JP2002085978A - Photocatalytic member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use light in the visible region or week ultraviolet rays which are contained in indoor lightening abundantly, by accelerating the reduction reaction of oxygen due to electron and the oxidation reaction of water due to positive hole, decreasing the re-bonding of electron with positive hole and lowering the energy potential necessary for reduction reaction. SOLUTION: The photocatalytic member is provided with a photocatalytic layer, a conductive base material formed by laminating a hydrophilic layer on the surface of the photocatalytic layer and a reduction catalytic part electrically connected to the conductive base material and for accelerating the reduction reaction of electron generated by the photoexcitation in the photocatalytic layer with the oxygen.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocatalyst member provided with a photocatalyst layer, and more particularly, to a photocatalyst member capable of exhibiting a photocatalytic function even with weak ultraviolet light or light in the visible light region.

[0002]

2. Description of the Related Art Conventionally, a photocatalyst layer made of a titanium oxide such as titanium dioxide has been applied as a photocatalyst on the surface of a substrate, and has an antibacterial function and a purifying function using superoxide and hydroxyl radicals generated by light irradiation. Many photocatalyst members are known.

[0003] For example, anatase type titanium dioxide is 38
Which is photo-excited by ultraviolet light having a wavelength of 0 nm or less,
When exposed to sunlight, titanium oxide is photo-excited by ultraviolet rays contained in sunlight, and holes (h +) are generated in the valence band.
In the conduction band, electrons (e-) are generated, and the holes undergo an oxidation reaction with water contained in the atmosphere to generate hydroxyl radicals, and the electrons undergo a reduction reaction with oxygen in the atmosphere to generate superoxide ions. It is known that the hydroxy radical and superoxide ion exert an antibacterial function and a purifying function.

[0004]

However, these oxidation and reduction reactions are sufficiently carried out in sunlight having abundant rays in the ultraviolet region where the photoparticle energy is high, but in indoor lighting, the amount of photons in the ultraviolet region is low. For example, in the case of a fluorescent lamp, the amount of photons is extremely small, about 0.5% of the total amount of photons, and the number of holes and electrons excited by weak ultraviolet light is small. Therefore, generation of hydroxyl radicals and superoxide ions is an odorous component. The photocatalytic functions such as the antibacterial function and the purifying function could not be sufficiently exhibited because the number was extremely small as compared with the number of molecules.

Therefore, it is conceivable to use light rays in the visible light range, which are abundantly contained in indoor lighting. However, the light particle energy of the light rays in the visible light range is low, and the excited electron energy is small. The reduction reaction is not performed sufficiently, and electrons remain. On the other hand, on the hole side, if there is abundant moisture that the holes can come in contact with, most of the holes will oxidize and react with water to generate hydroxyl radicals, which can exert antibacterial and purifying functions. In normal humidity conditions, the amount of water in contact with holes is small and the amount of hydroxyl radicals generated is small, and the surplus electrons recombine with holes to inhibit the oxidation reaction with water, and have antibacterial and purification functions. And so on, and as a result, indoor use was difficult.

The present invention solves the above problems, and focuses on the fact that the reduction reaction between electrons and oxygen and the oxidation reaction between holes and water are restricted. It promotes the oxidation reaction of water by holes, reduces the recombination of electrons and holes, and lowers the energy potential required for the reduction reaction to reduce the amount of visible light and weak ultraviolet light abundantly contained in indoor lighting. To enable the use of

[0007]

In order to solve the above-mentioned problems, a photocatalyst member according to the present invention comprises a photocatalyst layer, a conductive substrate having a hydrophilic layer laminated on the surface of the photocatalyst layer, and an electrically conductive substrate. And a reduction catalyst section for conducting a reduction reaction of electrons generated by the photoexcitation of the photocatalyst layer with oxygen to oxygen.

