WO2002053284A1

WO2002053284A1 - Method of activating a photocatalyst and device therefor

Info

Publication number: WO2002053284A1
Application number: PCT/JP2001/011576
Authority: WO
Inventors: Shinichi Sugihara
Original assignee: Ecodevice Laboratory Co., Ltd.
Priority date: 2000-12-28
Filing date: 2001-12-27
Publication date: 2002-07-11
Also published as: CN1494458A; KR20030072373A; JPWO2002053284A1

Abstract

A method of activating a photocatalyst, for applying a LED beam onto a visible light-responding photocatalyst having an activity by means of the action of light with a wavelength of at least 420 nm. A device having a visible light-responding photocatalyst-containing layer on a LED substrate. A device including a LED, a visible light-responding photocatalyst, and a light transfer means for transferring light from the LED to the visible light-responding photocatalyst.

Description

. . Specification

Method and apparatus for activating photocatalyst

The present invention relates to a method for activating a photocatalyst and an apparatus comprising a photocatalyst and a light source. Background art

It is known that photocatalysts composed of anatase-type titanium dioxide can be used for antibacterial tiles, self-cleaning building materials, superhydrophilic materials, deodorizing and deodorizing materials, water purification, cancer treatment, etc. The Lean Revolution (Akira Fujishima et al.) Has been actively developing various applications. Specifically, for example, WO94 / 11092 discloses an air treatment method using a photocatalyst under indoor lighting. Japanese Patent Application Laid-Open No. 7-102678 discloses a method for preventing hospital-acquired infection using a photocatalyst. JP 8 6 7 8 3 5 and JP Hei 8 - 1 6 4 3 3 4 No. further _t antimicrobial coatings are disclosed WO 9 6/2 9 3 7 to 5 superhydrophilic Materials are disclosed. However, anatase-type titanium dioxide requires ultraviolet light of 400 nm or less as excitation light. On the other hand, solar light and artificial light, which can be excitation light sources, contain more visible light than the ultraviolet light. Unfortunately, in the photocatalyst consisting of titanium dioxide, unfortunately, almost no visible light is available, and energy conversion efficiency is high. From this point of view, it was very inefficient. And this inefficiency was a major barrier toward practical application. For example, Japanese Patent Application Laid-Open No. 2000-218784 describes a dental light irradiation device used for sterilization and treatment of the oral cavity such as periodontal disease or decolorization of teeth by light irradiation, This is a dental irradiation device that uniformly irradiates the entire dentition with light and decolorizes using a plurality of light-emitting diodes arranged curved along the front surface of the dentition. However, in light irradiation devices for dental use, it is desirable that ultraviolet light is not contained as much as possible in consideration of adverse effects on the human body. On the other hand, with light from a light source that does not contain ultraviolet light, the conventional photocatalyst shows little activity, and the effect of the photocatalyst is very weak. Therefore, an object of the present invention is to provide a method and apparatus for activating a photocatalyst, which uses a light emitting diode containing a high content of visible light or a light emitting diode containing only visible light as a light source. Disclosure of the invention

The present invention relates to a method for activating a photocatalyst, in which a photocatalyst (visible light responsive photocatalyst) having activity by the action of light having a wavelength of 420 nm or more is irradiated with light from a light emitting diode. Further, the present invention provides an apparatus having a layer containing a visible light responsive photocatalyst on a light emitting diode substrate, a light emitting diode, a visible light responsive photocatalyst, and light from the light emitting diode being applied to the visible light responsive photocatalyst. Apparatus including light transport means for transport About. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an ESR spectrum of the visible light responsive photocatalyst (Reference Example 1) used in the present invention measured at 77K in vacuum. The upper row shows the spectrum in the dark, the middle row shows the spectrum under irradiation of light having a wavelength of 420 nm or more (cut off the light of less than 420 nm out of the mercury lamp light), and the lower row shows the spectrum. This is a spectrum when a light of a mercury lamp is irradiated without cutting off light of less than 420 nm. FIG. 2 is an ESR spectrum of the visible light responsive photocatalyst (Reference Example 1) used in the present invention measured at room temperature in a vacuum. The upper part is a spectrum in the dark, the middle part is a spectrum under irradiation of light having a wavelength of 420 nm or more (the light of 420 nm or less of the light of a mercury lamp is cut off), and the lower part is a spectrum. The spectrum is obtained when the light of a mercury lamp is irradiated without cutting off light of less than 420 nm.

Figure 3 shows the XRD measurement results of the product of Reference Example 1 (upper) and the hydrolyzate (dried at 50 ° C) (lower).

Figure 4 shows the emission spectra of the blue light emitting diode (B LUE), the green light emitting diode (GREEN), and the white light emitting diode (WHITE).

FIG. 5 shows the results of oxidation of isopropanol by a blue light emitting diode in Example 3.

Fig. 6 shows the product of Reference Example 4 (visible light responsive photocatalyst) in a vacuum at 77 K: light with a wavelength of 420 nm or more (of the mercury lamp, the light less than 420 nm is turned off). 2 is an ESR spectrum measured under the irradiation of FIG. Figure 7 shows that the product (visible light responsive photocatalyst) of Reference Example 5 under vacuum at 77K, with light having a wavelength of 420 nm or more (of the light of a mercury lamp, the light of less than 420 nm was cut off). It is an ESR spectrum measured under irradiation.

Figure 8 shows that the product of Reference Example 6 (visible light responsive photocatalyst) was irradiated with light having a wavelength of more than 420 nm at 77K (power of the mercury lamp was less than 420 nm) in a vacuum. ESR spectrum measured under irradiation. BEST MODE FOR CARRYING OUT THE INVENTION

[Visible light responsive photocatalyst]

