WO2021261434A1 - Method for manufacturing photocatalyst film, and photocatalyst structure - Google Patents

Method for manufacturing photocatalyst film, and photocatalyst structure Download PDF

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Publication number
WO2021261434A1
WO2021261434A1 PCT/JP2021/023373 JP2021023373W WO2021261434A1 WO 2021261434 A1 WO2021261434 A1 WO 2021261434A1 JP 2021023373 W JP2021023373 W JP 2021023373W WO 2021261434 A1 WO2021261434 A1 WO 2021261434A1
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film
photocatalyst
silver
oxide
content
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PCT/JP2021/023373
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French (fr)
Japanese (ja)
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慎也 小竹
輝一 井原
卓哉 福村
里美 後藤
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日東電工株式会社
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L9/00—Disinfection, sterilisation or deodorisation of air
    • A61L9/16—Disinfection, sterilisation or deodorisation of air using physical phenomena
    • A61L9/18—Radiation
    • A61L9/20—Ultraviolet radiation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B15/06—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of natural rubber or synthetic rubber
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B9/00—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00

Definitions

  • the present invention relates to a method for producing a photocatalyst film and a photocatalyst structure.
  • Photocatalyst can be applied to many applications such as self-cleaning, air and water purification, etc., and usually there is no non-renewable energy cost after application. This is because the photocatalyst can decompose pollutants such as dyes, VOCs, and NOx using not only sunlight but also ambient light such as indoor and outdoor lighting.
  • pollutants such as dyes, VOCs, and NOx using not only sunlight but also ambient light such as indoor and outdoor lighting.
  • VOC is an abbreviation for volatile organic compounds
  • volatile organic compounds are a general term for organic compounds that are volatile and become gaseous in the atmosphere, and are factors that cause air pollution and health hazards. It is known to be. Therefore, in recent years, VOC emissions into the atmosphere have been strictly regulated, and in particular, factories and the like that generate a large amount of VOCs are required to take measures to further reduce VOC emissions.
  • formaldehyde which is a kind of VOC
  • formaldehyde is a causative substance of sick house syndrome, and therefore, there is an increasing demand for decomposing and removing VOCs such as formaldehyde and purifying them even in a living environment.
  • a closed space such as a home, public, and commercial space, a laboratory, an inspection room, a factory, an aircraft, and a public building
  • a photocatalyst to clean the air in the space
  • various shapes of products using a photocatalyst have been proposed depending on the use of the product. For example, those manufactured by forming a photocatalytic film on a base material having a honeycomb structure, granules, film shape, etc. that can be used with good handleability have been proposed, but any shape does not impair the catalytic activity. It is desired to support the catalyst with high adhesion.
  • Patent Document 1 aims to provide a photocatalyst structure in which the brittleness and easiness of peeling of the photocatalyst layer are reduced and the deterioration of the photocatalyst function due to long-term light irradiation is suppressed, and an inorganic oxide is used as a resin base material.
  • a photocatalyst structure in which a layer and a photocatalyst layer are laminated is described.
  • Patent Document 2 describes an organic-inorganic composite material containing a chemical bond of an organic polymer compound and a metal-based compound, wherein the content of the metal-based compound in the material is in the depth direction from the surface of the material.
  • Organic-inorganic composite tilting materials with continuously varying component tilting structures have been described.
  • the present invention provides a method for producing a photocatalytic film capable of producing a photocatalytic film having a large thickness and high catalytic activity at low cost by a simple method.
  • the present inventors have completed the present invention as a result of repeated diligent studies for the purpose of finding a manufacturing method capable of manufacturing a photocatalytic film having a thick thickness and high catalytic activity at a low cost by a simple method. ..
  • a method for producing a photocatalyst film which comprises a first step of forming a silver interlayer film containing silver oxide on a substrate and a second step of forming a photocatalyst film containing photocatalyst particles on the silver interlayer film. ..
  • the photocatalytic particles include at least one metal oxide selected from titanium oxide, tungsten oxide, zinc oxide, tin oxide, strontium titanate, calcium titanate, barium titanate, bismuth oxide and iron oxide [1].
  • the photocatalyst film contains a silver component transferred from the silver interlayer film, and contains the silver component.
  • a certain b / a1 is 10 or less
  • a silver interlayer film containing silver oxide and a photocatalyst film are provided on the substrate in this order.
  • the photocatalyst film contains a silver component and contains The ratio of the silver content a1 in the photocatalyst film at 2 ⁇ m in the film thickness direction from the interface between the silver interlayer film and the photocatalyst film and the silver content b at the interface between the photocatalyst film and the silver intermediate film.
  • a certain b / a1 is 10 or less, and the silver content a2 in the photocatalyst film at 4 ⁇ m in the film thickness direction from the interface and the silver content b at the interface between the photocatalyst film and the silver intermediate film.
  • the photocatalytic film contains at least one metal oxide selected from titanium oxide, tungsten oxide, zinc oxide, tin oxide, strontium titanate, calcium titanate, barium titanate, bismuth oxide and iron oxide, [7] to The photocatalyst structure according to any one of [10].
  • a method for producing a photocatalyst film capable of producing a photocatalyst film having a thick thickness and high catalytic activity at low cost by a simple method, and a photocatalyst structure having a photocatalyst film having a thickness and high catalytic activity. be able to.
  • FIG. 1 is a schematic cross-sectional view of a photocatalyst structure according to an embodiment of the present invention.
  • FIG. 2 is a diagram showing an MNN Auger spectrum derived from Ag in Example 3.
  • FIG. 3 is a diagram showing the relationship between the amount of photocatalyst supported and the silver oxide content of the silver interlayer film in the photocatalyst structures of Examples 1 to 3, Examples 8 to 10, Comparative Example 1 and Comparative Example 8. ..
  • FIG. 4 shows the relationship between the distance of the photocatalyst structure in the thickness direction from the silver interlayer film and the content (% by mass) of silver and titanium obtained from the cross-sectional EDX observation result of the photocatalyst structure of Comparative Example 1. It is a figure which shows.
  • FIG. 4 shows the relationship between the distance of the photocatalyst structure in the thickness direction from the silver interlayer film and the content (% by mass) of silver and titanium obtained from the cross-sectional EDX observation result of the photocataly
  • FIG. 5 shows the relationship between the distance of the photocatalyst structure in the thickness direction from the silver interlayer film and the content (% by mass) of silver and titanium obtained from the cross-sectional EDX observation result of the photocatalyst structure of Example 3. It is a figure which shows.
  • FIG. 6 is a diagram showing the relationship between the UV irradiation time and the formaldehyde residual ratio in the photocatalytic structures of Examples 1 to 3, Comparative Example 1, Comparative Example 5 and Comparative Example 6.
  • FIG. 7 is a diagram showing the relationship between the UV irradiation time and the residual rate of methanol in the photocatalytic structures of Examples 1 to 3, Comparative Example 1, Comparative Example 5 and Comparative Example 6.
  • FIG. 6 is a diagram showing the relationship between the UV irradiation time and the formaldehyde residual ratio in the photocatalytic structures of Examples 1 to 3, Comparative Example 1, Comparative Example 5 and Comparative Example 6.
  • FIG. 7 is a diagram showing the relationship between the UV ir
  • FIG. 8 is a diagram showing the relationship between the UV irradiation time and the CO 2 conversion rate in the photocatalytic structures of Examples 1 to 3, Comparative Example 1, Comparative Example 5 and Comparative Example 6.
  • FIG. 9 is a diagram showing the relationship between the silver oxide ratio and the formaldehyde (HCHO) removal rate (%) 45 minutes after UV irradiation in the photocatalytic structures of Examples 1 to 3 and Comparative Example 1.
  • FIG. 10 is a diagram showing the relationship between the silver oxide ratio and the methanol (MeOH) removal rate (%) 45 minutes after UV irradiation in the photocatalytic structures of Examples 1 to 3 and Comparative Example 1.
  • the method for producing a photocatalyst film according to an embodiment of the present invention comprises a first step of forming a silver interlayer film containing silver oxide on a substrate, and a photocatalyst film containing photocatalytic particles on the silver interlayer film. Includes a second step of forming.
  • FIG. 1 is a schematic cross-sectional view of a photocatalyst structure according to an embodiment of the present invention, which will be described in detail later.
  • a silver interlayer film 12 containing silver oxide is formed on a base material 11 by the first step, and silver is formed by the second step.
  • a photocatalyst film 14 containing photocatalyst particles can be formed on the interlayer film 12.
  • the first step is a step of forming a silver interlayer film containing silver oxide on the base material.
  • the method for forming the silver interlayer film containing silver oxide is not particularly limited, but it can be formed by vacuum vapor deposition, sputtering, ion plating or the like. However, sputtering is preferable because the thickness can be strictly controlled even in a large area.
  • Base material examples of the material used for the base material according to the present embodiment include various materials regardless of whether they are inorganic materials or organic materials, and their shapes are not limited.
  • Preferred examples of the substrate include glass, ceramics, metal, substrate film, resin moldings, glass, rubber, stone, cement, concrete, fiber, fabric, wood, paper, and combinations thereof, which have a large area.
  • a base film is preferable from the viewpoint of ease of productivity.
  • the base film examples include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate, polyamide, polyvinyl chloride, polycarbonate (PC), cycloolefin polymer (COP), polystyrene, polypropylene (PP), and the like.
  • Homopolymers such as polyethylene, polycycloolefin, polyurethane, acrylic resin (eg, polymethylmethacrylate (PMMA), polyacrylic acid ester), polyacrylonitrile (PAN), polyacrylamide, ABS, polyimide, polytetrafluoroethylene, etc.
  • a polymer film made of a copolymer can be used.
  • the material can withstand high temperatures such as vapor deposition and spatter. Therefore, among the above materials, for example, polyethylene terephthalate, polyethylene naphthalate, acrylic, polycarbonate, cyclo. Olefin polymers, ABS, polypropylene, polyurethane, polyimide and polytetrafluoroethylene are preferred. Of these, polyethylene terephthalate, cycloolefin polymer, polycarbonate, acrylic, polyimide, and polytetrafluoroethylene are preferable because they have a good balance between heat resistance and cost.
  • a silver interlayer film containing silver oxide is formed on the substrate by the first step.
  • the silver interlayer contains silver and silver oxide. Since the silver interlayer film contains silver oxide, silver oxide is transferred from the silver interlayer film into the photocatalyst film when the photocatalyst film is provided in the second step, and a component gradient is generated. As a result, the affinity between the silver intermediate layer and the photocatalyst film is enhanced, so that the adhesion with the photocatalyst film is improved, peeling, cracking or warping of the photocatalyst film can be suppressed, and a thick photocatalyst film can be formed. .. Furthermore, the catalytic activity is improved by the carrier recombination inhibitory action of silver transferred to the photocatalytic membrane.
  • the silver oxide content in the silver interlayer film is preferably 5.6 area% or more, preferably 10 area% or more, and more preferably 15 area% or more.
  • the silver oxide content in the silver interlayer film is preferably 77 area% or less, more preferably 67.3 area% or less, further preferably 60 area% or less, still more preferably 55 area% or less.
  • components other than silver and silver oxide constituting the silver interlayer include carbon, oxygen and the like.
  • the silver oxide content in the silver interlayer is measured, for example, by performing a narrow scan measurement using a laminate having a silver interlayer formed on a substrate as a sample and using an analyzer by X-ray photoelectron spectroscopy (ESCA). , Ag-derived MNN Auger spectrum can be obtained, and the ratio of each element (atomic%) on the outermost surface of the sample can be calculated under the following measurement conditions.
  • X-ray source Monochrome AlK ⁇ Irradiation range: 100 mm ⁇ Radiant intensity: 15kV, 25W Photoelectron extraction angle: 45 ° with respect to the sample surface
  • a peak attributed to silver (metal) and a peak attributed to silver oxide so as to match the MNN Auger spectrum derived from Ag obtained above in the highest proportion. Adjust the ratio of and add them so that the total is 100%.
  • the silver (metal) / oxide ratio can be calculated from the ratio of each peak at that time. That is, as shown in FIG. 2, the measurement result of the obtained MNN Auger spectrum derived from Ag is defined as peak P1, and the peak P2 attributed to silver (metal) and the peak P3 attributed to silver oxide are added together.
  • the silver (metal) / oxide ratio can be calculated from the condition that the peak P4 and the MNN Auger spectrum P1 derived from Ag overlap.
  • the content of silver oxide in the silver interlayer film can be adjusted by selecting the material, manufacturing method, oxidation treatment, and the like.
  • the silver interlayer film can be formed by, for example, vacuum vapor deposition, a sputtering method, an ion plating method, or the like.
  • the sputtering method is preferable because the thickness can be strictly controlled even in a large area and the content of silver oxide in the silver interlayer film can be easily adjusted.
  • the target and the base material are placed facing each other in a vacuum chamber, gas is supplied and a voltage is applied from a power source to accelerate gas ions to irradiate the target, and the target material is ejected from the target surface.
  • the target material is laminated on the surface of the substrate.
  • Examples of the sputtering method include a bipolar sputtering method, an ECR (electron cyclotron resonance) sputtering method, a magnetron sputtering method, and an ion beam sputtering method. Preferred is the magnetron sputtering method.
  • examples of the target material include silver, a silver alloy, and silver oxide, and preferably silver and a silver alloy.
  • a method of containing silver oxide in the silver interlayer film for example, a method of using silver or a silver alloy and silver oxide as a target material and simultaneously sputtering each material using an inert gas as a sputter gas to form a film.
  • examples thereof include a method in which silver or a silver alloy is used as the target material and oxygen gas and an inert gas are used as the sputter gas. From the viewpoint that the content of silver oxide in the silver interlayer can be easily adjusted, a method in which silver or a silver alloy is used as the target material and oxygen gas and an inert gas are used as the sputter gas is preferable.
  • the sputtering gas used in the sputtering method examples include an inert gas such as argon (Ar) and an oxygen gas, and the inert gas and the oxygen gas can be used in combination.
  • the flow rate ratio of the inert gas and the oxygen gas is not particularly limited, but oxygen is obtained with respect to the total flow rate of the inert gas and the oxygen gas.
  • the gas preferably has a flow rate of more than 0%, preferably 0.5 flow rate% or more, and 1.0 flow rate% or more from the viewpoint of forming a silver intermediate layer having an appropriate silver oxide content.
  • the atmospheric pressure during sputtering is, for example, 1 Pa or less, preferably 0.1 Pa or more and 0.7 Pa or less, from the viewpoint of suppressing a decrease in the sputtering rate and discharging stability.
  • the power supply may be, for example, any of a DC power supply, an AC power supply, an MF power supply, and an RF power supply, or may be a combination thereof.
  • the film thickness of the silver interlayer film is preferably 20 nm or more, more preferably 50 nm or more, still more preferably 75 nm or more, from the viewpoint of adhesion to the photocatalyst film.
  • 200 nm or less is preferable, 175 nm or less is more preferable, and 150 nm or less is further preferable.
  • the silver interlayer film may be laminated as a single layer or two or more layers may be laminated on the base material.
  • the second step according to the embodiment of the present invention is a step of forming a photocatalyst film containing photocatalyst particles on the silver interlayer film.
  • a photocatalyst film containing photocatalyst particles can be formed on the silver interlayer film formed in the first step.
  • the method for forming the photocatalyst film is not particularly limited, and a known photocatalyst film forming means can be used.
  • a photocatalyst film can be formed by applying a photocatalyst composition containing photocatalyst particles on a silver interlayer film.
  • the method for applying the photocatalyst composition is not particularly limited, and examples thereof include known methods such as a dipping method, a spray method, a spin coating method, a bar coating method, a curtain coating method, a roll coating method, and a brush coating method. Above all, it is preferable to use the dipping method from the viewpoint of cost. Usually, the dipping method is low cost, but it is difficult to form a thick photocatalytic film. However, in the embodiment of the present invention, by forming the photocatalyst film containing the photocatalyst particles on the silver interlayer film containing silver oxide, silver oxide is transferred from the silver interlayer film to the photocatalyst film.
  • the photocatalytic membrane has a component gradient structure.
  • the photocatalyst film has this component gradient structure, a thick photocatalyst film can be formed, a thick photocatalyst film can be formed at low cost, and excellent photocatalytic activity can be obtained. ..
  • the photocatalyst film contains a silver component transferred from the silver interlayer film in the photocatalyst film, and the content of the silver component in the photocatalyst film continuously changes in the film thickness direction from the surface of the photocatalyst film.
  • the photocatalyst film contains a silver component transferred from the silver interlayer film, and the silver content a1 in the photocatalyst film at 2 ⁇ m in the film thickness direction from the interface between the silver interlayer film and the photocatalyst film, and the photocatalyst film and the silver interlayer film.
  • the ratio of b / a1 to the silver content b at the interface is 10 or less, the silver content a2 in the photocatalyst film at 4 ⁇ m in the film thickness direction from the interface, and the silver at the interface between the photocatalyst film and the silver interlayer film. It is preferable that b / a2, which is the ratio of the content b to the content b, is 20 or less.
  • the photocatalyst composition After the photocatalyst composition is applied, it may be heated or dried at room temperature to cure the photocatalyst film.
  • the heating method is not particularly limited, and a method of preheating the base material or a method of heating after coating may be used, and can be appropriately selected.
  • the heating temperature is preferably 5 ° C. or higher, more preferably 10 ° C. or higher, and even more preferably 15 ° C. or higher.
  • the upper limit of the heating temperature is not particularly limited, but is preferably 50 ° C. or lower from the viewpoint of suppressing deterioration of the photocatalyst film.
  • the photocatalyst composition is not particularly limited as long as it contains photocatalyst particles, and may be a photocatalyst dispersion liquid in which photocatalyst particles are dispersed in a solvent such as water, or a mixed liquid of photocatalyst particles and a binder solution. good. It is preferable to use a photocatalyst dispersion (suspension) or a sol in which the photocatalyst particles are dispersed in a solvent, because the content ratio of the photocatalyst particles in the photocatalyst film can be increased and the exposure of the photocatalyst can be increased.
  • the solvent examples include water, water-soluble alcohol solvents such as methanol, ethanol, propanol and butanol, acetone, methyl ethyl ketone and the like, and water is preferable.
  • the upper limit of the content of the photocatalyst particles in the photocatalyst composition used in the embodiment of the present invention is preferably 50% by mass, more preferably 40% by mass, and further preferably 30% by mass.
  • the lower limit of the content of the photocatalyst particles is preferably 1% by mass, more preferably 3% by mass, and further preferably 5% by mass.
  • the film thickness after curing of the photocatalyst film is not particularly limited, but is preferably 0.1 ⁇ m or more, more preferably 0.15 ⁇ m or more, and more preferably 0.2 ⁇ m or more from the viewpoint of photocatalytic activity. More preferred. On the other hand, from the viewpoint of the adhesion between the photocatalyst film and the silver intermediate layer, 50 ⁇ m or less is preferable, 40 ⁇ m or less is more preferable, and 30 ⁇ m or less is further preferable.
