JP2001179107A - Photocatalyst - Google Patents
PhotocatalystInfo
- Publication number
- JP2001179107A JP2001179107A JP36923599A JP36923599A JP2001179107A JP 2001179107 A JP2001179107 A JP 2001179107A JP 36923599 A JP36923599 A JP 36923599A JP 36923599 A JP36923599 A JP 36923599A JP 2001179107 A JP2001179107 A JP 2001179107A
- Authority
- JP
- Japan
- Prior art keywords
- photocatalyst
- metal
- water
- compound
- hydrogen
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000011941 photocatalyst Substances 0.000 title claims abstract description 62
- 229910052751 metal Inorganic materials 0.000 claims abstract description 39
- 239000002184 metal Substances 0.000 claims abstract description 39
- 239000001257 hydrogen Substances 0.000 claims abstract description 24
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 24
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 20
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 19
- 150000001875 compounds Chemical class 0.000 claims abstract description 18
- 239000002131 composite material Substances 0.000 claims abstract description 17
- 150000002736 metal compounds Chemical class 0.000 claims abstract description 17
- 229910052741 iridium Inorganic materials 0.000 claims abstract description 11
- 229910052742 iron Inorganic materials 0.000 claims abstract description 11
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 11
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 11
- 229910052703 rhodium Inorganic materials 0.000 claims abstract description 11
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 11
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 10
- 229910052697 platinum Inorganic materials 0.000 claims abstract description 10
- 229910052783 alkali metal Inorganic materials 0.000 claims abstract description 9
- 150000001340 alkali metals Chemical class 0.000 claims abstract description 9
- 229910052763 palladium Inorganic materials 0.000 claims abstract description 9
- 229910052707 ruthenium Inorganic materials 0.000 claims abstract description 9
- 229910052715 tantalum Inorganic materials 0.000 claims abstract description 9
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 9
- 125000004435 hydrogen atom Chemical class [H]* 0.000 claims 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 35
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 abstract description 19
- 230000001699 photocatalysis Effects 0.000 abstract description 11
- 238000000034 method Methods 0.000 description 12
- 239000002002 slurry Substances 0.000 description 11
- 239000007789 gas Substances 0.000 description 10
- 239000000843 powder Substances 0.000 description 10
- 239000007864 aqueous solution Substances 0.000 description 9
- 229910010413 TiO 2 Inorganic materials 0.000 description 8
- 230000000694 effects Effects 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 8
- 238000006243 chemical reaction Methods 0.000 description 7
- 239000000126 substance Substances 0.000 description 7
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 6
- 238000010438 heat treatment Methods 0.000 description 6
- 230000001678 irradiating effect Effects 0.000 description 5
- 229910044991 metal oxide Inorganic materials 0.000 description 5
- 150000004706 metal oxides Chemical class 0.000 description 5
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 4
- 150000002431 hydrogen Chemical class 0.000 description 4
- 239000001301 oxygen Substances 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 238000005215 recombination Methods 0.000 description 4
- 230000006798 recombination Effects 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 3
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 229910017604 nitric acid Inorganic materials 0.000 description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- 238000010532 solid phase synthesis reaction Methods 0.000 description 3
- 150000003568 thioethers Chemical class 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 101150003085 Pdcl gene Proteins 0.000 description 2
- -1 WF 6 Inorganic materials 0.000 description 2
- 239000003054 catalyst Substances 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 230000005284 excitation Effects 0.000 description 2
- 230000001747 exhibiting effect Effects 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- QGLKJKCYBOYXKC-UHFFFAOYSA-N nonaoxidotritungsten Chemical compound O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1 QGLKJKCYBOYXKC-UHFFFAOYSA-N 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- 238000006303 photolysis reaction Methods 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000006722 reduction reaction Methods 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 229910001930 tungsten oxide Inorganic materials 0.000 description 2
- 239000003039 volatile agent Substances 0.000 description 2
- 229910002012 Aerosil® Inorganic materials 0.000 description 1
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonium chloride Substances [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- 241000894006 Bacteria Species 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- 229910002367 SrTiO Inorganic materials 0.000 description 1
- 229910004529 TaF 5 Inorganic materials 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- 230000003373 anti-fouling effect Effects 0.000 description 1
- 239000011260 aqueous acid Substances 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000004332 deodorization Methods 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 150000004820 halides Chemical class 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 150000002823 nitrates Chemical class 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229910000069 nitrogen hydride Inorganic materials 0.000 description 1
- 150000002902 organometallic compounds Chemical class 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000013032 photocatalytic reaction Methods 0.000 description 1
- 230000015843 photosynthesis, light reaction Effects 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- CMPGARWFYBADJI-UHFFFAOYSA-L tungstic acid Chemical compound O[W](O)(=O)=O CMPGARWFYBADJI-UHFFFAOYSA-L 0.000 description 1
Landscapes
- Catalysts (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は光触媒に関し、特
に、可視光によって光触媒機能を有効に発揮することが
でき、例えば、水を光分解して水素と酸素とを効率的に
生成させることができる光触媒に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocatalyst, and more particularly to a photocatalyst capable of effectively exhibiting a photocatalytic function by visible light, for example, capable of efficiently decomposing water to produce hydrogen and oxygen. It relates to a photocatalyst.
【０００２】[0002]
【従来の技術】光触媒としては従来からＴｉＯ２やＳｒ
ＴｉＯ３等が知られており、光触媒の応用例として、こ
れらの光触媒を用いて水や有機物を光分解することによ
り水素を製造する方法が見出され、光エネルギーを化学
エネルギーに変換する方法が提案されている。 2. Description of the Related Art Conventionally, TiO 2 and Sr have been used as photocatalysts.
