JPH11216366A - Photocatalyst - Google Patents
PhotocatalystInfo
- Publication number
- JPH11216366A JPH11216366A JP10019320A JP1932098A JPH11216366A JP H11216366 A JPH11216366 A JP H11216366A JP 10019320 A JP10019320 A JP 10019320A JP 1932098 A JP1932098 A JP 1932098A JP H11216366 A JPH11216366 A JP H11216366A
- Authority
- JP
- Japan
- Prior art keywords
- photocatalyst
- visible light
- hydrogen
- oxygen
- water
- 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 81
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 43
- 239000001257 hydrogen Substances 0.000 claims abstract description 36
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 36
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 34
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 30
- 230000003197 catalytic effect Effects 0.000 claims abstract description 30
- 239000001301 oxygen Substances 0.000 claims abstract description 30
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 30
- 239000002131 composite material Substances 0.000 claims abstract description 27
- 239000000203 mixture Substances 0.000 claims abstract description 25
- 229910017052 cobalt Inorganic materials 0.000 claims abstract description 15
- 239000010941 cobalt Substances 0.000 claims abstract description 15
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims abstract description 15
- 239000010955 niobium Substances 0.000 claims abstract description 12
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 10
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910052721 tungsten Inorganic materials 0.000 claims description 15
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 14
- 239000010937 tungsten Substances 0.000 claims description 14
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 12
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 12
- 229910052759 nickel Inorganic materials 0.000 claims description 6
- 229910052742 iron Inorganic materials 0.000 claims description 5
- 239000002245 particle Substances 0.000 claims description 3
- 239000011236 particulate material Substances 0.000 claims description 3
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims 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 claims 1
- 229910001930 tungsten oxide Inorganic materials 0.000 claims 1
- 239000002243 precursor Substances 0.000 abstract description 23
- 239000002994 raw material Substances 0.000 abstract description 11
- 238000004519 manufacturing process Methods 0.000 abstract description 9
- 230000015572 biosynthetic process Effects 0.000 abstract description 8
- 238000003786 synthesis reaction Methods 0.000 abstract description 8
- 229910000428 cobalt oxide Inorganic materials 0.000 abstract description 2
- IVMYJDGYRUAWML-UHFFFAOYSA-N cobalt(ii) oxide Chemical compound [Co]=O IVMYJDGYRUAWML-UHFFFAOYSA-N 0.000 abstract description 2
- 229910000484 niobium oxide Inorganic materials 0.000 abstract description 2
- URLJKFSTXLNXLG-UHFFFAOYSA-N niobium(5+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Nb+5].[Nb+5] URLJKFSTXLNXLG-UHFFFAOYSA-N 0.000 abstract description 2
- 230000002194 synthesizing effect Effects 0.000 abstract 1
- 229910052751 metal Inorganic materials 0.000 description 11
- 239000002184 metal Substances 0.000 description 11
- 239000010419 fine particle Substances 0.000 description 9
- 239000011261 inert gas Substances 0.000 description 7
- 238000002156 mixing Methods 0.000 description 7
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 6
- 239000002803 fossil fuel Substances 0.000 description 5
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- -1 Co 2 O 3 Inorganic materials 0.000 description 4
- 229910020599 Co 3 O 4 Inorganic materials 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000000354 decomposition reaction Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000010304 firing Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 238000010532 solid phase synthesis reaction Methods 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Substances [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 3
- 229910020515 Co—W Inorganic materials 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- 150000002431 hydrogen Chemical class 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000010298 pulverizing process Methods 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- XTQHKBHJIVJGKJ-UHFFFAOYSA-N sulfur monoxide Chemical class S=O XTQHKBHJIVJGKJ-UHFFFAOYSA-N 0.000 description 2
- 229910052815 sulfur oxide Inorganic materials 0.000 description 2
- RZVAJINKPMORJF-UHFFFAOYSA-N Acetaminophen Chemical compound CC(=O)NC1=CC=C(O)C=C1 RZVAJINKPMORJF-UHFFFAOYSA-N 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical class OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 206010067482 No adverse event Diseases 0.000 description 1
- 238000003916 acid precipitation Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 239000004570 mortar (masonry) Substances 0.000 description 1
- 150000002823 nitrates Chemical class 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000013618 particulate matter Substances 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 238000000634 powder X-ray diffraction Methods 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 239000005297 pyrex Substances 0.000 description 1
- 238000011002 quantification Methods 0.000 description 1
- 238000006722 reduction reaction Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 229910052724 xenon Inorganic materials 0.000 description 1
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
Landscapes
- Catalysts (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、可視光照射下にお
いて水を分解し、水素と酸素のうち少なくとも一方を生
成させる可視光領域で触媒活性を有する光触媒に関する
ものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocatalyst having catalytic activity in a visible light region that decomposes water under irradiation with visible light and generates at least one of hydrogen and oxygen.