The visible light responsive photocatalyst used in the present invention contains at least anatase-type titanium dioxide and has a g-value of ESR measured in a vacuum at 77 K under irradiation of light having a wavelength of 420 nm or more at 77 K. The main signal with S2.004 to 2.07 and the two subsignals with g-values of 1.985 to 1.986 and 2.024 are observed. Furthermore, in the visible light responsive photocatalyst used in the present invention, the above three signals (main signal and two subsignals) are minutely observed or substantially observed in vacuum at 77K and in darkness. That is not done. The visible light-responsive photocatalyst used in the present invention preferably contains anatase type titanium dioxide as a main component, and may further contain rutile type titanium dioxide and / or amorphous titanium dioxide. Also, the anatase type titanium dioxide does not necessarily have to have high crystallinity. FIG. 1 shows a typical spectrum of the visible light responsive photocatalyst used in the present invention measured at 77 in a vacuum. In the figure, the upper row shows the spectrum under black, and the middle row shows the spectrum under irradiation of light having a wavelength of 420 nm or more (light of less than 420 nm of the mercury lamp light is cut off). It is. The lower part shows the spectrum when the light of the mercury lamp is irradiated without cutting off the light of less than 420 nm. Note that the upper, middle, and lower rows are all the results measured under the same gain (GA IN). Comparison of the upper and middle spectrums in Fig. 1 clearly shows that in the middle spectrum, the main signal with a g-value force of S 2.004 to 2.007 and a g-value of 1.985-1. The two sub-signals, 986 and 2.024, are stronger than in the upper spectrum. In addition, comparing the spectra in the middle and lower sections of Fig. 1, it is clear that the main signals with g values of 2.004 to 2.007 and the g values of 1.985 to 1.986 and 2.024 2 The intensities of the two sub-signals are substantially the same whether or not the irradiation light contains light of 420 nm or less. Further, as shown in FIG. 2, the visible light responsive photocatalyst used in the present invention is also measured by ESR under irradiation of light having a wavelength of at least 420 nm in black and at room temperature in the vacuum at room temperature. It can be done. In Fig. 2, the upper row shows the spectrum in the dark, and the middle row shows the spectrum under the irradiation of light having a wavelength of 420 nm or more (cut off the light of less than 420 nm out of the mercury lamp light).ぺ It is a kutor. The lower part is a spectrum when the light of a mercury lamp is irradiated without cutting off light of less than 420 nm. Note that the upper, middle, and lower rows are the results measured under the same gain (GAIN). Further, it is considered that the three signals in the visible light responsive photocatalyst used in the present invention are attributed to radicals caused by hole capture. This is evident from the ESR spectrum in the atmosphere of the electron donor molecule, isopropanol, and the ESR spectrum in the oxygen atmosphere, the electron acceptor molecule, as shown in the reference examples. The visible light responsive photocatalyst used in the present invention has, in addition to the above signals, a g-value force of S 2 .7 in ESR measured in vacuum at 77 K under irradiation with light having a wavelength of 420 nm or more. It may further have a side signal that is between 09 and 2.010. The side signal having a g value of 2.009 to 2.010 is shown in the middle ESR spectrum of FIG. The visible light responsive photocatalyst used in the present invention can be oxygen-deficient titanium oxide having a bond ratio between Ti (titanium) and 0 (oxygen) less than 2. Whether or not it is oxygen-deficient titanium oxide can be measured by X-ray photoelectron spectroscopy (XPS).

In order to determine the bonding state of titanium and oxygen and the stoichiometric ratio of the elements, which can be measured and specified by X-ray photoelectron spectroscopy (XPS), the Ti-0 of titanium oxide with close binding energy is used. 530 ± 0.5 eV and 532 belonging to the 0-0 bond of adsorbed oxygen It is preferable to separate ± 0.5 eV and obtain by calculation. From the results of measurement and calculation by this method, it can be seen that the visible light responsive photocatalyst described in Reference Examples described later is of an oxygen deficient type.

The commercially available titanium oxide catalysts ST-01 (manufactured by Ishihara Sangyo), other JRC-IT03 (catalysts referred to by the Catalysis Society of Japan), P- ²⁵ (manufactured by Nippon Aerosil), etc. are 0 / Ti Is a value of 2.0 ± 0.05. Although there are aspects that cannot be unambiguously defined for oxygen vacancies, the preferred range is 1.5 to 1.95. The visible light responsive photocatalyst used in the present invention can be produced using amorphous or imperfect crystalline titanium dioxide as a raw material. This raw material titanium dioxide can be produced by a sulfuric acid method, a chloride method, or the like. It can be obtained by a wet method using oxide as a raw material. More specifically, the raw material titanium dioxide can be obtained by hydrolyzing titanium chloride with ammonium hydroxide. This hydrolysis is suitably performed by adjusting the amount of ammonium hydroxide added so that the pH of the reaction solution is 6 or more. The titanium chloride may be any of titanium trichloride, titanium tetrachloride, titanium oxychloride and the like, and a mixture thereof may be used. The hydrolysis can be performed, for example, under cooling or at a temperature in the range of room temperature to 90 ° C., but the hydrolysis at room temperature is relatively low in crystallinity or non-crystalline dioxidation. It may be preferable from the viewpoint that titanium is obtained. Further, the hydrolyzate of titanium chloride with ammonium hydroxide is preferably used as a raw material titanium dioxide after being washed with an aqueous solution of ammonium hydroxide. In this washing with an aqueous solution of ammonium hydroxide, the remaining amount of ammonium chloride generated during hydrolysis is appropriate. It can be performed to reduce the amount, and preferably can be performed a plurality of times. The amorphous or incompletely crystalline titanium dioxide may be a commercially available product, for example, incompletely crystalline titanium dioxide such as ST-01 or C-02 manufactured by Ishihara Sangyo. There may be. Alternatively, in the production of a visible light responsive photocatalyst, a hydrolyzate obtained by hydrolyzing titanium sulfate or titanyl sulfate was washed with water to remove at least a part of sulfate ions contained in the hydrolyzate. Thereafter, the method can be carried out by a method comprising at least titanium oxide containing anatase-type titanium oxide, which comprises heating in the presence of ammonia or a derivative thereof. The above hydrolyzate can be washed with water or aqueous ammonia, but as a result of the subsequent studies, it has been found that a product with a higher BET specific surface area can be obtained by water washing as compared with ammonia water washing. The present invention employs water washing. More specifically, when the heating conditions are the same, the product obtained by water washing can obtain a product having a BET specific surface area that is almost twice that of ammonia water washing.

Since a product having a higher BET specific surface area can be expected to be excellent in terms of adsorption performance, it is extremely advantageous when the material obtained by the production method of the present invention is used as a photocatalyst. ~ Further, in the above production method, the washing with water is carried out by washing the sulfate ion concentration in the washing filtrate. It is preferable to carry out until the degree becomes 2000 ppm or less. More preferably, the washing with water is performed until the sulfate ion concentration in the washing filtrate becomes 1500 ppm or less. In the case where titanium sulfate or titanyl sulfate is hydrolyzed using ammonia, it is preferable to perform the washing with water until the concentration of ammonium ion in the washing filtrate becomes 200 ppm or less. The production of the visible light responsive photocatalyst used in the present invention can be performed, for example, as follows, in addition to the above method. Amorphous or incompletely crystalline titanium dioxide is heated in the presence of ammonia or its derivatives. Ammonia may be liquid or gaseous. When using ammonia gas, the raw material titanium dioxide is heated in an atmosphere gas atmosphere. Examples of the ammonia derivative include an ammonium salt such as ammonium chloride. For example, the raw material titanium dioxide is heated in the presence of ammonium chloride. When the raw titanium dioxide is heated in the presence of ammonia or its derivative, the absorption of light at a wavelength of 45 O nm of the material generated by heating is greater than the absorption of light at a wavelength of 45 O nm of the raw titanium dioxide This is done by terminating the heating at that point. Normally, the raw material titanium dioxide is white, and the light absorption at a wavelength of 45 O nm is around 10%. On the other hand, when the raw material titanium dioxide is heated in the presence of ammonia or its derivative, it gradually turns yellow. However, this coloring fades to a peak at a certain point in time, and eventually shows an absorption similar to that of the starting titanium dioxide. Types of raw material titanium dioxide and species of ammonia (derivative) to coexist Depending on the type and amount, heating temperature, time, etc., the absorption of light at a wavelength of 450 nm may reach up to about 60%. The characteristic of visible light responsive photocatalyst is wavelength

Although not uniquely determined by the light absorption intensity at 45 O nm, the wavelength 4