  • photocatalytic particles As the photocatalytic particles used in the embodiment of the present invention, fine particles of a photocatalyst containing a metal oxide having photocatalytic activity or the like can be used.
  • the main component of the photocatalyst include catalysts such as oxide semiconductors, such as titanium, zinc, tin, zirconium, tungsten, chromium, molybdenum, iron, nickel, ruthenium, vanadium niobium, tantalum, rhodium, and renium. Oxides, oxycarbides, oxynitrides, oxyhalides, halides, salts, dope or carrying compounds.
  • At least one metal oxide selected from titanium oxide, tungsten oxide, zinc oxide, tin oxide, strontium titanate, calcium titanate, barium titanate, bismuth oxide and iron oxide. Further, these may be doped with elements such as nitrogen, carbon and sulfur.
  • a precious metal element such as gold, silver, platinum, palladium, iridium, ruthenium, rhodium, or an oxide or hydroxide thereof is further added to these.
  • the photocatalytic particles used in the embodiment of the present invention can be produced by using a precipitation precipitation method, a hydrothermal synthesis method, a sol-gel method, a redox reaction, or the like.
  • the photocatalytic particles may be mechanically milled using a ball mill, a jet mill, or the like. Particle surface collisions due to mechanical milling can increase oxygen defect sites in photocatalytic particles.
  • the rotation speed of the ball mill is increased too much, it may crystallize and Mn + / Mn 4+ may become smaller, so the rotation speed of the ball mill should be 600 rpm or less. Is preferable.
  • the photocatalytic particles may be fired as long as the effects of the present invention are not impaired.
  • the average particle size of the photocatalytic particles according to the embodiment of the present invention is not particularly limited, but is, for example, 5 nm to 500 nm.
  • the photocatalyst particles according to the embodiment of the present invention may further contain other components such as a co-catalyst described later, as long as the effects of the present invention are not impaired.
  • the photocatalytic particles of the present embodiment may further contain a co-catalyst in addition to the photocatalyst in order to improve the catalytic activity, etc., as long as the effects of the present invention are not impaired.
  • the co-catalyst include a metal or a metal oxide.
  • the metal element contained in the metal or metal oxide referred to here includes a metalloid element.
  • the metal oxide may be a single oxide of a single metal element or a composite oxide of a plurality of metal elements.
  • the co-catalyst only one kind may be used, or two or more kinds may be combined.
  • the metal element that can be contained in the metal or metal oxide used as the co-catalyst include transition metal elements such as Ce (cerium), Fe (iron), Sn (tin), Ti (titanium), and Cu (copper). , Al (aluminum), Zn (zinc) and other typical metal elements, Si (silicon), Ge (germanium), As (arsenic) and other semi-metal elements.
  • a metal or metal oxidation containing at least one metal element selected from the group consisting of a transition metal element and Al a metal or metal oxidation containing at least one metal element selected from the group consisting of a transition metal element and Al.
  • the material is preferable, and a metal or a metal oxide containing at least one metal element selected from the group consisting of Ce, Fe and Al is more preferable. More specifically, cerium, cerium oxide such as CeO 2 , iron, iron oxide such as FeO and Fe 2 O 3 , aluminum, aluminum oxide such as Al 2 O 3 and Al 3 O 4 are preferable. Illustrated. Further, when cerium, cerium oxide, aluminum or aluminum oxide is contained, in addition to the effect of improving the catalytic activity at room temperature, the effect of improving the sustainability of the catalytic activity can be obtained, which is preferable.
  • the photocatalyst and the cocatalyst particles are physically mixed using a mortar, ultrasonic dispersion, or the like, or mechanical milling using a ball mill, jet mill, or the like. Can be mixed. Above all, physical mixing is preferable in order to obtain a better effect of improving the catalytic activity at room temperature.
  • the photocatalyst and the co-catalyst may be in the form of a mixture, the co-catalyst may be supported on the photocatalyst, and / or the photocatalyst may be supported on the co-catalyst, or , A combination of both may be used.
  • the co-catalyst contained in the photocatalyst used in the present embodiment is typically in the form of powder (co-catalyst particles) like the photocatalyst, and the average particle size thereof is not particularly limited, but is, for example, 5 nm. It is ⁇ 500 nm.
  • the content of the co-catalyst that can be contained in the photocatalyst used in the present embodiment can be appropriately adjusted according to the type of the co-catalyst, etc. On the other hand, it is preferably 5% by mass to 50% by mass, and more preferably 10% by mass to 30% by mass. From the same viewpoint, the mass ratio of the photocatalyst particles to the co-catalyst is preferably 95: 5 to 50:50, more preferably 90:10 to 70:30.
  • the photocatalyst used in this embodiment is used in a catalyst composition such as an adsorbent such as activated carbon, silicon oxide, zeolite, MOF (metal-organic framework), and a chemical adsorbent such as an amine compound.
  • a catalyst composition such as an adsorbent such as activated carbon, silicon oxide, zeolite, MOF (metal-organic framework), and a chemical adsorbent such as an amine compound.
  • an adsorbent such as activated carbon, silicon oxide, zeolite, MOF (metal-organic framework)
  • MOF metal-organic framework
  • a chemical adsorbent such as an amine compound.
  • a known component that can be used may be appropriately contained.
  • the photocatalyst structure according to the embodiment of the present invention includes a silver interlayer film containing silver oxide and a photocatalyst film in this order on a substrate, and the photocatalyst film contains a silver component, and the silver interlayer film and the photocatalyst are provided.
  • the ratio b / a1 of the silver content a1 in the photocatalyst film at 2 ⁇ m from the film interface to the silver content b at the interface between the photocatalyst film and the silver intermediate film is 10 or less.
  • the ratio b / a2 of the silver content a2 in the photocatalyst film at 4 ⁇ m in the film thickness direction from the interface and the silver content b at the interface between the photocatalyst film and the silver intermediate film is 20 or less.
  • the photocatalyst structure according to the embodiment of the present invention is preferably manufactured by using the above-mentioned method for manufacturing a photocatalyst film.
  • the photocatalytic structure according to the embodiment of the present invention exhibits high catalytic activity is presumed as follows. That is, by providing the photocatalyst structure with a silver interlayer film containing silver oxide and a photocatalyst film in this order on the substrate, not only the light emitted from the surface on the photocatalyst layer side but also the photocatalyst layer is transmitted to silver. Since the light reflected from the interlayer film can also be used, it is considered that high catalytic activity can be exhibited.
  • the silver component is transferred from the silver interlayer film into the photocatalyst film, and the silver component attracts the carriers generated by the photoexcitation of the photocatalyst, so that the carriers are recombined.
  • Catalytic activity can be improved by the suppressed effect.
  • the silver component transferred from the silver interlayer film at a specific content By including the silver component transferred from the silver interlayer film at a specific content, the balance between the number of carriers generated by photoexcitation of the photocatalyst and the carrier recombination suppressing effect is appropriately adjusted, and as a result, excellent catalytic activity can be exhibited. it is conceivable that.
  • the ratio of b / a1 to the content b needs to be 10 or less, preferably 8.5 or less, and more preferably 6.5 or less.
  • the lower limit of b / a1 is preferably 0.5 or more, more preferably 1.0 or more. Further, the ratio of the silver content a2 in the photocatalyst film at 4 ⁇ m in the film thickness direction from the interface between the photocatalyst film and the silver interlayer film and the silver content b at the interface between the photocatalyst film and the silver interlayer film b /. a2 needs to be 20 or less, preferably 17.5 or less, and more preferably 15 or less.
  • the lower limit of b / a2 is preferably 1.0 or more, and more preferably 1.5 or more.
  • the content a2 and the silver content b at the interface between the photocatalyst film and the silver interlayer film are observed by element mapping (section EDX) of the cross section of the photocatalyst structure using an energy dispersion type X-ray analysis (EDX) device. It can be measured by observation). Specifically, it can be measured by the method described in the column of Examples described later.
  • the cross-sectional EDX of the photocatalyst structure is observed at intervals of 1 ⁇ m in the thickness direction, the silver content is 10% by mass or more, and the silver content / photocatalyst metal.
  • the interface where the content is maximum is defined as the interface between the photocatalyst film and the silver interlayer film.
  • the silver oxide content in the silver interlayer film of the photocatalyst structure of the present embodiment is preferably 77 area% or less.
  • the silver oxide content is more preferably 67.3 area or less, further preferably 60 area% or less, and further preferably 55 area% or less.
  • the components constituting the silver interlayer film in the photocatalyst structure and the preferable range of the film thickness are the same as those described for the silver interlayer film in the first step described above.
  • the photocatalyst structure of the present embodiment preferably has a silver interlayer film having a thickness of 20 to 200 nm.
  • the components constituting the photocatalyst film in the photocatalyst structure and the preferable range of the film thickness are the same as those described for the photocatalyst film in the second step described above.
  • the thickness of the photocatalyst film is preferably 0.1 to 50 ⁇ m.
  • the photocatalytic film has at least one metal oxidation selected from titanium oxide, tungsten oxide, zinc oxide, tin oxide, strontium titanate, calcium titanate, barium titanate, bismuth oxide and iron oxide. It is preferable to include a substance.
  • the photocatalyst structure of the present embodiment may be molded into an appropriate shape according to the intended use. Since the photocatalytic structure of the present embodiment exhibits high catalytic activity when irradiated with light, it has an action of decomposing / removing harmful substances such as volatile organic compounds (VOC), an antibacterial action, a deodorizing / deodorizing action, a water purification action, and the like. Can exert various actions of. Above all, it can be particularly usefully used for various applications such as factories, offices, and houses where a decomposition action of a volatile organic compound (VOC) is desired.
  • VOC volatile organic compounds
  • VOCs examples include formaldehyde, acetaldehyde, toluene, xylene, benzene, ethyl acetate, methanol, dichloromethane and the like.
  • formaldehyde HCHO
  • CO 2 carbon dioxide
  • CO 2 water
  • O 2 adsorbed oxygen
  • Example 1 (Formation of silver interlayer)
  • a silver alloy target (APC-TR manufactured by Furuya Metal Co., Ltd.) is attached to a DC magnetron sputtering device (EB1100 manufactured by Cannon Alba Co., Ltd.), and the flow rate ratio (Ar / O 2 ratio) of Ar gas and O 2 gas is 147 /.
  • EB1100 DC magnetron sputtering device
  • Ar gas and O 2 gas is 147 /.
  • TIO 2 (P25 (Evonik Resources Efficiency GmbH) was added to ion-exchanged water as photocatalyst particles and dispersed for 30 minutes with an ultrasonic cleaner to prepare a photocatalyst dispersion having a concentration of 10 wt%.
  • SPV SPV-J-200 manufactured by Nitto Denko Co., Ltd.
  • SPV-J-200 which is a coating prevention sheet, is attached to the surface of the laminate on the base film side, immersed in the photocatalyst dispersion for 30 seconds, and then withdrawn from the photocatalyst dispersion.
  • the surface of the laminated body 1 was held for 2 minutes so as to be substantially vertical, and excess photocatalytic dispersion liquid was shed from the laminated body. After peeling off the SPV attached to the laminate, the SPV was allowed to stand at room temperature (25 ° C.) for 24 hours and dried to form a photocatalyst film to obtain a photocatalyst structure.
  • Example 2 The photocatalyst structure of Example 2 was obtained in the same manner as in Example 1 except that the Ar / O 2 ratio in the formation of the silver interlayer film was changed to 142/8.
  • Example 3 The photocatalyst structure of Example 3 was obtained in the same manner as in Example 1 except that the Ar / O 2 ratio in the formation of the silver interlayer film was changed to 140/10.
  • Example 4 The photocatalyst structure of Example 4 was obtained in the same manner as in Example 3 except that the thickness of the silver interlayer film was changed to 50 nm.
  • Example 5 The photocatalyst structure of Example 5 was obtained in the same manner as in Example 3 except that the thickness of the silver interlayer film was changed to 20 nm.
  • Example 6 The photocatalyst structure of Example 6 was obtained in the same manner as in Example 3 except that the base film was changed to a polyethylene naphthalate (PEN) film Theonex (R) Q51 (thickness 50 ⁇ m) manufactured by Teijin Limited.
  • PEN polyethylene naphthalate
  • R Theonex
  • Example 7 Photocatalyst of Example 7 in the same manner as in Example 3 except that the base film was changed to a glass base material synthetic quartz polishing plate (square plate) 50 ⁇ 50 ⁇ 1 ⁇ 50-1 (thickness 1000 ⁇ m) manufactured by AS ONE Corporation. Obtained a structure.
  • Example 8 The photocatalyst structure of Example 8 was obtained in the same manner as in Example 1 except that the photocatalyst particles were changed to tungsten trioxide (WO 3) (manufactured by High Purity Chemical Laboratory Co., Ltd.).
  • WO 3 tungsten trioxide
  • Example 9 The photocatalyst structure of Example 9 was obtained in the same manner as in Example 2 except that the photocatalyst particles were changed to tungsten trioxide (WO 3) (manufactured by High Purity Chemical Laboratory Co., Ltd.).
  • WO 3 tungsten trioxide
  • Example 10 The photocatalyst structure of Example 10 was obtained in the same manner as in Example 3 except that the photocatalyst particles were changed to tungsten trioxide (WO 3) (manufactured by High Purity Chemical Laboratory Co., Ltd.).
  • WO 3 tungsten trioxide
  • Comparative Example 1 The photocatalyst structure of Comparative Example 1 was obtained in the same manner as in Example 1 except that the Ar / O 2 ratio in the formation of the silver interlayer film was changed to 150/0.
  • Comparative Example 2 The photocatalyst structure of Comparative Example 2 was obtained in the same manner as in Example 1 except that the photocatalyst film was directly formed on the base film without providing the silver interlayer film.
  • Comparative Example 3 The photocatalyst structure of Comparative Example 3 was obtained in the same manner as in Example 6 except that the photocatalyst film was directly formed on the base film without providing the silver interlayer film.
  • Comparative Example 4 The photocatalyst structure of Comparative Example 4 was obtained in the same manner as in Example 7 except that the photocatalyst film was directly formed on the base film without providing the silver interlayer film.
  • a SiO 2 interlayer film having a thickness of 120 nm was formed on the substrate film, and a laminate of the substrate film and the SiO 2 interlayer film was obtained.
  • the temperature of the base film when forming the SiO 2 interlayer film was set to 25 ° C.
  • an Al 2 O 3 interlayer film having a thickness of 120 nm was formed on the base film, and a laminate of the base film and the Al 2 O 3 interlayer film was obtained.
  • the temperature of the base film when forming the Al 2 O 3 interlayer film was set to 25 ° C.
  • a TiO 2 interlayer film having a thickness of 10 nm was formed on the base film, and a laminate of the base film and the TiO 2 interlayer film was obtained.
  • the temperature of the base film when forming the TiO 2 interlayer film was set to 25 ° C.
  • Comparative Example 8 The photocatalyst structure of Comparative Example 8 was obtained in the same manner as in Comparative Example 1 except that the photocatalyst particles were changed to tungsten trioxide (WO 3) (manufactured by High Purity Chemical Laboratory Co., Ltd.).
  • WO 3 tungsten trioxide
  • Comparative Example 9 The photocatalyst structure of Comparative Example 9 was obtained in the same manner as in Comparative Example 2 except that the photocatalyst particles were changed to tungsten trioxide (WO 3) (manufactured by High Purity Chemical Laboratory Co., Ltd.).
  • WO 3 tungsten trioxide
  • ⁇ Measurement of silver oxide ratio (%) in silver interlayer film The content of silver oxide (Ag ⁇ 2 ) contained in the silver interlayer film was measured by the following procedure by X-ray photoelectron spectroscopy. Using the sample obtained by cutting out the laminate of the base material and the silver interlayer film obtained in Examples and Comparative Examples to a size of 10 mm ⁇ 10 mm, the narrow scan measurement of the ESCA analyzer (Quantara SXM manufactured by ULVAC-PHI) was performed under the following measurement conditions. The MNN Auger spectrum derived from Ag was obtained.
  • X-ray source Monochrome AlK ⁇ Irradiation range: 100 mm ⁇ Radiant intensity: 15kV, 25W Photoelectron extraction angle: 45 ° with respect to the sample surface
  • FIG. 2 is a diagram showing an MNN Auger spectrum derived from Ag in Example 3.
  • the ratio of the peak P2 attributed to silver (silver metal) obtained by the analysis software and the peak P3 attributed to silver oxide is set so as to match the MNN Auger spectrum derived from Ag at the highest ratio.
  • P4 was obtained by adjusting and adding so that the total of the two peaks was 100%. From the condition that P4 and the MNN Auger spectrum P1 derived from Ag overlap, the ratio of silver metal and the ratio of silver oxide in the silver interlayer film were calculated from the ratios of P2 and P3 calculated to obtain P4.
  • FIG. 3 shows the relationship between the amount of the photocatalyst supported and the silver oxide content of the silver interlayer film in the photocatalyst structures of Examples 1 to 3, Examples 8 to 10, Comparative Example 1 and Comparative Example 8. Further, the photocatalyst-supporting property (photocatalyst-supporting amount) was determined according to the following criteria and is shown in Table 1.
  • TIO 2 supportability criteria ⁇ : 0.30mg / cm 2 or more ⁇ : 0.20mg / cm 2 or more 0.30 mg / cm 2 less ⁇ : 0.20 mg / cm less than 2
  • WO 3 supported determination criterion ⁇ : 0.07mg / cm 2 or more ⁇ : 0.02mg / cm 2 more than 0.07mg / cm 2 less than ⁇ : 0.02mg / cm less than 2
  • ⁇ Thickness of photocatalyst film The thickness of the TiO 2 from the measured values and the sample size of the light amount of supported catalyst (5 cm ⁇ 5 cm), was calculated approximate thickness of TiO 2 density of 0.18 g / cm 3. The thickness of the WO 3 was calculated the approximate thickness from the measured values and the sample size of the light amount of supported catalyst (5 cm ⁇ 5 cm) of WO 3 density of 7.14 g / cm 3. The approximate thickness of the obtained photocatalyst film is shown in Table 1.
  • Table 3 shows the cross-sectional EDX observation results of the photocatalyst structure of Example 3. Further, the relationship between the distance of the photocatalyst structure in the thickness direction from the silver interlayer film and the content (% by mass) of silver and titanium obtained from the cross-sectional EDX observation result of the photocatalyst structure of Example 3 is shown in FIG. Shown in.
  • the photocatalyst layer and the silver intermediate layer are located where Ag is 10% by mass or more and Ag / Ti is the maximum value.
  • the photocatalyst film contains a silver component transferred from the silver interlayer film, and the silver content in the photocatalyst film at 2 ⁇ m in the film thickness direction from the interface between the silver interlayer film and the photocatalyst film and the interface between the photocatalyst film and the silver interlayer film.