【０００２】[0002]
【従来の技術】現在、エネルギー源としては主として、
石油や石炭等の化石燃料と原子力エネルギーが用いられ
ている。しかし、化石燃料は、その埋蔵量が有限であり
枯渇が問題視されている。また、化石燃料は、燃焼させ
た際に二酸化炭素、窒素酸化物、硫黄酸化物等を排出
し、その結果、二酸化炭素は地球の温暖化をもたらし、
窒素酸化物や硫黄酸化物は空気中の水分と反応して硝酸
や硫酸を生成して酸性雨となり、地球環境の破壊をもた
らしている。2. Description of the Related Art At present, energy sources mainly include:
Fossil fuels such as oil and coal and nuclear energy are used. However, fossil fuels have a finite reserve and depletion is a problem. Also, fossil fuels emit carbon dioxide, nitrogen oxides, sulfur oxides, etc. when burned, and as a result, carbon dioxide causes global warming,
Nitrogen oxides and sulfur oxides react with moisture in the air to produce nitric acid and sulfuric acid, resulting in acid rain and destruction of the global environment.
【０００３】また、新しいエネルギー源である原子力エ
ネルギーを利用すべく原子力発電が実用化されている
が、安全性や廃棄物処理等の問題を抱えている。このよ
うな状況の下で、エネルギー資源枯渇や地球環境破壊の
問題を解決する一つの方法として、クリーンなエネルギ
ー源である水素の利用が注目されている。水素は燃焼さ
せても水になるだけであり、環境汚染を引き起こさな
い。なお、この水素を発生させるために、化石燃料等を
用いたのでは意味がないことは言うまでもない。[0003] Nuclear power generation has been put into practical use to utilize nuclear energy, which is a new energy source, but has problems such as safety and waste disposal. Under such circumstances, attention has been paid to the use of hydrogen, which is a clean energy source, as one method for solving the problems of depletion of energy resources and destruction of the global environment. Hydrogen only turns into water when burned, and does not cause environmental pollution. Needless to say, it is meaningless to use fossil fuel or the like to generate this hydrogen.
【０００４】埋蔵量が有限である化石燃料に対して、太
陽光は無尽蔵にあり、水も地球には大量にある。そこ
で、太陽光のエネルギーを利用して水を分解することに
より水素を生成すれば、前記の各問題を解決することが
できる。そして、太陽光のエネルギーを利用して水を分
解する手段の一つとして水分解用の光触媒がある。光触
媒は一種の半導体であり、そのバンドギャップ以上のエ
ネルギーを吸収すると、ホール（正孔）とエレクトロン
（電子）を生成し、ホールが水を酸化して酸素を生成
し、エレクトロンが水を還元して水素を生成する機能を
有する。[0004] For fossil fuels with finite reserves, sunlight is inexhaustible and water is abundant on the earth. Then, if hydrogen is generated by decomposing water using the energy of sunlight, each of the above-mentioned problems can be solved. As one of the means for decomposing water using the energy of sunlight, there is a photocatalyst for water decomposition. A photocatalyst is a type of semiconductor. When it absorbs energy above its band gap, it generates holes (holes) and electrons (electrons), which oxidizes water to generate oxygen, and electrons reduce water. To generate hydrogen.
【０００５】ところで、地表で得られる太陽光は、波長
５００nm付近にピークを持つスペクトル分布を示す。ま
た、その分布割合は、紫外線領域（波長４００nm未満）
が約５％、可視光領域（波長４００nm以上、７５０nm未
満）が約４３％、赤外線領域（波長７５０nm以上）が約
５２％である。そのため、太陽光を効率良く利用するた
めには、バンドギャップのエネルギーが前記分布割合が
大きい可視光領域以上（波長４００nm以上）の光エネル
ギーに相当する光触媒（可視光領域で触媒活性を有する
光触媒）が望まれる。[0005] Incidentally, sunlight obtained on the ground surface has a spectrum distribution having a peak near a wavelength of 500 nm. The distribution ratio is in the ultraviolet region (wavelength less than 400 nm).
Is about 5%, the visible light region (wavelength 400 nm or more, less than 750 nm) is about 43%, and the infrared light region (wavelength 750 nm or more) is about 52%. Therefore, in order to use sunlight efficiently, a photocatalyst whose bandgap energy corresponds to light energy in the visible light region or more (wavelength 400 nm or more) where the distribution ratio is large (a photocatalyst having catalytic activity in the visible light region). Is desired.