When the light absorption at 5 O nm is 20% or more (reflectance is 80% or less), the material clearly shows visible light response. The heating conditions cannot necessarily be defined only by the temperature, but may be, for example, a temperature in the range of 300 to 500 ° C. This heating can be performed under normal pressure. In addition, the heating time can be appropriately determined based on the absorption of light at a wavelength of 45 O nm of the material generated by heating. For the heating, a rotary kiln, a tunnel kiln, a Matsufur furnace, or the like, which is generally used in this field, can be used. When individual particles of titanium oxide are aggregated or sintered by heating, they may be ground by a crusher as necessary. Further, the material obtained by heating as described above can be washed with water or an aqueous solution as needed. This washing may improve the visible light responsiveness of the obtained visible light responsive photocatalyst in some cases. For example, amorphous or incompletely crystalline titanium dioxide (material before heating) ι If titanium chloride is obtained by hydrolysis with ammonium hydroxide, a considerable amount of chloride is added to the hydrolyzate. Ammonia remains, resulting in amorphous or imperfectly crystalline titanium dioxide as described above. Can be converted to a visible light responsive photocatalyst. However, even after the heat treatment, a considerable amount of ammonium chloride may remain in the obtained material. In such a case, washing with water or an appropriate aqueous solution may remove ammonium chloride and improve the visible light responsiveness of the visible light responsive photocatalyst in some cases. In this case, the material obtained by heating can be washed with water or an aqueous solution such that the pH of the washed water or aqueous solution is, for example, 5 or more. The visible light responsive photocatalyst used in the present invention includes silicon, aluminum, tin, zirconium, antimony, phosphorus, platinum, gold, silver, copper, iron, niobium, tungsten, on its surface and / or inside depending on the application. Elements such as tantalum and compounds containing them can be coated, supported, or doped. For example, the above visible light responsive photocatalyst can be carried using a transparent activated alumina described in JP-A-2000-119017 as a carrier. As a result, a transparent visible light responsive photocatalyst can be obtained, and a transparent paint can be provided.

In the present invention, the visible light responsive photocatalyst may be contained in a coating film. This coating film can be formed using a paint containing at least the above visible light responsive photocatalyst, a binder and a solvent. The binder may be either an organic binder or an inorganic binder. Examples of the inorganic binder include alkyl silicate and silicon halide. And products obtained by hydrolyzing hydrolyzable silicon compounds such as partially hydrolyzed products thereof, silica, colloidal silica, water glass, silicon compounds such as organopolysiloxane, and organic polysiloxane compounds. Examples include inorganic binders such as condensates, phosphates such as zinc phosphate and aluminum phosphate, heavy phosphates, cement, lime, gypsum, frit for enamel, glaze for glass lining, and plaster. Examples of the organic binder include organic binders such as a fluorine-based polymer, a silicon-based polymer, an acrylic resin, an epoxy resin, a polyester resin, a melamine resin, a urethane resin, and an alkyd resin. Since the binder is degraded or decomposed by the photocatalytic function of the photocatalyst, it is necessary to appropriately select the type of binder according to the use scene, the degree of the photocatalytic function, and the application. However, in the present invention, a visible light responsive photocatalyst is used as the photocatalyst, so that the photocatalyst function is much less deteriorated compared to a conventional paint using an ultraviolet type photocatalyst, and the photocatalyst is used indoors where there is almost no ultraviolet light. Has almost no deterioration due to the photocatalytic function. Accordingly, organic binders such as acrylic resins, epoxy resins, polyester resins, melamine resins, urethane resins, and alkyd resins, which cannot be used in paints using an ultraviolet-type photocatalyst, can also be used favorably.

In the present invention, these binders can be used alone or in combination of two or more. The alkyl silicates, e.g., S i as a general formula _{_{n O n _! (OR)}} 2n + 2 ( where S i is Keimoto, O is oxygen, R represents an alkyl group.) The compound represented by N is, for example, 1 to 6, and R is, for example, an alkyl group having 1 to 4 carbon atoms. However, it is not limited to these.

Examples of cement include Portland cement, such as early-strength cement, ordinary cement, moderate heat cement, sulfate-resistant cement, white cement, oil well cement, geothermal well cement, fly ash cement, high sulfate cement, Mixed cements such as silica cement and blast furnace cement, and alumina cement can be used.

As the plaster, for example, secco plaster, lime plaster, doloma plaster and the like can be used.

Examples of the fluorinated polymer include polyvinyl fluoride, polyvinylidene fluoride, polychlorinated trifluoroethylene, polytetrafluoroethylene, polytetrafluoroethylene propylene copolymer, ethylene-polytetrafluoroethylene copolymer, and ethylene-polytetrafluoroethylene copolymer. Crystalline fluororesins such as ethylene monochloride trifluorene ethylene copolymer, tetrafluoroethylene monofluoroalkylbier ether copolymer, perfluoro-norelocyclopolymer, vinylinoleatenorreolenorreolefin copolymer, An amorphous fluororesin such as a nylester-fluorofluorin copolymer, various fluororubbers, and the like can be used. In particular, a fluoropolymer mainly composed of a vinyl ether-fluorene copolymer and a vinylinestenolefinolefluorene copolymer is preferred because it has little degradation and deterioration and is easy to handle.

Silicone polymers include linear silicone resin and acrylic-modified silicone resin Fats and various types of silicone rubber can be used. The organic polysiloxane compound used for the polycondensate of the organic polysiloxane compound is a substance known as a hydrolyzate of an organic silicon compound. For example, Japanese Patent Application Laid-Open Nos. 8-164, 334 and 8-6 Nos. 7 835, JP-A-8-155030, JP-A-10-66830, Patent No. 2756474, etc. Can be used.