With this configuration, holes generated by photoexcitation smoothly oxidize with water trapped in the hydrophilic layer to generate hydroxyl radicals, and some of the electrons move to the side of the reduction catalyst. To reduce oxygen with oxygen on the reduction catalyst side, and the rest of the electrons also reduce with oxygen on the photocatalyst layer side.
The recombination between electrons and holes is reduced, and the energy potential required for oxygen reduction is reduced by the reduction catalyst. As a result, 550 n of the visible light region abundantly present in indoor lighting is obtained.
A reduction reaction is possible even with electrons excited at the energy level held by the photoparticles up to near m. Therefore, superoxide ions are generated by a reduction reaction between electrons and oxygen on the reduction catalyst section side, and an oxidation reaction between holes and water trapped in the hydrophilic layer and a reduction reaction between electrons and oxygen on the photocatalyst layer side. Then, hydroxyl radicals and superoxide ions are generated, and a strong decomposition function, an antibacterial function, a purifying function, and the like can be efficiently exhibited.

As a main component of the photocatalyst layer, it is preferable to use titanium oxide excellent in oxidation and reduction reactions or Fe2O3 having an alpha-type crystal structure which is inexpensive.

When SiO2 is used as the main component of the hydrophilic layer, dry coating with a single oxide is easy and inexpensive, which is preferable.

If the conductive base material is plate-shaped, a photocatalyst layer and a hydrophilic layer are laminated on one surface, and a reduction catalyst portion is formed on the other surface, a strong antibacterial function and purification function can be efficiently performed on both surfaces. Irradiating the photocatalyst layer side with light is preferable because the reduction catalyst portion side can be shaded and exhibit an antibacterial function, decomposition and purification function without irradiating light.

When a large number of small holes penetrating the base material are provided in the conductive base material, air containing dioxin, formaldehyde, odorous substance, etc. is formed in the small holes from the photocatalyst layer side toward the reduction catalyst portion. In the photocatalytic layer, these substances are oxidized by superoxide ions and hydroxyl radicals, and in the reduction catalyst section, these substances are oxidized by superoxide ions. Can be preferred.

It is preferable that the photocatalyst layer, the hydrophilic layer, and the reduction catalyst portion are formed by a dry coating method. If formed in this manner, the film thickness can be controlled, and, for example, the photocatalytic layer can exhibit the photocatalytic effect optimally. About 200-500n
m, the thickness of the hydrophilic layer can be set to 1 to 5 nm which does not hinder the transmission of light and exhibits a hydrophilic effect, and the thickness of the reduction catalyst portion can be set to the minimum required thickness of 1 to 5 nm. The layer and the reduction catalyst portion adhere to each other at the molecular level, and can have extremely excellent durability.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a schematic view showing basic steps of a method for manufacturing a photocatalyst member, and FIG. 2 is a sectional view based on the manufacturing steps.
(A) is a cross-sectional view in which a reduction catalyst layer as a reduction catalyst portion mainly containing platinum is coated on the back surface of a conductive plate-like base material such as a stainless steel plate, and (b) is a titanium oxide thin film as a photocatalyst layer. 2 (c) is a cross-sectional view in which a titanium oxide thin film is further coated with a silicon oxide (SiO2) thin film as a hydrophilic layer, FIG. 3 is a graph showing oxidation potential, and FIG. 4 is reduction. FIG. 5 is a schematic view of an apparatus for coating a catalyst substance on a substrate, FIG. 5 is a schematic view of an apparatus for coating and laminating titanium oxide and silicon oxide, and FIG. 6 is a schematic view showing a manufacturing process of the apparatus of FIG.
Is a schematic diagram showing an example in which a photocatalyst member is applied to a filter and used in a range hood, FIG. 8 is a schematic diagram showing an example in which a photocatalyst member is applied to a filter and used in refrigeration / refrigeration equipment, and FIG. 9 is a main part of the filter. FIG.