  • the ratio of the silver content to the silver content in the photocatalyst film is 10 or less, and the ratio of the silver content in the photocatalyst film to the silver content at the interface between the photocatalyst film and the silver interlayer film at 4 ⁇ m in the film thickness direction from the interface is It is 20 or less. Then, silver oxide is transferred from the silver interlayer film into the photocatalyst film, and the content of the silver component in the photocatalyst film is continuously changed from the surface of the photocatalyst film in the film thickness direction, causing a component gradient. It turned out.
  • a concentration of 25 to 30 ppm and a methanol concentration of 120 to 140 ppm) were used.
  • the gas in the gas bag was analyzed after UV irradiation for 15 minutes, 75 minutes, 105 minutes, and 135 minutes.
  • formaldehyde and methanol were quantified using gas chromatography (Shimadzu GC-2010), and the removal rate (decrease rate) was calculated by the following formula. Each condition is as follows.
  • Formaldehyde removal rate (%) ⁇ formaldehyde concentration (ppm) / average value of formaldehyde concentration 15 minutes, 45 minutes, and 75 minutes before UV irradiation (ppm) ⁇
  • Methanol removal rate (%) ⁇ methanol concentration (ppm) / average value of methanol concentration 15 minutes, 45 minutes, and 75 minutes before UV irradiation (ppm) ⁇
  • Detector BID-2010 Plus Column: Rt-U-BOND manufactured by RESTEK Carrier gas: He Carrier gas flow rate: 30 mL / min Column temperature: 90 ° C (3 min), 170 ° C (3 min) Injector temperature: 100 ° C Detector temperature: 180 ° C
  • FIG. 6 shows the relationship between the UV irradiation time (minutes) and the formaldehyde residual rate (%).
  • the relationship between the UV irradiation time (minutes) and the methanol residual rate (%) is shown in FIG.
  • FIG. 8 shows the relationship between the UV irradiation time and the CO 2 conversion rate.
  • FIG. 9 shows the relationship between the silver oxide ratio and the formaldehyde (HCHO) removal rate (%) 45 minutes after UV irradiation in the photocatalytic structures of Examples 1 to 3 and Comparative Example 1.
  • the dotted line (SiO 2 ) in FIG. 9 indicates the formaldehyde (HCHO) removal rate (%) of Comparative Example 5.
  • the relationship between the silver oxide ratio and the methanol (MeOH) removal rate (%) 45 minutes after UV irradiation in the photocatalytic structures of Examples 1 to 3 and Comparative Example 1 is shown in FIG.
  • the dotted line (SiO 2 ) in FIG. 10 indicates the formaldehyde (HCHO) methanol (MeOH) removal rate (%) of Comparative Example 5.
  • FIG. 10 shows the formaldehyde (HCHO) methanol (MeOH) removal rate (%) of Comparative Example 5.
  • a method for producing a photocatalyst film capable of producing a photocatalyst film having a thick thickness and high catalytic activity at low cost by a simple method, and a photocatalyst structure having a photocatalyst film having a thickness and high catalytic activity. be able to.
  • Photocatalyst structure 11 Base material 12 Silver interlayer film 14 Photocatalyst film

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Abstract

The present invention pertains to: a method for manufacturing a photocatalyst film, the method comprising a first step for forming a silver oxide-containing intermediate film on a substrate, and a second step for forming a photocatalyst particle-containing photocatalyst film on the intermediate film; and a photocatalyst structure comprising, on a substrate, a silver oxide-containing intermediate film and a photocatalyst film in this order, wherein a silver component transferred from the intermediate film is contained in the photocatalyst film, b/a1, which is the ratio of the content b of silver in the boundary surface between the photocatalyst film and the intermediate film to the content a1 of silver in the photocatalyst film at a position of 2 μm in the film thickness direction from the boundary surface between the intermediate film and the photocatalyst film, is at most 10, and b/a2, which is the ratio of the content b of silver in the boundary surface between the photocatalyst film and the intermediate film to the content a2 of silver in the photocatalyst film at a position of 4 μm in the film thickness direction from the boundary surface, is at most 20.

Description

光触媒膜の製造方法及び光触媒構造体Photocatalyst film manufacturing method and photocatalyst structure
　本発明は、光触媒膜の製造方法及び光触媒構造体に関する。 The present invention relates to a method for producing a photocatalyst film and a photocatalyst structure.
　光触媒はセルフクリーニング、空気および水の清浄化等、多く用途に適用することができ、通常は適用後の再生不能エネルギーコストが生じない。これは、光触媒が太陽光だけでなく屋内及び屋外照明等の環境光を用いて染料、ＶＯＣ、およびＮＯｘ等の汚染物質を分解できるためである。 Photocatalyst can be applied to many applications such as self-cleaning, air and water purification, etc., and usually there is no non-renewable energy cost after application. This is because the photocatalyst can decompose pollutants such as dyes, VOCs, and NOx using not only sunlight but also ambient light such as indoor and outdoor lighting.
　ＶＯＣは、揮発性有機化合物（Ｖｏｌａｔｉｌｅ　Ｏｒｇａｎｉｃ　Ｃｏｍｐｏｕｎｄｓ）の略称であり、揮発性有機化合物は、揮発性を有し大気中でガス状となる有機化合物の総称であり、大気汚染や健康被害の要因となることが知られている。
　そのため、近年、大気中へのＶＯＣ排出量は厳しく規制されており、特にＶＯＣを多く発生する工場等においては、ＶＯＣ排出量のさらなる低減対策が求められている。また、例えばＶＯＣの一種であるホルムアルデヒドは、シックハウス症候群の原因物質であることから、住環境下においてもホルムアルデヒド等のＶＯＣを分解除去し、清浄化することへの需要が増大している。 VOC is an abbreviation for volatile organic compounds, and volatile organic compounds are a general term for organic compounds that are volatile and become gaseous in the atmosphere, and are factors that cause air pollution and health hazards. It is known to be.
Therefore, in recent years, VOC emissions into the atmosphere have been strictly regulated, and in particular, factories and the like that generate a large amount of VOCs are required to take measures to further reduce VOC emissions. Further, for example, formaldehyde, which is a kind of VOC, is a causative substance of sick house syndrome, and therefore, there is an increasing demand for decomposing and removing VOCs such as formaldehyde and purifying them even in a living environment.
　そして、例えば、家庭、公共、および商業スペース、実験室、検査室、工場、航空機、公共建築物等の閉鎖空間において、空間内の空気をクリーン化することに光触媒の適用が検討されている。また、光触媒を利用した製品の形状は、製品の用途に応じて、様々なものが提案されている。例えば、ハニカム構造、粒状、フィルム状等の、ハンドリング性良く使用できる基材に光触媒膜を製膜して製造されたものが提案されているが、いずれの形状であっても触媒活性を損なわず、高密着に触媒を担持することが望まれている。
　しかしながら、基材によっては光触媒膜との密着性が不十分であったり、薄い光触媒膜しか形成できず、触媒活性の高い厚い光触媒膜の形成にはコストがかかる等の問題があった。 Then, for example, in a closed space such as a home, public, and commercial space, a laboratory, an inspection room, a factory, an aircraft, and a public building, the application of a photocatalyst to clean the air in the space is being studied. Further, various shapes of products using a photocatalyst have been proposed depending on the use of the product. For example, those manufactured by forming a photocatalytic film on a base material having a honeycomb structure, granules, film shape, etc. that can be used with good handleability have been proposed, but any shape does not impair the catalytic activity. It is desired to support the catalyst with high adhesion.
However, depending on the substrate, there are problems that the adhesion to the photocatalyst film is insufficient, only a thin photocatalyst film can be formed, and the formation of a thick photocatalyst film having high catalytic activity is costly.
　そこで、基材と光触媒膜との密着性を改善するために中間層を設けることが検討されている。
　例えば、特許文献１には、光触媒層の脆さやはがれやすさを低減し、かつ長期の光照射による光触媒機能の低下が抑制された光触媒構造体の提供を目的とし、樹脂基材に無機酸化物層と、光触媒層とが積層された光触媒構造体が記載されている。
　特許文献２には、有機高分子化合物と金属系化合物との化学結合物を含有する有機－無機複合材料であって、材料中の金属系化合物の含有率が、材料の表面から深さ方向に連続的に変化する成分傾斜構造を有する有機－無機複合傾斜材料が記載されている。 Therefore, it is considered to provide an intermediate layer in order to improve the adhesion between the base material and the photocatalyst film.
For example, Patent Document 1 aims to provide a photocatalyst structure in which the brittleness and easiness of peeling of the photocatalyst layer are reduced and the deterioration of the photocatalyst function due to long-term light irradiation is suppressed, and an inorganic oxide is used as a resin base material. A photocatalyst structure in which a layer and a photocatalyst layer are laminated is described.
Patent Document 2 describes an organic-inorganic composite material containing a chemical bond of an organic polymer compound and a metal-based compound, wherein the content of the metal-based compound in the material is in the depth direction from the surface of the material. Organic-inorganic composite tilting materials with continuously varying component tilting structures have been described.
日本国特開２０１２－７１２５２号公報Japanese Patent Application Laid-Open No. 2012-71252 日本国特許第３８９７９３８号公報Japanese Patent No. 3897938
　しかしながら、本発明者らの知見によれば、特許文献１～２に記載された触媒はいずれも、光触媒膜と中間層の密着性が十分に高いとはいえず、厚い光触媒膜を形成する方法についてはさらなる改善の余地があった。また、厚い光触媒膜の形成にはコストがかかる等の問題があり、優れた触媒活性を有する光触媒膜を低コストで製造し得る製造方法が求められている。
　そこで、本発明は、厚みが厚く触媒活性の高い光触媒膜を簡便な方法により低コストで製造し得る光触媒膜の製造方法を提供する。 However, according to the findings of the present inventors, it cannot be said that the adhesion between the photocatalyst film and the intermediate layer is sufficiently high in any of the catalysts described in Patent Documents 1 and 2, and a method for forming a thick photocatalyst film. There was room for further improvement. Further, there is a problem that the formation of a thick photocatalyst film is costly, and there is a demand for a production method capable of producing a photocatalyst film having excellent catalytic activity at low cost.
Therefore, the present invention provides a method for producing a photocatalytic film capable of producing a photocatalytic film having a large thickness and high catalytic activity at low cost by a simple method.
　本発明者らは、厚みが厚く触媒活性の高い光触媒膜を簡便な方法により低コストで製造し得る製造方法を見出すことを目的として、鋭意検討を重ねた結果、本発明を完成するに至った。 The present inventors have completed the present invention as a result of repeated diligent studies for the purpose of finding a manufacturing method capable of manufacturing a photocatalytic film having a thick thickness and high catalytic activity at a low cost by a simple method. ..
　前記課題を解決するための手段は、以下の通りである。
〔１〕
　基材上に、酸化銀を含有する銀中間膜を形成する第一の工程と、前記銀中間膜上に、光触媒粒子を含む光触媒膜を形成する第二の工程を含む、光触媒膜の製造方法。
〔２〕
　前記第一の工程における銀中間膜中の酸化銀含有率が５．６～７７ａｒｅａ％である、〔１〕に記載の光触媒膜の製造方法。
〔３〕
　前記銀中間膜の厚みが２０～２００ｎｍである、〔１〕又は〔２〕に記載の光触媒膜の製造方法。
〔４〕
　前記光触媒膜の厚みが０．１～５０μｍである、〔１〕～〔３〕のいずれか１項に記載の光触媒膜の製造方法。
〔５〕
　前記光触媒粒子が、酸化チタン、酸化タングステン、酸化亜鉛、酸化錫、チタン酸ストロンチウム、チタン酸カルシウム、チタン酸バリウム、酸化ビスマスおよび酸化鉄から選択される少なくとも一種の金属酸化物を含む、〔１〕～〔４〕のいずれか１項に記載の光触媒膜の製造方法。
〔６〕
　前記光触媒膜中に前記銀中間膜から移行した銀成分を含み、
前記銀中間膜と前記光触媒膜の界面から膜厚方向に２μｍにおける前記光触媒膜内の銀の含有量ａ１と、前記光触媒膜と前記銀中間膜の前記界面における銀の含有量ｂとの比であるｂ／ａ１が１０以下であり、前記界面から膜厚方向に４μｍにおける前記光触媒膜内の銀の含有量ａ２と、前記光触媒膜と前記銀中間膜の前記界面における銀の含有量ｂとの比であるｂ／ａ２が２０以下である、〔１〕～〔５〕のいずれか１項に記載の光触媒膜の製造方法。
〔７〕
　基材上に、酸化銀を含む銀中間膜と光触媒膜とをこの順に備え、
前記光触媒膜中に銀成分を含み、
前記銀中間膜と前記光触媒膜の界面から膜厚方向に２μｍにおける前記光触媒膜内の銀の含有量ａ１と、前記光触媒膜と前記銀中間膜の前記界面における銀の含有量ｂとの比であるｂ／ａ１が１０以下であり、前記界面から膜厚方向に４μｍにおける前記光触媒膜内の銀の含有量ａ２と、前記光触媒膜と前記銀中間膜の前記界面における銀の含有量ｂとの比であるｂ／ａ２が２０以下である、光触媒構造体。
〔８〕
　前記銀中間膜中の酸化銀含有率が７７ａｒｅａ％以下である、〔７〕に記載の光触媒構造体。
〔９〕
　前記銀中間膜の厚みが２０～２００ｎｍである、〔７〕又は〔８〕に記載の光触媒構造体。
〔１０〕
　前記光触媒膜の厚みが０．１～５０μｍである、〔７〕～〔９〕のいずれか１項に記載の光触媒構造体。
〔１１〕
　前記光触媒膜が酸化チタン、酸化タングステン、酸化亜鉛、酸化錫、チタン酸ストロンチウム、チタン酸カルシウム、チタン酸バリウム、酸化ビスマスおよび酸化鉄から選択される少なくとも一種の金属酸化物を含む、〔７〕～〔１０〕のいずれか１項に記載の光触媒構造体。 The means for solving the above-mentioned problems are as follows.
[1]
A method for producing a photocatalyst film, which comprises a first step of forming a silver interlayer film containing silver oxide on a substrate and a second step of forming a photocatalyst film containing photocatalyst particles on the silver interlayer film. ..
[2]
The method for producing a photocatalyst film according to [1], wherein the silver oxide content in the silver interlayer film in the first step is 5.6 to 77 area%.
[3]
The method for producing a photocatalyst film according to [1] or [2], wherein the silver interlayer film has a thickness of 20 to 200 nm.
[4]
The method for producing a photocatalyst film according to any one of [1] to [3], wherein the photocatalyst film has a thickness of 0.1 to 50 μm.
[5]
The photocatalytic particles include at least one metal oxide selected from titanium oxide, tungsten oxide, zinc oxide, tin oxide, strontium titanate, calcium titanate, barium titanate, bismuth oxide and iron oxide [1]. The method for producing a photocatalyst film according to any one of [4].
[6]
The photocatalyst film contains a silver component transferred from the silver interlayer film, and contains the silver component.
The ratio of the silver content a1 in the photocatalyst film at 2 μm in the film thickness direction from the interface between the silver interlayer film and the photocatalyst film and the silver content b at the interface between the photocatalyst film and the silver intermediate film. A certain b / a1 is 10 or less, and the silver content a2 in the photocatalyst film at 4 μm in the film thickness direction from the interface and the silver content b at the interface between the photocatalyst film and the silver intermediate film. The method for producing a photocatalyst film according to any one of [1] to [5], wherein the ratio b / a2 is 20 or less.
[7]
A silver interlayer film containing silver oxide and a photocatalyst film are provided on the substrate in this order.
The photocatalyst film contains a silver component and contains
The ratio of the silver content a1 in the photocatalyst film at 2 μm in the film thickness direction from the interface between the silver interlayer film and the photocatalyst film and the silver content b at the interface between the photocatalyst film and the silver intermediate film. A certain b / a1 is 10 or less, and the silver content a2 in the photocatalyst film at 4 μm in the film thickness direction from the interface and the silver content b at the interface between the photocatalyst film and the silver intermediate film. A photocatalyst structure having a ratio of b / a2 of 20 or less.
[8]
The photocatalyst structure according to [7], wherein the silver oxide content in the silver interlayer film is 77 area% or less.
[9]
The photocatalytic structure according to [7] or [8], wherein the silver interlayer film has a thickness of 20 to 200 nm.
[10]
The photocatalyst structure according to any one of [7] to [9], wherein the photocatalyst film has a thickness of 0.1 to 50 μm.
[11]
The photocatalytic film contains at least one metal oxide selected from titanium oxide, tungsten oxide, zinc oxide, tin oxide, strontium titanate, calcium titanate, barium titanate, bismuth oxide and iron oxide, [7] to The photocatalyst structure according to any one of [10].
　本発明によれば、厚みが厚く触媒活性の高い光触媒膜を簡便な方法により低コストで製造し得る光触媒膜の製造方法、及び厚みが厚く触媒活性の高い光触媒膜を有する光触媒構造体を提供することができる。 INDUSTRIAL APPLICABILITY According to the present invention, there is provided a method for producing a photocatalyst film capable of producing a photocatalyst film having a thick thickness and high catalytic activity at low cost by a simple method, and a photocatalyst structure having a photocatalyst film having a thickness and high catalytic activity. be able to.