The organic polysiloxane compound is a hydrolyzate of an organic silicon compound, and examples of the organic silicon compound include those having an alkyl group and an alkoxy group. A hydrolyzate of an organosilicon compound having an alkyl group and an alkoxy group is also known, and is obtained, for example, by hydrolyzing an organosilicon compound represented by R ^ Si (OR ² ) _{4 —} _n . R ¹ and R ² can each be, for example, a lower alkyl group having 1 to 8 carbon atoms. Considering the film strength of the obtained coating, R ¹ is a lower alkyl group having 1 to 3 carbon atoms, preferably Is suitably a methyl group. N in the above formula is an integer of 0 to 2, and specifically, a film obtained by using a hydrolyzate (three-dimensionally crosslinked product) of a mixture of organic silicon compounds in which at least n is 1 or 2 is used. Appropriate considering the strength. Examples of the organosilicon compound include methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, and methyltributanol. Kishishiran, methylol tri chrono Les silane, methylcarbamoyl Honoré tribromomethyl silane; Echinoretori main Tokishishiran, E triethoxysilane, E tilt re-isopropoxyphenyl Sila down, E Ji ^ tri _t one butoxysilane, E Chino Les trichlorosilane, Echinoretoribu port Mushiran; n-propyltrimethoxysilane, n-propyltriethoxysilane, n-propyltriisopropoxysilane, n-propyltributoxysilane, n-propyltrichlorosilane, n-propyltribromosilane; n-hexyl / trime Toxoxysilane, n-hexinoletriethoxysilane, n-hexyltriisopropoxysilane, n-hexyltri-t-poxysilane, n-hexinoletrichlorosilane, n-hexyltribromosilane; n-decinoletrimethoxysilane, n-decyltriethoxysilane, n-decyltriisopropoxysilane, n-decyltri-t-butoxysilane, n-decyltrichlorosilane, n-decyltribromosilane; n-octadecyltrimethoxysilane, n-octadecyl Triethoxysilane, n-octadecyltriisopropoxysilane, n-octadecyltri-t-butoxysilane, n-octadecyltrichlorosilane, n-octadecyltrib-butanesilane, tetramethoxysilane, tetraethoxysilane, tetrabutoxy Silane, dimethoxy ethoxy silane; dimethyl dimethyl silane, dimethyl ethoxy silane, y-glycidoxypropyl methyl dimethyl silane, γ-glycidoxypropyl methyl ethoxy silane, y-glycidoxy propyl trimethoxy silane .gamma. Gurishidokishipuro pills triethoxysilane, .gamma.-glycidoxypropyltrimethoxysilane isopropoxyphenyl Sila down, y- glycidoxypropyltrimethoxysilane t Ru can be given an butoxysilane like. The compounding amount of the binder is about 100 to 2000% by weight, preferably 25 to 100% by weight, and preferably 25 to 100% by weight, based on the solid matter, based on the visible light-responsive photocatalyst particles. 500% by weight is more preferable, and 25 to 250% by weight is more preferable. By setting the blending amount of the binder within the above range, the visible light responsive photocatalyst can be maintained without desorbing the visible light responsive photocatalyst when a coating film is formed. As the solvent, an inorganic solvent, an organic solvent, or a mixture thereof can be used. Water is preferred as the inorganic solvent. As the organic solvent, alcohols such as methanol, ethanol, 2-propanol, and ethylene glycol, and ketones can be used. Those containing alcohol are preferred from the viewpoints of handleability and coatability. The compounding amount of the solvent can be appropriately set according to the workability. If necessary, the paint and the coating film can contain at least one compound selected from the group consisting of dicarboxylic acids and derivatives thereof. Dicarponic acid is an organic compound having two olepoxyl groups COOH in the molecule.For example, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid And aliphatic unsaturated dicarboxylic acids such as maleic acid and fumaric acid, and aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid. The dicarboxylic acid derivative is an esterified product of the dicarboxylic acid, Dicarboxylic acids such as salts, dicarboxylic anhydrides, dicarboxylic acid azides, dicarboxylic acid amides, dicarbonic acid imides, etc. Ethyl dicarboxylate, propyl dicarbonate, butyl dicarboxylate, sodium dicarboxylate, ammonium dicarboxylate and the like can be used. Further, a product containing dicarboxylic acid or a derivative thereof, for example, Rhodiasolve (trade name, manufactured by Rhone Pourin Japan Co., Ltd.) containing three kinds of dicarboxylic acid esters may be used. The content of the dicarboxylic acid and the derivative thereof is about 0.5 to 500% by weight, preferably 5 to 500% by weight, and more preferably 10 to 50% by weight based on the visible light responsive photocatalyst particles in the paint or coating film. ~ 500 wt% is more preferred, and 25 ~ 250 wt% is even more preferred. When the content of the dicarboxylic acid and its derivative is less than the above range, the effect of adding is difficult to be exhibited, and when the content is more than the above range, a further remarkable effect is hardly recognized. Note that a coating film formed using a visible light responsive coating composition containing a dicarboxylic acid or a derivative thereof becomes porous, and the visible light responsive photocatalytic function can be improved. In addition to the above-mentioned paint, in addition to at least one compound selected from the group consisting of dicarboxylic acids and derivatives thereof, visible light-responsive photocatalyst particles, binders, and solvents, dispersants, surfactants, curing agents, Various additives such as a crosslinking agent may be contained. The thickness of the visible light responsive photocatalyst coating film can be appropriately set according to the application, and can be, for example, about 0.01 to 1. Using paint, The coating film can be formed by applying or spraying a paint on the substrate. Specifically, the visible light responsive photocatalyst particles and the binder are dispersed in a solvent to form a coating composition, and then the coating composition is applied or sprayed on a substrate to form the visible light responsive photocatalyst particles and the binder. Is preferably arranged on at least a part of the substrate. As the solvent, water, an organic solvent such as toluene and alcohol can be used. Examples of the coating method include, for example, impregnation method, die coating method, spinner coating method, blade coating method, roller coating method, wire per coating method, lino-slowno coating method, brush coating method, and sponge coating method. It can be applied by a conventional method or sprayed by a usual method such as a spray coating method. After being applied or sprayed in this manner, the solvent is removed by drying or baking. The drying or firing is preferably performed at a temperature lower than 500 ° C., more preferably at a temperature from room temperature to 400 ° C. In this case, if the temperature is higher than 500 ° C., the visible light responsive photocatalytic function tends to decrease, which is not preferable. Further, if necessary, a method such as ultraviolet irradiation may be used to solidify the binder used. Before applying or spraying the coating composition, if necessary, the above-mentioned organic binder such as ataryl resin, epoxy resin, polyester resin, melamine resin, urethane resin, alkyd resin, etc. The organic binder or the inorganic binder described above may be applied or sprayed on the article in advance as a primer or a coating.

The paints and coatings described above include particulate matter, adsorbents, carriers and / or condensed phosphates. Can be included. The particulate matter has, for example, an average particle diameter of 1 η π! It can be up to 100 m of inorganic or organic particles. In the present invention, when the visible light responsive photocatalyst particles and the adsorbent and / or the carrier are adhered to the substrate via the binder, the photocatalytic particles can also have the function of adsorbing and / or supporting the substance to be treated. preferable. As the above-mentioned adsorbent and carrier, general adsorbents and carriers can be used. For example, activated carbon, zeolite, silica gel, transparent activated alumina (for example, JP-A-2000-119017), amorphous or Titanium dioxide, diatomaceous earth, etc. with low crystallinity can be used. Titanium dioxide of amorphous or low crystallinity is hydrolyzed with ammonium hydroxide after titanium sulfate or titanium sulfate is obtained, and then sulfated ions remain, for example, calcined at 400 ° C, and then washed if necessary. Can be obtained by doing so. When a visible light responsive photocatalyst is adsorbed or supported on an appropriate material (for example, transparent activated alumina) of the above adsorbent or carrier as a visible light responsive photocatalyst, the transparency is reduced when a coating film is formed. In some cases, mechanical strength and weather resistance can be improved. Further, the paint is a paint containing a binder, a condensed phosphate, a visible light responsive photocatalyst, and a solvent, and the solvent is preferably water. A paint containing water as a solvent and containing a condensed phosphate has good dispersibility of visible light-responsive photocatalyst particles, and a coating film obtained from this paint shows excellent visible light response.

In particular, the present invention includes a coating containing a binder, a condensed phosphate, and a visible light-responsive photocatalyst, and the coating shows hydrophilicity under light irradiation. Conventional hydrophilic paints and coatings (for example, JP-A-11-1659) contain silica and silicone to obtain weather resistance. In contrast, according to the present invention, a coating film having excellent weather resistance can be obtained without containing silica-silicone. A coating film with excellent weather resistance can be obtained without containing silica or silicone, so that there is more freedom in composition, for example, increasing the amount of binder or increasing the content of visible light responsive photocatalyst It is also possible.

