JP4246943B2 - Method for producing article having photocatalyst-containing porous thin film - Google Patents

Description

【００５２】
（注）
１）成膜法：
ＳＣ＝スピンコート法、ＤＣ＝ディップコート法、ＢＣ＝バーコート法
２）多孔質構造の有無
○：多孔質構造を有している。
×：多孔質構造を有していない。
【００５３】
表１より実施例１〜１０で得られた光触媒含有多孔性薄膜においては、膜厚が１７〜３９０ｎｍであり、本発明で規定された１０〜４５０ｎｍの範囲にあった。また空孔の直径も５０〜２０００ｎｍであり、本発明で規定された３０〜３０００ｎｍの範囲にあった。またいずれも空孔の直径が膜厚よりも大きいという関係を有していた。
一方、比較例１で得られた光触媒含有薄膜は膜厚が４９０ｎｍであり、本発明で規定された１０〜４５０ｎｍの上限を超えており、多孔質構造とはならなかった。
【００５４】
【発明の効果】
本発明によれば、簡単な操作で、かつ耐熱性に乏しい有機基材上にも形成が可能であって、光触媒反応が生じる表面積が大きく、優れた光触媒機能を発揮し得る光触媒含有多孔性薄膜を有する物品を製造する方法を提供することができる。
【図面の簡単な説明】
【図１】 実施例１で得られた薄膜のＳＥＭ写真である。
【図２】 実施例１０で得られた薄膜の顕微鏡写真である。[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a photocatalyst-containing porous thin filmArticles withIt relates to the manufacturing method. More specifically, the present invention relates to a photocatalyst-containing porous thin film that has a large surface area where photocatalytic reaction occurs and can exhibit an excellent photocatalytic function.Articles withIt is related with the manufacturing method.
[0002]
[Prior art]
A photocatalytically active material (hereinafter sometimes simply referred to as a photocatalyst) is excited to produce electrons in the conduction band and holes in the valence band when irradiated with light having energy higher than its band gap. The generated electrons reduce the surface oxygen to form a superoxide anion (.O₂ ^-), And the holes oxidize hydroxyl groups on the surface to generate hydroxyl radicals (.OH). These reactive active oxygen species exert a strong oxidative decomposition function and adhere to the surface of the photocatalyst. It is known to decompose organic substances with high efficiency.
By applying such photocatalytic functions, for example, deodorization, antifouling, antibacterial, sterilization, and decomposition / removal of various substances that cause environmental pollution in wastewater and waste gas are being studied. Yes.
[0003]
Further, as another function of the photocatalyst, when the photocatalyst is photoexcited, for example, as disclosed in International Patent Publication No. 96/29375, the photocatalyst surface has a contact angle with water of 10 degrees or less. It is also known to express superhydrophilization. Applying such a superhydrophilic function of the photocatalyst, for example, for prevention of contamination due to soot contained in the exhaust gas of automobiles for soundproof walls and street lights of highways, or for automobile body coats and side mirror films, The use of photocatalysts for antifogging and self-cleaning window glass has been studied.
[0004]
As such photocatalysts, compounds having various semiconductor characteristics such as metal oxides such as titanium dioxide, iron oxide, tungsten oxide and zinc oxide, and metal sulfides such as cadmium sulfide and zinc sulfide have been known. However, among these, titanium dioxide, particularly anatase titanium dioxide, is useful as a practical photocatalyst. This titanium dioxide exhibits excellent photocatalytic activity by absorbing light of a specific wavelength in the ultraviolet region contained in daily light such as sunlight.
[0005]
By the way, in such a thin film containing a photocatalyst, the total surface area of the photocatalytic thin film is extremely important in order to effectively exhibit the organic substance decomposition reaction due to the photocatalytic activity. This is because the photocatalytic reaction is a heterogeneous reaction that occurs only on the surface. In addition, when positively utilizing the superhydrophilicity of the photocatalytic function in order to provide easy washing properties, antifogging properties, etc., the surface of the photocatalytic thin film can be provided with an uneven structure to improve the wettability of the surface with water. preferable.