TiO 3 and the like are known, and as an application example of the photocatalyst, a method of producing hydrogen by photodecomposing water or an organic substance using these photocatalysts has been found. Proposed.
【０００３】しかしながら、前記ＴｉＯ２やＳｒＴｉＯ
３等の光触媒はいずれも３ｅＶ以上の大きなバンドギャ
ップを有するため、太陽光の大部分を占める可視光はほ
とんど利用できないという問題点がある。また、バンド
ギャップ以上のエネルギーを有する波長の光を吸収する
ことより生成したホールと電子は互いに反対の電荷を持
つために再結合が生じ易く、光触媒活性が持続しないと
いう問題点もある。[0003] However, the TiO 2 and SrTiO
Since all of the photocatalysts such as 3 have a large band gap of 3 eV or more, there is a problem that visible light which occupies most of the sunlight can hardly be used. Further, there is also a problem that holes and electrons generated by absorbing light having a wavelength having energy equal to or greater than the band gap have opposite charges, so recombination is likely to occur, and photocatalytic activity is not maintained.
【０００４】そのため、ＴｉＯ２等と、対極となる金属
又は金属酸化物とを組み合わせて、それぞれの極へホー
ルと電子を導くことによりホールと電子の再結合を防ぐ
ことが試みられており、例えばＴｉＯ２−Ｐｔ系光触媒
によって水の光分解を進行させることが知られている。
しかしながら、前記ＴｉＯ２−Ｐｔ系光触媒を水中に分
散懸濁させると水の分解反応がすぐ飽和してしまう。こ
れはＰｔが、水素と酸素から水を生成する反応に用いら
れる触媒でもあるので、水の分解により発生した水素と
酸素の一部がすぐに逆反応して水に戻るためと考えられ
る。For this reason, attempts have been made to prevent recombination of holes and electrons by combining TiO 2 or the like with a metal or metal oxide serving as a counter electrode and guiding holes and electrons to the respective poles. It is known that TiO 2 -Pt-based photocatalyst promotes water photolysis.
However, when the TiO 2 -Pt-based photocatalyst is dispersed and suspended in water, the decomposition reaction of water is immediately saturated. This is presumably because Pt is also a catalyst used in the reaction for producing water from hydrogen and oxygen, so that part of the hydrogen and oxygen generated by the decomposition of water immediately reversely react and return to water.
【０００５】また、バンドギャップエネルギーの小さな
硫化物を利用することも試みられている。例えば、Ｃｄ
Ｓはバンドギャップエネルギーが２．５ｅＶであり、可
視光により水あるいは水溶性有機物の光分解を進行させ
ることができる。しかしながら、ＣｄＳなどの硫化物は
光触媒反応により自分自身も分解する性質を有している
ため、水を分解するのに水中に光触媒としての硫化物を
分散懸濁させると、水素の発生とともに該光触媒自身も
分解して水に溶解してしまい、有効耐用寿命が極めて短
く、短時間で水素発生が停止するという問題点があっ
た。Attempts have also been made to utilize sulfides having a small band gap energy. For example, Cd
S has a band gap energy of 2.5 eV and can promote photodecomposition of water or a water-soluble organic substance by visible light. However, since sulfides such as CdS have the property of decomposing themselves by a photocatalytic reaction, if sulfides as photocatalysts are dispersed and suspended in water to decompose water, the generation of hydrogen and the photocatalysts occur. There is a problem in that it itself decomposes and dissolves in water, the effective useful life is extremely short, and hydrogen generation stops in a short time.
【０００６】[0006]
【発明が解決しようとする課題】本発明は、従来の技術
における上記問題点に鑑みてなされたものであり、その
目的は、太陽光によっても効率よく光触媒機能を発揮で
きる大きな可視光活性を有し、水中に分散懸濁させても
溶解せず、光触媒活性が消失しない光触媒を提供するこ
とにある。SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and has as its object a large visible light activity capable of efficiently exhibiting a photocatalytic function even by sunlight. Another object of the present invention is to provide a photocatalyst which does not dissolve even when dispersed and suspended in water and does not lose its photocatalytic activity.
【０００７】[0007]
【課題を解決するための手段】本発明者らは、光触媒と
してバンドギャップエネルギーの小さなタングステン酸
化物に着目し、鋭意検討の結果、ＷＯ３とＶ、Ｎｂ及び
Ｔａから成る群より選ばれた少なくとも1種の元素と、
水素及び／又はアルカリ金属とを複合して酸化物化し、
更に、特定の金属或いはこれらの金属酸化物を担持させ
たものは、タングステン酸化物がホールと電子とを分離
できる層状の結晶構造を有し、小さなバンドギャップで
可視光活性を発揮でき、また水に分散懸濁させても光触
媒機能が消失しない高光活性な光触媒を得ることができ
ることを知見し、本発明を完成した。Means for Solving the Problems The present inventors have at least focused on small tungsten oxide of the band gap energy as a photocatalyst, a result of intensive studies, selected from the group consisting of WO 3 and V, Nb and Ta One element,
Hydrogenate and / or alkali metal to form an oxide,
Furthermore, a specific metal or those supporting these metal oxides have a layered crystal structure in which tungsten oxide can separate holes and electrons, can exhibit visible light activity with a small band gap, and can be used in water. It has been found that a highly photoactive photocatalyst that does not lose its photocatalytic function even when dispersed and suspended in water can be obtained, and the present invention has been completed.