【０００６】かかる可視光領域で触媒活性を有する光触
媒としては、例えば化学式ａｂＯ2（ａ：１価の単一金
属元素、ｂ：３価の単一金属元素、（例）ＣｕＦｅ
Ｏ2）で表され、デラフォサイト（Delafossite）型の結
晶構造を有する微粒子状物質からなる光触媒（以下、ａ
ｂＯ2タイプの光触媒と呼ぶ場合がある）がある。この
光触媒は、通常の固相法により、即ち原料となる各金属
元素成分の酸化物を所定組成の比率にて混合し、不活性
ガス雰囲気中で焼成することにより製造できる。Examples of such a photocatalyst having catalytic activity in the visible light region include a chemical formula abO 2 (a: a monovalent single metal element, b: a trivalent single metal element, eg, CuFe
O 2 ) and a photocatalyst (hereinafter referred to as a) comprising a particulate material having a delafossite type crystal structure.
bO 2 type photocatalyst). This photocatalyst can be produced by a usual solid phase method, that is, by mixing oxides of respective metal element components as raw materials at a predetermined composition ratio, and firing the mixture in an inert gas atmosphere.
【０００７】或いは、この光触媒は、原料となる各金属
元素成分の酸化物を所定組成の比率にて混合し、不活性
ガス雰囲気中で焼成することにより、光触媒の前駆体で
ある粒子状の物質を合成した後、この前駆体を粉砕して
さらに微粒子状にすることにより製造できる。かかる光
触媒の構造を示す前記化学式ａｂＯ2におけるａは、１
価の金属元素であり、この金属元素ａが１価以外の価数
をとらない元素であれば大きな影響はないが、金属元素
ａが１価以外の価数をとることができる元素の場合に
は、前記光触媒または光触媒前駆体の合成を不活性雰囲
気中で行う必要がある。Alternatively, the photocatalyst is obtained by mixing oxides of respective metal element components as raw materials at a predetermined composition ratio and firing the mixture in an inert gas atmosphere to obtain a particulate material which is a precursor of the photocatalyst. Can be produced by pulverizing this precursor into fine particles. A in the above formula abO 2 showing the structure of the photocatalyst is 1
If the metal element a is an element that can take a valence other than monovalent, there is no significant effect if the metal element a does not take a valence other than monovalent. Requires that the synthesis of the photocatalyst or photocatalyst precursor be performed in an inert atmosphere.
【０００８】これは、空気中で熱処理して光触媒または
光触媒前駆体を合成すると、金属元素ａの価数変化が起
こり、その結果、目的物が得られない可能性があるため
である。This is because, when heat treatment is performed in the air to synthesize a photocatalyst or a photocatalyst precursor, the valence of the metal element a changes, and as a result, the target product may not be obtained.
【０００９】[0009]
【発明が解決しようとする課題】しかしながら、前記ａ
ｂＯ2タイプの光触媒において、金属元素ａが１価以外
の価数をとることができる元素の場合には、酸化反応
（価数変化）が起こらないように、不活性ガス雰囲気中
で光触媒または光触媒前駆体を合成したとしても、原料
に吸着した水の影響により、合成される光触媒または前
駆体の表面付近では価数変化が発生して、製造される光
触媒の触媒活性が阻害されるおそれがあり、問題となっ
ている。However, the aforementioned a
In the case of a bO 2 type photocatalyst, when the metal element a is an element capable of taking a valence other than monovalent, the photocatalyst or the photocatalyst in an inert gas atmosphere is used so that an oxidation reaction (valence change) does not occur. Even if the precursor is synthesized, the effect of water adsorbed on the raw material may cause a valence change near the surface of the synthesized photocatalyst or the precursor, which may inhibit the catalytic activity of the manufactured photocatalyst. Has been a problem.
【００１０】例えば、Ｃｕの酸化物とＦｅの酸化物を所
定組成の比率にて混合し、不活性ガス雰囲気中で焼成す
ることにより合成した光触媒や、Ｃｕの酸化物とＦｅの
酸化物を所定組成の比率にて混合し、不活性ガス雰囲気
中で焼成することにより合成した光触媒前駆体（粒子状
のＣｕＦｅＯX）をさらに微粒子化して製造した光触媒
（微粒子状のＣｕＦｅＯX）は、可視光照射により水を
水素と酸素に分解する機能（触媒活性）を有するもの
の、その触媒活性がかなり低い場合があり（製造ロット
によって光触媒の触媒活性にバラツキがあり）、また水
素と酸素を量論比で生成できないので、問題となってい
る。For example, a photocatalyst synthesized by mixing a Cu oxide and a Fe oxide in a predetermined composition ratio and firing in an inert gas atmosphere, or a Cu oxide and a Fe oxide formed by a predetermined method. The photocatalyst (particulate CuFeO x ) produced by further mixing the photocatalyst precursor (particulate CuFeO x ) synthesized by mixing at a composition ratio and baking in an inert gas atmosphere is further irradiated with visible light. Has the function of decomposing water into hydrogen and oxygen (catalytic activity), but its catalytic activity may be quite low (the catalytic activity of the photocatalyst varies depending on the production lot), and the stoichiometric ratio of hydrogen and oxygen This is a problem because it cannot be generated.
