JP2016059920A - Photocatalyst laminate and method for producing the same, optical catalyst module, and method for producing hydrogen - Google Patents
Photocatalyst laminate and method for producing the same, optical catalyst module, and method for producing hydrogen Download PDFInfo
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- JP2016059920A JP2016059920A JP2015155946A JP2015155946A JP2016059920A JP 2016059920 A JP2016059920 A JP 2016059920A JP 2015155946 A JP2015155946 A JP 2015155946A JP 2015155946 A JP2015155946 A JP 2015155946A JP 2016059920 A JP2016059920 A JP 2016059920A
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- photocatalyst
- hydrogen
- contact layer
- oxygen
- particles
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
- B01J23/20—Vanadium, niobium or tantalum
- B01J23/22—Vanadium
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
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Abstract
Description
本発明は、太陽光を利用した水分解反応を行うことにより水素や酸素を製造可能な光触媒積層体に関する。 The present invention relates to a photocatalyst laminate capable of producing hydrogen and oxygen by performing a water splitting reaction utilizing sunlight.
近年、光触媒と太陽エネルギーとを用いて水を分解し水素や酸素を製造する技術が注目されている。光触媒によって水を分解する場合、水の還元反応（プロトンの還元反応）と水の酸化反応との双方を触媒する光触媒を用いることが好ましいが、そのような光触媒は種類が限られている。そこで、水の還元反応を触媒する光触媒（水素発生用光触媒）と水の酸化反応を触媒する光触媒（酸素発生用光触媒）とを併用して水を効率的に分解することについて種々の検討がなされている。 In recent years, attention has been focused on a technique for producing hydrogen and oxygen by decomposing water using a photocatalyst and solar energy. In the case of decomposing water with a photocatalyst, it is preferable to use a photocatalyst that catalyzes both the water reduction reaction (proton reduction reaction) and the water oxidation reaction, but the types of such photocatalysts are limited. Therefore, various studies have been made on the efficient decomposition of water using a photocatalyst (hydrogen generation photocatalyst) that catalyzes the reduction reaction of water and a photocatalyst (photocatalyst for oxygen generation) that catalyzes the oxidation reaction of water. ing.
例えば、水素発生用光触媒と酸素発生用光触媒との間で電荷移動をさせて水分解反応を促進する技術が種々提案されている。具体的には、特許文献１及び非特許文献１、２には、水素発生用光触媒粒子と酸素発生用光触媒とを水中に分散させた分散体において、水素発生用光触媒粒子と酸素発生用光触媒粒子とを直接接触（凝集や接合）させることによって粒子間の電荷移動を可能とすることが提案されている。また、特許文献２及び非特許文献３には、水素発生用光触媒粒子と酸素発生用光触媒とを水中に分散させた分散体において、水素発生用光触媒粒子と酸素発生用光触媒粒子とを導電粒子を介して接触させることによって電荷移動を可能とすることが提案されている。或いは、特許文献３、４には、金属シートやワイヤの一方面に水素発生用光触媒を固定するとともに他方面に酸素発生用光触媒を固定した光触媒積層体が開示されており、特許文献５には、基材上に水素発生用光触媒と酸素発生用光触媒との混合物を積層・固定した光触媒積層体が開示されている。また、非特許文献４をはじめ、多くの公知文献では光触媒粒子を固定化することなく水中に分散させ、かつ均一系のレドックスメディエータ （Ｉ−／ＩＯ３ −）等を介して水を分解する手法が公開されている。 For example, various techniques for promoting a water splitting reaction by causing charge transfer between a hydrogen generating photocatalyst and an oxygen generating photocatalyst have been proposed. Specifically, in Patent Document 1 and Non-Patent Documents 1 and 2, in a dispersion in which hydrogen generating photocatalyst particles and oxygen generating photocatalyst are dispersed in water, hydrogen generating photocatalyst particles and oxygen generating photocatalyst particles are used. It has been proposed to enable charge transfer between particles by direct contact (aggregation or bonding). In Patent Document 2 and Non-Patent Document 3, in a dispersion in which hydrogen generating photocatalyst particles and oxygen generating photocatalyst are dispersed in water, hydrogen generating photocatalyst particles and oxygen generating photocatalyst particles are combined with conductive particles. It has been proposed that charge transfer can be achieved by contact through the substrate. Alternatively, Patent Documents 3 and 4 disclose a photocatalyst laminate in which a hydrogen generating photocatalyst is fixed to one surface of a metal sheet or wire and an oxygen generating photocatalyst is fixed to the other surface. A photocatalyst laminate in which a mixture of a hydrogen generating photocatalyst and an oxygen generating photocatalyst is laminated and fixed on a substrate is disclosed. Further, in many known documents including Non-Patent Document 4, a method in which photocatalyst particles are dispersed in water without being immobilized, and water is decomposed through a homogeneous redox mediator (I − / IO 3 − ) or the like. Is published.