However, the paint and the coating film in the present invention may contain silica or silicone. In the above paints and coatings, the amount of the condensed phosphate is 0.5 to 5%, preferably 1 to 1.2%, based on the weight of the visible light responsive photocatalyst, whereby dispersibility, viscosity, Good paint is obtained in terms of stability and the like. Generally, the larger the specific surface area of the visible light responsive photocatalyst and the larger the amount of the surface coating agent, the larger the optimal amount of the condensed phosphate. The optimum amount of condensed phosphate varies depending on the method of producing the visible light responsive photocatalyst and the type of surface coating agent. The condensed phosphate need not be limited to one kind, and two or more kinds may be used in combination. The paint and the coating film of the present invention may further contain a colloidal oxide in addition to the above components. Examples of the colloidal oxide include colloidal silica. Since the colloidal oxide is a fine particle, it can increase the surface area of the coating (make it porous) and increase the frequency of contact between the visible light responsive photocatalyst and the reactant. However, colloidal oxides are not Is not an essential component to show Further, in the present invention, a first layer comprising a binder and containing no visible light responsive photocatalyst particles is provided on a substrate, and further, a binder and visible light responsive photocatalyst particles are formed on the first layer. Can be provided. By providing the first layer not containing the visible light responsive photocatalyst particles, the connection between the substrate and the second layer containing the visible light responsive photocatalyst particles is strengthened. Can be adhered to the substrate more firmly and for a longer period of time. As such a binder, an organic binder is preferable. Further, the first layer preferably contains, as a filler, inorganic particles having no visible light responsive photocatalytic function. Such inorganic particles include titanium oxide, silicon oxide, and aluminum oxide that have been surface-treated with silicon oxide, aluminum oxide, zirconium oxide, or the like so as not to have a visible light responsive photocatalytic function. And magnesium oxide. In the present invention, the amount of the visible light responsive photocatalyst particles in the coating composition is 5 to 98%, preferably 20 to 90% by volume based on the total amount of the visible light responsive photocatalyst particles and the binder. It is 98%, more preferably 50-98%, and most preferably 70-98%. The coating composition may contain a crosslinking agent, a dispersing agent, a filler and the like. As the cross-linking agent, a normal cross-linking agent such as an isocyanate-based or melamine-based cross-linking agent can be used, and as the dispersing agent, a coupling agent or the like can be used. In particular, the content of the visible light responsive photocatalyst particles in the coating composition is determined by the When the content is 40 to 98% by volume based on the total amount of the acidic photocatalyst particles and the binder, it is preferable to add a coupling agent to the coating composition. The addition amount of the coupling agent is preferably 5 to 50%, more preferably 7 to 30%. After being applied or sprayed as described above, it is solidified to obtain a coating film containing a visible light responsive photocatalyst. Solidification can be carried out by drying, irradiating with ultraviolet light, heating, cooling, or using a cross-linking agent, but the solidification temperature is lower than 400 ° C. The reaction is preferably carried out at a temperature from room temperature to 200 ° C. In this case, if the temperature is higher than 400 ° C., the binder is thermally degraded, and the visible light-responsive photocatalyst particles are easily removed, which is not preferable. In the present invention, a method of solidifying using an isocyanate-based or melamine-based cross-linking agent is preferable.

[Light emitting diode]

The light emitting diode used in the method of the present invention is a light emitting diode having an emission wavelength at least in the visible light region or having an emission wavelength only in the visible light region. Examples of such a light emitting diode include a purple light emitting diode, a blue light emitting diode, a green light emitting diode, a yellow light emitting diode, and a white light emitting diode. The violet emission diode has an emission wavelength from the ultraviolet region to the visible light region. Further, a blue light emitting diode, a green light emitting diode, a yellow light emitting diode, or a white light emitting diode has an emission wavelength only in a visible light region. Blue light emitting diode (BLUE), green light emitting diode (GREEN), Fig. 4 shows the emission spectrum of the white light emitting diode (WH ITE). The photocatalyst activated by the photocatalyst activation method of the present invention can be used in, for example, a chemical reaction method, an environmental purification method, a sterilization method, a hydrophilization method, a cell growing method, an antifouling method, and the like. Further, the amount of light irradiation and the irradiation time can be appropriately set depending on the amount of the substance to be treated. The method of the present invention can also be used in a reaction system such as a microchemical chip. The present invention relates to a device having a layer containing a visible light responsive photocatalyst on a light emitting diode substrate. The light-emitting diode substrate may include, for example, at least a light-emitting diode and a light-transmitting layer provided thereon, and a layer including the visible light-responsive photocatalyst provided on the light-transmitting layer. it can.

Further, in the device of the present invention, the light emitting diode is a violet light emitting diode, and light having a wavelength of 400 nm or less is transmitted between the light transmitting layer and the layer containing the visible light responsive photocatalyst. A layer that does not transmit light may be further provided. The violet light emitting diode also contains ultraviolet rays of 400 nm or less, but by providing a layer (one layer of filter) that does not transmit light of wavelengths of 400 nm or less, the ultraviolet rays are cut off, for example, visible light response. Even when a living body such as a cell is grown in a layer containing an acidic photocatalyst, there is an advantage that an adverse effect of ultraviolet light on the living body can be suppressed. Also, when using blue light emitting diodes, green light emitting diodes, yellow light emitting diodes, and white light emitting diodes, specific wavelengths are required for cell growth, etc. When there is a situation where light has a particular effect, an appropriate filter function should be used so that only light in a specific wavelength region of the light from the light emitting diode reaches the layer containing the visible light responsive photocatalyst. One filter layer may be provided. This filter layer can be a layer that does not transmit light having an arbitrary wavelength of 410 to 550 nm or less. Also, two types of filters having different transmission characteristics can be combined. Further, the present invention relates to an apparatus including a light emitting diode, a visible light responsive photocatalyst, and a light transfer means for transferring light from the light emitting diode to the visible light responsive photocatalyst. Here, the light transfer means may be, for example, an optical fiber. As described above, the layer containing the visible light responsive photocatalyst can be a coating film formed by using a paint, and for example, the visible light responsive photocatalyst in a powder state is provided on a light emitting diode. It can be formed by applying to a substrate such as a light-transmitting layer. Alternatively, when the visible light-responsive photocatalyst is the above-mentioned visible light-responsive photocatalyst, a raw material titanium compound such as amorphous or incompletely crystalline titanium oxide on a base material is added together with a suitable binder if necessary. A layer containing a visible light responsive photocatalyst can also be formed by applying the above and heating the film by applying an ammonia or a derivative thereof in an atmosphere or by including an ammonia or a derivative thereof in an atmosphere. . The device of the present invention described above can be used for chemical reaction, environmental purification, sterilization, decolorization, hydrophilization, cell growth, or imparting antifouling properties. In particular, the device of the present invention is useful as a microchemical reactor. Further, the device of the present invention can also be used as illumination such as an illumination lamp or an indicator lamp. Example

Examples of the present invention will be described below, but the present invention is not limited to these examples. Example 1