【０００８】即ち、本発明の光触媒は、一般式AMWO
6（式中、Aはアルカリ金属及び／又は水素であり、Mは
V、Nb及びTaから成る群より選ばれた少なくとも1種の元
素を示す）で表される化合物に、Pt、Ru、Pd、Rh、Ir、
V、W、Nb、Ta、Cu、Co、Mn、Cr、Fe、NiおよびTiからな
る群から選ばれる少なくとも1種の金属又は当該金属の
酸化物が担持されている層状複合金属化合物を含むこと
を特徴とする。また特に、前記Pt、Ru、Pd、Rh、Ir、
V、W、Nb、Ta、Cu、Co、Mn、Cr、Fe、NiおよびTiからな
る群から選ばれる少なくとも1種の金属あるいは当該金
属の金属酸化物の担持量は金属換算で、層状複合金属化
分物中の０．０５〜５重量％であることが好ましい。That is, the photocatalyst of the present invention has the general formula AMWO
6 (where A is an alkali metal and / or hydrogen, and M is
V, represents at least one element selected from the group consisting of Nb and Ta), Pt, Ru, Pd, Rh, Ir,
V, W, Nb, Ta, Cu, Co, Mn, Cr, Fe, Ni, and at least one metal selected from the group consisting of Ti or a layered composite metal compound carrying an oxide of the metal is included It is characterized by. More particularly, the Pt, Ru, Pd, Rh, Ir,
V, W, Nb, Ta, Cu, Co, Mn, Cr, Fe, Ni, and at least one metal selected from the group consisting of Ti or a metal oxide of the metal is a metal-containing metal oxide. It is preferably from 0.05 to 5% by weight in the compound.
【０００９】[0009]
【発明の実施の形態】以下、本発明の光触媒の好適な実
施の形態を、水分解に適用する場合を例に、具体的に説
明する。なお、当該発明の実施の形態は、発明の趣旨を
より良く理解させるためのものであり、特に限定のない
限り、発明内容を制限するものでない。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the photocatalyst of the present invention will be specifically described below by taking, as an example, a case where the present invention is applied to water splitting. The embodiments of the present invention are for better understanding of the spirit of the invention, and do not limit the contents of the invention unless otherwise limited.
【００１０】本発明の光触媒は、一般式AMWO6（式中、A
はアルカリ金属及び／又は水素であり、MはV、Nb及びTa
から成る群より選ばれた少なくとも1種の元素を示す）
で表される化合物に、Pt、Ru、Pd、Rh、Ir、V、W、Nb、
Ta、Cu、Co、Mn、Cr、Fe、NiおよびTiからなる群から選
ばれる少なくとも1種の金属又は当該金属の酸化物が担
持されている層状複合金属化合物を含む。The photocatalyst of the present invention has the general formula AMWO 6 (wherein A
Is an alkali metal and / or hydrogen, M is V, Nb and Ta
Represents at least one element selected from the group consisting of
In the compound represented by, Pt, Ru, Pd, Rh, Ir, V, W, Nb,
At least one metal selected from the group consisting of Ta, Cu, Co, Mn, Cr, Fe, Ni and Ti or a layered composite metal compound carrying an oxide of the metal is included.
【００１１】本発明の光触媒は、層状構造を有するた
め、ホールと電子とが異なった層に誘導され、これらの
再結合が抑制できる。またバンドギャップは約２．７〜
３．０ｅＶであり、従来の光触媒よりもバンドギャップ
を小さくすることができ、３ｅＶ以下のエネルギーの光
である可視光でも励起可能な光触媒となり、可視光であ
る２．６〜３．０ｅＶのエネルギー範囲の光を反応に有
効に利用することができる。更に、酸化物であることか
ら水溶液中ではほとんど溶解することがなく、化学的に
安定しているので、例えば水溶性有機物を効率よく分解
することができる。Since the photocatalyst of the present invention has a layered structure, holes and electrons are induced in different layers, and recombination thereof can be suppressed. The band gap is about 2.7-
3.0 eV, the bandgap can be made smaller than that of the conventional photocatalyst, and the photocatalyst can be excited even with visible light, which is light having an energy of 3 eV or less, and has an energy of 2.6 to 3.0 eV, which is visible light. The light in the range can be effectively used for the reaction. Furthermore, since it is an oxide, it hardly dissolves in an aqueous solution and is chemically stable, so that, for example, a water-soluble organic substance can be efficiently decomposed.
【００１２】また、本発明の光触媒は、好適には前記層
状複合金属化合物中に０．０５〜５重量％（金属換算）
のPt、Ru、Pd、Rh、Ir、V、W、Nb、Ta、Cu、Co、Mn、C
r、Fe、NiおよびTiからなる群から選ばれる少なくとも1
種の金属あるいは当該金属の酸化物が担持される。従っ
てかかる範囲の担持物質が、層状複合金属化合物に可視
光の励起によって発生した電子を引き寄せて還元反応、
例えば水を分解して水素を発生させる反応を起こすサイ
トとなるため、更に高光活性な光触媒となり、水を効率
よく分解することができる。The photocatalyst of the present invention preferably contains 0.05 to 5% by weight (in terms of metal) of the layered composite metal compound.
Pt, Ru, Pd, Rh, Ir, V, W, Nb, Ta, Cu, Co, Mn, C
at least one selected from the group consisting of r, Fe, Ni and Ti
A seed metal or an oxide of the metal is supported. Therefore, the support substance in such a range attracts electrons generated by excitation of visible light to the layered composite metal compound, and the reduction reaction,
For example, since the site is a site where a reaction for decomposing water to generate hydrogen is generated, the photocatalyst becomes more highly photoactive, and water can be decomposed efficiently.