【００１１】このように、従来の光触媒（ａｂＯ2タイ
プ）は、製造ロットによって触媒活性にバラツキがあ
り、また水から水素と酸素を量論比で生成できないとい
う問題点を有していた。本発明は、かかる問題点に鑑み
てなされたものであり、光触媒または前駆体の合成時に
おける原料に吸着した水や前記合成の雰囲気に影響され
ず、可視光照射下において水を水素と酸素に安定して分
解し（水から水素と酸素をほぼ量論比で生成し）、かつ
製造ロットによる触媒活性のバラツキのない光触媒を提
供することにある。As described above, the conventional photocatalyst (abO 2 type) has problems in that the catalytic activity varies depending on the production lot, and that hydrogen and oxygen cannot be produced at a stoichiometric ratio from water. The present invention has been made in view of the above-described problems, and is not affected by water or the atmosphere of the synthesis that is adsorbed on the raw materials during the synthesis of the photocatalyst or the precursor, and converts water into hydrogen and oxygen under visible light irradiation. An object of the present invention is to provide a photocatalyst which is decomposed stably (produces hydrogen and oxygen from water in almost a stoichiometric ratio) and has no variation in catalytic activity among production lots.
【００１２】[0012]
【課題を解決するための手段】そのため、本発明は第一
に「可視光照射下において水を分解し、水素と酸素のう
ち少なくとも一方を生成させる可視光領域で触媒活性を
有する光触媒であり、ニオブ及びコバルトを含む複合酸
化物により、或いはニオブ及びコバルトを含む複合酸化
物、ニオブの酸化物、コバルトの酸化物のうちの少なく
とも二以上の酸化物を含む混合物により、構成されてな
る光触媒（請求項１）」を提供する。Therefore, the present invention firstly provides a photocatalyst having a catalytic activity in a visible light region which decomposes water under irradiation with visible light and generates at least one of hydrogen and oxygen; A photocatalyst composed of a composite oxide containing niobium and cobalt, or a mixture containing at least two oxides of a composite oxide containing niobium and cobalt, an oxide of niobium, and an oxide of cobalt (claim Item 1) ”is provided.
【００１３】また、本発明は第二に「可視光照射下にお
いて水を分解し、水素と酸素のうち少なくとも一方を生
成させる可視光領域で触媒活性を有する光触媒であり、
タングステン及びコバルトを含む複合酸化物により、或
いはタングステン及びコバルトを含む複合酸化物、タン
グステンの酸化物、コバルトの酸化物のうちの少なくと
も二以上の酸化物を含む混合物により、構成されてなる
光触媒（請求項２）」を提供する。The present invention also provides a photocatalyst having catalytic activity in a visible light region that decomposes water under visible light irradiation and generates at least one of hydrogen and oxygen,
A photocatalyst composed of a composite oxide containing tungsten and cobalt, or a mixture containing at least two oxides of a composite oxide containing tungsten and cobalt, an oxide of tungsten, and an oxide of cobalt (claim Item 2) "is provided.
【００１４】また、本発明は第三に「可視光照射下にお
いて水を分解し、水素と酸素のうち少なくとも一方を生
成させる可視光領域で触媒活性を有する光触媒であり、
タングステン及び鉄を含む複合酸化物により、或いはタ
ングステン及び鉄を含む複合酸化物、タングステンの酸
化物、鉄の酸化物のうちの少なくとも二以上の酸化物を
含む混合物により、構成されてなる光触媒（請求項
３）」を提供する。Further, the present invention provides a photocatalyst having catalytic activity in a visible light region that decomposes water under irradiation with visible light to generate at least one of hydrogen and oxygen,
A photocatalyst composed of a composite oxide containing tungsten and iron, or a mixture containing at least two oxides of a composite oxide containing tungsten and iron, an oxide of tungsten, and an oxide of iron (claim Item 3) "is provided.
【００１５】また、本発明は第四に「可視光照射下にお
いて水を分解し、水素と酸素のうち少なくとも一方を生
成させる可視光領域で触媒活性を有する光触媒であり、
タングステン及びニッケルを含む複合酸化物により、或
いはタングステン及びニッケルを含む複合酸化物、タン
グステンの酸化物、ニッケルの酸化物のうちの少なくと
も二以上の酸化物を含む混合物により、構成されてなる
光触媒（請求項４）」を提供する。The present invention also provides a photocatalyst having a catalytic activity in a visible light region that decomposes water under irradiation with visible light to generate at least one of hydrogen and oxygen,
A photocatalyst composed of a composite oxide containing tungsten and nickel, or a mixture containing at least two oxides of a composite oxide containing tungsten and nickel, an oxide of tungsten, and an oxide of nickel (claim Item 4) "is provided.
【００１６】また、本発明は第五に「粒径が0.1〜10ミクロ
ン（好ましくは、0.1〜1ミクロン）の微粒子状物質により構
成されていることを特徴とする請求項１〜４のいずれか
に記載の光触媒（請求項５）」を提供する。Further, the present invention provides, in a fifth aspect, any one of claims 1 to 4, characterized in that it is constituted by a particulate substance having a particle size of 0.1 to 10 microns (preferably 0.1 to 1 micron). And a photocatalyst according to claim 5 (claim 5).