Methylene blue decolorization test

0.2 g of the powder produced in Reference Example 3 was uniformly applied to a glass plate (6 × 6 cm) using water, and dried at room temperature. About 2 ml of a 0.05 wt% aqueous solution of methylene blue was dropped near the center of the plate glass and dried at room temperature. The light source was set so as to be 1 cm relative to the sample. The light source was a blue LED (Nichia Chemical Industry Co., Ltd., Model No. NS SB 450), a 2 x 2 grid of 4 pieces, so that one side could fit into 1.5 cm. Lighting was performed by applying a voltage to the light emitting diode to 3.7 V. The light irradiation time for the sample was 1 hour. Table 1 shows the color change of the light-irradiated part of each sample after light irradiation. Comparative Example 1

A methylene blue decolorization test was performed in the same manner as in Example 1 except that a commercially available ultrafine titanium oxide powder (ST-01 manufactured by Ishihara Sangyo) was used instead of the powder produced in Reference Example 3. Table 1 shows the results. Comparative Example 2

A methylene blue decolorization test was performed in the same manner as in Example 1 except that a commercially available titanium oxide powder for photocatalyst P-25 (manufactured by Dedasa) was used instead of the powder produced in Reference Example 3. Table 1 shows the results. table 1

Example 2 (green light emitting diode)

0.2 g of the powder produced in Reference Example 3 was uniformly applied to a glass plate (6 × 6 cm) using water, and dried at room temperature. About 2 ml of a 0.05 wt% aqueous solution of methylene blue was dropped near the center of the plate glass and dried at room temperature. The light source was set so as to be 1 cm from the sample. The part where methylene blue coloring was observed was irradiated with light. The light source used is a green LED (Nichia Corporation, Model No.NSSG450) with a total of 4 2X2 sticks in a checkerboard shape that fits into a 1.5 cm square on each side. The lamp was lit by applying voltage so that the voltage became 7V. The light irradiation time for the sample was 1 hour. Table 2 shows the color change of the light-irradiated part of each sample after light irradiation. Comparative Example 3

A decolorization test of methylene blue was performed in the same manner as in Example 2 except that a commercially available ultrafine titanium oxide powder (ST-01 manufactured by Ishihara Sangyo) was used instead of the powder produced in Reference Example 3. Table 1 shows the results.

Comparative Example 4

A decolorization test of methylene blue was performed in the same manner as in Example 2 except that commercially available titanium oxide powder for photocatalyst P-25 (manufactured by Dedasa) was used instead of the powder produced in Reference Example 3. Table 2 shows the results.

Color transformation

Example 2 The color was completely erased.

Comparative Example 3 Although no decoloration was observed, the color was slightly changed to purple.

Comparative Example 4 Although no decoloration was observed, the color was slightly changed to purple. Example 3

Oxidation of isopropanol by blue emitting diode

Using a 2L bell jar type reaction vessel, 0.2 g of the sample (visible light responsive photocatalyst) prepared in Reference Example 5 was suspended in water on a glass plate (5 x 5 cm x 2 mm), and the suspension was coated with a light source. cm. The light source is a blue light emitting diode

Nichia Chemical's model: NSPB500S was illuminated and placed in a checkerboard shape with a total of 9 pieces of 3x3 so as to fit into a 1.5 cm square on each side. One light emitting diode Lighting was applied by applying a voltage so that the voltage became 3 V with respect to the diode. The illuminance at the position of the sample was 250001X.

In the reaction, isopropanol was added so that the inside of the reaction system became 540 ppm. The inside of the reaction system was set at 1 atm in an air atmosphere, and the humidity was 30%. The respective concentrations of isopropanol, acetone, and carbon dioxide in the reaction system were collected from the reaction system using a syringe, and measured using FID and TCD.

Figure 5 shows the results of the reaction after irradiation with light.

6.00 _{g of} the sample (visible light responsive photocatalyst) obtained in Reference Example 7 and 0.04 _{g of the} condensed phosphate (sodium pyrophosphate) shown in Table 3 and a predetermined amount of pure water were placed in a 100 mL polyethylene container. Pulverized for 1 hour using a zircon pole having a diameter of 5 mm. A fluororesin dispersion, a film-forming aid, and an antifoaming agent were mixed with the dispersion so as to have the following composition to prepare an aqueous paint.

Paint composition

Sample of Reference Example 1 19.9%

Condensed phosphate 1.0%

Fluororesin (solid content) 9.1%

Coating aid 1.5%

Antifoaming agent 0.05%

water

Total 100% A water-based sealer layer (30 μιη) and an acrylic silicon-based paint layer (100 μπι2 layer) are provided on a glass substrate, and the above paint is applied on one layer (30 ^ m: coating film 1) or two layers (30 μΐηΧ). 2: Coating film 2) was provided. The NO oxidation activity (removal rate) of the obtained coating film was measured by the same method as that described in the above Test Example. Table 3 shows the NO removal rate (%) (coating area 5 X 5 cm).

Table 3

Reference example 1

50 Og of titanium tetrachloride (special grade, manufactured by Kanto Chemical Co., Ltd.) was added to pure water of ice water (2 liters as water), stirred and dissolved to obtain an aqueous solution of titanium tetrachloride. While stirring 200 g of the aqueous solution with a stirrer, about 50 ml of aqueous ammonia (containing 13 wt% as NH ₃ ) was added as quickly as possible. The addition amount of aqueous ammonia was adjusted so that the final pH of the aqueous solution was about 8. This turned the aqueous solution into a white slurry. After further stirring for 15 minutes, the mixture was filtered with a suction filter. The precipitate collected by filtration was dispersed in 2 Om 1 of aqueous ammonia (containing 6 wt% as NH ₃ ), stirred for about 20 hours with a stirrer, and suction-filtered again to obtain a white hydrolyzate. The obtained white hydrolyzate was transferred to a crucible and heated at 400 ° C. for 1 hour in the air using an electric furnace to obtain a yellow product. The XRD measurement results of the obtained product are shown in the upper part of FIG. The lower part of Fig. 3 also shows the XRD measurement results of the white hydrolyzate dried at 50 ° C. From these results, it can be seen that the white hydrolyzate dried at 50 ° C. is amorphous, and the obtained product is anatase-type titanium dioxide.

The absorption spectrum of the obtained product and the white hydrolyzate dried at 50 ° C was measured under the following conditions using a Hitachi autograph spectrophotometer (U-3210) equipped with an integrating sphere.

scan speed: 120nm / min,

response: MEDIUM ^

band pass: 2.00nm,

Reference: Palladium sulfate

As a result, the white hydrolyzate was dried at 50 ° C, whereas the reflectance at 450 nm was 61% when the reflectance at 700 nm of the obtained product was 100%. The reflectance at 450 nm was 95% when the reflectance at 700 nm was 100%. In addition, the ESR spectrum of the obtained product was measured. The measurement was carried out in a vacuum (0.1 Torr) at 77K or at room temperature. The measurement conditions are as follows.