[0006]
On the other hand, application to solar cells using photocatalysts such as titanium oxide is also being actively promoted. Also in this case, increasing the surface area of the photocatalyst layer is one of the important issues. By increasing the surface area of the photocatalyst layer and improving the contact area with the sensitizing dye, the power generation efficiency is greatly improved. Expected to get.
[0007]
However, in general, a remarkable concavo-convex structure scatters light and causes a significant decrease in the transparency of the photocatalytic thin film. Therefore, in order to maintain high transparency, it is often necessary to control the concavo-convex structure to have a size of visible light wavelength or less (400 nm or less).
[0008]
Thus, in many uses of photocatalysts, there is a strong demand for photocatalytic thin films that maintain transparency and have a large surface area (uneven structure). As such a photocatalyst thin film, for example, a photocatalytic thin film made porous by adding polyethylene glycol to a coating solution and burning out the polyethylene glycol during firing is known. However, in this case, in order to completely burn off the organic matter, a heat treatment of 200 ° C. or higher is required. Therefore, for example, a porous photocatalytic thin film is formed by this method on an organic substrate having poor heat resistance. There is a problem that can not be. In addition, an attempt has been made to form a porous photocatalytic thin film by adding a water-soluble polymer compound such as polyvinyl alcohol to the coating liquid and removing the additive by washing with water after film formation. However, in this case, there is a problem that an additive removal step is required, the operation becomes complicated, and the cost is unavoidable.
[0009]
[Problems to be solved by the invention]
  Under such circumstances, the present invention can be formed on an organic base material with a simple operation and poor heat resistance, has a large surface area for causing a photocatalytic reaction, and exhibits an excellent photocatalytic function. Photocatalyst-containing porous thin filmArticles withAn object of the present invention is to provide a manufacturing method.
[0010]
[Means for Solving the Problems]
As a result of extensive research on the photocatalyst-containing porous thin film, the present inventors applied a coating liquid containing a photocatalytically active material or its precursor and a sublimation agent to a substrate, and then sublimated the sublimation agent to obtain a diameter. The inventors have found that the above object can be achieved by a photocatalyst-containing porous thin film having a specific film thickness formed by forming pores in a certain range, and based on this finding, the present invention has been completed.
[0011]
  That is, the present invention
(1) After applying a coating liquid containing a photocatalytically active material and / or a precursor thereof and a sublimation agent that sublimes at 120 ° C. or lower under normal pressure or reduced pressure, the sublimation agent is sublimated.SkyBy forming the holes, the film thickness of the thin film after forming the holes is 10 to 450 nm, the diameter of the holes is 30 to 3000 nm, the holes have a diameter larger than the film thickness of the thin film, and A method for producing an article having a photocatalyst-containing porous thin film, characterized by forming a photocatalyst-containing porous thin film having a structure having an opening on the surface of the thin film and penetrating to the substrate surface,
(2) The photocatalyst according to the above item (1), in which a coating liquid is applied to a substrate, a sublimation agent is sublimated to form pores, and then crystallized to convert a photocatalytically active material precursor into a photocatalytically active material. A method for producing an article having a porous thin film containing,
[0012]
(3The above (1), wherein the sublimation agent is naphthalene and / or an analogue thereof, and the content of the sublimation agent in the solid content of the coating liquid is 35 to 60% by weight.Or(2)In termsThe photocatalyst-containing porous thin film describedArticles withManufacturing method,
(4(1) to (1) above, wherein the photocatalytically active material is titanium dioxide.3The photocatalyst-containing porous thin film according to any one of items 1)Articles withManufacturing method,
Is to provide.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
  Photocatalyst-containing porous thin film of the present inventionArticles withThe production method of the present invention comprises applying a coating liquid containing a photocatalytically active material and / or a precursor thereof as a photocatalytically active component and a sublimation agent that sublimates at 120 ° C. or less under normal pressure or reduced pressure to a substrate, and then the sublimation agent. Is formed by sublimating the pores to form pores.