【００１７】[0017]
【発明の実施の形態】可視光照射下において水を分解
し、水素と酸素のうち少なくとも一方を生成させる可視
光領域で触媒活性を有する本発明（請求項１〜５）にか
かる光触媒は、複合酸化物（Ｃｏ−Ｎｂ、Ｃｏ−Ｗ、Ｆ
ｅ−Ｗ、またはＮｉ−Ｗの組み合わせにかかる各複合酸
化物）により、或いは前記複合酸化物と該複合酸化物の
成分である各金属元素の酸化物（複数）のうちの少なく
とも二以上の酸化物を含む混合物により、構成されてな
るので、原料に吸着した水や光触媒または前駆体の合成
雰囲気に影響されず、可視光照射により水を水素と酸素
に安定して分解し（水から水素と酸素を量論比で生成
し）、かつ製造ロットによる触媒活性のバラツキがな
い。BEST MODE FOR CARRYING OUT THE INVENTION The photocatalyst according to the present invention (Claims 1 to 5), which has a catalytic activity in a visible light region in which water is decomposed under irradiation with visible light to generate at least one of hydrogen and oxygen, Oxides (Co-Nb, Co-W, F
or at least two or more of the composite oxides and oxides (plural) of each metal element that is a component of the composite oxides. It is composed of a mixture containing substances, and is not affected by water adsorbed on the raw materials or the synthesis atmosphere of the photocatalyst or precursor, and stably decomposes water into hydrogen and oxygen by irradiating visible light (from water to hydrogen and Oxygen is produced in a stoichiometric ratio), and there is no variation in catalytic activity among production lots.
【００１８】前記複合酸化物及び混合物としては、前述
したＣｏ−Ｎｂ、Ｃｏ−Ｗ、Ｆｅ−Ｗ、またはＮｉ−Ｗ
の組み合わせ（各系）以外が存在する可能性はあるが、
本発明者らは、前記組み合わせにかかる複合酸化物また
は混合物により構成される光触媒が安定に存在し、しか
も触媒活性が高いことを見いだした。本発明にかかる複
合酸化物としては、例えばCo-Nb系の複合酸化物であるC
o4Nb2O9, CoNb2O6等があり、またCo-Nb系の混合物とし
ては、前記複合酸化物（Co4Nb2O9, CoNb2O6等）と該複
合酸化物の成分である各金属元素の酸化物（例えば Co3
O4, Co2O3, CoO等）のうちの少なくとも二以上の酸化物
を含む混合体がある。The composite oxide and the mixture include the above-mentioned Co-Nb, Co-W, Fe-W, or Ni-W
There is a possibility that there is a combination other than (each system),
The present inventors have found that a photocatalyst composed of a composite oxide or a mixture according to the above-mentioned combination exists stably and has high catalytic activity. As the composite oxide according to the present invention, for example, a Co-Nb-based composite oxide C
o 4 Nb 2 O 9 , CoNb 2 O 6 and the like, and as a Co-Nb-based mixture, the composite oxide (Co 4 Nb 2 O 9 , CoNb 2 O 6 and the like) and components of the composite oxide Is an oxide of each metal element (eg, Co 3
O 4 , Co 2 O 3 , CoO, etc.).
【００１９】前述したように、可視光領域で触媒活性を
有するａｂＯ2タイプの光触媒の場合には、価数変化を
おさえるために不活性ガス雰囲気中で前駆体を合成する
必要があり制約があるが、本発明にかかる光触媒では、
空気中で前駆体を合成しても価数変化の問題は発生しな
いので前記制約はない。つまり、本発明にかかる光触媒
は、前駆体合成時の雰囲気や原料の吸着水による悪影響
がないので、不活性ガス雰囲気などの特殊な雰囲気の下
で前駆体を合成する必要がなく、空気中で前駆体を合成
しても製造ロットによる触媒活性のバラツキが見られな
い。As described above, in the case of an abO 2 type photocatalyst having catalytic activity in the visible light region, it is necessary to synthesize a precursor in an inert gas atmosphere in order to suppress a change in valence, and there is a limitation. However, in the photocatalyst according to the present invention,
Even if the precursor is synthesized in the air, the problem of valence change does not occur, and thus there is no such restriction. In other words, the photocatalyst according to the present invention has no adverse effects due to the atmosphere at the time of precursor synthesis or the water adsorbed on the raw materials, so that it is not necessary to synthesize the precursor under a special atmosphere such as an inert gas atmosphere and the like. Even when the precursor is synthesized, there is no variation in the catalytic activity depending on the production lot.