[Basic parameters] Measurement temperature 77 K or normal temperature

Field 324mT ± 25mT

Scan time 4 minutes

Mod. 0.1 mT

Receiver · Gain 10 ~: L 00 (measurement sensitivity)

Time constant 0.1 second

Light source High-pressure mercury lamp 500W

Phil 7 Letter L 42

(Sample preparation)

Vacuum deaeration 1 hour or more

(Calculation of g value)

G = g _mn XH _mn / (H _mn + AH) based on Mn ^{2 +} marker (g _mn = l. 981 (third from high magnetic field side))

H _mn: field of Mn ^{2 +} markers, .DELTA..eta: H variation Figure 1 (measurement temperature 77 K) of the magnetic field from _∞n and 2 (Measurement temperature room temperature), E SR spectrum of in the dark in the upper part, An ESR spectrum measured with a filter (L-42) that cuts light of 420 nm or less (using a 500 W high-pressure mercury lamp) in the middle, and a light of 420 nm or less in the lower. The ESR spectrum measured with a 500W high-pressure mercury lamp irradiated without using a filter (L-42) is shown below. Comparing the upper and middle spectrums in Fig. 1 clearly shows that in the middle spectrum, the g-value power S 2.00: the main signal, which is ~ 2.07, and the g-value is 1.985 ~ The two sub-signals, 1.986 and 2.024, were more intense in the upper spectrum. Also, comparing the middle and lower spectra in Fig. 1, it is clear that the main signal has a g value of 2.004 to 2.007, and the g value is 1.985 to 1.986 and 2.024. The intensities of the two sub-signals were not substantially different even when the irradiation light contained light of 420 nm or less. Furthermore, as shown in FIG. 2, the visible light responsive photocatalyst of Reference Example 1 was also measured by ESR when the three signals were in the air, at room temperature, in the dark, and under light irradiation having a wavelength of 420 nm or more. It was a thing to be done.

In addition, when the white hydrolyzate was dried at 50 ° C, the main signal having a g-value power of S 2.004 to 2.007 and a g-value of 1.985 to 1.986 and 2. Two sub-signals, 024, were not observed under any of the ESR measurement conditions. Reference example 2

3 g of the powder obtained in Reference Example 1 was suspended in 100 ml of pure water, and stirred for 1 hour using a magnetic stirrer. The obtained solution was subjected to suction filtration. The sample remaining on the filter paper was again stirred in pure water and suction filtered. Filtration was repeated three times until the filtrate became 6 to 7 with pH test paper. The obtained powder was allowed to stand in a drier set at 11 ° C. for 24 hours, and dried to obtain a visible light responsive photocatalyst. Reference example 3

23 kg of titanium tetrachloride was gradually added to 207 kg of water at a temperature of 0 filled in a 300 liter reaction vessel (which can be cooled and stirred). At this time, the temperature of the aqueous solution was up to 6 ° C. Titanium chloride was stirred for 2 days to produce a transparent titanium tetrachloride aqueous solution. When 12.5% ammonia water was added dropwise while stirring the prepared titanium tetrachloride aqueous solution, the solution gradually became cloudy. The amount of aqueous ammonia was adjusted so that the cloudy solution had a pH of 8.

The cloudy solution was subjected to suction filtration. The amount of the white precipitate remaining on the filter paper was 131 kg. The white precipitate was dispersed in 200 kg of aqueous ammonia (6%), stirred for 24 hours, and subjected to suction filtration. After filtration, the white precipitate was 108 kg. The white precipitate was placed in a forced-air-type shelf dryer set at 50 ° C and dried for 4 days. The sample after drying was 17 kg.

The dried sample was placed in an alumina crucible (20 x 20 x 5 cm) at lkg, placed in a gas furnace, a thermocouple was placed on the sample surface, and the sample was fired for 1 hour at a temperature of 400 ° C.

3 g of the prepared powder was suspended in 10 Om 1 of pure water, and stirred for 1 hour using a magnetic stirrer. The obtained solution was subjected to suction filtration. The sample remaining on the filter paper was again stirred in pure water, and suction filtration was performed. Filtration was repeated three times until the filtrate reached 6-7 with pH test paper. The obtained powder was allowed to stand in a drier set at 11 ° C. for 24 hours, and dried to obtain a visible light responsive photocatalyst. Reference Example 4 (Method of manufacturing visible light responsive material from titanium sulfate (1))

As titanium sulfate (IV) solution, titanium sulfate (IV) solution (manufactured by Kanto Chemical Co., trade name:. Titanium sulfate (IV) (1 grade deer, ² 4 weight of titanium sulfate (IV) / ₀ above containing a solution )) Stock solution was used as is. While stirring 50 g of this aqueous solution with a stirrer and adding 58 ml of aqueous ammonia (ammonia stock solution: water = 1: 1) as quickly as possible with a burette, stirring was continued. Heightened. Further, ammonia water was added, and the pH was adjusted to 7 with a universal test strip. After 24 hours, the mixture was filtered with a suction filter. The white matter attached to the filter paper was stirred eight times in ammonia water adjusted to pH 11 and filtered again eight times, and washed to obtain a white powder. The obtained powder was dried at 50 ° C. to obtain a sample powder. The BET surface area of the obtained hydrolyzate (sample powder) was 308.7 m ² / g. 8 g of the obtained sample powder was placed in a crucible, transferred to an electric furnace, and baked at 400 ° C for 60 minutes to obtain 6.3 g of a bright yellow powder having a BET surface area of 89.4 m ² / g. Was. An X-ray diffraction (XRD) test of this powder shows that it contains anatase-type titanium oxide. Furthermore, it was measured with an X-ray photoelectron spectrometer (trade name: Quanturn 2000, manufactured by ULVAC FAI Co., Ltd.). As a result of the X-ray photoelectron spectroscopy (XPS) test, The abundance ratio (OZTi) between the oxygen element and the titanium element calculated from the area of the peak to be measured and the area of the peak attributed to the 1 s electron of oxygen is as follows: Lack of It showed that there was a loss. Due to this oxygen deficiency, Powder A is colored bright or pale yellow, and is considered to have visible light activity (photocatalytic activity).

The ESR spectrum of the obtained powder was measured. The measurement was performed at 77 K in a vacuum (0. The measurement conditions are the same as in Reference Example 1.

Fig. 6 (measuring temperature 77Κ) shows the ESR spectrum measured with light irradiated through a filter (L-42) that cuts light below 420 nm (using a high-pressure mercury lamp of 500 W). . In addition, the ESR spectrum under 喑 black was also measured, but practically no signal was observed. In the spectrum shown in Fig. 6, a main signal with a g-value of 2.004 to 2.007 and two sub-signals with a g-value of 1.985 to 1.986 and 2.024 were observed. .

Incidentally, when the white hydrolyzate was dried at 50 ° C, the main signal having a g value of 2.004 to 2.007, and the g value of 1.985 to 1.986 and 2.02 The two secondary signals of 4 were not observed under any of the ESR measurement conditions. Reference Example 5 (Production method of visible light responsive material from titanium sulfate (2))

Add 50 g of a 24% titanium sulfate solution (Kanto Chemical Co., Ltd., deer grade) to 400 mL of distilled water, and stir with a magnetic stirrer. There, concentrated ammonia water (28%, Kanto Chemical, special grade) is added to perform neutralization reaction. After the neutralization reaction, adjust the pH to 7 and stir for 15 minutes. At this time, add distilled water (200 mL). Fifteen After one minute, stop stirring and let stand for a while. Discard the supernatant. Filter by Nutsche and wash with 2 L of aqueous ammonia (5:95). This work is a method of adding ammonia water when the cake is formed on the filter paper. Thereafter, the obtained product was dried at 60 ° C. for 24 hours, and calcined at 400 ° C. for 1 hour to obtain a visible light responsive photocatalyst of the present invention.