[0014]
The photocatalytically active material is not particularly limited, and conventionally known materials such as titanium dioxide, strontium titanate (SrTiO)._Three), Barium titanate (BaTi)_FourO₉), Sodium titanate (Na₂Ti₆O₁₃), Zirconium dioxide, α-Fe₂O_Three, Tungsten oxide, K_FourNb₆O₁₇, Rb_FourNb₆O₁₇, K₂Rb₂Nb₆O₁₇, Cadmium sulfide, zinc sulfide and the like. These may be used alone or in combination of two or more. Among these, titanium dioxide, particularly anatase titanium dioxide, is useful as a practical photocatalytically active material. This titanium dioxide exhibits excellent photocatalytic activity by absorbing light of a specific wavelength in the ultraviolet region contained in daily light such as sunlight.
[0015]
The precursor of these photocatalytically active materials is not particularly limited as long as it is converted into a photocatalytically active material by any treatment including crystallization, and conventionally known compounds can be used. For example, as the precursor of titanium dioxide, one containing a partial hydrolyzate of titanium alkoxide is used.
In the present invention, only the photocatalytically active material may be used as the photocatalytically active component, or only the precursor thereof may be used, or a combination thereof may be used.
[0016]
On the other hand, the sublimation agent is preferably one that can be completely dissolved in the coating solution and can be sublimated at a temperature of 120 ° C. or lower under a normal pressure or a reduced pressure of about 1 hPa, such as naphthalene or Examples thereof include p-dichlorobenzene, camphor, camphene, ε-caprolactam, salicylic acid, oxalic acid, nitroaniline, nitrophenol, p-benzoquinone and the like. Those that sublime at temperature are particularly preferred. These may be used individually by 1 type and may be used in combination of 2 or more type.
[0017]
In the present invention, as a method of applying a coating liquid on a substrate to form a photocatalyst-containing porous thin film, for example, (1) after applying a coating liquid containing a photocatalytically active material precursor and a sublimation agent to the substrate, The sublimation agent is sublimated to form pores, and then subjected to some treatment including heat treatment to convert the precursor into a photocatalytically active material and promote adhesion to the substrate, thereby photocatalyst-containing porous thin film And (2) a coating liquid containing photocatalytically active material particles and a sublimation agent in an inorganic binder that can be solidified at a temperature of room temperature to 120 ° C. A method of heat treating at the following temperature to sublimate the sublimator and solidifying the binder to form a photocatalyst-containing porous thin film can be preferably used.
[0018]
First, the method (1) will be described.
In this method, as the photocatalytically active material precursor contained in the coating liquid, any of the above-mentioned photocatalytically active material precursors can be used. In particular, a precursor of titanium dioxide, for example, a partial hydrolyzate of titanium alkoxide is used. The inclusion is suitable. Moreover, when a photocatalytically active material precursor is a particulate form, what contains an inorganic binder with this precursor particle | grain can be used.
[0019]
The inorganic binder is not particularly limited, and examples thereof include conventionally known ones such as those containing metal alkoxides such as Si, Ti, and Zr, metal chlorides, and metal isocyanates.
[0020]
The coating liquid can be prepared by adding the photocatalytically active material precursor, or the precursor particles, an inorganic binder, and a sublimation agent in a suitable solvent. In the present invention, the sublimation agent is preferably present in a completely dissolved state in the coating solution. The solid content concentration in the coating solution is not particularly limited as long as it has a viscosity capable of being applied on a substrate and forming a thin film having a desired film thickness. The solvent is not particularly limited as long as it can dissolve the photocatalyst precursor (not in a particulate form) or the inorganic binder and the sublimation agent. For example, a partial hydrolyzate of titanium alkoxide as the photocatalyst precursor or the inorganic binder. When using naphthalene as a sublimation agent, alcohol solvents such as ethanol, isopropanol, and ethyl cellosolve are preferable.
[0021]
The content of the sublimation agent in the solid content of the coating liquid depends on the type of the sublimation agent, the photocatalytically active material precursor and the inorganic binder, and cannot be determined in general. However, the sublimation agent is naphthalene or an analog thereof. In some cases, it is usually selected in the range of 35 to 60% by weight, preferably 45 to 55% by weight. When this content deviates from the above range, it is difficult to form a thin film having a desired porous structure.