Referring to FIGS. 1 and 2, the basic manufacturing process of the method for manufacturing a photocatalyst member according to the present invention will be described. A is mainly made of Pt or the like on one side surface of a conductive plate-like base material 1 such as stainless steel. A step of coating a reduction catalyst layer 2 as a reduction catalyst part which promotes reduction of electrons and oxygen as a component; a step B of coating a photocatalyst layer 3 made of, for example, TiO2 on the other surface of the conductive plate-like base material 1 , C is, for example, S
The step of laminating the hydrophilic layer 4 made of iO2, and the step D is a step of performing a heat treatment thereafter.

The base material 1 is formed by knitting a stainless steel wire having a wire diameter of 0.1 mm to 0.5 mm to form a large number of small holes 5.
Mesh ~ 100 mesh net or thickness 0.1 ~
A plate material of 1 mm is used, and a reduction catalyst layer 2 mainly composed of platinum is formed on one surface by a dry coating method.

On the other surface of the substrate 1, a photocatalytic layer 3 made of, for example, titanium dioxide (TiO2) and an extremely thin hydrophilic layer 4 made of silicon oxide (SiO2) are formed by a dry coating method. .

The hydrophilic layer 4 has a surface having a water wettability of about 10 degrees or less in terms of a contact angle with water.
In the case of iO2, the angle is about 5 degrees, and the water wettability is good, and the water spreads evenly and thinly over the entire surface without being hardened in the form of water droplets.

When the reduction catalyst layer 2 is formed of platinum on the surface of the reduction catalyst layer 2 as shown in FIG.
The reduction potential of-) and oxygen (O2) is 0.491 eV in terms of a hydrogen reference potential, whereas in the case of a fabric without the reduction catalyst layer 2, the reduction potential of electrons and oxygen on the surface is- 0.284 eV.

On the other hand, the oxidation potential of rutile-type TiO2 is 3 eV, and if a reduction catalyst layer 2 containing platinum as a main component is present, the potential difference between them becomes 2.51 eV and the photocatalyst layer 3 is irradiated with visible light. And about 55 in the visible light region
Part of the electrons (e−) that are photoexcited at a wavelength of up to 0 nm move to the surface of the reduction catalyst layer 2 and the electrons (e−) undergo a reduction reaction with oxygen (O2) on the surface of the reduction catalyst layer 2. Generates superoxide ions and produces electrons (e-)
And the holes (h +) move to the surface side of the photocatalyst layer 3, and electrons (e−) are converted to oxygen (O 2) on the surface of the hydrophilic layer 4.
Reacts with the superoxide ion to form a hole (h
+) Undergoes an oxidation reaction with water trapped in the hydrophilic layer 4 to generate a hydroxyl radical.

As described above, it is possible to use electrons having energy excited by light rays (light particles) in a visible light region abundantly present in room lighting, particularly in a region near 550 nm. The oxidizing power due to the hydroxyl radical and the oxidizing power due to the superoxide ion act on the side, and the oxidizing power due to the superoxide ion acts on the reduction catalyst layer 2 side, so that a strong antibacterial function and a purifying function are effectively exerted on both surfaces of the substrate 1. It becomes possible to do.

Of course, even with a small number of electrons and holes generated by photoexcitation with the weak ultraviolet light contained in the fluorescent lamp, the oxidation and reduction reactions can be efficiently performed.

The reduction catalyst layer 2, the photocatalyst layer 3 and the hydrophilic layer 4 on the substrate 1 can be realized by a dry coating method shown in FIGS.

The reduction catalyst layer 2 on the base material 1 uses a sputtering method as a method for dry coating.
As shown in FIG. 4, a substrate 1 made of a stainless steel net material wound in a roll shape is wound from a supply drum 7 into a winding drum 8 in a substantially vacuum sputtering chamber 6 in which an inert gas such as argon gas is sealed. The catalyst is sputtered with platinum while being continuously supplied to the substrate 1 to form a reduction catalyst layer 2 composed of a platinum thin film having a thickness of 1 to 20 nm.
Formed on one side surface.