特許文献１、２等に開示された分散体を用いた場合、光触媒粒子の攪拌が必要となるため製造設備が複雑となる。また、分散体とした場合、静電引力によって２種類の光触媒を直接接触させる必要があるために使用可能な光触媒の種類や反応液の液性が限定されるほか、光触媒粒子の交換が必要となった際に作業性に劣る。さらには、懸濁した分散体の内部にまで光を照射することが困難であるため十分な水分解活性が得られない場合がある。また、非特許文献４のように溶液中のレドックスメディエータを必要とする系では、溶液中にメディエータを必要とするうえ、メディエータが好ましくない副反応を生じさせ、効率を低下させる問題がある。これらのことを鑑みると、光触媒粒子を水中に分散させた分散体を用いるよりも、光触媒粒子を固定化した光触媒積層体を用いた方が好ましいと考えられる。しかしながら、特許文献３、４等のように導電体を介して一方面側と他方面側とで水素発生用光触媒粒子と酸素発生用光触媒粒子とを分けて固定した場合、導電体を介して電子の移動が可能となるもののイオンを移動させることができない。すなわち、イオン移動距離が長く、ｐＨ勾配が大きくなり、十分な水分解活性が得られない場合がある。また、特許文献５のように基材上に水素発生用光触媒粒子と酸素発生用光触媒粒子との混合物を積層しただけでは、光触媒粒子間の電荷移動が不十分であるために十分な水分解活性が得られない場合がある。このように、従来の光触媒積層体においては水分解活性が十分とは言えなかった。さらには、特許文献３、４などにみられるように、水素と酸素を別々に回収する機構を備える技術を除くと、上に挙げた従来技術では、水素と酸素が混合気体として発生するため、水素もしくは酸素を利用する前に分離操作が必要となる。 When the dispersions disclosed in Patent Documents 1 and 2 are used, the photocatalyst particles need to be stirred, so that the production equipment becomes complicated. In addition, when the dispersion is used, it is necessary to directly contact the two types of photocatalysts by electrostatic attraction, so that the types of usable photocatalysts and the liquidity of the reaction liquid are limited, and the photocatalyst particles need to be replaced. When it becomes, workability is inferior. Furthermore, since it is difficult to irradiate light into the suspended dispersion, sufficient water splitting activity may not be obtained. Moreover, in the system which requires the redox mediator in a solution like a nonpatent literature 4, while a mediator is required in a solution, a mediator produces a side reaction which is not preferable, and there exists a problem of reducing efficiency. In view of these matters, it is considered preferable to use a photocatalyst laminate in which photocatalyst particles are immobilized rather than using a dispersion in which photocatalyst particles are dispersed in water. However, when the photocatalyst particles for hydrogen generation and the photocatalyst particles for oxygen generation are separately fixed on one side and the other side through a conductor as in Patent Documents 3 and 4, etc., electrons are passed through the conductor. However, ions cannot be moved. That is, the ion migration distance is long, the pH gradient becomes large, and sufficient water splitting activity may not be obtained. In addition, as described in Patent Document 5, if the mixture of the photocatalyst particles for generating hydrogen and the photocatalyst particles for generating oxygen is simply laminated on the base material, the charge transfer between the photocatalyst particles is insufficient, so that sufficient water splitting activity is achieved. May not be obtained. Thus, the conventional photocatalyst laminate was not sufficient in water splitting activity. Furthermore, as seen in Patent Documents 3 and 4 and the like, except for the technology provided with a mechanism for separately collecting hydrogen and oxygen, in the conventional technology listed above, hydrogen and oxygen are generated as a mixed gas. A separation operation is required before using hydrogen or oxygen.