【００１３】本発明の光触媒の製造方法は、特に限定さ
れず公知の方法、例えば下記の第１〜３の方法を用いて
製造することができる。第１の製造方法によれば、まず
原料となる各金属成分の酸化物または炭酸塩や硝酸塩な
どの塩類を所定の組成比にて混合し、例えば大気中、焼
成温度８００℃で約２４時間焼成することにより、一般
式AMWO6（式中、Aはアルカリ金属であり、MはV、Nb及び
Taから成る群より選ばれた少なくとも1種の元素を示
す）で表される化合物を製造する。The method for producing the photocatalyst of the present invention is not particularly limited, and it can be produced by a known method, for example, the following first to third methods. According to the first production method, first, oxides or salts such as carbonates and nitrates of the respective metal components serving as raw materials are mixed at a predetermined composition ratio, and the mixture is baked in the atmosphere at a calcination temperature of 800 ° C. for about 24 hours. By the general formula AMWO 6 (where A is an alkali metal, M is V, Nb and
At least one element selected from the group consisting of Ta).
【００１４】次いで、前記AMWO6化合物に金属換算で、
層状複合金属化合物中に０．０５〜５重量％のPt、Ru、
Pd、Rh、Ir、V、W、Nb、Ta、Cu、Co、Mn、Cr、Fe、Niお
よびTiからなる群から選ばれる少なくとも1種の金属あ
るいはこれらの金属の酸化物を担持させる。担持させる
方法としては、例えば光析出法、固相法、液相法、気相
法を使用することができる。Next, the AMWO 6 compound is converted into metal
0.05 to 5% by weight of Pt, Ru, in the layered composite metal compound
At least one metal selected from the group consisting of Pd, Rh, Ir, V, W, Nb, Ta, Cu, Co, Mn, Cr, Fe, Ni and Ti, or an oxide of these metals is supported. As a method of carrying the material, for example, a light deposition method, a solid phase method, a liquid phase method, or a gas phase method can be used.
【００１５】光析出法によれば、前記AMWO6化合物粉末
を分散させたスラリー溶液に、例えば［Ｐｔ（ＮＨ３）
４］Ｃｌ２、あるいはPdCl2のような担持する各金属成
分の水溶性化合物を所定量添加し、紫外光を５時間程度
照射して金属を光析出させて、層状複合金属化合物を製
造することができる。紫外光を照射する際の温度は室温
で十分であり、特に加熱する必要はない。According to the photoprecipitation method, for example, [Pt (NH 3 ) 2] is added to a slurry solution in which the AMWO 6 compound powder is dispersed.
4 ] A layered composite metal compound is produced by adding a predetermined amount of a water-soluble compound of each metal component to be supported such as Cl 2 or PdCl 2 and irradiating with ultraviolet light for about 5 hours to cause the metal to photoprecipitate. Can be. The temperature at the time of irradiating the ultraviolet light is sufficient at room temperature, and there is no particular need for heating.
【００１６】固相法によれば、前記AMWO6化合物粉末
と、担持する金属粉末または金属酸化物粉末とを所定量
混合し、ボールミルや振とう器等で充分混合するか、又
は激しく振り混ぜ、層状複合金属化合物を製造すること
ができる。混合又は振り混ぜる際の温度は、室温で充分
であり、特に加熱する必要はない。According to the solid phase method, a predetermined amount of the AMWO 6 compound powder and a supported metal powder or metal oxide powder are mixed and sufficiently mixed with a ball mill or a shaker or vigorously shaken. A layered composite metal compound can be produced. Room temperature is sufficient at the time of mixing or shaking, and there is no particular need for heating.
【００１７】液相法によれば、前記AMWO6化合物粉末
を、例えば［Ｐｔ（ＮＨ３）４］Ｃｌ ２、PdCl2のよう
な担持する各金属成分の水溶性化合物に浸漬し、乾燥
後、水素、窒素、アルゴン、真空中等の還元性雰囲気下
で熱処理し、層状複合金属化合物を製造することができ
る。熱処理温度は、例えば４００〜７００℃が好適であ
る。According to the liquid phase method, the AMWO6Compound powder
For example, [Pt (NH3)4] Cl 2,PdClTwoAs
Immersed in a water-soluble compound of each metal component to be supported and dried
Then, under reducing atmosphere such as hydrogen, nitrogen, argon, vacuum
Heat treatment to produce a layered composite metal compound
You. The heat treatment temperature is preferably, for example, 400 to 700 ° C.
You.
【００１８】また、気相法によれば、例えばＰｔＦ５、
ＷＦ６、ＴａＦ５等のような、担持する金属の揮発性化
合物を前記AMWO6化合物が設置された反応容器内に導入
し、例えば９００℃程度の温度で保持し、層状複合金属
化合物を製造することができる。保持時間は通常、１〜
３時間で充分である。According to the gas phase method, for example, PtF 5 ,
A volatile compound of a supported metal such as WF 6 , TaF 5 or the like is introduced into a reaction vessel in which the AMWO 6 compound is installed, and is held at a temperature of, for example, about 900 ° C. to produce a layered composite metal compound. be able to. The holding time is usually 1 to
3 hours is enough.
【００１９】第２の製造方法によれば、タングステン酸
水溶液に各金属成分の塩化物等を溶解した溶液にアンモ
ニア溶液を添加してゲル化し、ゲル化物を濾過、乾燥し
た後、乾燥物を例えば大気中、温度７００℃で約２４時
間熱処理することにより、一般式AMWO6（式中、Aはアル
カリ金属であり、MはV、Nb及びTaから成る群より選ばれ
た少なくとも1種の元素を示す）で表される化合物を製
造する。次いで、前記第１の製造方法に準じて、前記AM
WO6化合物に金属換算で、層状複合金属化合物中０．０
５〜５重量％のPt、Ru、Pd、Rh、Ir、V、W、Nb、Ta、C
u、Co、Mn、Cr、Fe、NiおよびTiからなる群から選ばれ
る少なくとも1種の金属又は当該金属の酸化物を担持さ
せて層状複合金属化合物を製造することができる。According to the second production method, an ammonia solution is added to a solution obtained by dissolving chlorides and the like of each metal component in an aqueous solution of tungstic acid to form a gel, and the gel is filtered and dried. By heat treatment in the atmosphere at a temperature of 700 ° C. for about 24 hours, a general formula AMWO 6 (where A is an alkali metal and M is at least one element selected from the group consisting of V, Nb and Ta) Is shown). Next, according to the first manufacturing method, the AM
In terms of metal, WO 6 compound contained 0.0
5-5% by weight of Pt, Ru, Pd, Rh, Ir, V, W, Nb, Ta, C
The layer composite metal compound can be produced by supporting at least one metal selected from the group consisting of u, Co, Mn, Cr, Fe, Ni and Ti or an oxide of the metal.