In this example, by changing the speed of the substrate 1 while keeping the electric field application condition for evaporating the platinum constant,
The thickness of the reduction catalyst layer 2 can be set.

The method of dry coating the photocatalyst layer 3 and the hydrophilic layer 4 on the substrate 1 can be formed in the same ion plating chamber 9 by an ion plating method as shown in FIG.

In this example, the photocatalytic layer 3 is changed by changing the speed at which the roll-shaped substrate 1 coated with the reduction catalyst layer 2 is supplied to the ion plating chamber 9 and the conditions for applying an electric field to the electron gun 15. And the thickness of the hydrophilic layer 4 can be set.

That is, the base material 1 wound into a roll is set on rollers 12 and 13 in a setting chamber 11, and is rotated forward and reverse to form the base material 1 on the surface of a drum 14 in an ion plating chamber 9. The electron gun 15 is actuated while the is positioned, and the photocatalyst layer 3 composed of a titanium dioxide thin film is evaporated by evaporating, for example, titanium dioxide as a photocatalytic substance filled in the crucible 16, and then the silicon oxide filled in the crucible 16 is removed. The hydrophilic layer 4 is formed by evaporation.

First, as shown in FIG. 6A, the lid 17 of the setting chamber 11 is opened.
The base material 1 wound in a roll is set on a roller 12, and the tip is attached to the roller 13.

Next, the lid 17 is closed and both chambers 9 and 1 are closed.
After the interior of the substrate 1 is set to a substantially vacuum state in which an inert gas such as an argon gas or the like and a nitrogen gas condition are adjusted, the substrate 1 is wound around a roller 13 as shown in FIG. At this time, the electron gun 15 is operated to evaporate the titanium dioxide filled in the crucible 16 and at the same time supply oxygen gas from the oxygen supply source 10 to the vicinity of the surface of the substrate 1, thereby ensuring that TiO 2 is mainly contained. 100-500nm thickness
Is formed on the surface of the substrate 1.

Then, when the substrate 1 having the surface coated with the photocatalyst layer 3 is wound up by the roller 13 as shown in FIG. 6C, the substrate 1 is wound up by the roller 12.

When winding the substrate 1 around the roller 12,
As shown in FIG. 6D, the electron gun 15 is operated to evaporate the silicon oxide filled in the crucible 16 and at the same time supply oxygen gas from the oxygen supply source 10 to the vicinity of the surface of the substrate 1, thereby ensuring reliable operation. With a thickness of 1 to 2 mainly composed of SiO2
A 20 nm hydrophilic layer 4 is laminated on the surface of the photocatalyst layer 3.

In order to increase the thickness of the photocatalyst layer 3 and the hydrophilic layer 4, the winding speed must be reduced or the electron gun
In order to increase and reduce the electric field applied output, the winding speed may be increased or the electric field applied output may be reduced.

Further, the photocatalyst layer 3 and the hydrophilic layer 4 are laminated,
For example, TiO having oxygen defects is heated and annealed for about 2 hours in an atmosphere of 400 to 500 ° C., and then rapidly cooled.
When a photocatalytic layer 3 composed of anatase-type titanium dioxide whose main component is x (X is a number smaller than 2 close to 2), two electrons are introduced into the crystal every time one oxygen atom is desorbed. And the remaining two electrons convert Ti4 + in the crystal to Ti4 +
This is effective because it can be reduced to 3+ and this Ti3 + is strongly polarized to form a visible light absorption mechanism.

In this case, it is preferable to provide a heater for heat treatment in the setting chamber 11 so as to serve also as a heat treatment device because the production efficiency is increased.

Reference numeral 18 denotes a slit through which the substrate 1 passes,
A shutter member that shuts the substrate 1 in a sandwiched state and shuts off the ion plating chamber 9 and the setting chamber 11, and maintains a vacuum degree in the ion plating chamber 9 when the substrate 1 is set. It is.