図１は、本発明の実施形態に係る光触媒構造体の断面模式図である。FIG. 1 is a schematic cross-sectional view of a photocatalyst structure according to an embodiment of the present invention. 図２は、実施例３におけるＡｇ由来のＭＮＮオージェスペクトルを示す図である。FIG. 2 is a diagram showing an MNN Auger spectrum derived from Ag in Example 3. 図３は、実施例１～３、実施例８～１０、比較例１及び比較例８の光触媒構造体における、光触媒担持量と、銀中間膜の酸化銀含有率との関係を示す図である。FIG. 3 is a diagram showing the relationship between the amount of photocatalyst supported and the silver oxide content of the silver interlayer film in the photocatalyst structures of Examples 1 to 3, Examples 8 to 10, Comparative Example 1 and Comparative Example 8. .. 図４は、比較例１の光触媒構造体の断面ＥＤＸ観察結果により求めた、光触媒構造体の銀中間膜からの厚み方向への距離と、銀及びチタンの含有量（質量％）との関係を示す図である。FIG. 4 shows the relationship between the distance of the photocatalyst structure in the thickness direction from the silver interlayer film and the content (% by mass) of silver and titanium obtained from the cross-sectional EDX observation result of the photocatalyst structure of Comparative Example 1. It is a figure which shows. 図５は、実施例３の光触媒構造体の断面ＥＤＸ観察結果により求めた、光触媒構造体の銀中間膜からの厚み方向への距離と、銀及びチタンの含有量（質量％）との関係を示す図である。FIG. 5 shows the relationship between the distance of the photocatalyst structure in the thickness direction from the silver interlayer film and the content (% by mass) of silver and titanium obtained from the cross-sectional EDX observation result of the photocatalyst structure of Example 3. It is a figure which shows. 図６は、実施例１～３、比較例１、比較例５及び比較例６の光触媒構造体における、ＵＶ照射時間と、ホルムアルデヒド残存率との関係を示す図である。FIG. 6 is a diagram showing the relationship between the UV irradiation time and the formaldehyde residual ratio in the photocatalytic structures of Examples 1 to 3, Comparative Example 1, Comparative Example 5 and Comparative Example 6. 図７は、実施例１～３、比較例１、比較例５及び比較例６の光触媒構造体における、ＵＶ照射時間と、メタノール残存率との関係を示す図である。FIG. 7 is a diagram showing the relationship between the UV irradiation time and the residual rate of methanol in the photocatalytic structures of Examples 1 to 3, Comparative Example 1, Comparative Example 5 and Comparative Example 6. 図８は、実施例１～３、比較例１、比較例５及び比較例６の光触媒構造体における、ＵＶ照射時間と、ＣＯ２変換率との関係を示す図である。FIG. 8 is a diagram showing the relationship between the UV irradiation time and the CO 2 conversion rate in the photocatalytic structures of Examples 1 to 3, Comparative Example 1, Comparative Example 5 and Comparative Example 6. 図９は、実施例１～３、及び比較例１の光触媒構造体における、酸化銀比率と、ＵＶ照射４５分後のホルムアルデヒド（ＨＣＨＯ）除去率（％）との関係を示す図である。FIG. 9 is a diagram showing the relationship between the silver oxide ratio and the formaldehyde (HCHO) removal rate (%) 45 minutes after UV irradiation in the photocatalytic structures of Examples 1 to 3 and Comparative Example 1. 図１０は、実施例１～３及び比較例１の光触媒構造体における、酸化銀比率と、ＵＶ照射４５分後のメタノール（ＭｅＯＨ）除去率（％）との関係を示す図である。FIG. 10 is a diagram showing the relationship between the silver oxide ratio and the methanol (MeOH) removal rate (%) 45 minutes after UV irradiation in the photocatalytic structures of Examples 1 to 3 and Comparative Example 1.
　以下、本発明の実施形態について、詳細に説明する。
＜光触媒膜の製造方法＞
　本発明の実施形態に係る光触媒膜の製造方法は、基材上に、酸化銀を含有する銀中間膜を形成する第一の工程と、前記銀中間膜上に、光触媒粒子を含む光触媒膜を形成する第二の工程を含む。
　図１は、後に詳述する本発明の実施形態に係る光触媒構造体の断面模式図である。本発明の実施形態に係る光触媒膜の製造方法は、図１に示すように、第一の工程により基材１１上に酸化銀を含有する銀中間膜１２を形成し、第二の工程により銀中間膜１２上に光触媒粒子を含む光触媒膜１４を形成することができる。 Hereinafter, embodiments of the present invention will be described in detail.
<Manufacturing method of photocatalytic membrane>
The method for producing a photocatalyst film according to an embodiment of the present invention comprises a first step of forming a silver interlayer film containing silver oxide on a substrate, and a photocatalyst film containing photocatalytic particles on the silver interlayer film. Includes a second step of forming.
FIG. 1 is a schematic cross-sectional view of a photocatalyst structure according to an embodiment of the present invention, which will be described in detail later. In the method for producing a photocatalyst film according to an embodiment of the present invention, as shown in FIG. 1, a silver interlayer film 12 containing silver oxide is formed on a base material 11 by the first step, and silver is formed by the second step. A photocatalyst film 14 containing photocatalyst particles can be formed on the interlayer film 12.
〔第一の工程〕
　第一の工程は、基材上に、酸化銀を含有する銀中間膜を形成する工程である。
　酸化銀を含有する銀中間膜の形成方法としては、特に制限はないが、真空蒸着、スパッタリング、イオンプレーティング等によって形成することができる。但し、大面積でも厚さを厳密に制御できる点から、スパッタリングが好ましい。 [First step]
The first step is a step of forming a silver interlayer film containing silver oxide on the base material.
The method for forming the silver interlayer film containing silver oxide is not particularly limited, but it can be formed by vacuum vapor deposition, sputtering, ion plating or the like. However, sputtering is preferable because the thickness can be strictly controlled even in a large area.
（基材）
　本実施形態に係る基材に用いる材料としては、無機材料、有機材料を問わず種々の材料が挙げられ、その形状も限定されない。基材の好ましい例としては、ガラス、セラミックス、金属、基材フィルム、樹脂成型物、ガラス、ゴム、石、セメント、コンクリート、繊維、布帛、木、紙、及びこれらの組合せが挙げられ、大面積での生産性のしやすさの観点から基材フィルムが好ましい。 (Base material)
Examples of the material used for the base material according to the present embodiment include various materials regardless of whether they are inorganic materials or organic materials, and their shapes are not limited. Preferred examples of the substrate include glass, ceramics, metal, substrate film, resin moldings, glass, rubber, stone, cement, concrete, fiber, fabric, wood, paper, and combinations thereof, which have a large area. A base film is preferable from the viewpoint of ease of productivity.
　基材フィルムとしては、例えば、ポリエチレンテレフタレート（ＰＥＴ）、ポリエチレンナフタレート（ＰＥＮ）、ポリブチレンテレフタレート、ポリアミド、ポリ塩化ビニル、ポリカーボネート（ＰＣ）、シクロオレフィンポリマー（ＣＯＰ）、ポリスチレン、ポリプロピレン（ＰＰ）、ポリエチレン、ポリシクロオレフィン、ポリウレタン、アクリル樹脂（例えば、ポリメタクリル酸メチル（ＰＭＭＡ）、ポリアクリル酸エステル）、ポリアクリロニトリル（ＰＡＮ）、ポリアクリルアミド、ＡＢＳ、ポリイミド、ポリテトラフルオロエチレンなどの単独重合体や共重合体からなる高分子フィルムを用いることができる。 Examples of the base film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate, polyamide, polyvinyl chloride, polycarbonate (PC), cycloolefin polymer (COP), polystyrene, polypropylene (PP), and the like. Homopolymers such as polyethylene, polycycloolefin, polyurethane, acrylic resin (eg, polymethylmethacrylate (PMMA), polyacrylic acid ester), polyacrylonitrile (PAN), polyacrylamide, ABS, polyimide, polytetrafluoroethylene, etc. A polymer film made of a copolymer can be used.
　銀中間膜及び光触媒膜を後に形成する観点から、蒸着やスパッタ等の高温に耐え得るものであることが好ましく、従って、上記材料の中でも、例えば、ポリエチレンテレフタレート、ポリエチレンナフタレート、アクリル、ポリカーボネート、シクロオレフィンポリマー、ＡＢＳ、ポリプロピレン、ポリウレタン、ポリイミド、ポリテトラフルオロエチレンが好ましい。なかでも、耐熱性とコストとのバランスがよいことからポリエチレンテレフタレートやシクロオレフィンポリマー、ポリカーボネート、アクリル、ポリイミド、ポリテトラフルオロエチレンが好ましい。 From the viewpoint of later forming the silver interlayer film and the photocatalyst film, it is preferable that the material can withstand high temperatures such as vapor deposition and spatter. Therefore, among the above materials, for example, polyethylene terephthalate, polyethylene naphthalate, acrylic, polycarbonate, cyclo. Olefin polymers, ABS, polypropylene, polyurethane, polyimide and polytetrafluoroethylene are preferred. Of these, polyethylene terephthalate, cycloolefin polymer, polycarbonate, acrylic, polyimide, and polytetrafluoroethylene are preferable because they have a good balance between heat resistance and cost.
（銀中間膜）
　本発明の実施形態においては、第一の工程により基材上に酸化銀を含有する銀中間膜を形成する。銀中間膜は、銀及び酸化銀を含有する。銀中間膜が酸化銀を含有することにより、第二の工程で光触媒膜を設ける際に銀中間膜から酸化銀が光触媒膜中に移行し、成分傾斜を生じる。これにより銀中間層と光触媒膜の親和性が高まるため、光触媒膜との密着性が向上し、光触媒膜の剥離、割れ又は反りを抑制することができ厚みの厚い光触媒膜を形成することができる。更に、光触媒膜に移行した銀によるキャリアの再結合抑止作用により触媒活性が向上する。 (Silver interlayer)
In the embodiment of the present invention, a silver interlayer film containing silver oxide is formed on the substrate by the first step. The silver interlayer contains silver and silver oxide. Since the silver interlayer film contains silver oxide, silver oxide is transferred from the silver interlayer film into the photocatalyst film when the photocatalyst film is provided in the second step, and a component gradient is generated. As a result, the affinity between the silver intermediate layer and the photocatalyst film is enhanced, so that the adhesion with the photocatalyst film is improved, peeling, cracking or warping of the photocatalyst film can be suppressed, and a thick photocatalyst film can be formed. .. Furthermore, the catalytic activity is improved by the carrier recombination inhibitory action of silver transferred to the photocatalytic membrane.
　そして、第一の工程における銀中間膜中の酸化銀含有率を特定の範囲に調整することにより、より優れた触媒活性が得られることが本発明者らの検討により判明した。後述の実施例に基づく図９及び図１０に示すとおり、銀中間膜中の酸化銀含有率とＶＯＣの分解除去作用には相関性があり、銀中間膜中の酸化銀含有率を特定の範囲にすることにより、顕著に優れたＶＯＣの分解除去効果を発揮することが判った。
　銀中間膜中の酸化銀含有率は、５．６ａｒｅａ％以上であることが好ましく、１０ａｒｅａ％以上であることが好ましく、１５ａｒｅａ％以上であることが更に好ましい。
　銀中間膜中の酸化銀含有率を５．６ａｒｅａ％以上とすることにより、光触媒膜中への銀の移行の促進の効果が得られる。
　また、銀中間膜中の酸化銀含有率は、７７ａｒｅａ％以下であることが好ましく、６７．３ａｒｅａ％以下であることがより好ましく、６０ａｒｅａ％以下が更に好ましく、５５ａｒｅａ％以下がより更に好ましい。
　銀中間膜中の酸化銀含有率を５．６ａｒｅａ％以上７７ａｒｅａ％以下とすることにより、顕著に優れたＶＯＣの分解除去効果を発揮する。 Then, it was found by the studies of the present inventors that more excellent catalytic activity can be obtained by adjusting the silver oxide content in the silver interlayer film in the first step to a specific range. As shown in FIGS. 9 and 10 based on the examples described later, there is a correlation between the silver oxide content in the silver interlayer film and the decomposition / removal action of VOC, and the silver oxide content in the silver interlayer film is within a specific range. It was found that the effect of decomposing and removing VOC was remarkably excellent.
The silver oxide content in the silver interlayer film is preferably 5.6 area% or more, preferably 10 area% or more, and more preferably 15 area% or more.
By setting the silver oxide content in the silver interlayer film to 5.6 area% or more, the effect of promoting the transfer of silver into the photocatalyst film can be obtained.
The silver oxide content in the silver interlayer film is preferably 77 area% or less, more preferably 67.3 area% or less, further preferably 60 area% or less, still more preferably 55 area% or less.
By setting the silver oxide content in the silver interlayer film to 5.6 area% or more and 77 area% or less, a remarkably excellent VOC decomposition / removal effect is exhibited.
　銀中間膜を構成する銀及び酸化銀以外の成分としては、炭素、酸素等が挙げられる。 Examples of components other than silver and silver oxide constituting the silver interlayer include carbon, oxygen and the like.
　銀中間膜中の酸化銀含有率は、例えば、基材に銀中間膜を形成した積層体を試料として、Ｘ線光電子分光法（ＥＳＣＡ）による分析装置等を用いてナロースキャン測定を行うことにより、Ａｇ由来のＭＮＮオージェスペクトルを取得し、試料最表面の各元素比率（ａｔｏｍｉｃ％）を下記の測定条件にて算出することができる。
　Ｘ線源：モノクロＡｌＫα
　照射範囲：１００ｍｍΦ
　照射強度：１５ｋＶ、２５Ｗ
　光電子取出し角：試料表面に対して４５° The silver oxide content in the silver interlayer is measured, for example, by performing a narrow scan measurement using a laminate having a silver interlayer formed on a substrate as a sample and using an analyzer by X-ray photoelectron spectroscopy (ESCA). , Ag-derived MNN Auger spectrum can be obtained, and the ratio of each element (atomic%) on the outermost surface of the sample can be calculated under the following measurement conditions.
X-ray source: Monochrome AlKα
Irradiation range: 100 mmΦ
Radiant intensity: 15kV, 25W
Photoelectron extraction angle: 45 ° with respect to the sample surface
　次いで、解析ソフト（ＣａｓａＸＰＳ）を用いて、上記で得られたＡｇ由来のＭＮＮオージェスペクトルに最も高い割合で適合するように、銀（メタル）に帰属されるピークと銀酸化物に帰属されるピークの比率を調整し、合計が１００％になるように足し合わせる。その際の各ピークの比率から銀（メタル）／酸化物比率を算出することができる。すなわち、図２に示すように、得られたＡｇ由来のＭＮＮオージェスペクトルの測定結果をピークＰ１とし、銀（メタル）に帰属されるピークＰ２と銀酸化物に帰属されるピークＰ３とを足し合わせて得られるピークをピークＰ４とした場合に、ピークＰ４とＡｇ由来のＭＮＮオージェスペクトルＰ１とが重なる条件から、銀（メタル）／酸化物比率を算出できる。 Then, using analysis software (CasaXPS), a peak attributed to silver (metal) and a peak attributed to silver oxide so as to match the MNN Auger spectrum derived from Ag obtained above in the highest proportion. Adjust the ratio of and add them so that the total is 100%. The silver (metal) / oxide ratio can be calculated from the ratio of each peak at that time. That is, as shown in FIG. 2, the measurement result of the obtained MNN Auger spectrum derived from Ag is defined as peak P1, and the peak P2 attributed to silver (metal) and the peak P3 attributed to silver oxide are added together. When the peak obtained is the peak P4, the silver (metal) / oxide ratio can be calculated from the condition that the peak P4 and the MNN Auger spectrum P1 derived from Ag overlap.
　銀中間膜中の酸化銀の含有量は、材料の選択、製造方法、酸化処理等により調整することができる。 The content of silver oxide in the silver interlayer film can be adjusted by selecting the material, manufacturing method, oxidation treatment, and the like.
　銀中間膜は、例えば、真空蒸着、スパッタリング法、イオンプレーティング法等によって形成することができる。但し、大面積でも厚さを厳密に制御できる点、及び銀中間膜中の酸化銀の含有量を調整しやすい点からスパッタリング法が好ましい。 The silver interlayer film can be formed by, for example, vacuum vapor deposition, a sputtering method, an ion plating method, or the like. However, the sputtering method is preferable because the thickness can be strictly controlled even in a large area and the content of silver oxide in the silver interlayer film can be easily adjusted.
　スパッタリング法は、真空チャンバー内にターゲットおよび基材を対向配置し、ガスを供給するとともに電源から電圧を印加することによりガスイオンを加速しターゲットに照射させて、ターゲット表面からターゲット材料をはじき出して、そのターゲット材料を基材表面に積層させる。 In the sputtering method, the target and the base material are placed facing each other in a vacuum chamber, gas is supplied and a voltage is applied from a power source to accelerate gas ions to irradiate the target, and the target material is ejected from the target surface. The target material is laminated on the surface of the substrate.
　スパッタリング法としては、例えば、２極スパッタリング法、ＥＣＲ（電子サイクロトロン共鳴）スパッタリング法、マグネトロンスパッタリング法、イオンビームスパッタリング法などが挙げられる。好ましくは、マグネトロンスパッタリング法が挙げられる。 Examples of the sputtering method include a bipolar sputtering method, an ECR (electron cyclotron resonance) sputtering method, a magnetron sputtering method, and an ion beam sputtering method. Preferred is the magnetron sputtering method.
　スパッタリング法を採用する場合、ターゲット材料としては、銀、銀合金、酸化銀が挙げられ、好ましくは、銀、銀合金が挙げられる。 When the sputtering method is adopted, examples of the target material include silver, a silver alloy, and silver oxide, and preferably silver and a silver alloy.
　銀中間膜中に酸化銀を含有させる方法としては、例えば、ターゲット材料として銀又は銀合金及び酸化銀を用い、スパッタガスとして不活性ガスを用いてそれぞれの材料を同時にスパッタリングして製膜する方法、ターゲット材料として銀又は銀合金を用い、スパッタガスとして酸素ガス及び不活性ガスを用いる方法等が挙げられる。銀中間膜中の酸化銀の含有量を調整しやすい点から、ターゲット材料として銀又は銀合金を用い、スパッタガスとして酸素ガス及び不活性ガスを用いる方法が好ましい。 As a method of containing silver oxide in the silver interlayer film, for example, a method of using silver or a silver alloy and silver oxide as a target material and simultaneously sputtering each material using an inert gas as a sputter gas to form a film. Examples thereof include a method in which silver or a silver alloy is used as the target material and oxygen gas and an inert gas are used as the sputter gas. From the viewpoint that the content of silver oxide in the silver interlayer can be easily adjusted, a method in which silver or a silver alloy is used as the target material and oxygen gas and an inert gas are used as the sputter gas is preferable.
　スパッタリング法に使用するスパッタガスとしては、例えば、アルゴン（Ａｒ）などの不活性ガス及び酸素ガスが挙げられ、不活性ガスと酸素ガスを併用することができる。不活性ガスと酸素ガスを併用する場合において、不活性ガスおよび酸素ガスの流量比（ｓｃｃｍ：Ｓｔａｎｄａｒｄ　Ｃｕｂｉｃ　Ｃｅｎｔｉｍｅｔｅｒ　ｐｅｒ　Ｍｉｎｕｔｅ）は特に限定しないが、不活性ガスおよび酸素ガスの合計流量に対して、酸素ガスが例えば、０流量％超であることが好ましく、適切な酸化銀含有率の銀中間層の形成の観点から０．５流量％以上であることが好ましく、１．０流量％以上であることがより好ましく、１．５流量％以上であることがさらに好ましい。また、適切な酸化銀含有率の銀中間層の形成の観点から９．０流量％以下であることが好ましく、８．０流量％以下であることがより好ましく、７．０流量％以下であることがさらに好ましい。 Examples of the sputtering gas used in the sputtering method include an inert gas such as argon (Ar) and an oxygen gas, and the inert gas and the oxygen gas can be used in combination. When the inert gas and the oxygen gas are used in combination, the flow rate ratio of the inert gas and the oxygen gas (sccm: Standard Cubic Centimator per Minute) is not particularly limited, but oxygen is obtained with respect to the total flow rate of the inert gas and the oxygen gas. For example, the gas preferably has a flow rate of more than 0%, preferably 0.5 flow rate% or more, and 1.0 flow rate% or more from the viewpoint of forming a silver intermediate layer having an appropriate silver oxide content. Is more preferable, and 1.5 flow rate% or more is further preferable. Further, from the viewpoint of forming a silver intermediate layer having an appropriate silver oxide content, it is preferably 9.0 flow rate% or less, more preferably 8.0 flow rate% or less, and 7.0 flow rate% or less. Is even more preferable.