【００２０】また、ａｂＯ2タイプの光触媒の場合に
は、水を分解した結果、水素と酸素は量論比で生成され
なかったが、本発明にかかる光触媒は、ほぼ量論比で水
素と酸素を生成できる。本発明にかかる光触媒の形状
は、可視光を有効に利用できるように、表面積の大きな
微粒子（微粒子サイズ0.1〜10ミクロン）とすることが好ま
しく、特に好ましい微粒子サイズは0.1〜1ミクロンである
（請求項５）。Further, in the case of the abO 2 type photocatalyst, hydrogen and oxygen were not generated in a stoichiometric ratio as a result of decomposition of water. Can be generated. The shape of the photocatalyst according to the present invention is preferably fine particles having a large surface area (fine particle size of 0.1 to 10 microns), and particularly preferable fine particle size is 0.1 to 1 micron so that visible light can be effectively used. Item 5).
【００２１】かかる微粒子サイズの光触媒は、粒子状の
光触媒前駆体をボールミルや遊星ミルで粉砕して微粒子
化することにより得ることができる。本発明にかかる光
触媒の前駆体は、通常の固相法により、即ち原料である
各金属成分の酸化物、炭酸塩、硝酸塩等の塩類を所定の
組成比で混合し焼成することにより合成できるが、湿式
法や気相法により合成してもかまわない。Such a photocatalyst having a fine particle size can be obtained by pulverizing a particulate photocatalyst precursor with a ball mill or a planetary mill to form fine particles. The precursor of the photocatalyst according to the present invention can be synthesized by a usual solid phase method, that is, by mixing and sintering salts such as oxides, carbonates, and nitrates of respective metal components as raw materials at a predetermined composition ratio. Alternatively, it may be synthesized by a wet method or a gas phase method.
【００２２】なお、助触媒（例えばＰｔ、ＮｉＯ等）の
担持等、光触媒の製造において一般的に使用される修飾
を本発明にかかる光触媒についても行うことができる。
また、本発明にかかる水分解反応を行う際に使用する水
は純水に限らず、炭酸塩や炭酸水素塩等の塩類を混ぜた
水を使用してもよい。或いは、アルコールや銀イオン等
の犠牲試薬を使用してもよい。It is to be noted that the photocatalyst according to the present invention can be modified as generally used in the production of a photocatalyst, such as supporting a cocatalyst (eg, Pt, NiO, etc.).
Further, the water used when performing the water splitting reaction according to the present invention is not limited to pure water, and water mixed with salts such as carbonates and bicarbonates may be used. Alternatively, a sacrificial reagent such as alcohol or silver ions may be used.
【００２３】本発明の光触媒は、水の分解反応だけでな
く、他の化学反応（例えば、有機物の分解反応や貴金属
イオンの還元反応）にも適用可能である。以下、実施例
により本発明を具体的に説明するが、本発明はこれに限
定されるものではない。The photocatalyst of the present invention can be applied to not only a water decomposition reaction but also other chemical reactions (for example, a decomposition reaction of an organic substance and a reduction reaction of a noble metal ion). Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto.
【００２４】[0024]
【実施例】本実施例の光触媒は、ニオブ及びコバルトを
含む複合酸化物、ニオブの酸化物、コバルトの酸化物の
混合物（Cｏ4Ｎｂ2Ｏ9、ＣｏＮｂ2Ｏ6、Ｃｏ3Ｏ4、Ｃｏ
2Ｏ3、ＣｏＯの混合物）により構成されてなる。 （１）本実施例の光触媒を製造する方法 まず、各原料を所定組成の比率にて混合し、空気中で焼
成することにより（固相法）、光触媒の前駆体（粒子
状）を合成した。EXAMPLES The photocatalyst of this example is a composite oxide containing niobium and cobalt, a mixture of niobium oxide and cobalt oxide (Co 4 Nb 2 O 9 , CoNb 2 O 6 , Co 3 O 4 , Co 3 O 4 ).
( A mixture of 2 O 3 and CoO). (1) Method for Producing Photocatalyst of the Present Example First, precursors (particulates) of the photocatalyst were synthesized by mixing the respective raw materials at a predetermined composition ratio and firing in air (solid phase method). .
【００２５】即ち、各原料（ＣｏＯ:５．３ｇ、Ｎｂ2Ｏ
5：４．７ｇ）をそれぞれ秤量し、白金ルツボに入れ
て、空気中で８００℃、２６時間焼成することにより
（固相法）、光触媒の前駆体（粒子状）を合成した。次
に、得られた前駆体（粒子状）を乳鉢で１０μｍ以下の
微粒子に粉砕することにより、本実施例の光触媒（微粒
子状）を製造した。That is, each raw material (CoO: 5.3 g, Nb 2 O
5 : 4.7 g) were each weighed, placed in a platinum crucible, and calcined in air at 800 ° C. for 26 hours (solid phase method) to synthesize a photocatalyst precursor (particle form). Next, the obtained precursor (particulate form) was pulverized into fine particles of 10 μm or less in a mortar to produce the photocatalyst (particulate form) of this example.
