanged water are preferable, and purified water is more preferable.

The method for producing the photocatalyst dispersion liquid is not particularly limited. The photocatalyst dispersion may be a dispersion obtained by adjusting the photocatalyst structure to a predetermined particle diameter and dispersing the photocatalyst structure in a dispersion medium. The photocatalyst structure is prepared, for example, by adjusting the particle diameter of spherical beads made of zirconia having a diameter of 5 to 100 μm to a predetermined particle diameter by a bead mill having a hollow cylindrical container, a stirring member disposed in the container, and a bead separation means. The photocatalyst dispersion liquid is produced, for example, by the following production method. In the first step, a stirring member is rotated at a first rotation speed (r1) to stir the photocatalyst structure containing photocatalyst particles, a dispersion medium, and a raw material dispersion containing a basic substance and having a pH of 8-11 with beads, and the average particle diameter (D50) of the photocatalyst structure, which is obtained by a dynamic light scattering method, is 250-350% of the particle diameter of primary particles of the photocatalyst structure. In the second step, the stirring member is rotated at a second rotation speed (r2) which is 50% to 90% of the first rotation speed (r1), and the average particle diameter of the photocatalyst structures is 150% to 250% of the particle diameter of the primary particles. Such a photocatalyst dispersion liquid can be used by applying a photocatalyst structure containing photocatalyst particles to an object.

In addition, the present invention can also be used for decomposition of aldehydes in the above embodiments. Examples of the aldehydes include: formaldehyde, acetaldehyde, and the like.