[0022]
For the purpose of promoting the photocatalytic activity, the coating liquid may contain a conventionally known photocatalyst promoter, if desired. Preferred examples of the photocatalyst promoter include platinum group metals such as platinum, palladium, rhodium, and ruthenium. These may be used alone or in combination of two or more. The addition amount of the photocatalyst promoter is usually selected in the range of 1 to 20% by weight based on the total weight of the photocatalytic active material and the photocatalyst promoter formed by the crystallization treatment described later from the viewpoint of photocatalytic activity. .
[0023]
In the present invention, the coating liquid thus obtained is applied to a substrate by a known method such as dip coating, spin coating, spray coating, bar coating, knife coating, roll coating, blade The thin film finally formed by coating method, die coating method, gravure coating method, etc. is applied so that the film thickness is 10 to 450 nm, preferably 30 to 200 nm, and the pressure is reduced to normal pressure or about 1 hPa. Usually, by heating and drying at a temperature of 120 ° C. or less, the sublimation agent sublimates simultaneously with the solidification of the thin film, and a porous thin film is formed. Next, the photocatalytically active material precursor in the thin film is crystallized and converted into a photocatalytically active material. The crystallization method is not particularly limited, and a conventionally known method such as a method using heating, a method using ultraviolet irradiation, a method using microwave irradiation, or a method using electron beam irradiation can be used.
[0024]
  In this way, the pore diameter is in the range of 30 to 3000 nm, and the film thickness is in the range of 10 to 450 nm, preferably 30 to 200 nm.ManyA porous photocatalyst-containing thin film can be formed.
  Those having a film thickness of less than 10 nm are difficult to form, and even if formed, a sufficient photocatalytic function is hardly exhibited. On the other hand, if the film thickness exceeds 450 nm, it becomes difficult to make the film porous, and the object of the present invention cannot be achieved.
[0025]
Next, the method (2) will be described.
In this method, as the photocatalytically active material particles contained in the coating liquid, any of the above-mentioned photocatalytically active material particles can be used, and titanium dioxide particles are particularly preferable. The particle size of the photocatalytically active material particles is not particularly limited, but from the viewpoint of increasing the surface area, particles having a primary particle size of about 1 to 10 nm are aggregated to have a size of about 50 to 400 nm are preferable. Moreover, there is no restriction | limiting in particular as an inorganic binder, For example, what contains conventionally well-known things, for example, metal alkoxide, metal chloride, metal isocyanate, etc., such as Si type, Ti type, and Zr type, can be mentioned. On the other hand, examples of the sublimation agent include the same as in the case of (1).
[0026]
The said coating liquid can be prepared by adding the said photocatalytically active material particle, an inorganic binder, and a sublimation agent in a suitable solvent. In the present invention, the sublimation agent is preferably present in a completely dissolved state in the coating solution. The solid content concentration in the coating solution is not particularly limited as long as it has a viscosity capable of being applied on a substrate and forming a thin film having a desired film thickness. The solvent is not particularly limited as long as it can dissolve the inorganic binder and the sublimation agent. For example, a solvent containing a partial hydrolyzate of silicon alkoxide is used as the inorganic binder, and naphthalene is used as the sublimation agent. Alcohol solvents such as methanol, ethanol and isopropanol are preferred.
[0027]
The content of the sublimation agent in the solid content of the coating liquid depends on the types of the sublimation agent and the inorganic binder, and cannot be determined in general, but when the sublimation agent is naphthalene or an analog thereof, It is selected in the range of 35 to 60% by weight, preferably 45 to 55% by weight. When this content deviates from the above range, it is difficult to form a thin film having a desired porous structure.
[0028]
For the purpose of promoting the photocatalytic activity, the coating liquid may contain a conventionally known photocatalyst promoter, if desired. As this photocatalyst promoter, the same ones as exemplified in the above (1) can be mentioned, and the addition amount thereof is usually the total weight of the photocatalytically active material particles and the photocatalyst promoter from the viewpoint of photocatalytic activity. Based on the range of 1 to 20% by weight.
[0029]
  In the present invention, the coating liquid thus obtained is formed on the substrate in the same manner as in (1) above, and the film thickness of the finally formed thin film is 10 to 450 nm, preferably 30 to 200 nm. The sublimation agent is sublimated at the same time as the thin film is solidified by heating and drying at a temperature of usually 120 ° C. or less under normal pressure or a reduced pressure of about 1 hPa. The hole diameter is in the range of 30 to 3000 nm, and the film thickness is in the range of 10 to 450 nm, preferably 30 to 200 nm.LightA catalyst-containing porous thin film is formed.