Further, alpha-type Fe2 is used as a photocatalytic substance.
When O3 is used, the crucible 16 is similarly filled with Fe2O.
3, a Fe2O3 thin film is formed by a dry coating method while supplying oxygen, and then about 560-77.
The photocatalyst layer 3 may be formed by heating the film at 0 ° C. for about 1 to 3 hours, annealing, and then cooling to form the Fe 2 O 3 thin film into an alpha-type crystal structure.

The band gap of alpha-type Fe2O3 is 2.2 eV and the reduction potential is about 0.1 eV. The reduction of oxygen by electrons is lower than the reduction potential of -0.284 eV between electrons and oxygen. Although not sufficiently performed, when the reduction catalyst thin film 2 containing platinum as a main component is present, the reduction-side potential of the alpha-type Fe2O3 becomes higher than the reduction potential of electrons and oxygen, and the reduction reaction of oxygen by electrons is performed smoothly. Even with visible light up to about 700 nm or weak ultraviolet light of a lighting device such as a fluorescent lamp, a part of the photo-excited electrons (e-) move to the surface of the reduction catalyst thin film 2 to reduce the reduction catalyst. On the surface of the thin film 2, electrons (e-) and oxygen (O2) undergo a reduction reaction to generate superoxide ions, and a part of the electrons (e-) and holes (h +) are laminated on the photocatalytic layer 3. Navigate to the water layer 4 surface, to produce a superoxide ion and the hydroxyl radical in the hydrophilic layer 4 surface.

In FIG. 7, a stainless steel plate having a thickness of 0.5 mm is punched as a substrate 1 to form a large number of small holes 5, on which a photocatalytic layer 3 and a hydrophilic layer 4 are laminated on the front side. This is an example in which a photocatalyst member having a reduction catalyst layer 2 formed on the back side is attached to a range hood 20 as a filter 19, and a filter 21 is provided on the back side of the filter 19 to exhaust indoor air to the outside air. On the front side, a normal lighting fixture 23 such as a fluorescent lamp for illuminating the gas range 22 or the like is attached to the range hood 20.

Thus, of the holes and electrons excited from the photocatalyst layer 3 by the visible light or the weak ultraviolet light generated when the lighting apparatus 23 is turned on, the surface of the photocatalyst layer 3 on the surface side generates moisture in the atmosphere or during cooking. The generated water vapor is captured by the hydrophilic layer 4, and the water oxidizes and reacts with the holes to generate hydroxyl radicals, and a reduction reaction between a part of the electrons and oxygen in the atmosphere to generate superoxide ions. On the reduction catalyst layer 2 side, a part of the electrons and oxygen in the atmosphere undergo a reduction reaction to generate superoxide ions, and while the exhaust gas passes through the small holes 5, the reduction catalyst on the front side hydrophilic layer 4 side and the back side Odor substances, smoke, oil and the like in the exhaust gas are oxidized and decomposed by touching the layer 2.

It is preferable that the filter 19 be detachably attached to the range hood 20 so that when the filter 19 is clogged, the filter 19 can be removed and washed with water.

FIG. 8 shows an example in which a filter-like photocatalyst member is used as a deodorizing device in a freezing / refrigerating facility 25 such as a refrigerator car, a refrigerator, or a refrigerator for transferring fresh food products 24.

In this example, the substrate 1 has a thickness of 0.5 mm
A large number of small holes 5 are formed in a stainless steel plate material by punching or etching, a photocatalyst layer 3 and a hydrophilic layer 4 are formed on the front side of the substrate 1, and a reduction catalyst layer 2 is formed on the back side. An intake filter 19a whose periphery is reinforced by a stainless steel plate member 26 and a photocatalyst layer 3 and a hydrophilic layer 4 are formed only on the surface side of the substrate 1, and a reduction catalyst layer 2 is formed on the periphery thereof. Exhaust filter 1 in which stainless steel plate member 27 formed on the side is caulked conductively to substrate 1 and reinforced.
9b is used.