【００２６】なお、製造した光触媒微粒子を粉末Ｘ線回
折により同定したところ、Cｏ4Ｎｂ2Ｏ9、ＣｏＮｂ
2Ｏ6、Ｃｏ3Ｏ4、Ｃｏ2Ｏ3、ＣｏＯの混合物であった。 （２）触媒活性の評価 製造した光触媒の触媒活性の評価は、閉鎖循環系触媒反
応装置を使用し、以下に示すように、反応溶液として純
水を用いて水素及び酸素を生成させることにより行っ
た。When the produced photocatalyst fine particles were identified by powder X-ray diffraction, Co 4 Nb 2 O 9 , CoNb
It was a mixture of 2 O 6 , Co 3 O 4 , Co 2 O 3 , and CoO. (2) Evaluation of catalytic activity The catalytic activity of the produced photocatalyst was evaluated by using a closed-circulation catalytic reactor and generating hydrogen and oxygen using pure water as a reaction solution as shown below. Was.
【００２７】まず、製造した光触媒０．５gを純水３０
０mｌ中に入れて、マグネチックスターラーで攪拌しな
がら外部から光を照射した。この際、光源として５００
Ｗキセノンランプ、反応管としてパイレックスガラス製
の管を用いた。また、フィルターにより波長４２０ｎｍ
以下の光をカットして光照射を行なった。次に、生成し
た水素、酸素の測定（検出及び定量）をガスクロマトグ
ラフィーにより行った。測定の結果、水素及び酸素の発
生が認められ、触媒活性は水素：１．４μmol/h、酸
素：０．６μmol/hであった。First, 0.5 g of the produced photocatalyst was added to 30 parts of pure water.
The mixture was placed in 0 ml, and irradiated with light from the outside while stirring with a magnetic stirrer. At this time, 500
A tube made of Pyrex glass was used as a W xenon lamp and a reaction tube. In addition, wavelength 420nm by filter
The following light was cut and light irradiation was performed. Next, measurement (detection and quantification) of the generated hydrogen and oxygen was performed by gas chromatography. As a result of the measurement, generation of hydrogen and oxygen was recognized, and the catalytic activity was 1.4 μmol / h for hydrogen and 0.6 μmol / h for oxygen.
【００２８】比較のために従来の光触媒（ＣｕＦｅ
Ｏ2）についてその触媒活性を同様に測定したところ、
水素の活性は高々１μmol/h程度であり、また水素と酸
素を量論比で生成しなかった。即ち、本実施例の光触媒
は、従来の光触媒（ＣｕＦｅＯ2）よりも高い水素生成
活性を有し、またほぼ量論比で水素、酸素を生成できる
ことが確認された。For comparison, a conventional photocatalyst (CuFe
O 2 ) was similarly measured for its catalytic activity.
The activity of hydrogen was at most about 1 μmol / h, and hydrogen and oxygen were not produced in a stoichiometric ratio. That is, it was confirmed that the photocatalyst of this example had a higher hydrogen generation activity than the conventional photocatalyst (CuFeO 2 ) and could generate hydrogen and oxygen at almost stoichiometric ratios.
【００２９】[0029]
【発明の効果】以上説明した通り、本発明（請求項１〜
５）の光触媒は、光触媒または前駆体の合成時において
原料に吸着した水や、光触媒または前駆体の合成雰囲気
に影響されず、可視光照射下で水を水素と酸素に安定し
て分解し（水から水素と酸素をほぼ量論比で生成し）、
かつ製造ロットによる触媒活性のバラツキがない。As described above, the present invention (Claims 1 to 5)
The photocatalyst of 5) is not affected by water adsorbed on the raw material during the synthesis of the photocatalyst or the precursor or the synthesis atmosphere of the photocatalyst or the precursor, and stably decomposes water to hydrogen and oxygen under irradiation of visible light ( Hydrogen and oxygen are produced from water in almost stoichiometric ratio),
In addition, there is no variation in catalytic activity between production lots.
【００３０】本発明（請求項１〜５）の光触媒によれ
ば、太陽光スペクトル中に多く含まれる可視光を水分解
に利用することができるので、紫外光にしか触媒活性を
示さない光触媒と比較して、太陽光エネルギーの使用効
率を格段に向上させることができる。本発明の光触媒
（微粒子状物質）の形状を径0.1〜10ミクロン（好ましく
は、0.1〜1ミクロン）の微粒子状とすると、光触媒の表面積
が大きくなって、照射される可視光を有効に利用するこ
とができる（請求項５）。 以上According to the photocatalyst of the present invention (claims 1 to 5), visible light, which is largely contained in the sunlight spectrum, can be used for water splitting. In comparison, the use efficiency of solar energy can be remarkably improved. When the shape of the photocatalyst (particulate matter) of the present invention is in the form of fine particles having a diameter of 0.1 to 10 μm (preferably 0.1 to 1 μm), the surface area of the photocatalyst becomes large, and the irradiated visible light is effectively used. (Claim 5). that's all
Claims (5)
と酸素のうち少なくとも一方を生成させる可視光領域で
触媒活性を有する光触媒であり、ニオブ及びコバルトを
含む複合酸化物により、或いはニオブ及びコバルトを含
む複合酸化物、ニオブの酸化物、コバルトの酸化物のう
ちの少なくとも二以上の酸化物を含む混合物により、構
成されてなる光触媒。1. A photocatalyst having catalytic activity in a visible light region that decomposes water under irradiation with visible light to generate at least one of hydrogen and oxygen, and is composed of a composite oxide containing niobium and cobalt, or A photocatalyst comprising a mixture containing at least two oxides of a composite oxide containing cobalt, an oxide of niobium, and an oxide of cobalt.