【００２０】第３の製造方法では、ハロゲン化物、有機
金属化合物などの、原料となる各金属成分を含む揮発性
化合物を所定の組成比となるよう反応容器内に導入し、
例えば９００℃程度の温度に保持することにより、一般
式AMWO6（式中、Aはアルカリ金属であり、MはV、Nb及び
Taから成る群より選ばれた少なくとも1種の元素を示
す）で表される化合物を製造する。次いで、前記の第１
の製造方法に準じて、前記AMWO6化合物に金属換算で、
層状複合金属化合物中０．０５〜５重量％のPt、Ru、P
d、Rh、Ir、V、W、Nb、Ta、Cu、Co、Mn、Cr、Fe、Niお
よびTiからなる群から選ばれる少なくとも1種の金属又
は当該金属の酸化物を担持させる。In the third production method, a volatile compound containing each metal component as a raw material such as a halide and an organometallic compound is introduced into a reaction vessel so as to have a predetermined composition ratio.
For example, by maintaining the temperature at about 900 ° C., the general formula AMWO 6 (where A is an alkali metal, M is V, Nb and
At least one element selected from the group consisting of Ta). Then, the first
According to the production method, the AMWO 6 compound in terms of metal,
0.05-5% by weight of Pt, Ru, P in the layered composite metal compound
At least one metal selected from the group consisting of d, Rh, Ir, V, W, Nb, Ta, Cu, Co, Mn, Cr, Fe, Ni and Ti, or an oxide of the metal is supported.
【００２１】また、AMWO6 化合物のＡ位置における元
素が水素元素である光触媒を製造するには、前記Ａ位置
における元素がアルカリ金属からなる化合物を、予め例
えば、前記固相法、湿式法、気相法のいずれかで製造し
ておき、その後、この化合物を硝酸などの酸水溶液中で
イオン交換して、前記Ａ位置における元素が水素元素で
ある一般式AMWO6（式中、MはV、Nb及びTaから成る群よ
り選ばれた少なくとも1種の元素を示す）で表される化
合物を製造する。イオン交換する際の温度は室温で十分
であり、特に加熱する必要はない。次いで、前記の第１
の製造方法に準じて、前記AMWO6化合物に、金属換算で
層状複合金属化合物中０．０５〜５重量％のPt、Ru、P
d、Rh、Ir、V、W、Nb、Ta、Cu、Co、Mn、Cr、Fe、Niお
よびTiからなる群から選ばれる少なくとも1種の金属又
は当該金属の酸化物を担持させて、層状複合金属化合物
を製造することができる。In order to produce a photocatalyst in which the element at position A of the AMWO 6 compound is a hydrogen element, a compound in which the element at position A is composed of an alkali metal is prepared in advance by, for example, the solid phase method, the wet method, or the gas method. The compound is ion-exchanged in an aqueous acid solution such as nitric acid, and then the compound at the position A is a hydrogen element represented by the general formula AMWO 6 (where M is V, At least one element selected from the group consisting of Nb and Ta). Room temperature for ion exchange is sufficient, and there is no particular need for heating. Then, the first
According to the method of manufacturing, the AMWO to 6 compounds, layered composite metal compound was 0.05 to 5 wt% of Pt in terms of metal, Ru, P
d, Rh, Ir, V, W, Nb, Ta, Cu, Co, Mn, Cr, Fe, Ni and at least one metal selected from the group consisting of Ti and an oxide of the metal are supported, and the A composite metal compound can be produced.
【００２２】次に、本発明の光触媒を使用した水素の製
造方法（水の分解方法）について、以下に説明する。水
分解に用いる水溶液は、純水に限られず、従来からよく
使用されているアルコールなどの犠牲還元剤や、炭酸塩
などの塩類が溶解した水溶液を用いてもよい。かかる水
溶液に、前記光触媒を添加量０．５〜１．５ｇ／ｄｍ３
で添加することが好ましく、特に０．７〜０．９ｇ／ｄ
ｍ３の添加量が好ましい。このように光触媒を添加した
水溶液に光を照射することによって水が分解され、水素
と酸素が発生する。照射する光の波長は４５０ｎｍ以下
が好ましい。太陽光の波長は３５０〜２０００ｎｍ程度
であるため、太陽光を照射してもよく、また、水溶液の
温度は２０〜７０℃が好ましい。Next, a method for producing hydrogen (a method for decomposing water) using the photocatalyst of the present invention will be described below. The aqueous solution used for the water splitting is not limited to pure water, and an aqueous solution in which a conventionally used sacrificial reducing agent such as alcohol or a salt such as carbonate is dissolved may be used. The photocatalyst is added to the aqueous solution in an amount of 0.5 to 1.5 g / dm 3.
, Preferably 0.7 to 0.9 g / d.