Then, a fan 21 installed in a duct 28 for circulating the air in the freezing / refrigeration equipment 25 space is installed.
The outlet is provided with an exhaust filter 19b such that the hydrophilic layer 4 side faces the indoor surface.

A lighting device 23 such as a fluorescent lamp or an incandescent lamp for illuminating the inside of the device 25 is provided on the ceiling of the freezing / refrigerating device 25, and visible light emitted by the lighting device 23 is also provided on the surfaces of the filters 19a and 19b. Is to be irradiated.

When the fan 21 is operated while the lighting device 23 is turned on, the visible light or the weak ultraviolet light generated by the lighting of the lighting device 23 causes the intake filter 19a on the inlet side of the duct 28 to emit light. On the photocatalyst layer 3 side of the surface, water in the freezing / refrigeration equipment 25 is captured by the hydrophilic layer 4, and the water is oxidized by holes to form hydroxyl radicals, and some of the electrons and oxygen in the atmosphere. Is reduced to generate superoxide ions. On the back side of the reduction catalyst layer 2, some of the electrons and oxygen in the air undergo a reduction reaction to generate superoxide ions, and the air passes through the small holes 5. In the meantime, by touching the hydrophilic layer 4 on the front surface and the reduction catalyst layer 2 on the back surface, odorous substances and fungi in the air are oxidized, decomposed and antibacterial.

On the reduction catalyst layer 2 side on the back surface of the intake filter 19a, a part of electrons and oxygen in the atmosphere undergo a reduction reaction to generate superoxide ions, and the air passing through the small holes 5 is The odorous substances and fungi contained in the water are oxidized, decomposed and antibacterial by superoxide ions.

On the other hand, in the exhaust filter 19b on the outlet side of the duct 28, only the hydroxyl radical and superoxide ion generated in the photocatalyst layer 3 on the surface side cause
Odorous substances, fungi, and the like remaining in the exhausted air and not completely decomposed by the intake filter 19a are oxidized, decomposed, and antibacterial.

Of course, some of the electrons generated by the light excitation move to the reduction catalyst layer 2 of the stainless steel plate member 27,
Although oxygen is reduced on the surface to generate superoxide, since it is away from the photocatalyst layer 3, it is suppressed from being bonded to holes.

As described above, the reduction catalyst layer 2 is provided on the back side of the exhaust filter 19b attached to the outlet side of the duct 28.
The reduction catalyst layer 2 is provided on the stainless steel plate member 27 at the peripheral portion without air. When air flows from the reduction catalyst layer 2 side to the photocatalyst layer 3 or the hydrophilic layer 4 side, the reduction catalyst is accompanied by photoexcitation. Some of the superoxide ions generated in layer 2 disappear by oxidation reaction with odorous substances in the air.
The remaining superoxide ions pass through the small holes 5 as they are together with the air flow and are combined with the holes on the surface of the hydrophilic layer 4, so that the generation of hydroxy radicals on the hydrophilic layer 4 side is impaired, the oxidizing power decreases, and decomposition occurs. This is because the functions such as are halved.

That is, when air passes from the hydrophilic layer 4 side to the reduction catalyst layer 2 side, the hydroxyl radicals and superoxide ions generated on the photocatalyst layer 4 side move to the reduction catalyst layer 2 side without completely disappearing. However, the electrons on the side of the reduction catalyst layer 2 do not combine with the hydroxyl radicals and superoxide ions, but reduce oxygen to further generate superoxide ions, and oxidize with odorous substances in the air that could not be completely decomposed. However, these are effective because they are oxidatively decomposed. However, in the reverse flow, if the superoxide ions generated on the side of the reduction catalyst layer 2 remain, they are combined with the holes on the side of the hydrophilic layer 4 so that the effect is reduced by half.

Therefore, the intake filter 19a may be attached to the intake side of the duct 28, and the exhaust filter 19b may be attached to the exhaust side. In this case, the disassembly, purification, and antibacterial abilities are doubled.