[0030]
  lightIn the catalyst-containing porous thin film, the pores are usually larger in diameter than the thin film, have pores on the thin film surface, and penetrate to the substrate surface. That is, the base material at the bottom of the hole is normally exposed, and the characteristics of the base material can be preferably used.
[0031]
For example, when an article provided with a photocatalyst layer is used for air purification or water purification treatment, the effect is often determined by the ability of the substance to be removed to adsorb to the article. The removal target that exhibits good adsorption ability to the photocatalyst layer provided on the article is effectively removed by photocatalysis, but the removal target inferior to the photocatalyst layer cannot be expected to be removed by photocatalysis. . However, in the present invention, since the base material surface at the bottom of the pores is exposed, the base material is a substance capable of effectively adsorbing the removal target inferior to the photocatalytic layer. Alternatively, the above problem can be easily solved by preloading this substance on the substrate surface.
[0032]
  lightThe substrate on which the catalyst-containing porous thin film is formed is not particularly limited, and various substrates such as inorganic substrates such as metal, glass and ceramics, organic substrates such as plastics, organic fibers, and woody materials can be used. Can be mentioned. In the case of an organic base material, if a photocatalyst-containing porous thin film is directly provided on the surface, deterioration of the base material is unavoidable due to photocatalytic action. For example, an inorganic coating layer or the organic matter previously found by the present inventors -It is preferably provided via an inorganic composite gradient film (Japanese Patent Application No. 11-264592).
[0033]
  The organic-inorganic composite gradient film is preferably applied to an organic base material such as a plastic substrate. By providing the composite gradient film on the substrate, the surface layer is a metal component in the composite gradient film. Is approximately 100% and gradually decreases in the direction of the base material, and is almost 0% in the vicinity of the base material. That is, in the organic-inorganic composite gradient film, the surface in contact with the organic base material is substantially composed of only the organic polymer compound component, and the other open system surface is composed of only the metal oxide compound component. ing. Therefore, on this composite gradient membrane,lightBy providing the catalyst-containing porous thin film, deterioration of the organic base material can be suppressed.
An organic base material made of cocoon can also be used.
[0034]
The inorganic base material can be used in any of the methods (1) and (2) described above, but in the method (1), the photocatalytically active material precursor is crystallized by heat treatment to produce a photocatalytically active material. In the case of conversion to, since heat treatment is usually performed at a temperature of 400 ° C. or higher, an inorganic base material excellent in heat resistance as a base material, or a polyimide base material excellent in heat resistance even in an organic base material is preferable. Used. In the method (1), when crystallization is performed by means that does not require high-temperature heating, organic base materials made of the following general-purpose plastics can also be used.
[0035]
On the other hand, in the method (2), an organic base material made of a general-purpose plastic such as polypropylene, polyethylene terephthalate or polymethyl methacrylate having a heat resistant temperature of 120 ° C. or higher can also be used.
[0037]
  lightThere is no restriction | limiting in particular as an application of the articles | goods which have a catalyst containing porous thin film, All can be used for the use which can apply a photocatalytic reaction. For example, it is useful for deodorization, antifouling, antibacterial, sterilization, decomposition / removal of various substances that are problems in environmental pollution in wastewater and waste gas, and solar cell components. Furthermore, by applying the superhydrophilic function of the photocatalyst, for example, for the prevention of contamination due to soot contained in the exhaust gas of automobiles such as noise barriers on highways and street lights, or films for automobile body coats and side mirrors It can also be used for antifogging and self-cleaning window glass.
[0038]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
In addition, the film thickness and pore diameter of the thin film obtained in each example were measured according to the following methods.
(1) Film thickness
The thin film is partially peeled off at 10 points with a sharp tip such as tweezers, and the step is measured with a surface shape measuring microscope (VF-7500, manufactured by Keyence Corporation). Thickness.