　スパッタリング時の気圧は、スパッタリングレートの低下抑制、放電安定性などの観点から、例えば、１Ｐａ以下であり、好ましくは、０．１Ｐａ以上０．７Ｐａ以下である。 The atmospheric pressure during sputtering is, for example, 1 Pa or less, preferably 0.1 Pa or more and 0.7 Pa or less, from the viewpoint of suppressing a decrease in the sputtering rate and discharging stability.
　電源は、例えば、ＤＣ電源、ＡＣ電源、ＭＦ電源およびＲＦ電源のいずれであってもよく、また、これらの組み合わせであってもよい。 The power supply may be, for example, any of a DC power supply, an AC power supply, an MF power supply, and an RF power supply, or may be a combination thereof.
　銀中間膜の膜厚は、光触媒膜との密着性の観点から、２０ｎｍ以上であることが好ましく、５０ｎｍ以上であることがより好ましく、７５ｎｍ以上であることが更に好ましい。一方、銀中間層の柔軟性維持の観点から、２００ｎｍ以下が好ましく、１７５ｎｍ以下がより好ましく、１５０ｎｍ以下が更に好ましい。
　銀中間膜は、基材上に単層で積層しても、２層以上を積層させてもよい。 The film thickness of the silver interlayer film is preferably 20 nm or more, more preferably 50 nm or more, still more preferably 75 nm or more, from the viewpoint of adhesion to the photocatalyst film. On the other hand, from the viewpoint of maintaining the flexibility of the silver intermediate layer, 200 nm or less is preferable, 175 nm or less is more preferable, and 150 nm or less is further preferable.
The silver interlayer film may be laminated as a single layer or two or more layers may be laminated on the base material.
〔第二の工程〕
　本発明の実施形態に係る第二の工程は銀中間膜上に、光触媒粒子を含む光触媒膜を形成する工程である。
　第二の工程により、第一の工程において形成した銀中間膜上に、光触媒粒子を含む光触媒膜を形成することができる。
　光触媒膜を形成する方法には、特に制限はなく、公知の光触媒膜形成手段を用いることができる。例えば光触媒粒子を含む光触媒組成物を銀中間膜上に塗布することにより光触媒膜を形成することができる。 [Second step]
The second step according to the embodiment of the present invention is a step of forming a photocatalyst film containing photocatalyst particles on the silver interlayer film.
By the second step, a photocatalyst film containing photocatalyst particles can be formed on the silver interlayer film formed in the first step.
The method for forming the photocatalyst film is not particularly limited, and a known photocatalyst film forming means can be used. For example, a photocatalyst film can be formed by applying a photocatalyst composition containing photocatalyst particles on a silver interlayer film.
　光触媒組成物を塗布する方法は、特に限定されず、ディッピング法、スプレー法、スピンコート法、バーコート法、カーテンコート法、ロールコート法、刷毛塗り法等の公知の方法を挙げることができる。中でも、コストの観点から、ディッピング法を用いることが好ましい。
　通常、ディッピング法は低コストであるが、膜厚の厚い光触媒膜を形成するのは困難であった。しかしながら、本発明の実施形態においては、酸化銀を含む銀中間膜上に光触媒粒子を含む光触媒膜を形成することにより、銀中間膜から酸化銀が光触媒膜に移行する。これにより、銀中間膜と光触媒膜の界面から光触媒膜の表面方向に連続的に酸化銀濃度が変化するような成分傾斜を生じるため、銀中間膜との密着性に優れた光触媒膜が得られる。すなわち、光触媒膜が成分傾斜構造を有する。更に、光触媒膜がこの成分傾斜構造を有するにより厚膜の光触媒膜を形成することができるようになり、低コストで膜厚の厚い光触媒膜を形成することができ、優れた光触媒活性が得られる。 The method for applying the photocatalyst composition is not particularly limited, and examples thereof include known methods such as a dipping method, a spray method, a spin coating method, a bar coating method, a curtain coating method, a roll coating method, and a brush coating method. Above all, it is preferable to use the dipping method from the viewpoint of cost.
Usually, the dipping method is low cost, but it is difficult to form a thick photocatalytic film. However, in the embodiment of the present invention, by forming the photocatalyst film containing the photocatalyst particles on the silver interlayer film containing silver oxide, silver oxide is transferred from the silver interlayer film to the photocatalyst film. As a result, a component gradient is generated such that the silver oxide concentration continuously changes from the interface between the silver interlayer film and the photocatalyst film toward the surface of the photocatalyst film, so that a photocatalyst film having excellent adhesion to the silver interlayer film can be obtained. .. That is, the photocatalytic membrane has a component gradient structure. Further, since the photocatalyst film has this component gradient structure, a thick photocatalyst film can be formed, a thick photocatalyst film can be formed at low cost, and excellent photocatalytic activity can be obtained. ..
　光触媒膜は、光触媒膜中に銀中間膜から移行した銀成分を含み、光触媒膜中における該銀成分の含有率が、光触媒膜の表面から膜厚方向に連続的に変化することが好ましい。
　光触媒膜中に前記銀中間膜から移行した銀成分を含み、銀中間膜と光触媒膜の界面から膜厚方向に２μｍにおける前記光触媒膜内の銀の含有量ａ１と、光触媒膜と銀中間膜の界面における銀の含有量ｂとの比であるｂ／ａ１が１０以下であり、界面から膜厚方向に４μｍにおける光触媒膜内の銀の含有量ａ２と、光触媒膜と銀中間膜の界面における銀の含有量ｂとの比であるｂ／ａ２が２０以下であることが好ましい。 It is preferable that the photocatalyst film contains a silver component transferred from the silver interlayer film in the photocatalyst film, and the content of the silver component in the photocatalyst film continuously changes in the film thickness direction from the surface of the photocatalyst film.
The photocatalyst film contains a silver component transferred from the silver interlayer film, and the silver content a1 in the photocatalyst film at 2 μm in the film thickness direction from the interface between the silver interlayer film and the photocatalyst film, and the photocatalyst film and the silver interlayer film. The ratio of b / a1 to the silver content b at the interface is 10 or less, the silver content a2 in the photocatalyst film at 4 μm in the film thickness direction from the interface, and the silver at the interface between the photocatalyst film and the silver interlayer film. It is preferable that b / a2, which is the ratio of the content b to the content b, is 20 or less.
　光触媒組成物を塗布後は、加熱しても、常温で乾燥させて光触媒膜を硬化させてもよい。
　加熱方法は特に限定されず、基材を予熱する方法でも、塗布後に加熱する方法でもよく、適宜選択することができる。
　塗布後に加熱する場合には、加熱温度は、５℃以上であることが好ましく、１０℃以上であることがより好ましく、１５℃以上であることが更に好ましい。加熱温度の上限は特に限定はないが、光触媒膜の変質を抑制する観点から５０℃以下が好ましい。 After the photocatalyst composition is applied, it may be heated or dried at room temperature to cure the photocatalyst film.
The heating method is not particularly limited, and a method of preheating the base material or a method of heating after coating may be used, and can be appropriately selected.
When heating after coating, the heating temperature is preferably 5 ° C. or higher, more preferably 10 ° C. or higher, and even more preferably 15 ° C. or higher. The upper limit of the heating temperature is not particularly limited, but is preferably 50 ° C. or lower from the viewpoint of suppressing deterioration of the photocatalyst film.
　光触媒組成物は、光触媒粒子を含むものであれば特に制限はなく、水等の溶媒に光触媒粒子を分散した光触媒分散液であってもよく、光触媒粒子とバインダー溶液との混合液であってもよい。光触媒膜中の光触媒粒子の含有比率を高め、光触媒の露出を多くし得る点で、光触媒粒子が溶媒に分散された光触媒分散液（懸濁液）又はゾルを用いることが好ましい。溶媒としては水、メタノール、エタノール、プロパノール、ブタノールなどの水溶性アルコール溶媒、アセトン、メチルエチルケトン等が挙げられ、水が好ましい。
　本発明の実施形態に用いる光触媒組成物中の光触媒粒子の含有量の上限は、好ましくは５０質量％であり、より好ましくは４０質量％であり、さらに好ましくは３０質量％である。また、光触媒粒子の含有量の下限は、好ましくは１質量％であり、より好ましくは３質量％であり、さらに好ましくは５質量％である。 The photocatalyst composition is not particularly limited as long as it contains photocatalyst particles, and may be a photocatalyst dispersion liquid in which photocatalyst particles are dispersed in a solvent such as water, or a mixed liquid of photocatalyst particles and a binder solution. good. It is preferable to use a photocatalyst dispersion (suspension) or a sol in which the photocatalyst particles are dispersed in a solvent, because the content ratio of the photocatalyst particles in the photocatalyst film can be increased and the exposure of the photocatalyst can be increased. Examples of the solvent include water, water-soluble alcohol solvents such as methanol, ethanol, propanol and butanol, acetone, methyl ethyl ketone and the like, and water is preferable.
The upper limit of the content of the photocatalyst particles in the photocatalyst composition used in the embodiment of the present invention is preferably 50% by mass, more preferably 40% by mass, and further preferably 30% by mass. The lower limit of the content of the photocatalyst particles is preferably 1% by mass, more preferably 3% by mass, and further preferably 5% by mass.
　光触媒膜の硬化後の膜厚は、特に限定されないが、光触媒活性の観点から、０．１μｍ以上であることが好ましく、０．１５μｍ以上であることがより好ましく、０．２μｍ以上であることが更に好ましい。一方、光触媒膜と銀中間層の密着性の観点から、５０μｍ以下が好ましく、４０μｍ以下がより好ましく、３０μｍ以下が更に好ましい。 The film thickness after curing of the photocatalyst film is not particularly limited, but is preferably 0.1 μm or more, more preferably 0.15 μm or more, and more preferably 0.2 μm or more from the viewpoint of photocatalytic activity. More preferred. On the other hand, from the viewpoint of the adhesion between the photocatalyst film and the silver intermediate layer, 50 μm or less is preferable, 40 μm or less is more preferable, and 30 μm or less is further preferable.
（光触媒粒子）
　本発明の実施形態に用いる光触媒粒子としては、光触媒活性を有する金属酸化物等を含む光触媒の微粒子を用いることができる。
　光触媒の主成分としては、酸化物半導体等の触媒を挙げることができ、例えば、チタン、亜鉛、錫、ジルコニウム、タングステン、クロム、モリブデン、鉄、ニッケル、ルテニウム、バナジウムニオブ、タンタル、ロジウム、レニウム等の酸化物、オキシ炭化物、オキシ窒化物、オキシハロゲン化物、ハロゲン化物、塩、ドープまたは担持化合物が挙げられる。これらの中でも、酸化チタン、酸化タングステン、酸化亜鉛、酸化錫、チタン酸ストロンチウム、チタン酸カルシウム、チタン酸バリウム、酸化ビスマスおよび酸化鉄から選択される少なくとも一種の金属酸化物を含むことが好ましい。さらにこれらに窒素、炭素、硫黄等の元素をドープしたものであってもよい。 (Photocatalytic particles)
As the photocatalytic particles used in the embodiment of the present invention, fine particles of a photocatalyst containing a metal oxide having photocatalytic activity or the like can be used.
Examples of the main component of the photocatalyst include catalysts such as oxide semiconductors, such as titanium, zinc, tin, zirconium, tungsten, chromium, molybdenum, iron, nickel, ruthenium, vanadium niobium, tantalum, rhodium, and renium. Oxides, oxycarbides, oxynitrides, oxyhalides, halides, salts, dope or carrying compounds. Among these, it is preferable to contain at least one metal oxide selected from titanium oxide, tungsten oxide, zinc oxide, tin oxide, strontium titanate, calcium titanate, barium titanate, bismuth oxide and iron oxide. Further, these may be doped with elements such as nitrogen, carbon and sulfur.
　また、これらに、金、銀、白金、パラジウム、イリジウム、ルテニウム、ロジウム等の貴金属元素又はその酸化物若しくは水酸化物を更に添加したものも用いることができる。 Further, a precious metal element such as gold, silver, platinum, palladium, iridium, ruthenium, rhodium, or an oxide or hydroxide thereof is further added to these.
　本発明の実施形態に用いる光触媒粒子は、析出沈殿法、水熱合成法、ゾル－ゲル法や、酸化還元反応を利用すること等により製造することができる。 The photocatalytic particles used in the embodiment of the present invention can be produced by using a precipitation precipitation method, a hydrothermal synthesis method, a sol-gel method, a redox reaction, or the like.
　また、本実施形態においては、光触媒粒子に対して、ボールミル、ジェットミル等を用いたメカニカルミリングを行ってもよい。メカニカルミリングによる粒子表面衝突によって、光触媒粒子中の酸素欠陥サイトを増加しうる。ただし、例えばボールミル処理を行うにあたっては、ボールミルの回転数を上げ過ぎると、結晶化してしまいＭｎ＋／Ｍｎ４＋がかえって小さくなる場合があることから、ボールミルの回転数としては、６００ｒｐｍ以下であることが好ましい。 Further, in the present embodiment, the photocatalytic particles may be mechanically milled using a ball mill, a jet mill, or the like. Particle surface collisions due to mechanical milling can increase oxygen defect sites in photocatalytic particles. However, for example, when performing ball mill processing, if the rotation speed of the ball mill is increased too much, it may crystallize and Mn + / Mn 4+ may become smaller, so the rotation speed of the ball mill should be 600 rpm or less. Is preferable.
　なお、本実施形態においては、本発明の効果を損なわない限りにおいて、光触媒粒子を焼成してもよい。 In the present embodiment, the photocatalytic particles may be fired as long as the effects of the present invention are not impaired.
　本発明の実施形態に係る光触媒粒子の平均粒子径としては特に限定されるものではないが、例えば５ｎｍ～５００ｎｍである。 The average particle size of the photocatalytic particles according to the embodiment of the present invention is not particularly limited, but is, for example, 5 nm to 500 nm.
　本発明の実施形態に係る光触媒粒子は、本発明の効果を損なわない限りにおいて、後述する助触媒等のその他の成分をさらに含有してもよい。 The photocatalyst particles according to the embodiment of the present invention may further contain other components such as a co-catalyst described later, as long as the effects of the present invention are not impaired.
　本実施形態の光触媒粒子は、本発明の効果を損なわない限りにおいて、触媒活性の向上等のために、光触媒に加えて、助触媒をさらに含有してもよい。助触媒としては、金属または金属酸化物等が例示される。なお、ここでいう金属または金属酸化物に含有される金属元素には、半金属元素が包含される。また、金属酸化物は、単独の金属元素の単独酸化物であってもよく、複数の金属元素の複合酸化物であってもよい。さらに、助触媒としては、１種のみを用いてもよく、あるいは２種以上を組み合わせてもよい。 The photocatalytic particles of the present embodiment may further contain a co-catalyst in addition to the photocatalyst in order to improve the catalytic activity, etc., as long as the effects of the present invention are not impaired. Examples of the co-catalyst include a metal or a metal oxide. The metal element contained in the metal or metal oxide referred to here includes a metalloid element. Further, the metal oxide may be a single oxide of a single metal element or a composite oxide of a plurality of metal elements. Further, as the co-catalyst, only one kind may be used, or two or more kinds may be combined.
　助触媒として用いられる金属または金属酸化物に含有されうる金属元素としては、例えば、Ｃｅ（セリウム）、Ｆｅ（鉄）、Ｓｎ（錫）、Ｔｉ（チタン）、Ｃｕ（銅）等の遷移金属元素、Ａｌ（アルミニウム）、Ｚｎ（亜鉛）等の典型金属元素、Ｓｉ（ケイ素）、Ｇｅ（ゲルマニウム）、Ａｓ（ヒ素）等の半金属元素等が挙げられる。中でも、本実施形態の触媒に用いられる助触媒としては、触媒活性の向上の観点からは、遷移金属元素、及びＡｌからなる群から選択される少なくとも１種の金属元素を含有する金属または金属酸化物が好ましく、Ｃｅ、Ｆｅ及びＡｌからなる群から選択される少なくとも１種の金属元素を含有する金属または金属酸化物がより好ましい。より具体的には、セリウム、ＣｅＯ２等のセリウム酸化物、鉄、ＦｅＯやＦｅ２Ｏ３等の鉄酸化物、アルミニウム、Ａｌ２Ｏ３やＡｌ３Ｏ４等のアルミニウム酸化物等が好適に例示される。また、セリウム、セリウム酸化物、アルミニウムまたはアルミニウム酸化物を含有させる場合、常温での触媒活性の向上効果に加えて、触媒活性の持続性の向上効果も得られるため好ましい。 Examples of the metal element that can be contained in the metal or metal oxide used as the co-catalyst include transition metal elements such as Ce (cerium), Fe (iron), Sn (tin), Ti (titanium), and Cu (copper). , Al (aluminum), Zn (zinc) and other typical metal elements, Si (silicon), Ge (germanium), As (arsenic) and other semi-metal elements. Among them, as the auxiliary catalyst used for the catalyst of the present embodiment, from the viewpoint of improving the catalytic activity, a metal or metal oxidation containing at least one metal element selected from the group consisting of a transition metal element and Al. The material is preferable, and a metal or a metal oxide containing at least one metal element selected from the group consisting of Ce, Fe and Al is more preferable. More specifically, cerium, cerium oxide such as CeO 2 , iron, iron oxide such as FeO and Fe 2 O 3 , aluminum, aluminum oxide such as Al 2 O 3 and Al 3 O 4 are preferable. Illustrated. Further, when cerium, cerium oxide, aluminum or aluminum oxide is contained, in addition to the effect of improving the catalytic activity at room temperature, the effect of improving the sustainability of the catalytic activity can be obtained, which is preferable.
　本実施形態に用いる光触媒に助触媒を含有させるにあたっては、例えば、光触媒と助触媒粒子とを、乳鉢、超音波分散等を用いた物理混合や、ボールミル、ジェットミル等を用いたメカニカルミリング等により混合することができる。中でも、常温での触媒活性の向上効果をより良好に得るためには、物理混合が好ましい。
　なお、本実施形態において、光触媒と助触媒とは混合物の形態であってもよく、助触媒が光触媒に担持され、及び／又は、光触媒が助触媒に担持された形態であってもよく、あるいは、その両方を組み合わせた形態であってもよい。 In incorporating the cocatalyst into the photocatalyst used in the present embodiment, for example, the photocatalyst and the cocatalyst particles are physically mixed using a mortar, ultrasonic dispersion, or the like, or mechanical milling using a ball mill, jet mill, or the like. Can be mixed. Above all, physical mixing is preferable in order to obtain a better effect of improving the catalytic activity at room temperature.