It should be noted that the food is sterilized and deodorized by a fluorescent lamp or an incandescent lamp which illuminates the interior without using an ultraviolet lamp, and the fresh food does not discolor like the ultraviolet lamp. In addition, it is possible to prevent a sunburn or the like caused by ultraviolet irradiation for a person working in a cold storage vehicle, and the effect is enormous.

The present invention can be variously modified without being limited to the above-described embodiment.
A metal such as iron may be used, and the thickness and thickness of the base material are also arbitrary.

As a material for forming the photocatalyst layer, ZnO,
SnO2, SrTiO3, WO3, Bi2O3 and Ti
O, Ti2O3, Ti3O5, TiOx (1.99 <X <
Titanium oxide such as 2) may be used.
A small amount of transition metal ions such as Cr and V may be injected into the photocatalyst layer to increase the efficiency of the photocatalytic reaction.

When titanium dioxide is used as the photocatalytic substance, it is preferable to heat-treat it at 400 to 500 ° C. to form an anatase crystal structure, or to heat it at 600 to 700 ° C. to form a rutile crystal structure. The photocatalyst layer may be formed by a sol-gel method other than the dry coating method.

Further, as a method of forming a photocatalyst layer containing titanium dioxide having oxygen vacancies as a main component, a titanium dioxide thin film is formed, heated to about 400 to 700 ° C. for several hours, and then quenched in the open air. It can also be formed by performing.

If the thickness of the photocatalyst layer is about 100 nm to about 1000 nm, the function can be sufficiently exhibited.

As a material for forming the hydrophilic layer, SiO 2 is used.
Al 2 O 3 etc. may be used in addition to 2, the thickness is 1
If it is about 20 nm, the function can be sufficiently exhibited.

As a material for forming the reduction catalyst layer, platinum, palladium or an alloy containing these as a main component may be used.

As a method of dry-coating the photocatalyst layer, the hydrophilic layer and the reduction catalyst layer, a method such as an ion plating method, a sputtering method, an electron beam method, and a hollow cathode method may be employed.

The reduction catalyst layer can be formed on a substrate by a platinum plating method, a cladding method, or the like, in addition to the dry coating method.

The thickness of the reduction catalyst layer is preferably about 1 to 20 nm, and if it is 1 nm or less, the function as a reduction catalyst cannot be exhibited well, and if it is 20 nm or more, the cost increases due to the use of expensive substances. There is no merit.

After the reduction catalyst substance is coated on both sides of the substrate, a photocatalyst layer and a hydrophilic layer may be formed on one side thereof, and the photocatalyst layer and the hydrophilic layer may be formed on the substrate first. Thereafter, the back surface may be coated with a reduction catalyst material.

Of course, it is also possible to use a dry coating apparatus shown in FIG. 5 to coat with a catalytic substance such as platinum or panadium, and then laminate a titanium oxide thin film or a titanium thin film.

Of course, it is needless to say that the photocatalytic effect of the present invention is doubled when it is used under outdoor sunlight or under the condition of irradiation with an ultraviolet lamp.

Further, the photocatalyst member of the present invention is used for purifying an aquarium or a lake which is hard to transmit ultraviolet rays, removing harmful substances such as dioxin contained in exhaust gas of an incinerator, a filter for removing odor of a household fan heater, It can be used for many products such as antibacterial purification filters for air conditioners.

[0068]

As described above, the photocatalyst member of the present invention forms a photocatalyst layer on one of the surfaces of the conductive plate-like base material, and forms the photocatalyst layer formed on the other surface by photoexcitation of the photocatalyst layer. Since the catalyst layer that promotes the reduction action is formed, the reduction reaction of electrons, particularly the reduction reaction to oxygen, is promoted on the catalyst layer side, and the recombination of electrons and holes is reduced. The energy potential is low, and as a result, the visible light region 5
A reduction reaction is possible even with electrons excited at the energy level held by the photoparticles up to about 50 nm. In addition, superoxide ions are generated by a reduction reaction between electrons and oxygen on the catalyst layer side, and oxidation is performed on the photocatalyst layer side. Hydroxyl radicals and superoxide ions are generated by the reduction reaction, and together with both surfaces, it is possible to efficiently exert a strong decomposing function, an antibacterial function, a purifying function, and the like.