と酸素のうち少なくとも一方を生成させる可視光領域で
触媒活性を有する光触媒であり、タングステン及びコバ
ルトを含む複合酸化物により、或いはタングステン及び
コバルトを含む複合酸化物、タングステンの酸化物、コ
バルトの酸化物のうちの少なくとも二以上の酸化物を含
む混合物により、構成されてなる光触媒。2. A photocatalyst having catalytic activity in a visible light region that decomposes water under irradiation with visible light and generates at least one of hydrogen and oxygen, and is formed of a composite oxide containing tungsten and cobalt, or A photocatalyst comprising a mixture containing at least two oxides of a composite oxide containing cobalt, an oxide of tungsten, and an oxide of cobalt.
と酸素のうち少なくとも一方を生成させる可視光領域で
触媒活性を有する光触媒であり、タングステン及び鉄を
含む複合酸化物により、或いはタングステン及び鉄を含
む複合酸化物、タングステンの酸化物、鉄の酸化物のう
ちの少なくとも二以上の酸化物を含む混合物により、構
成されてなる光触媒。3. A photocatalyst having catalytic activity in a visible light region that decomposes water under irradiation with visible light to generate at least one of hydrogen and oxygen, and is a composite oxide containing tungsten and iron, or A photocatalyst comprising a mixture containing at least two oxides of a composite oxide containing iron, a tungsten oxide, and an iron oxide.
と酸素のうち少なくとも一方を生成させる可視光領域で
触媒活性を有する光触媒であり、タングステン及びニッ
ケルを含む複合酸化物により、或いはタングステン及び
ニッケルを含む複合酸化物、タングステンの酸化物、ニ
ッケルの酸化物のうちの少なくとも二以上の酸化物を含
む混合物により、構成されてなる光触媒。4. A photocatalyst having catalytic activity in a visible light region that decomposes water under irradiation with visible light to generate at least one of hydrogen and oxygen, and is formed of a composite oxide containing tungsten and nickel, or A photocatalyst comprising a mixture containing at least two oxides of a composite oxide containing nickel, an oxide of tungsten, and an oxide of nickel.
1ミクロン）の微粒子状物質により構成されていることを特
徴とする請求項１〜４のいずれかに記載の光触媒。5. A particle size of 0.1 to 10 microns (preferably 0.1 to 10 microns).
The photocatalyst according to any one of claims 1 to 4, wherein the photocatalyst is composed of a particulate material (1 micron).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10019320A JPH11216366A (en) | 1998-01-30 | 1998-01-30 | Photocatalyst |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10019320A JPH11216366A (en) | 1998-01-30 | 1998-01-30 | Photocatalyst |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH11216366A true JPH11216366A (en) | 1999-08-10 |
Family
ID=11996125
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10019320A Pending JPH11216366A (en) | 1998-01-30 | 1998-01-30 | Photocatalyst |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH11216366A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2016145408A (en) * | 2015-02-03 | 2016-08-12 | パナソニックＩｐマネジメント株式会社 | Water splitting method, water splitting device and anodal electrode for oxygen generation |
| CN113548891A (en) * | 2021-08-19 | 2021-10-26 | 陕西天璇涂层科技有限公司 | Two-phase cobalt tantalate ceramic block and preparation method thereof |
| CN115025783A (en) * | 2022-06-15 | 2022-09-09 | 河南大学 | Synthesis method and application of niobium-oxygen-rich cluster/ZIF-67 derivative composite material |
-
1998
- 1998-01-30 JP JP10019320A patent/JPH11216366A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2016145408A (en) * | 2015-02-03 | 2016-08-12 | パナソニックＩｐマネジメント株式会社 | Water splitting method, water splitting device and anodal electrode for oxygen generation |
| CN113548891A (en) * | 2021-08-19 | 2021-10-26 | 陕西天璇涂层科技有限公司 | Two-phase cobalt tantalate ceramic block and preparation method thereof |
| CN115025783A (en) * | 2022-06-15 | 2022-09-09 | 河南大学 | Synthesis method and application of niobium-oxygen-rich cluster/ZIF-67 derivative composite material |
| CN115025783B (en) * | 2022-06-15 | 2023-10-27 | 河南大学 | Synthetic method and application of multi-niobium oxygen cluster/ZIF-67 derivative composite material |
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