そこで本発明は、従来よりも優れた水分解活性を有する光触媒積層体及びその製造方法、および、当該光触媒積層体を用いて水分解を行った場合に生成する混合ガスを水素と酸素とに分離することのできる光触媒モジュール、当該混合ガスを水素と酸素とに分離方法を備える水素製造方法を提供することを課題とする。 Therefore, the present invention provides a photocatalyst laminate having a water splitting activity superior to that of the prior art, a method for producing the same, and a mixed gas produced when water splitting is performed using the photocatalyst laminate, separated into hydrogen and oxygen. It is an object of the present invention to provide a photocatalytic module that can be used, and a hydrogen production method that includes a method for separating the mixed gas into hydrogen and oxygen.
本発明者らは、シート状のコンタクト層の同一表面側に水素発生用光触媒粒子と酸素発生用光触媒粒子とを互いに分散させて固定化することで、高い水分解活性を有する光触媒積層体とすることができることを知見した。 The inventors of the present invention provide a photocatalyst laminate having high water splitting activity by dispersing and fixing the hydrogen generating photocatalyst particles and the oxygen generating photocatalyst particles on the same surface side of the sheet-like contact layer. I found out that I can do it.
本発明は上記知見に基づいてなされたものである。すなわち、
第１の本発明は、シート状のコンタクト層と、コンタクト層の表面に固定された光触媒粒子層とを備え、光触媒粒子層において、複数の水素発生用光触媒粒子と複数の酸素発生用光触媒粒子とが互いに分散されており、コンタクト層の同一表面側において、複数の水素発生用光触媒粒子の少なくとも一部と複数の酸素発生用光触媒粒子の少なくとも一部とが、コンタクト層と接触している、光触媒積層体である。
The present invention has been made based on the above findings. That is,
The first aspect of the present invention comprises a sheet-like contact layer and a photocatalyst particle layer fixed to the surface of the contact layer, and in the photocatalyst particle layer, a plurality of hydrogen generating photocatalyst particles and a plurality of oxygen generating photocatalyst particles are provided. Are dispersed with each other, and on the same surface side of the contact layer, at least some of the plurality of hydrogen generating photocatalyst particles and at least some of the plurality of oxygen generating photocatalyst particles are in contact with the contact layer. It is a laminate.
本発明において、「シート状」とはフィルム状や極めて薄い膜状をも含む概念である。大きさや厚さは特に限定されないが、例えば厚さが０．３ｎｍ以上１ｍｍ以下であり、面方向の大きさが厚さ方向の２倍以上の大きさを持つ形態を指す。
「コンタクト層」とは、水素発生用光触媒粒子からなる層及び酸素発生用光触媒粒子からなる層よりも相対的に大きな電子伝導性を有する層を意味する。
「シート状のコンタクト層」とは、光触媒積層体において見かけ上シート状であるコンタクト層を意味し、コンタクト層自体が自立して取り扱うことができないものであってもよい。例えば、光触媒粒子層の受光面とは反対側の表面にスパッタリングによって積層された薄膜状のコンタクト層も、本発明にいう「シート状のコンタクト層」に含まれる。
「コンタクト層の表面に固定された光触媒粒子層」とは、コンタクト層と光触媒粒子層とが互いに面し合って接触した状態で固定されていることを意味する。
「光触媒粒子層において、複数の水素発生用光触媒粒子と複数の酸素発生用光触媒粒子とが互いに分散されており」とは、言い換えれば、光触媒粒子層が複数の水素発生用光触媒粒子と複数の酸素発生用光触媒粒子との混合物を含んでなり、水素発生用光触媒粒子と酸素発生用光触媒粒子が粒子単位で互いに隣接している状態であり、水素発生用光触媒粒子同士が連続して隣接している部分を含んでいてもよいし、同様に酸素発生用光触媒粒子同士が連続して隣接している部分を含んでいてもよいが、異種粒子間の隣接の頻度が比較的高い状態であることを意味する。なお、ここでいう粒子は１次粒子および２次粒子以上の粒子を含む。
「コンタクト層の同一表面側において、複数の水素発生用光触媒粒子の少なくとも一部と複数の酸素発生用光触媒粒子の少なくとも一部とが、コンタクト層と接触している」とは、光触媒粒子層のコンタクト層側の表面に、複数の水素発生用光触媒粒子と複数の酸素発生用光触媒粒子とが互いに分散して存在しており、これらがコンタクト層に直接接触していることを意味する。また、「少なくとも一部」とは、本発明に係る光触媒積層体おいて、光触媒粒子層中に、コンタクト層と接触していない水素発生用光触媒粒子や酸素発生用光触媒粒子が存在していてもよい主旨である。
In the present invention, the “sheet shape” is a concept including a film shape and a very thin film shape. Although the size and thickness are not particularly limited, for example, the thickness is 0.3 nm or more and 1 mm or less, and the size in the surface direction is twice or more that in the thickness direction.