In the present embodiment, the photocatalyst and the co-catalyst may be in the form of a mixture, the co-catalyst may be supported on the photocatalyst, and / or the photocatalyst may be supported on the co-catalyst, or , A combination of both may be used.
　本実施形態に用いる光触媒に含有される助触媒は、光触媒と同様に、典型的には粉末状（助触媒粒子）であり、その平均粒子径としては特に限定されるものではないが、例えば５ｎｍ～５００ｎｍである。 The co-catalyst contained in the photocatalyst used in the present embodiment is typically in the form of powder (co-catalyst particles) like the photocatalyst, and the average particle size thereof is not particularly limited, but is, for example, 5 nm. It is ~ 500 nm.
　本実施形態に用いる光触媒に含有されうる助触媒の含有量は、助触媒の種類等に応じて適宜調整し得るが、上述した効果を良好に発揮するためには、光触媒と助触媒の総量に対して、５質量％～５０質量％であることが好ましく、１０質量％～３０質量％であることがより好ましい。
　また、同様の観点から、光触媒粒子と助触媒との質量比は、９５：５～５０：５０であることが好ましく、９０：１０～７０：３０であることがより好ましい。 The content of the co-catalyst that can be contained in the photocatalyst used in the present embodiment can be appropriately adjusted according to the type of the co-catalyst, etc. On the other hand, it is preferably 5% by mass to 50% by mass, and more preferably 10% by mass to 30% by mass.
From the same viewpoint, the mass ratio of the photocatalyst particles to the co-catalyst is preferably 95: 5 to 50:50, more preferably 90:10 to 70:30.
　本実施形態に用いる光触媒には、助触媒の他にも、活性炭、シリコン酸化物、ゼオライト、ＭＯＦ（金属有機構造体）等の吸着剤や、アミン化合物など化学吸着剤等、触媒組成物に用いられうる公知の成分を適宜含有させてもよい。 In addition to the auxiliary catalyst, the photocatalyst used in this embodiment is used in a catalyst composition such as an adsorbent such as activated carbon, silicon oxide, zeolite, MOF (metal-organic framework), and a chemical adsorbent such as an amine compound. A known component that can be used may be appropriately contained.
＜光触媒構造体＞
　本発明の実施形態に係る光触媒構造体は、基材上に、酸化銀を含む銀中間膜と光触媒膜とをこの順に備え、前記光触媒膜中に銀成分を含み、前記銀中間膜と前記光触媒膜の界面から膜厚方向に２μｍにおける前記光触媒膜内の銀の含有量ａ１と、光触媒膜と銀中間膜の界面における銀の含有量ｂとの比であるｂ／ａ１が１０以下であり、前記界面から膜厚方向に４μｍにおける前記光触媒膜内の銀の含有量ａ２と、光触媒膜と銀中間膜の界面における銀の含有量ｂとの比であるｂ／ａ２が２０以下である。 <Photocatalytic structure>
The photocatalyst structure according to the embodiment of the present invention includes a silver interlayer film containing silver oxide and a photocatalyst film in this order on a substrate, and the photocatalyst film contains a silver component, and the silver interlayer film and the photocatalyst are provided. The ratio b / a1 of the silver content a1 in the photocatalyst film at 2 μm from the film interface to the silver content b at the interface between the photocatalyst film and the silver intermediate film is 10 or less. The ratio b / a2 of the silver content a2 in the photocatalyst film at 4 μm in the film thickness direction from the interface and the silver content b at the interface between the photocatalyst film and the silver intermediate film is 20 or less.
　本発明の実施形態に係る光触媒構造体は、上述の光触媒膜の製造方法を用いることにより好ましく製造される。 The photocatalyst structure according to the embodiment of the present invention is preferably manufactured by using the above-mentioned method for manufacturing a photocatalyst film.
　本発明の実施形態に係る光触媒構造体が、高い触媒活性を発現する理由は、以下のように推察される。
　すなわち、光触媒構造体が、基材上に、酸化銀を含む銀中間膜と光触媒膜とをこの順に備えることで、光触媒層側の面から照射した光だけでなく、光触媒層を透過し、銀中間膜から反射した光も利用できるため、高い触媒活性を発現できると考えられる。更に、銀中間膜が酸化銀を含むことにより、光触媒膜中に前記銀中間膜から銀成分が移行し、その銀成分が光触媒の光励起により発生したキャリアを吸引することで、キャリアの再結合が抑制される効果により触媒活性を向上し得る。 The reason why the photocatalytic structure according to the embodiment of the present invention exhibits high catalytic activity is presumed as follows.
That is, by providing the photocatalyst structure with a silver interlayer film containing silver oxide and a photocatalyst film in this order on the substrate, not only the light emitted from the surface on the photocatalyst layer side but also the photocatalyst layer is transmitted to silver. Since the light reflected from the interlayer film can also be used, it is considered that high catalytic activity can be exhibited. Further, when the silver interlayer film contains silver oxide, the silver component is transferred from the silver interlayer film into the photocatalyst film, and the silver component attracts the carriers generated by the photoexcitation of the photocatalyst, so that the carriers are recombined. Catalytic activity can be improved by the suppressed effect.
　そして、銀中間膜から移行した銀成分を特定の含有量で含むことにより、光触媒の光励起により生じるキャリア数とキャリア再結合抑制効果のバランスが適切に調整される結果、優れた触媒活性を発現できると考えられる。
　本発明の実施形態に係る光触媒構造体においては、銀中間膜と光触媒膜の界面から膜厚方向に２μｍにおける光触媒膜内の銀の含有量ａ１と、光触媒膜と銀中間膜の界面における銀の含有量ｂとの比であるｂ／ａ１は、１０以下である必要があり、８．５以下が好ましく、６．５以下がより好ましい。また、ｂ／ａ１の下限値としては、０．５以上が好ましく、１．０以上がより好ましい。
　また、光触媒膜と銀中間膜の界面から膜厚方向に４μｍにおける前記光触媒膜内の銀の含有量ａ２と、光触媒膜と銀中間膜の界面における銀の含有量ｂとの比であるｂ／ａ２が２０以下である必要があり、１７．５以下が好ましく、１５以下がより好ましい。また、ｂ／ａ２の下限値としては、１．０以上が好ましく、１．５以上がより好ましい。 By including the silver component transferred from the silver interlayer film at a specific content, the balance between the number of carriers generated by photoexcitation of the photocatalyst and the carrier recombination suppressing effect is appropriately adjusted, and as a result, excellent catalytic activity can be exhibited. it is conceivable that.
In the photocatalyst structure according to the embodiment of the present invention, the silver content a1 in the photocatalyst film at 2 μm from the interface between the silver interlayer film and the photocatalyst film and the silver at the interface between the photocatalyst film and the silver interlayer film. The ratio of b / a1 to the content b needs to be 10 or less, preferably 8.5 or less, and more preferably 6.5 or less. The lower limit of b / a1 is preferably 0.5 or more, more preferably 1.0 or more.
Further, the ratio of the silver content a2 in the photocatalyst film at 4 μm in the film thickness direction from the interface between the photocatalyst film and the silver interlayer film and the silver content b at the interface between the photocatalyst film and the silver interlayer film b /. a2 needs to be 20 or less, preferably 17.5 or less, and more preferably 15 or less. The lower limit of b / a2 is preferably 1.0 or more, and more preferably 1.5 or more.
　なお、本実施形態の光触媒構造体において、銀中間膜と光触媒膜の界面から膜厚方向に２μｍにおける光触媒膜内の銀の含有量ａ１、界面から膜厚方向に４μｍにおける前記光触媒膜内の銀の含有量ａ２、及び光触媒膜と銀中間膜の界面における銀の含有量ｂは、光触媒構造体の断面について、エネルギー分散型Ｘ線分析（ＥＤＸ）装置を用いて、元素マッピングによる観察（断面ＥＤＸ観察）により測定することができる。具体的には、後述の実施例の欄に記載の方法により測定することができる。
　ここで、本発明の実施形態においては、光触媒構造体の断面について厚み方向に１μｍおきに断面ＥＤＸ観察し、銀の含有量が１０質量％以上であり、かつ、銀の含有量／光触媒金属の含有量とが最大値になる箇所を光触媒膜と銀中間膜の界面とする。 In the photocatalyst structure of the present embodiment, the silver content a1 in the photocatalyst film at 2 μm in the film thickness direction from the interface between the silver interlayer film and the photocatalyst film, and the silver in the photocatalyst film at 4 μm in the film thickness direction from the interface. The content a2 and the silver content b at the interface between the photocatalyst film and the silver interlayer film are observed by element mapping (section EDX) of the cross section of the photocatalyst structure using an energy dispersion type X-ray analysis (EDX) device. It can be measured by observation). Specifically, it can be measured by the method described in the column of Examples described later.
Here, in the embodiment of the present invention, the cross-sectional EDX of the photocatalyst structure is observed at intervals of 1 μm in the thickness direction, the silver content is 10% by mass or more, and the silver content / photocatalyst metal. The interface where the content is maximum is defined as the interface between the photocatalyst film and the silver interlayer film.
　本実施形態の光触媒構造体における銀中間膜中の酸化銀含有率は、７７ａｒｅａ％以下であることが好ましい。酸化銀含有率は、６７．３ａｒｅａ％以下であることがより好ましく、６０ａｒｅａ％以下が更に好ましく、５５ａｒｅａ％以下がより更に好ましい。
　光触媒構造体における銀中間膜中の酸化銀含有率を７７ａｒｅａ％以下とすることにより、顕著に優れたＶＯＣの分解除去効果を発揮する。 The silver oxide content in the silver interlayer film of the photocatalyst structure of the present embodiment is preferably 77 area% or less. The silver oxide content is more preferably 67.3 area or less, further preferably 60 area% or less, and further preferably 55 area% or less.
By setting the silver oxide content in the silver interlayer film of the photocatalyst structure to 77 area% or less, a remarkably excellent VOC decomposition / removal effect is exhibited.
　光触媒構造体における銀中間膜を構成する成分、膜厚の好ましい範囲としては、上述の第一の工程における銀中間膜として記載した内容と同様である。 The components constituting the silver interlayer film in the photocatalyst structure and the preferable range of the film thickness are the same as those described for the silver interlayer film in the first step described above.
　本実施形態の光触媒構造体は、銀中間膜の厚みが２０～２００ｎｍであることが好ましい。 The photocatalyst structure of the present embodiment preferably has a silver interlayer film having a thickness of 20 to 200 nm.
　光触媒構造体における光触媒膜を構成する成分、膜厚の好ましい範囲としては、上述の第二の工程における光触媒膜として記載した内容と同様である。 The components constituting the photocatalyst film in the photocatalyst structure and the preferable range of the film thickness are the same as those described for the photocatalyst film in the second step described above.
　本実施形態の光触媒構造体は、光触媒膜の厚みが０．１～５０μｍであることが好ましい。 In the photocatalyst structure of the present embodiment, the thickness of the photocatalyst film is preferably 0.1 to 50 μm.
　本実施形態の光触媒構造体は、光触媒膜が酸化チタン、酸化タングステン、酸化亜鉛、酸化錫、チタン酸ストロンチウム、チタン酸カルシウム、チタン酸バリウム、酸化ビスマスおよび酸化鉄から選択される少なくとも一種の金属酸化物を含むことが好ましい。 In the photocatalytic structure of the present embodiment, the photocatalytic film has at least one metal oxidation selected from titanium oxide, tungsten oxide, zinc oxide, tin oxide, strontium titanate, calcium titanate, barium titanate, bismuth oxide and iron oxide. It is preferable to include a substance.
　本実施形態の光触媒構造体は、用途に応じて適宜な形状に成形して用いてもよい。
　本実施形態の光触媒構造体は、光照射により高い触媒活性を奏することから、揮発性有機化合物（ＶＯＣ）等の有害物質の分解・除去作用、抗菌作用、消臭・脱臭作用、水浄化作用等の種々の作用を発揮することができる。中でも、揮発性有機化合物（ＶＯＣ）の分解作用が所望される、工場、オフィス、住宅等の各種用途に、特に有用に用いることができる。 The photocatalyst structure of the present embodiment may be molded into an appropriate shape according to the intended use.
Since the photocatalytic structure of the present embodiment exhibits high catalytic activity when irradiated with light, it has an action of decomposing / removing harmful substances such as volatile organic compounds (VOC), an antibacterial action, a deodorizing / deodorizing action, a water purification action, and the like. Can exert various actions of. Above all, it can be particularly usefully used for various applications such as factories, offices, and houses where a decomposition action of a volatile organic compound (VOC) is desired.
　なお、ＶＯＣとしては、例えば、ホルムアルデヒド、アセトアルデヒド、トルエン、キシレン、ベンゼン、酢酸エチル、メタノール及びジクロロメタン等が挙げられる。ここで、例えばホルムアルデヒド（ＨＣＨＯ）であれば、本実施形態の触媒に吸着された吸着酸素（Ｏ２）との間で、下記式（１）の反応によって、二酸化炭素（ＣＯ２）と水（Ｈ２Ｏ）に分解される。
　　ＨＣＨＯ　＋　Ｏ２　→　ＣＯ２　＋　Ｈ２Ｏ　（１） Examples of VOCs include formaldehyde, acetaldehyde, toluene, xylene, benzene, ethyl acetate, methanol, dichloromethane and the like. Here, for example, in the case of formaldehyde (HCHO) , carbon dioxide (CO 2 ) and water (CO 2) are subjected to the reaction of the following formula (1) with the adsorbed oxygen (O 2) adsorbed by the catalyst of the present embodiment. It is decomposed into H 2 O).
HCHO + O 2 → CO 2 + H 2 O (1)
　以下、実施例及び比較例を示して本発明を詳細に説明する。ただし、本発明はこれらの実施例に限定されるものではない。 Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited to these examples.
〔実施例１〕
（銀中間膜の形成）
　基材フィルムとして、サイズ５ｃｍ×５ｃｍの東レ・デュポン株式会社製ポリイミド（ＰＩ）フィルム　カプトン２００Ｈ（厚さ５０μｍ）を用いた。
　先ず、ＤＣマグネトロンスパッタリング装置（キャノンアルバ株式会社製ＥＢ１１００）に銀合金ターゲット（フルヤ金属株式会社製　ＡＰＣ－ＴＲ）を取り付け、ＡｒガスとＯ２ガスの流量比率（Ａｒ／Ｏ２比率）を１４７／３で導入しながら、出力３００Ｗでスパッタリングをすることで、基材フィルム上に、１００ｎｍの厚さの銀中間膜を形成し、基材フィルムと銀中間膜の積層体を得た。銀中間膜を形成する際の基材フィルムの温度は、２５℃に設定した。 [Example 1]
(Formation of silver interlayer)
As the base film, a polyimide (PI) film Kapton 200H (thickness 50 μm) manufactured by Toray DuPont Co., Ltd. having a size of 5 cm × 5 cm was used.
First, a silver alloy target (APC-TR manufactured by Furuya Metal Co., Ltd.) is attached to a DC magnetron sputtering device (EB1100 manufactured by Cannon Alba Co., Ltd.), and the flow rate ratio (Ar / O 2 ratio) of Ar gas and O 2 gas is 147 /. By sputtering at an output of 300 W while introducing in No. 3, a silver interlayer film having a thickness of 100 nm was formed on the base film, and a laminate of the base film and the silver interlayer film was obtained. The temperature of the base film when forming the silver interlayer film was set to 25 ° C.
（光触媒膜の形成）
　光触媒粒子としてＴｉＯ２（Ｐ２５（Ｅｖｏｎｉｋ　Ｒｅｓｏｕｒｃｅ　Ｅｆｆｉｃｉｅｎｃｙ　ＧｍｂＨ））をイオン交換水に添加し、超音波洗浄機にて３０分間分散し、濃度１０ｗｔ％の光触媒分散液を調製した。
　積層体の基材フィルム側の面にコート防止のシートであるＳＰＶ（日東電工株式会社製ＳＰＶ－Ｊ－２００）を貼付し、光触媒分散液中に３０秒間浸漬した後、光触媒分散液より引揚げ、積層体１の表面を略垂直となるように２分間保持し、余分な光触媒分散液を積層体から脱落させた。積層体に貼付したＳＰＶを剥離した後、常温（２５℃）で２４時間静置して乾燥して光触媒膜を形成し、光触媒構造体を得た。 (Formation of photocatalytic film)
TIO 2 (P25 (Evonik Resources Efficiency GmbH)) was added to ion-exchanged water as photocatalyst particles and dispersed for 30 minutes with an ultrasonic cleaner to prepare a photocatalyst dispersion having a concentration of 10 wt%.
SPV (SPV-J-200 manufactured by Nitto Denko Co., Ltd.), which is a coating prevention sheet, is attached to the surface of the laminate on the base film side, immersed in the photocatalyst dispersion for 30 seconds, and then withdrawn from the photocatalyst dispersion. The surface of the laminated body 1 was held for 2 minutes so as to be substantially vertical, and excess photocatalytic dispersion liquid was shed from the laminated body. After peeling off the SPV attached to the laminate, the SPV was allowed to stand at room temperature (25 ° C.) for 24 hours and dried to form a photocatalyst film to obtain a photocatalyst structure.
〔実施例２〕
　銀中間膜の形成におけるＡｒ／Ｏ２比率を１４２／８に変更した以外は実施例１と同様にして実施例２の光触媒構造体を得た。 [Example 2]
The photocatalyst structure of Example 2 was obtained in the same manner as in Example 1 except that the Ar / O 2 ratio in the formation of the silver interlayer film was changed to 142/8.
〔実施例３〕
　銀中間膜の形成におけるＡｒ／Ｏ２比率を１４０／１０に変更した以外は実施例１と同様にして実施例３の光触媒構造体を得た。 [Example 3]
The photocatalyst structure of Example 3 was obtained in the same manner as in Example 1 except that the Ar / O 2 ratio in the formation of the silver interlayer film was changed to 140/10.
〔実施例４〕
　銀中間膜の厚さを５０ｎｍに変更した以外は実施例３と同様にして実施例４の光触媒構造体を得た。 [Example 4]
The photocatalyst structure of Example 4 was obtained in the same manner as in Example 3 except that the thickness of the silver interlayer film was changed to 50 nm.
〔実施例５〕
　銀中間膜の厚さを２０ｎｍに変更した以外は実施例３と同様にして実施例５の光触媒構造体を得た。 [Example 5]
The photocatalyst structure of Example 5 was obtained in the same manner as in Example 3 except that the thickness of the silver interlayer film was changed to 20 nm.
〔実施例６〕
　基材フィルムを帝人株式会社製ポリエチレンナフタレート（ＰＥＮ）フィルム　テオネックス（Ｒ）Ｑ５１（厚さ５０μｍ）に変更した以外は実施例３と同様にして実施例６の光触媒構造体を得た。 [Example 6]
The photocatalyst structure of Example 6 was obtained in the same manner as in Example 3 except that the base film was changed to a polyethylene naphthalate (PEN) film Theonex (R) Q51 (thickness 50 μm) manufactured by Teijin Limited.