The added amount of m 3 is preferable. By irradiating the aqueous solution to which the photocatalyst is added with light as described above, water is decomposed, and hydrogen and oxygen are generated. The wavelength of the light to be irradiated is preferably 450 nm or less. Since the wavelength of sunlight is about 350 to 2000 nm, it may be irradiated with sunlight, and the temperature of the aqueous solution is preferably 20 to 70 ° C.
【００２３】なお、本発明の光触媒は、他の物質に対し
て高い酸化能力と還元能力を併せて有しているので、水
の分解反応だけでなく、例えば有機物の分解反応や金属
イオンの還元反応による脱臭、防汚、除菌、除黴あるい
は水質や土壌の浄化処理、さらには窒素酸化物の処理の
ような環境浄化にも応用できる。Since the photocatalyst of the present invention has both high oxidizing ability and reducing ability with respect to other substances, it not only decomposes water but also decomposes organic substances and reduces metal ions. The present invention can be applied to deodorization, antifouling, bacteria elimination, mold removal, or purification of water and soil by a reaction, and also to environmental purification such as treatment of nitrogen oxides.
【００２４】[0024]
【実施例】以下、本発明を次の実施例および比較例を掲
げて更に詳述する。実施例１ Ｌｉ２ＣＯ３、ＷＯ３、およびＴａ２Ｏ5を所定比に混
合し、８００℃で２４時間焼成してＬｉＴａＷＯ６を合
成し、これを粒径１μｍ程度に粉砕した。次に該粉砕物
を２ｍｏｌ／ｌの硝酸中に添加し、３０℃で４８時間イ
オン交換して、ＨＴａＷＯ６を合成した。次いで、かか
るＨＴａＷＯ６を水中に分散させてスラリーとし、この
スラリーに［Ｐｔ（ＮＨ３）４］Ｃｌ２を添加し、紫外
光を６０℃で５時間照射してＰｔを析出させることによ
り、Ｐｔを担持したＨＴａＷＯ６光触媒を得た。この際
のＰｔ担持量は、Ｐｔ換算で、Ｐｔを担持したＨＴａＷ
Ｏ６光触媒中２．３重量％であった。当該光触媒のバン
ドギャップを測定したところ、２．７ｅＶであった。The present invention will be described in more detail with reference to the following examples and comparative examples. Example 1 Li 2 CO 3, WO 3 , and Ta 2 O 5 were mixed in a predetermined ratio, and fired at 800 ° C. 24 hours to synthesize LiTaWO 6, was pulverized into a particle size of about 1 [mu] m. Then adding the ground product in nitric acid of 2 mol / l, 48 hours and ion-exchanged with 30 ° C., was synthesized HTaWO 6. Next, the HTaWO 6 is dispersed in water to form a slurry, [Pt (NH 3 ) 4 ] Cl 2 is added to the slurry, and Pt is precipitated by irradiating ultraviolet light at 60 ° C. for 5 hours to precipitate Pt. HTAWO 6 photocatalyst carrying was obtained. The amount of Pt carried at this time is, in terms of Pt, HTaW carrying Pt
2.3% by weight in the O 6 photocatalyst. When the band gap of the photocatalyst was measured, it was 2.7 eV.
【００２５】得られた光触媒の活性の評価は、当該光触
媒（ＨＮｂＷＯ６／Ｐｔ）１ｇを１．２５ｄｍ３の１０
容量％メタノール水溶液に分散し、内部照射型の反応器
を用い、波長４００ｎｍ以下の光をカットした４５０Ｗ
のＨｇランプの光を６０℃の温度下、３時間照射して発
生するガス量を測定した。その結果を表１に示す。な
お、発生したガスは水素であった。The activity of the obtained photocatalyst was evaluated by adding 1 g of the photocatalyst (HNbWO 6 / Pt) to 1.25 dm 3 of 10
450 W dispersed in a volume% methanol aqueous solution and using an internal irradiation type reactor to cut light having a wavelength of 400 nm or less.
Was irradiated at 60 ° C. for 3 hours, and the amount of gas generated was measured. Table 1 shows the results. The generated gas was hydrogen.
【００２６】実施例２ 実施例１のＨＴａＷＯ６を水中に分散させてスラリーと
し、このスラリーに［Ｃｕ（ＮＨ４）２］Ｃｌ２を添加
し、紫外光を６０℃で５時間照射してＣｕを析出させる
ことにより、Ｃｕを担持したＨＴａＷＯ６光触媒を得
た。この際のＣｕ担持量は、Ｃｕ換算で、Ｃｕを担持し
たＨＴａＷＯ６光触媒中２．５重量％であった。当該光
触媒のバンドギャップを測定したところ、２．８ｅＶで
あった。次いで、この光触媒の活性の評価を実施例１に
準じて行い、その結果を表１に示す。なお、発生したガ
スは水素であった。 Example 2 The HTaWO 6 of Example 1 was dispersed in water to form a slurry, and [Cu (NH 4 ) 2 ] Cl 2 was added to the slurry. Was deposited to obtain a Cu-supported HTaWO 6 photocatalyst. At this time, the amount of supported Cu was 2.5% by weight in terms of Cu in the HTaWO 6 photocatalyst supporting Cu. When the band gap of the photocatalyst was measured, it was 2.8 eV. Next, the activity of the photocatalyst was evaluated in accordance with Example 1, and the results are shown in Table 1. The generated gas was hydrogen.