The “contact layer” means a layer having a relatively larger electron conductivity than a layer made of hydrogen generating photocatalyst particles and a layer made of oxygen generating photocatalyst particles.
The “sheet-like contact layer” means a contact layer that is apparently sheet-like in the photocatalyst laminate, and the contact layer itself may not be able to be handled independently. For example, a thin film contact layer laminated by sputtering on the surface of the photocatalyst particle layer opposite to the light receiving surface is also included in the “sheet contact layer” referred to in the present invention.
The “photocatalyst particle layer fixed to the surface of the contact layer” means that the contact layer and the photocatalyst particle layer are fixed in a state of facing each other and in contact with each other.
In the photocatalyst particle layer, the plurality of hydrogen generating photocatalyst particles and the plurality of oxygen generating photocatalyst particles are dispersed with each other. In other words, the photocatalyst particle layer includes a plurality of hydrogen generating photocatalyst particles and a plurality of oxygen. A mixture of generation photocatalyst particles, wherein the hydrogen generation photocatalyst particles and the oxygen generation photocatalyst particles are adjacent to each other in units of particles, and the hydrogen generation photocatalyst particles are adjacent to each other continuously. Part may be included, and similarly, the part where the photocatalyst particles for oxygen generation are continuously adjacent to each other may be included, but the adjacent frequency between the different types of particles is relatively high. means. The particles here include primary particles and secondary or higher particles.
"At the same surface side of the contact layer, at least some of the plurality of hydrogen generating photocatalyst particles and at least some of the plurality of oxygen generating photocatalyst particles are in contact with the contact layer" means that the photocatalyst particle layer It means that a plurality of hydrogen generating photocatalyst particles and a plurality of oxygen generating photocatalyst particles are dispersed on the surface on the contact layer side and are in direct contact with the contact layer. Further, “at least a part” means that, in the photocatalyst laminate according to the present invention, the photocatalyst particle layer includes hydrogen generating photocatalyst particles and oxygen generating photocatalyst particles that are not in contact with the contact layer. It is a good point.
第１の本発明においては、光触媒粒子層とコンタクト層との積層方向における水素発生用光触媒粒子及び酸素発生用光触媒粒子の積層数が１以上５０以下であることが好ましく、１以上３０以下であることがより好ましく、１以上２０以下であることがさらに好ましく、１以上１０以下であることがさらに好ましく、１以上３以下であることが特に好ましい。 In the first aspect of the present invention, the number of hydrogen generating photocatalyst particles and oxygen generating photocatalyst particles in the stacking direction of the photocatalyst particle layer and the contact layer is preferably 1 or more and 50 or less, and preferably 1 or more and 30 or less. Is more preferably 1 or more and 20 or less, further preferably 1 or more and 10 or less, and particularly preferably 1 or more and 3 or less.
本発明において、「光触媒粒子層とコンタクト層との積層方向における水素発生用光触媒粒子及び酸素発生用光触媒粒子の積層数」とは、コンタクト層の表面から、光触媒層のコンタクト層とは反対側までの光触媒粒子の積層数を意味する。尚、本発明において、光触媒粒子の全体がコンタクト層内に埋没したものについては、光触媒粒子層を構成する粒子としてカウントせず、積層数にもカウントしない。一方で、光触媒粒子の一部のみがコンタクト層に埋没したものについては、光触媒粒子層を構成する粒子としてカウントし、積層数にもカウントする。 In the present invention, “the number of stacked photocatalyst particles for generating hydrogen and photocatalyst for generating oxygen in the stacking direction of the photocatalyst particle layer and the contact layer” means from the surface of the contact layer to the side opposite to the contact layer of the photocatalyst layer. Means the number of stacked photocatalyst particles. In the present invention, the entire photocatalyst particles embedded in the contact layer are not counted as particles constituting the photocatalyst particle layer, and are not counted in the number of stacked layers. On the other hand, those in which only a part of the photocatalyst particles are buried in the contact layer are counted as particles constituting the photocatalyst particle layer, and are counted as the number of stacked layers.