〔実施例７〕
　基材フィルムをアズワン株式会社製ガラス基材　合成石英研磨板（角板）５０×５０×１　□５０－１（厚さ１０００μｍ）に変更した以外は実施例３と同様にして実施例７の光触媒構造体を得た。 [Example 7]
Photocatalyst of Example 7 in the same manner as in Example 3 except that the base film was changed to a glass base material synthetic quartz polishing plate (square plate) 50 × 50 × 1 □ 50-1 (thickness 1000 μm) manufactured by AS ONE Corporation. Obtained a structure.
〔実施例８〕
　光触媒粒子を三酸化タングステン（ＷＯ３）（株式会社高純度化学研究所製）に変更した以外は実施例１と同様にして実施例８の光触媒構造体を得た。 [Example 8]
The photocatalyst structure of Example 8 was obtained in the same manner as in Example 1 except that the photocatalyst particles were changed to tungsten trioxide (WO 3) (manufactured by High Purity Chemical Laboratory Co., Ltd.).
〔実施例９〕
　光触媒粒子を三酸化タングステン（ＷＯ３）（株式会社高純度化学研究所製）に変更した以外は実施例２と同様にして実施例９の光触媒構造体を得た。 [Example 9]
The photocatalyst structure of Example 9 was obtained in the same manner as in Example 2 except that the photocatalyst particles were changed to tungsten trioxide (WO 3) (manufactured by High Purity Chemical Laboratory Co., Ltd.).
〔実施例１０〕
　光触媒粒子を三酸化タングステン（ＷＯ３）（株式会社高純度化学研究所製）に変更した以外は実施例３と同様にして実施例１０の光触媒構造体を得た。 [Example 10]
The photocatalyst structure of Example 10 was obtained in the same manner as in Example 3 except that the photocatalyst particles were changed to tungsten trioxide (WO 3) (manufactured by High Purity Chemical Laboratory Co., Ltd.).
〔比較例１〕
　銀中間膜の形成におけるＡｒ／Ｏ２比率を１５０／０に変更した以外は実施例１と同様にして比較例１の光触媒構造体を得た。 [Comparative Example 1]
The photocatalyst structure of Comparative Example 1 was obtained in the same manner as in Example 1 except that the Ar / O 2 ratio in the formation of the silver interlayer film was changed to 150/0.
〔比較例２〕
　銀中間膜を設けず、基材フィルム上に直接光触媒膜を形成したこと以外は実施例１と同様にして比較例２の光触媒構造体を得た。 [Comparative Example 2]
The photocatalyst structure of Comparative Example 2 was obtained in the same manner as in Example 1 except that the photocatalyst film was directly formed on the base film without providing the silver interlayer film.
〔比較例３〕
　銀中間膜を設けず、基材フィルム上に直接光触媒膜を形成したこと以外は実施例６と同様にして比較例３の光触媒構造体を得た。 [Comparative Example 3]
The photocatalyst structure of Comparative Example 3 was obtained in the same manner as in Example 6 except that the photocatalyst film was directly formed on the base film without providing the silver interlayer film.
〔比較例４〕
　銀中間膜を設けず、基材フィルム上に直接光触媒膜を形成したこと以外は実施例７と同様にして比較例４の光触媒構造体を得た。 [Comparative Example 4]
The photocatalyst structure of Comparative Example 4 was obtained in the same manner as in Example 7 except that the photocatalyst film was directly formed on the base film without providing the silver interlayer film.
〔比較例５〕
（ＳｉＯ２中間膜の形成）
　基材フィルムとして、サイズ５ｃｍ×５ｃｍの東レ・デュポン株式会社製ポリイミド（ＰＩ）フィルム　カプトン２００Ｈ（厚さ５０μｍ）を用いた。
　先ず、ＤＣマグネトロンスパッタリング装置（キャノンアルバ株式会社製ＥＢ１１００）にＳｉＯ２ターゲット（株式会社アドバンテック製）を取り付け、ＡｒガスとＯ２ガスの比率（Ａｒ／Ｏ２比率）を１４７／３で導入しながら、出力３００Ｗでスパッタリングをすることで、基材フィルム上に、１２０ｎｍの厚さのＳｉＯ２中間膜を形成し、基材フィルムとＳｉＯ２中間膜の積層体を得た。ＳｉＯ２中間膜を形成する際の基材フィルムの温度は、２５℃に設定した。 [Comparative Example 5]
( Formation of SiO 2 interlayer film)
As the base film, a polyimide (PI) film Kapton 200H (thickness 50 μm) manufactured by Toray DuPont Co., Ltd. having a size of 5 cm × 5 cm was used.
First, a SiO 2 target (manufactured by Advantech Co., Ltd.) is attached to a DC magnetron sputtering device (EB1100 manufactured by Cannon Alba Co., Ltd.), and the ratio of Ar gas to O 2 gas (Ar / O 2 ratio) is introduced at 147/3. By sputtering at an output of 300 W, a SiO 2 interlayer film having a thickness of 120 nm was formed on the substrate film, and a laminate of the substrate film and the SiO 2 interlayer film was obtained. The temperature of the base film when forming the SiO 2 interlayer film was set to 25 ° C.
（光触媒膜の形成）
　得られた積層体上に実施例１と同様にして光触媒膜を形成し、比較例５の光触媒構造体を得た。 (Formation of photocatalytic film)
A photocatalyst film was formed on the obtained laminate in the same manner as in Example 1 to obtain a photocatalyst structure of Comparative Example 5.
〔比較例６〕
（Ａｌ２Ｏ３中間膜の形成）
　基材フィルムとして、サイズ５ｃｍ×５ｃｍの東レ・デュポン株式会社製ポリイミド（ＰＩ）フィルム　カプトン２００Ｈ（厚さ５０μｍ）を用いた。
　先ず、ＤＣマグネトロンスパッタリング装置（キャノンアルバ株式会社製ＥＢ１１００）にＡｌ２Ｏ３ターゲット（株式会社アドバンテック製）を取り付け、ＡｒガスとＯ２ガスの比率（Ａｒ／Ｏ２比率）を１４７／３で導入しながら、出力３００Ｗでスパッタリングをすることで、基材フィルム上に、１２０ｎｍの厚さのＡｌ２Ｏ３中間膜を形成し、基材フィルムとＡｌ２Ｏ３中間膜の積層体を得た。Ａｌ２Ｏ３中間膜を形成する際の基材フィルムの温度は、２５℃に設定した。 [Comparative Example 6]
( Formation of Al 2 O 3 interlayer film)
As the base film, a polyimide (PI) film Kapton 200H (thickness 50 μm) manufactured by Toray DuPont Co., Ltd. having a size of 5 cm × 5 cm was used.
First, an Al 2 O 3 target (manufactured by Advantech Co., Ltd.) was attached to a DC magnetron sputtering device (EB1100 manufactured by Cannon Alba Co., Ltd.), and the ratio of Ar gas to O 2 gas (Ar / O 2 ratio) was introduced at 147/3. Then, by sputtering at an output of 300 W, an Al 2 O 3 interlayer film having a thickness of 120 nm was formed on the base film, and a laminate of the base film and the Al 2 O 3 interlayer film was obtained. The temperature of the base film when forming the Al 2 O 3 interlayer film was set to 25 ° C.
（光触媒膜の形成）
　得られた積層体上に実施例１と同様にして光触媒膜を形成し、比較例６の光触媒構造体を得た。 (Formation of photocatalytic film)
A photocatalyst film was formed on the obtained laminate in the same manner as in Example 1 to obtain a photocatalyst structure of Comparative Example 6.
〔比較例７〕
（ＴｉＯ２中間膜の形成）
　基材フィルムとして、サイズ５ｃｍ×５ｃｍの東レ・デュポン株式会社製ポリイミド（ＰＩ）フィルム　カプトン２００Ｈ（厚さ５０μｍ）を用いた。
　先ず、ＤＣマグネトロンスパッタリング装置（キャノンアルバ株式会社製ＥＢ１１００）にＴｉＯ２ターゲット（株式会社アドバンテック製）を取り付け、ＡｒガスとＯ２ガスの比率（Ａｒ／Ｏ２比率）を１４７／３で導入しながら、出力３００Ｗでスパッタリングをすることで、基材フィルム上に、１０ｎｍの厚さのＴｉＯ２中間膜を形成し、基材フィルムとＴｉＯ２中間膜の積層体を得た。ＴｉＯ２中間膜を形成する際の基材フィルムの温度は、２５℃に設定した。 [Comparative Example 7]
( Formation of TiO 2 interlayer film)
As the base film, a polyimide (PI) film Kapton 200H (thickness 50 μm) manufactured by Toray DuPont Co., Ltd. having a size of 5 cm × 5 cm was used.
First, a TiO 2 target (manufactured by Advantech Co., Ltd.) is attached to a DC magnetron sputtering device (EB1100 manufactured by Cannon Alba Co., Ltd.), and the ratio of Ar gas to O 2 gas (Ar / O 2 ratio) is introduced at 147/3. By sputtering at an output of 300 W, a TiO 2 interlayer film having a thickness of 10 nm was formed on the base film, and a laminate of the base film and the TiO 2 interlayer film was obtained. The temperature of the base film when forming the TiO 2 interlayer film was set to 25 ° C.
（光触媒膜の形成）
　得られた積層体上に実施例１と同様にして光触媒膜を形成し、比較例７の光触媒構造体を得た。 (Formation of photocatalytic film)
A photocatalyst film was formed on the obtained laminate in the same manner as in Example 1 to obtain a photocatalyst structure of Comparative Example 7.
〔比較例８〕
　光触媒粒子を三酸化タングステン（ＷＯ３）（株式会社高純度化学研究所製）に変更した以外は比較例１と同様にして比較例８の光触媒構造体を得た。 [Comparative Example 8]
The photocatalyst structure of Comparative Example 8 was obtained in the same manner as in Comparative Example 1 except that the photocatalyst particles were changed to tungsten trioxide (WO 3) (manufactured by High Purity Chemical Laboratory Co., Ltd.).
〔比較例９〕
　光触媒粒子を三酸化タングステン（ＷＯ３）（株式会社高純度化学研究所製）に変更した以外は比較例２と同様にして比較例９の光触媒構造体を得た。 [Comparative Example 9]
The photocatalyst structure of Comparative Example 9 was obtained in the same manner as in Comparative Example 2 except that the photocatalyst particles were changed to tungsten trioxide (WO 3) (manufactured by High Purity Chemical Laboratory Co., Ltd.).
＜銀中間膜中の酸化銀比率（％）の測定＞
　銀中間膜に含まれる酸化銀（ＡｇО２）の含有率は、Ｘ線光電子分光法により以下の手順で測定した。
　実施例及び比較例で得られた基材と銀中間膜の積層体をサイズ１０ｍｍ×１０ｍｍに切り出した試料を用い、ＥＳＣＡ分析装置（アルバック・ファイ製　Ｑｕａｎｔｅｒａ　ＳＸＭ）のナロースキャン測定を下記の測定条件にて行うことで、Ａｇ由来のＭＮＮオージェスペクトルを得た。 <Measurement of silver oxide ratio (%) in silver interlayer film>
The content of silver oxide (AgО 2 ) contained in the silver interlayer film was measured by the following procedure by X-ray photoelectron spectroscopy.
Using the sample obtained by cutting out the laminate of the base material and the silver interlayer film obtained in Examples and Comparative Examples to a size of 10 mm × 10 mm, the narrow scan measurement of the ESCA analyzer (Quantara SXM manufactured by ULVAC-PHI) was performed under the following measurement conditions. The MNN Auger spectrum derived from Ag was obtained.
（測定条件）
　Ｘ線源：モノクロＡｌＫα
　照射範囲：１００ｍｍΦ
　照射強度：１５ｋＶ、２５Ｗ
　光電子取出し角：試料表面に対して４５° (Measurement condition)
X-ray source: Monochrome AlKα
Irradiation range: 100 mmΦ
Radiant intensity: 15kV, 25W
Photoelectron extraction angle: 45 ° with respect to the sample surface
　解析ソフト（ＣａｓａＸＰＳ）を用いて、試料最表面の各元素比率（ａｔｏｍｉｃ％）を算出した。図２は、実施例３におけるＡｇ由来のＭＮＮオージェスペクトルを示す図である。図２に示すようにＡｇ由来のＭＮＮオージェスペクトルに最も高い割合で適合するように、解析ソフトにより得られる銀（銀メタル）に帰属するピークＰ２と、酸化銀に帰属するピークＰ３との比率を調整し、２種類のピークの合計が１００％になるように足し合わせることでＰ４を得た。Ｐ４とＡｇ由来のＭＮＮオージェスペクトルＰ１が重なる条件から、Ｐ４を得るために算出されたＰ２およびＰ３の比率により銀中間膜中の銀メタルの比率及び酸化銀の比率を算出した。 Using analysis software (CasaXPS), the ratio of each element (atomic%) on the outermost surface of the sample was calculated. FIG. 2 is a diagram showing an MNN Auger spectrum derived from Ag in Example 3. As shown in FIG. 2, the ratio of the peak P2 attributed to silver (silver metal) obtained by the analysis software and the peak P3 attributed to silver oxide is set so as to match the MNN Auger spectrum derived from Ag at the highest ratio. P4 was obtained by adjusting and adding so that the total of the two peaks was 100%. From the condition that P4 and the MNN Auger spectrum P1 derived from Ag overlap, the ratio of silver metal and the ratio of silver oxide in the silver interlayer film were calculated from the ratios of P2 and P3 calculated to obtain P4.
＜光触媒担持量の算出＞
　基材フィルム上に銀中間膜を形成して得られた積層体の質量を測定した。
　得られた光触媒構造体の質量を測定し、積層体の質量との差及び試料サイズ（５ｃｍ×５ｃｍ）より光触媒担持量（ｍｇ／ｃｍ２）を算出した。
　実施例１～３、実施例８～１０、比較例１及び比較例８の光触媒構造体における、光触媒担持量と、銀中間膜の酸化銀含有率との関係を図３に示した。
　また、光触媒担持性（光触媒担持量）を下記の判断基準により判定し、表１に記載した。 <Calculation of photocatalyst loading amount>
The mass of the laminate obtained by forming the silver interlayer film on the base film was measured.
The mass of the obtained photocatalyst structure was measured, and the amount of photocatalyst supported (mg / cm 2 ) was calculated from the difference from the mass of the laminate and the sample size (5 cm × 5 cm).
FIG. 3 shows the relationship between the amount of the photocatalyst supported and the silver oxide content of the silver interlayer film in the photocatalyst structures of Examples 1 to 3, Examples 8 to 10, Comparative Example 1 and Comparative Example 8.
Further, the photocatalyst-supporting property (photocatalyst-supporting amount) was determined according to the following criteria and is shown in Table 1.
　（ＴｉＯ２担持性判定基準）
　○：０．３０ｍｇ／ｃｍ２以上
　△：０．２０ｍｇ／ｃｍ２以上０．３０ｍｇ／ｃｍ２未満
　×：０．２０ｍｇ／ｃｍ２未満
　（ＷＯ３担持性判定基準）
　○：０．０７ｍｇ／ｃｍ２以上
　△：０．０２ｍｇ／ｃｍ２以上０．０７ｍｇ／ｃｍ２未満
　×：０．０２ｍｇ／ｃｍ２未満 (TIO 2 supportability criteria)
○: 0.30mg / cm 2 or more △: 0.20mg / cm 2 or more 0.30 mg / cm 2 less ×: 0.20 mg / cm less than 2 (WO 3 supported determination criterion)
○: 0.07mg / cm 2 or more △: 0.02mg / cm 2 more than 0.07mg / cm 2 less than ×: 0.02mg / cm less than 2
＜光触媒膜の厚み＞
　ＴｉＯ２の厚みは、光触媒担持量の測定値及び試料サイズ（５ｃｍ×５ｃｍ）から、ＴｉＯ２密度を０．１８ｇ／ｃｍ３として概算厚みを算出した。
　ＷＯ３の厚みは、光触媒担持量の測定値及び試料サイズ（５ｃｍ×５ｃｍ）からＷＯ３密度を７．１４ｇ／ｃｍ３として概算厚みを算出した。
　得られた光触媒膜の概算厚みを表１に記載した。 <Thickness of photocatalyst film>
The thickness of the TiO 2 from the measured values and the sample size of the light amount of supported catalyst (5 cm × 5 cm), was calculated approximate thickness of TiO 2 density of 0.18 g / cm 3.
The thickness of the WO 3 was calculated the approximate thickness from the measured values and the sample size of the light amount of supported catalyst (5 cm × 5 cm) of WO 3 density of 7.14 g / cm 3.
The approximate thickness of the obtained photocatalyst film is shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
＜光触媒構造体の断面ＥＤＸ観察＞
　実施例３及び比較例１の光触媒構造体の断面について、エネルギー分散型Ｘ線分析装置（ＥＤＸ、アメテック株式会社製、「Ｅｌｅｍｅｎｔ　ＥＤＳ　Ｓｙｓｔｅｍ」）を用いて、元素マッピングによる観察（断面ＥＤＸ観察）を実施した。
　比較例１の光触媒構造体の断面ＥＤＸ観察結果を表２に示す。また、比較例１の光触媒構造体の断面ＥＤＸ観察結果により求めた、光触媒構造体の銀中間膜からの厚み方向への距離と、銀及びチタンの含有量（質量％）との関係を図４に示す。 <Observation of cross-section EDX of photocatalyst structure>
Observation of the cross sections of the photocatalytic structures of Example 3 and Comparative Example 1 by element mapping (cross-sectional EDX observation) using an energy dispersive X-ray analyzer (EDX, manufactured by Ametec Co., Ltd., "Element EDS System"). Carried out.