[Brief description of the drawings]

FIG. 1 is a schematic view showing steps of a method for producing a photocatalyst member of the present invention.

FIG. 2 is a cross-sectional view based on a manufacturing process, in which (a) is a cross-sectional view in which a reduction catalyst layer serving as a reduction catalyst portion containing platinum as a main component is coated on the back surface of a conductive plate-like base material such as a stainless steel plate; (B) is a cross-sectional view in which a titanium oxide thin film is coated on the substrate surface as a photocatalyst layer, and (c) is a silicon oxide (SiO 2) as a hydrophilic layer on the titanium oxide thin film.
2) It is sectional drawing which coated the thin film.

FIG. 3 is a graph showing an energy potential.

FIG. 4 is a schematic view of an apparatus for coating a substrate with a reduction catalyst substance.

FIG. 5 is a schematic view of an apparatus for laminating a photocatalytic substance and a hydrophilic substance.

FIG. 6 is a schematic view showing a manufacturing process of the device of FIG.

FIG. 7 is a schematic view showing an example in which a photocatalyst member is applied to a filter and used in a range hood.

FIG. 8 is a schematic diagram showing an example in which a photocatalyst member is applied to a filter and used in refrigeration / refrigeration equipment.

FIG. 9 is an enlarged sectional view of a main part of a filter used in the facility.

[Explanation of symbols]

 A: Step of coating catalytic substance on substrate B: Step of coating photocatalytic substance on substrate C: Step of laminating hydrophilic substance D: Step of heat treatment 1: Substrate 2: Reduction catalyst layer 3: Photocatalyst layer 4: Hydrophilic layer 5: Small hole 6: Sputtering chamber 7: Supply drum 8: Winding drum 9: Ion plating chamber 10: Oxygen supply source 11: Setting chamber 12: Roller 13: Roller 14: Drum 15: Electron gun 16: Crucible 17: Lid 18: Shutter member 19: Filter 20: Range hood 21: Fan 22: Gas range 23: Lighting equipment 24: Fresh food 25: Refrigeration / freezing equipment 26: Stainless steel plate member 27: Stainless steel plate member 28 :duct

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F100 AA20B AA21A AA23A AA25 AB02 AB04 AB17 AB24 BA02 DC11 DC16 EH46 EH462 JB05B JC00 JL08A 4G069 AA11 BA04A BA04B BA48A BB04A BB04B BC66A BC66 EC02 FA05

Claims (8)

[Claims] 1. A photocatalyst layer, a conductive substrate having a hydrophilic layer laminated on the surface of the photocatalyst layer, and a reduction reaction of oxygen generated by photoexcitation of the photocatalyst layer by being electrically connected to the conductive substrate. A photocatalyst member comprising: a reduction catalyst section for promoting the reaction. 2. The photocatalyst member according to claim 1, wherein a main component of the photocatalyst layer is titanium oxide. 3. The photocatalyst member according to claim 1, wherein a main component of the photocatalyst layer is Fe2O3 having an alpha-type crystal structure. 4. The photocatalyst member according to claim 1, wherein a main component of the hydrophilic layer is SiO2. 5. The method according to claim 1, wherein the conductive substrate has a plate shape, the photocatalyst layer and the hydrophilic layer are laminated on one surface, and the reduction catalyst portion is formed on the other surface. Photocatalyst member. 6. The photocatalyst member according to claim 5, wherein the conductive base material is provided with a large number of small holes penetrating the base material. 7. The photocatalyst member according to claim 5, wherein the photocatalyst layer and the hydrophilic layer are formed by a dry coating method. 8. The photocatalyst member according to claim 7, wherein said reduction catalyst portion is formed in a layer by a dry coating method.