第１の本発明において、光触媒粒子層の表面形状に沿ってコンタクト層が設けられていることが好ましい。これにより、コンタクト層と光触媒粒子層との密着性が向上する。 In the first aspect of the present invention, a contact layer is preferably provided along the surface shape of the photocatalyst particle layer. Thereby, the adhesiveness of a contact layer and a photocatalyst particle layer improves.
第１の本発明において、コンタクト層と接触している水素発生用光触媒粒子の一部、及び、コンタクト層と接触している酸素発生用光触媒粒子の一部が、コンタクト層に埋没していてもよい。これによっても、コンタクト層と光触媒粒子層との密着性が向上する。 In the first invention, even if a part of the hydrogen generating photocatalyst particles in contact with the contact layer and a part of the oxygen generating photocatalyst particles in contact with the contact layer are buried in the contact layer, Good. This also improves the adhesion between the contact layer and the photocatalyst particle layer.
第１の本発明において、光触媒粒子層の表面に占める水素発生用光触媒粒子の面積と酸素発生用光触媒粒子の面積との面積比は、水素発生用光触媒粒子の面積と酸素発生用光触媒粒子の面積との合計を１００％として、水素発生用光触媒粒子の面積が１％以上９９％以下であることが好ましく、５％以上９５％以下であることがより好ましい。「光触媒粒子層の表面」とは、光触媒粒子層の光照射面側の表面を意味する。 In the first aspect of the present invention, the area ratio between the area of the hydrogen generating photocatalyst particles and the area of the oxygen generating photocatalyst particles occupying the surface of the photocatalyst particle layer is the area of the hydrogen generating photocatalyst particles and the area of the oxygen generating photocatalyst particles. The area of the photocatalyst particles for hydrogen generation is preferably 1% or more and 99% or less, and more preferably 5% or more and 95% or less. The “surface of the photocatalyst particle layer” means the surface on the light irradiation surface side of the photocatalyst particle layer.
第１の本発明において、コンタクト層の一方面に光触媒粒子層が固定され、他方面に基材が固定されていてもよい。これにより光触媒積層体の強度が増大し、取り扱いが一層容易となる。 In the first aspect of the present invention, the photocatalyst particle layer may be fixed to one surface of the contact layer, and the base material may be fixed to the other surface. Thereby, the intensity | strength of a photocatalyst laminated body increases, and handling becomes still easier.
第２の本発明は、水素発生用光触媒粒子と酸素発生用光触媒粒子とを混合して混合物を得る工程と、水素発生用光触媒粒子と酸素発生用光触媒粒子とがシート状のコンタクト層の同一表面と接触するように、コンタクト層の表面と混合物とを固定する工程と、を備える、光触媒積層体の製造方法である。 According to a second aspect of the present invention, there is provided a step of mixing a hydrogen generating photocatalyst particle and an oxygen generating photocatalyst particle to obtain a mixture, and the hydrogen generating photocatalyst particle and the oxygen generating photocatalyst particle on the same surface of the sheet-like contact layer. And a step of fixing the surface of the contact layer and the mixture so as to come into contact with each other.
本発明において、「水素発生用光触媒粒子と酸素発生用光触媒粒子とを混合」とは、水素発生用光触媒粒子と酸素発生用光触媒粒子とが互いに分散されるように混合することを意味し、乾式混合、湿式混合のいずれであってもよい。 In the present invention, “mixing the hydrogen generating photocatalyst particles and the oxygen generating photocatalyst particles” means mixing the hydrogen generating photocatalyst particles and the oxygen generating photocatalyst particles so as to be dispersed with each other. Either mixing or wet mixing may be used.
第２の本発明において、コンタクト層と接触していない水素発生用光触媒粒子及び酸素発生用光触媒粒子の少なくとも一部を除去する工程を備えることが好ましい。これにより、コンタクト層に直接接触した光触媒粒子を表面に露出させ、かつ光触媒粒子層を薄くすることができ、光触媒積層体の水分解活性を一層向上させることができる。 The second aspect of the present invention preferably includes a step of removing at least a part of the hydrogen generating photocatalyst particles and the oxygen generating photocatalyst particles that are not in contact with the contact layer. As a result, the photocatalyst particles that are in direct contact with the contact layer can be exposed on the surface, and the photocatalyst particle layer can be thinned, and the water splitting activity of the photocatalyst laminate can be further improved.