【００２７】実施例３ 実施例１のＨＴａＷＯ６を水中に分散させてスラリーと
し、このスラリーにＮｉ（ＮＯ３）２を添加し、紫外光
を６０℃で５時間照射してＮｉを析出させることによ
り、Ｎｉが担持されたＨＴａＷＯ６光触媒を得た。この
際のＮｉ担持量は、Ｎｉ換算で、Ｎｉを担持したＨＴａ
ＷＯ６光触媒中２．８重量％であった。当該光触媒のバ
ンドギャップを測定したところ、２．８ｅＶであった。
次いで、この光触媒の活性の評価を実施例１に準じて行
い、その結果を表１に示す。なお、発生したガスは水素
であった。 Example 3 The HTaWO 6 of Example 1 was dispersed in water to form a slurry, Ni (NO 3 ) 2 was added to the slurry, and UV light was irradiated at 60 ° C. for 5 hours to precipitate Ni. As a result, a Ni-supported HTaWO 6 photocatalyst was obtained. The amount of Ni carried at this time is, in terms of Ni, HTa carrying Ni
It was 2.8% by weight in WO 6 photocatalyst. When the band gap of the photocatalyst was measured, it was 2.8 eV.
Next, the activity of the photocatalyst was evaluated in accordance with Example 1, and the results are shown in Table 1. The generated gas was hydrogen.
【００２８】実施例４ Ｌｉ２ＣＯ３、ＷＯ３、およびＮｂ２Ｏ5を所定比に混
合し、８００℃で２４時間焼成してＬｉＮｂＷＯ６を合
成し、これを粒径１μｍ程度に粉砕した。次に該粉砕物
を２ｍｏｌ／ｌの硝酸中に添加し、３０℃で４８時間イ
オン交換して、ＨＮｂＷＯ６を合成した。次いで、かか
るＨＮｂＷＯ６を水中に分散させてスラリーとし、実施
例１と同様にしてＰｔを担持したＨＮｂＷＯ６光触媒を
得た。当該光触媒のバンドギャップを測定したところ、
２．９ｅＶであった。次いで、この光触媒の活性の評価
を実施例１に準じて行い、その結果を表１に示す。な
お、発生したガスは水素であった。 EXAMPLE 4 Li 2 CO 3 , WO 3 , and Nb 2 O 5 were mixed at a predetermined ratio and fired at 800 ° C. for 24 hours to synthesize LiNbWO 6 , which was ground to a particle size of about 1 μm. Next, the pulverized product was added to 2 mol / l nitric acid, and ion-exchanged at 30 ° C. for 48 hours to synthesize HNbWO 6 . Next, HNbWO 6 was dispersed in water to form a slurry, and a Pt-supported HNbWO 6 photocatalyst was obtained in the same manner as in Example 1. When the band gap of the photocatalyst was measured,
It was 2.9 eV. Next, the activity of the photocatalyst was evaluated in accordance with Example 1, and the results are shown in Table 1. The generated gas was hydrogen.
【００２９】実施例５ 実施例１のＨＴａＷＯ６粉末と、Ｐｔ粉末とを、エタノ
ール中、ボールミルにて７２時間混合し、Ｐｔを担持し
たＨＴａＷＯ６触媒を得た。この際のＰｔ担持量は、Ｐ
ｔ換算で、Ｐｔを担持したＨＴａＷＯ６光触媒中２．３
重量％であった。当該光触媒のバンドギャップを測定し
たところ、２．８ｅＶであった。次いで、この光触媒の
活性の評価を実施例１に準じて行い、その結果を表１に
示す。なお、発生したガスは水素であった。 Example 5 The HTaWO 6 powder of Example 1 and the Pt powder were mixed in ethanol in a ball mill for 72 hours to obtain an HTaWO 6 catalyst carrying Pt. The amount of Pt carried at this time is P
In terms of t, 2.3 in Pt-supported HTaWO 6 photocatalyst
% By weight. When the band gap of the photocatalyst was measured, it was 2.8 eV. Next, the activity of the photocatalyst was evaluated in accordance with Example 1, and the results are shown in Table 1. The generated gas was hydrogen.
【００３０】実施例６ 実施例１のＨＴａＷＯ６を水中に分散させてスラリーと
し、このスラリーにＰｄＣｌ2を添加し、紫外光を60℃
で5時間照射してPｄを析出させることによりPｄを担持
したＨＴａＷＯ6光触媒を得た。この際のPｄ担持量はP
ｄ換算でPｄを担持した光触媒中１．８重量％であっ
た。当該光触媒のバンドギャップを測定したところ２．
５ｅＶであった。次いでこの光触媒の活性の評価を実施
例１に準じて行い、その結果を表１に示す。なお発生し
たガスは水素であった。 Example 6 The HTaWO 6 of Example 1 was dispersed in water to form a slurry. PdCl 2 was added to the slurry, and ultraviolet light was irradiated at 60 ° C.
For 5 hours to precipitate Pd, thereby obtaining an HTaWO 6 photocatalyst carrying Pd. The amount of Pd carried at this time is P
In terms of d, the content was 1.8% by weight in the photocatalyst supporting Pd. 1. The band gap of the photocatalyst was measured.
It was 5 eV. Next, the activity of this photocatalyst was evaluated in accordance with Example 1, and the results are shown in Table 1. The generated gas was hydrogen.
【００３１】比較例１ 光触媒として市販の光触媒用ＴｉＯ２粉末であるデグサ
Ｐ−２５（日本アエロジル（株）製）を用いた。実施例
１に準じて同様の評価を行い、その結果を表１に示す。[0031] Using Degussa P-25 is a TiO 2 powder for commercial photocatalyst Comparative Example 1 Photocatalytic (manufactured by Nippon Aerosil Co.). The same evaluation was performed according to Example 1, and the results are shown in Table 1.