Table 2 shows the cross-sectional EDX observation results of the photocatalyst structure of Comparative Example 1. Further, FIG. 4 shows the relationship between the distance of the photocatalyst structure in the thickness direction from the silver interlayer film and the content (% by mass) of silver and titanium obtained from the cross-sectional EDX observation result of the photocatalyst structure of Comparative Example 1. Shown in.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　実施例３の光触媒構造体の断面ＥＤＸ観察結果を表３に示す。また、実施例３の光触媒構造体の断面ＥＤＸ観察結果により求めた、光触媒構造体の銀中間膜からの厚み方向への距離と、銀及びチタンの含有量（質量％）との関係を図５に示す。 Table 3 shows the cross-sectional EDX observation results of the photocatalyst structure of Example 3. Further, the relationship between the distance of the photocatalyst structure in the thickness direction from the silver interlayer film and the content (% by mass) of silver and titanium obtained from the cross-sectional EDX observation result of the photocatalyst structure of Example 3 is shown in FIG. Shown in.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　図４、図５、及び表３から明らかなように、実施例３の光触媒構造体は、Ａｇが１０質量％以上であり、かつＡｇ／Ｔｉが最大値になるところを光触媒層と銀中間層の界面とする。そして、光触媒膜中に銀中間膜から移行した銀成分を含み、銀中間膜と光触媒膜の界面から膜厚方向に２μｍにおける光触媒膜内の銀の含有量と、光触媒膜と銀中間膜の界面における銀の含有量との比が１０以下であり、界面から膜厚方向に４μｍにおける前記光触媒膜内の銀の含有量と、光触媒膜と銀中間膜の界面における銀の含有量との比が２０以下である。そして、銀中間膜から酸化銀が光触媒膜中に移行して、光触媒膜中における銀成分の含有率が光触媒膜の表面から膜厚方向に連続的に変化しており、成分傾斜を生じていることが判った。 As is clear from FIGS. 4, 5 and 3, in the photocatalyst structure of Example 3, the photocatalyst layer and the silver intermediate layer are located where Ag is 10% by mass or more and Ag / Ti is the maximum value. The interface of. The photocatalyst film contains a silver component transferred from the silver interlayer film, and the silver content in the photocatalyst film at 2 μm in the film thickness direction from the interface between the silver interlayer film and the photocatalyst film and the interface between the photocatalyst film and the silver interlayer film. The ratio of the silver content to the silver content in the photocatalyst film is 10 or less, and the ratio of the silver content in the photocatalyst film to the silver content at the interface between the photocatalyst film and the silver interlayer film at 4 μm in the film thickness direction from the interface is It is 20 or less. Then, silver oxide is transferred from the silver interlayer film into the photocatalyst film, and the content of the silver component in the photocatalyst film is continuously changed from the surface of the photocatalyst film in the film thickness direction, causing a component gradient. It turned out.
　＜ホルムアルデヒド及びメタノールの分解試験＞
　実施例１～３及び比較例１、５、６で得られた各光触媒構造体試料（サイズ５ｃｍ×５ｃｍ）について、下記のＶＯＣガス（ホルムアルデヒド、メタノール）分解試験を行った。
　まず、光触媒構造体試料を入れた容量５Ｌのガスバッグに、３．６Ｌの試験ガスを導入した。試験ガスは、ホルマリン（３７％）を０．１　ＬのＡｉｒでバブリング（２５℃）させ、発生したホルムアルデヒドとメタノールと合成空気（７９％窒素＋２１％酸素、５０％ＲＨ）との混合ガス（ホルムアルデヒド濃度２５～３０ｐｐｍ、メタノール濃度１２０～１４０ｐｐｍ）を用いた。
　ＵＶ－ＬＥＤ（ＯＳＲＡＭ社製、ＬＺ１－１０ＵＶ００、λ＝３６５ｎｍ、１．５ｍＷ／ｃｍ２）によりＵＶ照射を４５分間行った後、ガスバック中のガスの分析を行った。 <Decomposition test of formaldehyde and methanol>
The following VOC gas (formaldehyde, methanol) decomposition tests were carried out on each photocatalytic structure sample (size 5 cm × 5 cm) obtained in Examples 1 to 3 and Comparative Examples 1, 5 and 6.
First, 3.6 L of test gas was introduced into a gas bag having a capacity of 5 L containing a photocatalyst structure sample. The test gas was a mixed gas (formaldehyde) of formalin (37%) bubbling (25 ° C) with 0.1 L of Air, generated formaldehyde, methanol, and synthetic air (79% nitrogen + 21% oxygen, 50% RH). A concentration of 25 to 30 ppm and a methanol concentration of 120 to 140 ppm) were used.
After UV irradiation with a UV-LED (OSRAM, LZ1-10UV00, λ = 365 nm, 1.5 mW / cm 2 ) for 45 minutes, the gas in the gas bag was analyzed.
　同様に、１５分間、７５分間、１０５分間、１３５分間ＵＶ照射を行った後のガスバック中のガスの分析を行った。
　ガスの分析には、ガスクロマトグラフィ（島津製作所　ＧＣ－２０１０）を用いてホルムアルデヒド及びメタノールを定量し、下記の式により除去率（減少率）を算出した。各条件は、以下のとおりである。 Similarly, the gas in the gas bag was analyzed after UV irradiation for 15 minutes, 75 minutes, 105 minutes, and 135 minutes.
For gas analysis, formaldehyde and methanol were quantified using gas chromatography (Shimadzu GC-2010), and the removal rate (decrease rate) was calculated by the following formula. Each condition is as follows.
　ホルムアルデヒド除去率（％）＝｛ホルムアルデヒド濃度（ｐｐｍ）／ＵＶ照射１５分前、４５分前、７５分前のホルムアルデヒド濃度の平均値（ｐｐｍ）｝ Formaldehyde removal rate (%) = {formaldehyde concentration (ppm) / average value of formaldehyde concentration 15 minutes, 45 minutes, and 75 minutes before UV irradiation (ppm)}
　メタノール除去率（％）＝｛メタノール濃度（ｐｐｍ）／ＵＶ照射１５分前、４５分前、７５分前のメタノール濃度の平均値（ｐｐｍ）｝ Methanol removal rate (%) = {methanol concentration (ppm) / average value of methanol concentration 15 minutes, 45 minutes, and 75 minutes before UV irradiation (ppm)}
　　検出器：ＢＩＤ－２０１０　Ｐｌｕｓ
　　カラム：ＲＥＳＴＥＫ社製、Ｒｔ－Ｕ－ＢＯＮＤ
　　キャリアガス：Ｈｅ
　　キャリアガス流速：３０ｍＬ／ｍｉｎ　　　　　　
　　カラム温度：９０℃（３ｍｉｎ）、１７０℃（３ｍｉｎ）
　　インジェクタ温度：１００℃
　　ディテクタ温度：１８０℃ Detector: BID-2010 Plus
Column: Rt-U-BOND manufactured by RESTEK
Carrier gas: He
Carrier gas flow rate: 30 mL / min
Column temperature: 90 ° C (3 min), 170 ° C (3 min)
Injector temperature: 100 ° C
Detector temperature: 180 ° C
　得られた結果及びホルムアルデヒドの除去性及びメタノールの除去性を下記の判断基準により判断し、結果を表４に示す。（ホルムアルデヒド（ＨＣＨＯ）除去性判断基準）
　〇：ＵＶ照射４５分後のホルムアルデヒド除去率（％）が７０％以上
　△：ＵＶ照射４５分後のホルムアルデヒド除去率（％）が５０％以上７０％未満
　×：ＵＶ照射４５分後のホルムアルデヒド除去率（％）が５０％未満
（メタノール（ＭｅＯＨ）除去性判断基準）
　〇：ＵＶ照射４５分後のメタノール除去率（％）が３０％以上
　△：ＵＶ照射４５分後のメタノール除去率（％）が１０％以上３０％未満
　×：ＵＶ照射４５分後のメタノール除去率（％）が１０％未満 The obtained results, formaldehyde removability and methanol removability were judged according to the following criteria, and the results are shown in Table 4. (Formaldehyde (HCHO) removability criteria)
〇: Formaldehyde removal rate (%) after 45 minutes of UV irradiation is 70% or more Δ: Formaldehyde removal rate (%) after 45 minutes of UV irradiation is 50% or more and less than 70% ×: Formaldehyde removal rate after 45 minutes of UV irradiation (%) Is less than 50% (Criteria for determining removability of methanol (MeOH))
〇: Methanol removal rate (%) after 45 minutes of UV irradiation is 30% or more Δ: Methanol removal rate (%) after 45 minutes of UV irradiation is 10% or more and less than 30% ×: Methanol removal rate after 45 minutes of UV irradiation (%) Is less than 10%
　上記で得られた結果に基づき、ホルムアルデヒド残存率（％）とメタノール残存率（％）を算出した。ＵＶ照射時間（分）と、ホルムアルデヒド残存率（％）との関係を図６に示す。ＵＶ照射時間（分）と、メタノール残存率（％）との関係を図７に示す。また、ＵＶ照射時間と、ＣＯ２変換率との関係を図８に示す。 Based on the results obtained above, the formaldehyde residual rate (%) and the methanol residual rate (%) were calculated. FIG. 6 shows the relationship between the UV irradiation time (minutes) and the formaldehyde residual rate (%). The relationship between the UV irradiation time (minutes) and the methanol residual rate (%) is shown in FIG. Further, FIG. 8 shows the relationship between the UV irradiation time and the CO 2 conversion rate.
　図８における「ＣＯ２変換率（％）」は、以下の式により算出したものである。なお、以下の式における「ＣＯ２濃度」は、前記ガスクロマトグラフィを用いて検出した値を用いた。
　（ＣＯ２変換率（％））＝｛（ＶＯＣ分解試験後のＣＯ２濃度（ｐｐｍ））／（ホルムアルデヒドおよびメタノールが完全分解した場合のＣＯ２濃度（ｐｐｍ））｝×１００（％） The "CO 2 conversion rate (%)" in FIG. 8 is calculated by the following formula. As the "CO 2 concentration" in the following formula, the value detected by the gas chromatography was used.
(CO 2 conversion rate (%)) = {(CO 2 concentration (ppm) after VOC decomposition test) / (CO 2 concentration (ppm) when formaldehyde and methanol are completely decomposed)} x 100 (%)
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　また、実施例１～３、及び比較例１の光触媒構造体における、酸化銀比率とＵＶ照射４５分後のホルムアルデヒド（ＨＣＨＯ）除去率（％）との関係を図９に示す。なお、図９中の点線（ＳｉＯ２）は比較例５のホルムアルデヒド（ＨＣＨＯ）除去率（％）を示す。
　そして、実施例１～３、及び比較例１の光触媒構造体における、酸化銀比率とＵＶ照射４５分後のメタノール（ＭｅＯＨ）除去率（％）との関係を図１０に示す。なお、図１０中の点線（ＳｉＯ２）は比較例５のホルムアルデヒド（ＨＣＨＯ）メタノール（ＭｅＯＨ）除去率（％）を示す。
　図９に示されるように、酸化銀比率が７７ａｒｅａ％以下であれば、７０％以上のホルムアルデヒド除去率が得られると推察でき、中間膜がＳｉＯ２である比較例５の光触媒構造体に比較して、顕著に高い触媒活性を示すことが判る。また、図１０に示されるように、酸化銀比率が５．６ａｒｅａ％以上６７．３ａｒｅａ％以下であれば、３０％以上のメタノール除去率が得られると推察でき、中間膜がＳｉＯ２である比較例５の光触媒構造体に比較して、顕著に高い触媒活性を示すことが判る。 Further, FIG. 9 shows the relationship between the silver oxide ratio and the formaldehyde (HCHO) removal rate (%) 45 minutes after UV irradiation in the photocatalytic structures of Examples 1 to 3 and Comparative Example 1. The dotted line (SiO 2 ) in FIG. 9 indicates the formaldehyde (HCHO) removal rate (%) of Comparative Example 5.
The relationship between the silver oxide ratio and the methanol (MeOH) removal rate (%) 45 minutes after UV irradiation in the photocatalytic structures of Examples 1 to 3 and Comparative Example 1 is shown in FIG. The dotted line (SiO 2 ) in FIG. 10 indicates the formaldehyde (HCHO) methanol (MeOH) removal rate (%) of Comparative Example 5.
As shown in FIG. 9, if the silver oxide ratio is 77area% or less, it can be inferred that a formaldehyde removal rate of 70% or more can be obtained, as compared with the photocatalyst structure of Comparative Example 5 in which the interlayer film is SiO 2. It can be seen that the catalytic activity is remarkably high. Further, as shown in FIG. 10, if the silver oxide ratio is 5.6 area% or more and 67.3 area% or less, it can be inferred that a methanol removal rate of 30% or more can be obtained, and a comparison in which the interlayer film is SiO 2. It can be seen that the catalytic activity is significantly higher than that of the photocatalytic structure of Example 5.
　本発明によれば、厚みが厚く触媒活性の高い光触媒膜を簡便な方法により低コストで製造し得る光触媒膜の製造方法、及び厚みが厚く触媒活性の高い光触媒膜を有する光触媒構造体を提供することができる。 INDUSTRIAL APPLICABILITY According to the present invention, there is provided a method for producing a photocatalyst film capable of producing a photocatalyst film having a thick thickness and high catalytic activity at low cost by a simple method, and a photocatalyst structure having a photocatalyst film having a thickness and high catalytic activity. be able to.
　本発明を詳細にまた特定の実施態様を参照して説明したが、本発明の精神と範囲を逸脱することなく様々な変更や修正を加えることができることは当業者にとって明らかである。
　本出願は、２０２０年６月２６日出願の日本特許出願（特願２０２０－１１０４４６）に基づくものであり、その内容はここに参照として取り込まれる。 Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application filed on June 26, 2020 (Japanese Patent Application No. 2020-110446), the contents of which are incorporated herein by reference.
１０　光触媒構造体
１１　基材
１２　銀中間膜
１４　光触媒膜 10 Photocatalyst structure 11 Base material 12 Silver interlayer film 14 Photocatalyst film

Claims (11)

  1. 　基材上に、酸化銀を含有する銀中間膜を形成する第一の工程と、前記銀中間膜上に、光触媒粒子を含む光触媒膜を形成する第二の工程を含む、光触媒膜の製造方法。 A method for producing a photocatalyst film, which comprises a first step of forming a silver interlayer film containing silver oxide on a substrate and a second step of forming a photocatalyst film containing photocatalyst particles on the silver interlayer film. ..
  2. 　前記第一の工程における銀中間膜中の酸化銀含有率が５．６～７７ａｒｅａ％である、請求項１に記載の光触媒膜の製造方法。 The method for producing a photocatalyst film according to claim 1, wherein the silver oxide content in the silver interlayer film in the first step is 5.6 to 77 area%.
  3. 　前記銀中間膜の厚みが２０～２００ｎｍである、請求項１又は２に記載の光触媒膜の製造方法。 The method for producing a photocatalyst film according to claim 1 or 2, wherein the thickness of the silver interlayer film is 20 to 200 nm.
  4. 　前記光触媒膜の厚みが０．１～５０μｍである、請求項１～３のいずれか１項に記載の光触媒膜の製造方法。 The method for producing a photocatalyst film according to any one of claims 1 to 3, wherein the photocatalyst film has a thickness of 0.1 to 50 μm.
  5. 　前記光触媒粒子が、酸化チタン、酸化タングステン、酸化亜鉛、酸化錫、チタン酸ストロンチウム、チタン酸カルシウム、チタン酸バリウム、酸化ビスマスおよび酸化鉄から選択される少なくとも一種の金属酸化物を含む、請求項１～４のいずれか１項に記載の光触媒膜の製造方法。 1. The photocatalytic particles include at least one metal oxide selected from titanium oxide, tungsten oxide, zinc oxide, tin oxide, strontium titanate, calcium titanate, barium titanate, bismuth oxide and iron oxide. The method for producing a photocatalyst film according to any one of 4 to 4.
  6. 　前記光触媒膜中に前記銀中間膜から移行した銀成分を含み、
    前記銀中間膜と前記光触媒膜の界面から膜厚方向に２μｍにおける前記光触媒膜内の銀の含有量ａ１と、前記光触媒膜と前記銀中間膜の前記界面における銀の含有量ｂとの比であるｂ／ａ１が１０以下であり、前記界面から膜厚方向に４μｍにおける前記光触媒膜内の銀の含有量ａ２と、前記光触媒膜と前記銀中間膜の前記界面における銀の含有量ｂとの比であるｂ／ａ２が２０以下である、請求項１～５のいずれか１項に記載の光触媒膜の製造方法。     The photocatalyst film contains a silver component transferred from the silver interlayer film, and contains the silver component.
    The ratio of the silver content a1 in the photocatalyst film at 2 μm in the film thickness direction from the interface between the silver interlayer film and the photocatalyst film and the silver content b at the interface between the photocatalyst film and the silver intermediate film. A certain b / a1 is 10 or less, and the silver content a2 in the photocatalyst film at 4 μm in the film thickness direction from the interface and the silver content b at the interface between the photocatalyst film and the silver intermediate film. The method for producing a photocatalyst film according to any one of claims 1 to 5, wherein the ratio b / a2 is 20 or less.
  7. 　基材上に、酸化銀を含む銀中間膜と光触媒膜とをこの順に備え、
    前記光触媒膜中に銀成分を含み、
    前記銀中間膜と前記光触媒膜の界面から膜厚方向に２μｍにおける前記光触媒膜内の銀の含有量ａ１と、前記光触媒膜と前記銀中間膜の前記界面における銀の含有量ｂとの比であるｂ／ａ１が１０以下であり、前記界面から膜厚方向に４μｍにおける前記光触媒膜内の銀の含有量ａ２と、前記光触媒膜と前記銀中間膜の前記界面における銀の含有量ｂとの比であるｂ／ａ２が２０以下である、光触媒構造体。     A silver interlayer film containing silver oxide and a photocatalyst film are provided on the substrate in this order.
    The photocatalyst film contains a silver component and contains
    The ratio of the silver content a1 in the photocatalyst film at 2 μm in the film thickness direction from the interface between the silver interlayer film and the photocatalyst film and the silver content b at the interface between the photocatalyst film and the silver intermediate film. A certain b / a1 is 10 or less, and the silver content a2 in the photocatalyst film at 4 μm in the film thickness direction from the interface and the silver content b at the interface between the photocatalyst film and the silver intermediate film. A photocatalyst structure having a ratio of b / a2 of 20 or less.
  8. 　前記銀中間膜中の酸化銀含有率が７７ａｒｅａ％以下である、請求項７に記載の光触媒構造体。 The photocatalyst structure according to claim 7, wherein the silver oxide content in the silver interlayer film is 77 area% or less.
  9. 　前記銀中間膜の厚みが２０～２００ｎｍである、請求項７又は８に記載の光触媒構造体。 The photocatalytic structure according to claim 7 or 8, wherein the silver interlayer film has a thickness of 20 to 200 nm.
  10. 　前記光触媒膜の厚みが０．１～５０μｍである、請求項７～９のいずれか１項に記載の光触媒構造体。 The photocatalyst structure according to any one of claims 7 to 9, wherein the photocatalyst film has a thickness of 0.1 to 50 μm.
  11. 　前記光触媒膜が酸化チタン、酸化タングステン、酸化亜鉛、酸化錫、チタン酸ストロンチウム、チタン酸カルシウム、チタン酸バリウム、酸化ビスマスおよび酸化鉄から選択される少なくとも一種の金属酸化物を含む、請求項７～１０のいずれか１項に記載の光触媒構造体。 7. To claim 7, the photocatalytic film contains at least one metal oxide selected from titanium oxide, tungsten oxide, zinc oxide, tin oxide, strontium titanate, calcium titanate, barium titanate, bismuth oxide and iron oxide. 10. The photocatalyst structure according to any one of 10.
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