第２の本発明において、混合物を第１基材上に積層して該第１基材上に光触媒粒子層を形成する工程と、光触媒粒子層の第１基材とは反対側とシート状のコンタクト層とを固定して第１積層体を得る工程と、第１積層体から第１基材を除去する工程と、を備えることが好ましい。 In the second aspect of the present invention, the step of laminating the mixture on the first substrate to form a photocatalyst particle layer on the first substrate, the opposite side of the photocatalyst particle layer from the first substrate and the sheet-like shape It is preferable to include a step of fixing the contact layer to obtain the first laminate, and a step of removing the first base material from the first laminate.
第２の本発明において、混合物を第１基材上に積層して該第１基材上に光触媒粒子層を形成する工程と、光触媒粒子層の第１基材とは反対側とシート状のコンタクト層とを固定して第１積層体を得る工程と、コンタクト層の光触媒粒子層とは反対側に第２基材を固定して第２積層体を得る工程と、第２積層体から第１基材を除去する工程と、を備えることが好ましい。 In the second aspect of the present invention, the step of laminating the mixture on the first substrate to form a photocatalyst particle layer on the first substrate, the opposite side of the photocatalyst particle layer from the first substrate and the sheet-like shape Fixing the contact layer to obtain a first laminate, fixing the second substrate on the side of the contact layer opposite to the photocatalyst particle layer, obtaining a second laminate, and from the second laminate to 1 It is preferable to provide the process of removing a base material.
第２の本発明では、コンタクト層の表面と混合物とを固定する工程において、コンタクト層の混合物による被覆率は、高いほうが好ましく、少なくとも１０％以上、好ましくは２０％以上である。またコンタクト層の混合物による被覆率について、水素発生用光触媒粒子と酸素発生用光触媒粒子との合計を１００％として、水素発生用光触媒粒子による被覆率を１％以上９９％以下とすることが好ましい。「コンタクト層の混合物による被覆率」とは、言い換えれば、コンタクト層の光照射面側表面において混合物によって被覆されている面積を意味する。「水素発生用光触媒粒子による被覆率」とは、コンタクト層の光照射面側表面において混合物によって被覆されている面積を１００％とした場合において、当該面積のうち水素発生光触媒粒子の面積が占める割合を意味する。 In the second aspect of the present invention, in the step of fixing the surface of the contact layer and the mixture, the coverage of the contact layer with the mixture is preferably higher, and is at least 10% or more, preferably 20% or more. Regarding the coverage by the contact layer mixture, the total of the hydrogen generating photocatalyst particles and the oxygen generating photocatalyst particles is preferably 100%, and the coverage by the hydrogen generating photocatalyst particles is preferably 1% or more and 99% or less. In other words, the “covering ratio of the contact layer with the mixture” means an area covered with the mixture on the light irradiation surface side surface of the contact layer. “The coverage with the photocatalyst particles for hydrogen generation” means the ratio of the area of the hydrogen generating photocatalyst particles in the area when the area covered with the mixture on the light irradiation surface side surface of the contact layer is 100% Means.
第２の本発明において、混合物を光触媒粒子層とし、光触媒粒子層の表面に真空蒸着、スパッタリング等の物理蒸着法、化学気相成長法等の化学蒸着法、電解めっき法、無電解めっき法、塗布法などによってコンタクト層を積層することによって、光触媒粒子層とコンタクト層とを固定することが好ましい。これにより、コンタクト層と光触媒粒子層との密着性が向上する。 In the second aspect of the present invention, the mixture is used as a photocatalyst particle layer, and the surface of the photocatalyst particle layer is vacuum vapor deposition, physical vapor deposition such as sputtering, chemical vapor deposition such as chemical vapor deposition, electroplating, electroless plating, It is preferable to fix the photocatalyst particle layer and the contact layer by laminating the contact layer by a coating method or the like. Thereby, the adhesiveness of a contact layer and a photocatalyst particle layer improves.
第２の本発明では、コンタクト層の表面と混合物とを固定する工程において、コンタクト層及び混合物を加熱することが好ましい。 In the second aspect of the present invention, it is preferable to heat the contact layer and the mixture in the step of fixing the surface of the contact layer and the mixture.