The N 2 O oxidation activity of the obtained material was measured in the same manner as in the above Test Example, and is shown in Table 4. Table 4

The ESR spectrum of the obtained material was measured. The measurement was performed at 77 K in a vacuum (00 Ι Τ rr). The measurement conditions are the same as in Reference Example 1.

Fig. 7 (measuring temperature 77 77) shows the ESR spectrum measured under the condition that light was irradiated through a filter (L-42) that cuts light of 420 nm or less (using a high-pressure mercury lamp of 500 W). . In the spectrum shown in Fig. 7, the main signal whose g-value power is S2.004 to 2.007 is And two sub-signals with g-values of 1.895 to 1.896 and 2.024.

In addition, when the white hydrolyzate was dried at 50 ° C., the main signal having a g-value force of S 2 004 to 2.007 and a g-value of 1.985 to Two side signals, 1.986 and 2.024, were not observed under any of the ESR measurement conditions. Reference Example 6 (Production method from alkoxide)

While stirring in 200 g of pure water, 30 g of titanium isopropoxide was gradually added (molar ratio of water to titanium isopropoxide = about 10: 1). After stirring the obtained solution for about 30 minutes, the precipitate (hydrolyzate) was collected by filtration, and the precipitate (hydrolyzate) suspended in pure water and stirred for 1 day was filtered. C. and dried at 400.degree. C. for 1 hour. The obtained white powder is designated as Sample A.

Instead of suspending the precipitate (hydrolyzate) in pure water and stirring for 1Θ, suspend the precipitate (hydrolyzate) in ammonia water (ammonia concentration: 6%) and stir for 1 day. The yellow powder is used as Sample B in the same manner as above, except that the mixture is used. The NO activities of Samples A and B were measured in the same manner as in the above test method. The results are shown in Table 5 below. Table 5

NO activity

Sample A

Sample B

From the results shown in Table 5, it can be seen that a material composed of titanium oxide having visible light response can be obtained by heat-treating titanium oxide (titanium hydrolyzate) in the presence of ammonia. The ESR spectrum of the obtained material was measured. The measurement is performed in vacuum (0. Ι Ι ο rr) 77 K. The measurement conditions are the same as in Reference Example 1.

Fig. 8 (Measurement temperature 77 K) ESR measured with light irradiated through a filter (L-42) that cuts light below 420 nm (using a 500 W high-pressure mercury lamp) Indicates the spectrum. In the spectrum shown in FIG. 8, the main signal has a g value of 2.004 to 2.007, and g values of 1.985 to 1.986 and 2.024. Two minor signals were observed.

In addition, when the white hydrolyzate was dried at 50 ° C., the main signal having a g-value force of S 2.004 to 2.007 and a g-value of 1.985 to Two side signals, 1.986 and 2.024, were not observed under any of the ESR measurement conditions. Reference Example 7 (Production method from titanyl sulfate)

240raL pure water was prepared in a 1L beaker. 60 g of Kishida Chemical Titanium Sulfate (Product No. 020-78905) was added thereto, and the mixture was stirred and dissolved with a laboratory mixer. Next, 55 mL of Kanto Chemical (special grade) aqueous ammonia was added to this aqueous solution to obtain a hydrolyzed precipitate. The obtained precipitate was subjected to suction filtration to separate a white solid (precipitated cake). Furthermore, the cake was rinsed with 1.0 L of pure water three times (in a procedure of pouring immediately before the cake cracks) for a total of 3.0 L, and filtered and washed. Finally, the filtered cake was dried at 110 ° C. for 12 hours until no filtrate came out, and then ground in a mortar. By firing this white powder in air at 400 ° C for 1 hour, the same A yellow material was obtained showing a major signal with a g value and two minor signals. Industrial applicability

According to the present invention, it is possible to provide a method and an apparatus for activating a photocatalyst using a light-emitting diode having a high visible light content or containing only visible light as a light source.

Claims

The scope of the claims

1. A method for activating a photocatalyst in which a photocatalyst having activity by the action of light having a wavelength of 420 nm or more (hereinafter referred to as a visible light responsive photocatalyst) is irradiated with light of a light emitting diode.

2. The method according to claim 1, wherein the visible light responsive photocatalyst is contained in a coating film, and the light of the light emitting diode is applied to the coating film.

3. The visible light-responsive photocatalyst is a titanium oxide containing at least anatase-type titanium oxide, and has a wavelength of 420 nm or more at 77 K in a vacuum. A main signal of 004 to 2.00 7 and two sub-signals with g values of 1.985 to 1.986 and 2.024 were observed, and these three signals were in vacuum, 77K, dark 3. The method according to claim 1, which is a visible light responsive photocatalyst under which a force is slightly observed or a visible light is not substantially observed.

4. The method according to claim 1, wherein the light emitting diode is a violet light emitting diode, a blue light emitting diode, a green light emitting diode, a yellow light emitting diode, or a white light emitting diode.

5. A chemical reaction method, an environmental purification method, a sterilization method, a hydrophilization method, a cell growing method, or an antifouling method using the method according to any one of claims 1 to 4.

6. An apparatus having a layer containing a visible light responsive photocatalyst on a light emitting diode substrate.

7. The light-emitting diode substrate according to claim 6, wherein the light-emitting diode substrate comprises at least a light-emitting diode and a light-transmitting layer provided thereon, and a layer containing the visible light-responsive photocatalyst is provided on the light-transmitting layer. apparatus.

8. The light-emitting diode is a violet light-emitting diode, and a layer that does not transmit light having a wavelength of 400 nm or less is further provided between the light-transmitting layer and the layer containing the visible light-responsive photocatalyst. Item 7. An apparatus according to Item 7.

9. An apparatus comprising a light emitting diode, a visible light responsive photocatalyst, and light transfer means for transferring light from the light emitting diode to the visible light responsive photocatalyst.

10. The visible light responsive photocatalyst is contained in a coating film, and the light transferring means is for transferring light from the light emitting diode to the visible light responsive photocatalyst contained in the coating film. The device according to claim 9, which is a means.

1 1. The g value of the visible light responsive photocatalyst is a titanium oxide containing at least anatase-type titanium oxide, and the ESR measured in a vacuum at 77 K under irradiation with light having a wavelength of 420 nm or more at 77 K. The main signal is 2.004 to 2.007, and the two sub-signals with g-values are 1.985 to 1.986 and 2.024. Claims 6 to 10 wherein the signal is a visible light responsive photocatalyst in which a signal is observed, and these three signals are minutely observed or substantially not observed in vacuum at 77 K in the dark. The device according to any one of the preceding claims.

12. The device according to any one of claims 6 to 11, wherein the light emitting diode is a violet light emitting diode, a blue light emitting diode, a green light emitting diode, a yellow light emitting diode, or a white light emitting diode.

13. The device according to any one of claims 6 to 12, wherein the device is used for chemical reaction, environmental purification, sterilization, decolorization, hydrophilization, cell growth, or imparting antifouling properties.

14. The device according to any one of claims 6 to 12, which is used for lighting or display.