(2) Hole diameter
A scanning electron microscope (SEM) image was obtained on the surface of the thin film, 20 vacancies were randomly selected from the image, their diameters were measured, and the average value was taken as the vacancy diameter of the thin film.
[0039]
Example 1
A 65 × 15 × 1 mm slide glass substrate was used as the substrate.
Photocatalyst coating agent containing photocatalyst particles and silica-based binder [manufactured by Ishihara Sangyo Co., Ltd., trade name “ST-K03”, solid concentration 90 g / liter] 2 ml and 50 g / liter naphthalene ethanol solution 2 ml, ethanol 6 ml A coating solution was prepared by mixing and stirring.
[0040]
Using this coating solution, a film is formed on a slide glass substrate by a spin coating method (1500 rpm, 12 seconds), sufficiently dried, and then heat-treated at 120 ° C. for 10 minutes. Formed. Table 1 shows the properties of this thin film. Moreover, the SEM photograph when the obtained thin film is seen from the top is shown in FIG.
[0041]
Example 2
In Example 1, except that the amount of the naphthalene ethanol solution having a concentration of 50 g / liter was 1.6 ml and the amount of ethanol was 6.4 ml, the operation was performed in the same manner as in Example 1 to obtain the target photocatalyst-containing porous A functional thin film was formed. Table 1 shows the properties of this thin film.
[0042]
Example 3
In Example 1, the same procedure as in Example 1 was performed except that the amount of the naphthalene ethanol solution having a concentration of 50 g / liter was 2.4 ml and the amount of ethanol was 5.6 ml. A functional thin film was formed. Table 1 shows the properties of this thin film.
[0043]
Example 4
Concentrated hydrochloric acid [Wako Pure Chemical Industries, Ltd.] mixed with 6.4 g of titanium tetraisopropoxide [Wako Pure Chemical Industries, Ltd.] and 60 ml of 2-propanol [Wako Pure Chemical Industries, Ltd.] Made] A mixture of 1.8 g and 6 ml of 2-propanol was slowly added dropwise and stirred as it was for 1 hour. This is designated as Binder A.
Add 2 ml of titanium oxide suspension (trade name “PCT-15T”, solid concentration 135 g / liter, manufactured by Sumitomo Osaka Cement Co., Ltd.) to 11 ml of 2-propanol and stir well. 6 ml of a liter-concentrated naphthalene ethanol solution was added, mixed and stirred to prepare a coating solution.
Using this coating solution, the target photocatalyst-containing porous thin film was formed in the same manner as in Example 1. Table 1 shows the properties of this thin film.
[0044]
Example 5
A 65 × 15 × 1 mm slide glass substrate was used as the substrate.
11 ml of Binder A produced in the same manner as in Example 4 and 13 ml of 2-propanol were mixed and stirred, and 6 ml of a 50 g / liter naphthalene ethanol solution was further added thereto, followed by mixing and stirring to prepare a coating solution.
Using this coating solution, a film is formed on a slide glass substrate by a spin coating method (1500 rpm, 12 seconds), sufficiently dried, heat-treated at 120 ° C. for 10 minutes to form a thin film, and further heated to 500 ° C. The target photocatalyst-containing porous thin film was formed by firing. Table 1 shows the properties of this thin film.
[0045]
Example 6
A 65 × 15 × 1 mm slide glass substrate was used as the substrate.
8 ml of a photocatalyst coating agent containing a photocatalyst particle and a silica-based binder [manufactured by Ishihara Sangyo Co., Ltd., trade name “ST-K03”, solid matter concentration 90 g / liter] and 8 ml of a naphthalene ethanol solution having a concentration of 50 g / liter, A coating solution was prepared by mixing and stirring.
Using this coating solution, a film is formed on a slide glass substrate by a dip coating method (pulling rate = 100 m / min), sufficiently dried, and then heat-treated at 120 ° C. for 10 minutes to obtain a target photocatalyst-containing porous material. A functional thin film was formed. Table 1 shows the properties of this thin film.
[0046]
Example 7
In Example 6, the same procedure as in Example 6 was performed, except that the bar coating method (coating liquid film 6.9 μm) was used instead of the dip coating method, and the target photocatalyst-containing porous thin film was obtained. Formed. Table 1 shows the properties of this thin film.