【００３２】比較例２ 市販の光触媒用ＴｉＯ２粉末であるデグサＰ−２５にＰ
ｔを２．３重量％担持した光触媒を用いた。実施例１に
準じて同様の評価を行い、その結果を表１に示す。な
お、Ｐｔの担持は、前記ＴｉＯ２粉末を水中に分散した
スラリー内に、［Ｐｔ（ＮＨ３）４］Ｃｌ２を所定量添
加して、６０℃で紫外光を５時間照射してＰｔを光析出
させることにより行った。 Comparative Example 2 Commercially available TiO 2 powder for photocatalyst, Degussa P-25
A photocatalyst supporting 2.3% by weight of t was used. The same evaluation was performed according to Example 1, and the results are shown in Table 1. Note that Pt is loaded by adding a predetermined amount of [Pt (NH 3 ) 4 ] Cl 2 to a slurry in which the TiO 2 powder is dispersed in water, and irradiating the Pt with ultraviolet light at 60 ° C. for 5 hours. This was performed by photo-precipitation.
【００３３】[0033]
【表１】 以上の測定結果より、本発明の光触媒は４００ｎｍ以上
の波長の可視光においてもメタノール水溶液を分解して
水素を発生できることがわかる。[Table 1] From the above measurement results, it is understood that the photocatalyst of the present invention can decompose the aqueous methanol solution to generate hydrogen even with visible light having a wavelength of 400 nm or more.
【００３４】[0034]
【発明の効果】本発明の光触媒は、ホールと電子の再結
合を抑制して、可視光においても高い光触媒性能を備
え、太陽光で効率よく光触媒機能を発揮でき、また、水
溶液中でほとんど溶解することなく化学的に安定してい
るので、水中に懸濁しても光触媒活性が消失せず、例え
ば、効率よく水を分解することができる。また、その担
持物質が前記層状複合金属化合物内に可視光の励起によ
って発生した電子を引き寄せて還元反応、例えば水を分
解して水素を発生させる反応を起こすサイトとなり高活
性な光触媒である。The photocatalyst of the present invention suppresses the recombination of holes and electrons, has a high photocatalytic performance even in visible light, can exhibit a photocatalytic function efficiently in sunlight, and is almost soluble in an aqueous solution. Since it is chemically stable without water, the photocatalytic activity does not disappear even when suspended in water, and for example, water can be efficiently decomposed. In addition, the support substance attracts electrons generated by the excitation of visible light into the layered composite metal compound and becomes a site where a reduction reaction, for example, a reaction for decomposing water to generate hydrogen, becomes a highly active photocatalyst.
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Claims (2)
び／又は水素であり、MはV、Nb及びTaから成る群より選
ばれた少なくとも1種の元素を示す）で表される化合物
に、Pt、Ru、Pd、Rh、Ir、V、W、Nb、Ta、Cu、Co、Mn、
Cr、Fe、Ni及びTiからなる群から選ばれる少なくとも1
種の金属又は当該金属の酸化物が担持されている層状複
合金属化合物を含むことを特徴とする光触媒。1. A compound represented by the general formula AMWO 6 , wherein A is an alkali metal and / or hydrogen, and M represents at least one element selected from the group consisting of V, Nb and Ta. Compounds include Pt, Ru, Pd, Rh, Ir, V, W, Nb, Ta, Cu, Co, Mn,
At least one selected from the group consisting of Cr, Fe, Ni and Ti
A photocatalyst comprising a layered composite metal compound carrying a kind of metal or an oxide of the metal.
u、Co、Mn、Cr、Fe、Ni及びTiからなる群から選ばれる
少なくとも１種の金属又は当該金属の酸化物の担持量は
金属換算で、層状複合金属化合物中０．０５〜５重量％
であることを特徴とする請求項１記載の光触媒。2. Pt, Ru, Pd, Rh, Ir, V, W, Nb, Ta, C
The carried amount of at least one metal selected from the group consisting of u, Co, Mn, Cr, Fe, Ni and Ti or an oxide of the metal is 0.05 to 5% by weight in the layered composite metal compound in terms of metal.
The photocatalyst according to claim 1, wherein
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP36923599A JP2001179107A (en) | 1999-12-27 | 1999-12-27 | Photocatalyst |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP36923599A JP2001179107A (en) | 1999-12-27 | 1999-12-27 | Photocatalyst |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2001179107A true JP2001179107A (en) | 2001-07-03 |
Family
ID=18493921
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP36923599A Pending JP2001179107A (en) | 1999-12-27 | 1999-12-27 | Photocatalyst |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2001179107A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006088019A (en) * | 2004-09-22 | 2006-04-06 | Science Univ Of Tokyo | Photocatalyst having iridium oxide-based cocatalyst deposited in oxidizing atmosphere in presence of nitrate ion, and method for producing the same |
| JP2011036770A (en) * | 2009-08-07 | 2011-02-24 | Hokkaido Univ | Method for producing noble metal-supported photocatalyst particle |
| US11340510B1 (en) * | 2017-05-03 | 2022-05-24 | Halio, Inc. | Electrochromic devices with nanostructure thin film cathodes |
-
1999
- 1999-12-27 JP JP36923599A patent/JP2001179107A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006088019A (en) * | 2004-09-22 | 2006-04-06 | Science Univ Of Tokyo | Photocatalyst having iridium oxide-based cocatalyst deposited in oxidizing atmosphere in presence of nitrate ion, and method for producing the same |
| JP4528944B2 (en) * | 2004-09-22 | 2010-08-25 | 学校法人東京理科大学 | Photocatalyst carrying Ir oxide cocatalyst in oxidative atmosphere in the presence of nitrate ion and method for producing the same |
| JP2011036770A (en) * | 2009-08-07 | 2011-02-24 | Hokkaido Univ | Method for producing noble metal-supported photocatalyst particle |
| US11340510B1 (en) * | 2017-05-03 | 2022-05-24 | Halio, Inc. | Electrochromic devices with nanostructure thin film cathodes |
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