第３の本発明は、第１の本発明に係る光触媒積層体を有する光触媒モジュールであって、水素及び酸素を分離する分離装置をさらに備えることを特徴とする光触媒モジュールである。 3rd this invention is a photocatalyst module which has the photocatalyst laminated body which concerns on 1st this invention, Comprising: The separation apparatus which isolate | separates hydrogen and oxygen is further provided, It is a photocatalyst module characterized by the above-mentioned.
第３の本発明及び後述の第４の本発明において「水素及び酸素を分離する」とは、水素及び酸素から水素を分離する形態と、水素及び酸素から酸素を分離する形態との双方を含む概念である。
尚、水素及び酸素から、水素又は酸素を純度１００％で分離することは現実的でない。すなわち、第３の本発明及び後述の第４の本発明においては、水素及び酸素から水素を分離するにあたって、分離ガスに少量の酸素が含まれていてもよく、また、水素及び酸素から酸素を分離するにあたって、分離ガスに少量の水素が含まれていてもよい。
In the third aspect of the present invention and the fourth aspect of the present invention described later, “separate hydrogen and oxygen” includes both forms of separating hydrogen from hydrogen and oxygen and forms of separating oxygen from hydrogen and oxygen. It is a concept.
It is not practical to separate hydrogen or oxygen with a purity of 100% from hydrogen and oxygen. That is, in the third aspect of the present invention and the fourth aspect of the present invention described later, when separating hydrogen from hydrogen and oxygen, the separation gas may contain a small amount of oxygen. In the separation, the separation gas may contain a small amount of hydrogen.
第３の本発明において、上記の分離装置は、第１の本発明に係る光触媒積層体によって発生する水素及び酸素による爆発を回避しつつ、当該水素及び酸素から水素を分離する、水素分離装置であることが好ましい。 In the third aspect of the present invention, the separation apparatus is a hydrogen separation apparatus that separates hydrogen from the hydrogen and oxygen while avoiding an explosion caused by hydrogen and oxygen generated by the photocatalyst laminate according to the first aspect of the present invention. Preferably there is.
第３の本発明および後述の第４の本発明において、「光触媒積層体によって発生する水素及び酸素」とは、光触媒積層体の光触媒粒子層に、水或いは水溶液等を接触させるとともに光を照射し、水分解反応を生じさせることによって発生する水素及び酸素を意味する。
「水素及び酸素による爆発を回避しつつ水素を分離する水素分離装置」とは、種々の機構が挙げられる。例えば、不活性な希釈ガスを用いる機構、水中で分離する機構、隙間径が小さい細隙材と分子篩膜とを接続する機構が挙げられる。
In the third invention and the fourth invention described later, “hydrogen and oxygen generated by the photocatalyst laminate” means that the photocatalyst particle layer of the photocatalyst laminate is brought into contact with water or an aqueous solution and irradiated with light. And hydrogen and oxygen generated by causing water splitting reaction.
“Hydrogen separator that separates hydrogen while avoiding explosion caused by hydrogen and oxygen” includes various mechanisms. For example, a mechanism that uses an inert diluent gas, a mechanism that separates in water, and a mechanism that connects a slit material having a small gap diameter and a molecular sieve membrane.
第３の本発明においては、発生した水素および酸素は、分離装置により分離される。また、第３の本発明の好ましい形態においては、生成ガス（水素および酸素の混合ガス）による爆発を回避するため、第１の本発明に係る光触媒積層体は爆発を回避可能な構造の光触媒モジュールに設置され、そこで回収された生成ガスは、やはり爆発回避可能しつつ水素を分離可能な水素分離装置に輸送され、そこで水素と酸素に分離される。 In the third aspect of the present invention, the generated hydrogen and oxygen are separated by the separation device. In a preferred embodiment of the third aspect of the present invention, the photocatalyst laminate according to the first aspect of the present invention has a structure capable of avoiding an explosion in order to avoid an explosion caused by a product gas (mixed gas of hydrogen and oxygen). The product gas collected there is transported to a hydrogen separator capable of separating hydrogen while preventing explosion, where it is separated into hydrogen and oxygen.
第４の本発明は、第１の本発明に係る光触媒積層体によって水素及び酸素を発生させる発生ステップと、発生ステップにおいて発生した水素及び酸素を分離する分離ステップとを備える、水素製造方法である。 4th this invention is a hydrogen production method provided with the generation | occurrence | production step which generates hydrogen and oxygen with the photocatalyst laminated body which concerns on 1st this invention, and the isolation | separation step which isolate | separates the hydrogen and oxygen which generate | occur | produced in the generation | occurrence | production step. .