[0047]
Example 8
In Example 6, the operation was performed in the same manner as in Example 6 except that the pulling rate in the dip coating method was set to 10 m / min, and the target photocatalyst-containing porous thin film was formed. Table 1 shows the properties of this thin film.
[0048]
Example 9
A 65 × 15 × 1 mm slide glass substrate was used as the substrate.
40 ml of a photocatalyst coating agent containing a photocatalyst particle and a silica-based binder [manufactured by Ishihara Sangyo Co., Ltd., trade name “ST-K03”, solid concentration: 90 g / liter] and 40 ml of a naphthalene ethanol solution having a concentration of 50 g / liter, A coating solution was prepared by mixing and stirring.
Using this coating solution, a film is formed on a slide glass substrate by a dip coating method (pulling speed = 20 m / min), sufficiently dried, and then heat-treated at 120 ° C. for 10 minutes to obtain a target photocatalyst-containing porous material. A functional thin film was formed. Table 1 shows the properties of this thin film.
[0049]
Example 10
In Example 9, the operation was performed in the same manner as in Example 9 except that the pulling rate in the dip coating method was set to 150 m / min, and the target photocatalyst-containing porous thin film was formed. Table 1 shows the properties of this thin film. Moreover, the micrograph when the obtained thin film is seen from the top is shown in FIG.
[0050]
Comparative Example 1
In Example 9, a thin film was formed in the same manner as in Example 9 except that the pulling speed in the dip coating method was 300 m / min. Table 1 shows the properties of this thin film.
[0051]
[Table 1]

[0052]
(note)
1) Film formation method:
SC = spin coating method, DC = dip coating method, BC = bar coating method
2) Presence or absence of porous structure
○: It has a porous structure.
X: It does not have a porous structure.
[0053]
In Table 1, the photocatalyst-containing porous thin films obtained in Examples 1 to 10 had a film thickness of 17 to 390 nm, which was in the range of 10 to 450 nm defined in the present invention. The diameter of the holes was also 50 to 2000 nm, and was in the range of 30 to 3000 nm defined in the present invention. Moreover, all had the relationship that the diameter of a void | hole is larger than a film thickness.
On the other hand, the photocatalyst-containing thin film obtained in Comparative Example 1 had a film thickness of 490 nm, exceeding the upper limit of 10 to 450 nm defined in the present invention, and did not have a porous structure.
[0054]
【The invention's effect】
  According to the present invention, a photocatalyst-containing porous thin film that can be formed on an organic substrate with a simple operation and poor in heat resistance, has a large surface area where a photocatalytic reaction occurs, and can exhibit an excellent photocatalytic function.Articles withCan be provided.
[Brief description of the drawings]
1 is an SEM photograph of a thin film obtained in Example 1. FIG.
2 is a micrograph of the thin film obtained in Example 10. FIG.

Claims (4)

Photocatalyst active material and / or its precursor, after coating a coating solution containing a sublimation agent sublimates at 120 ° C. or less at normal pressure or reduced pressure to a substrate, thereby forming pores by sublimating the sublimation agent Therefore, the film thickness of the thin film after the formation of the vacancy is 10 to 450 nm, the diameter of the vacancy is 30 to 3000 nm, the vacancy has a diameter larger than the film thickness of the thin film, and is open on the thin film surface A method for producing an article having a photocatalyst-containing porous thin film, comprising forming a photocatalyst-containing porous thin film having a part and a structure penetrating to the substrate surface.   The photocatalyst-containing porous thin film according to claim 1, wherein the coating liquid is applied to the substrate, the pores are formed by sublimating the sublimation agent, and then crystallized to convert the photocatalytically active material precursor into a photocatalytically active material. A method for manufacturing an article having the same.   The article having a photocatalyst-containing porous thin film according to claim 1 or 2, wherein the sublimation agent is naphthalene and / or an analogue thereof, and the content of the sublimation agent in the solid content of the coating liquid is 35 to 60% by weight. Manufacturing method.   The method for producing an article having a photocatalyst-containing porous thin film according to any one of claims 1 to 3, wherein the photocatalytically active material is titanium dioxide.

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