第４の本発明では、分離ステップにおいて、発生ステップにおいて発生した水素及び酸素による爆発を回避しつつ、当該水素及び酸素から水素を分離することが好ましい。 In 4th this invention, it is preferable to isolate | separate hydrogen from the said hydrogen and oxygen in a separation step, avoiding the explosion by the hydrogen and oxygen which generate | occur | produced in the generation | occurrence | production step.
本発明によれば、従来よりも優れた水分解活性を有する光触媒積層体及びその製造方法を提供することができる。また、当該光触媒積層体を用いて水分解を行った場合に生成する混合ガスを水素と酸素とに分離することのできる光触媒モジュール、当該混合ガスを水素と酸素とに分離する分離方法を備える水素製造方法を提供することができる。 ADVANTAGE OF THE INVENTION According to this invention, the photocatalyst laminated body which has the water splitting activity superior to the past, and its manufacturing method can be provided. Further, a photocatalyst module capable of separating a mixed gas produced when water splitting is performed using the photocatalyst laminate into hydrogen and oxygen, and a hydrogen provided with a separation method for separating the mixed gas into hydrogen and oxygen. A manufacturing method can be provided.
１．光触媒積層体
本発明に係る光触媒積層体は、シート状のコンタクト層と、コンタクト層の表面に固定された光触媒粒子層とを備え、光触媒粒子層において、複数の水素発生用光触媒粒子と複数の酸素発生用光触媒粒子とが互いに分散されており、コンタクト層の同一表面側において、複数の水素発生用光触媒粒子の少なくとも一部と複数の酸素発生用光触媒粒子の少なくとも一部とが、コンタクト層と接触していることを特徴とする。
1. The photocatalyst laminate The photocatalyst laminate according to the present invention includes a sheet-like contact layer and a photocatalyst particle layer fixed to the surface of the contact layer, and in the photocatalyst particle layer, a plurality of hydrogen generating photocatalyst particles and a plurality of oxygen are provided. The generation photocatalyst particles are dispersed from each other, and at least a part of the plurality of hydrogen generation photocatalyst particles and at least a part of the plurality of oxygen generation photocatalyst particles are in contact with the contact layer on the same surface side of the contact layer. It is characterized by that.
１．１．第１実施形態
図１に第１実施形態に係る本発明の光触媒積層体１０を概略的に示す。光触媒積層体１０はシート状のコンタクト層２と、コンタクト層２の表面に固定された複数の水素発生用光触媒粒子１ａ及び酸素発生用光触媒粒子１ｂとを備えている。光触媒積層体１０においては、複数の水素発生用光触媒粒子１ａ及び酸素発生用光触媒粒子１ｂにより光触媒粒子層１が形成されている。また、光触媒粒子層１において水素発生用光触媒粒子１ａと酸素発生用光触媒粒子１ｂとは互いに分散されている。
1.1. First Embodiment FIG. 1 schematically shows a photocatalyst laminate 10 of the present invention according to a first embodiment. The photocatalyst laminate 10 includes a sheet-like contact layer 2 and a plurality of hydrogen-generating photocatalyst particles 1 a and oxygen-generating photocatalyst particles 1 b fixed on the surface of the contact layer 2. In the photocatalyst laminate 10, a photocatalyst particle layer 1 is formed by a plurality of hydrogen generating photocatalyst particles 1a and oxygen generating photocatalyst particles 1b. In the photocatalyst particle layer 1, the hydrogen generating photocatalyst particles 1a and the oxygen generating photocatalyst particles 1b are dispersed with each other.
１．１．１．水素発生用光触媒粒子
水素発生用光触媒粒子１ａは、水若しくは水素イオンの還元反応を触媒する材料からなる粒子であればよい。そのような材料としては、Ｃｒ、Ｓｂ、Ｔａ、Ｒｈ、La等をドープし得るＳｒＴｉＯ３、Ｃｒ、Ｆｅ等をドープし得るＬａ２Ｔｉ２Ｏ７、ＳｎＮｂ２Ｏ６などの酸化物；ＬａＴｉＯ２Ｎ、ＴａＯＮ、Ｔａ３Ｎ５、Ｍｇ，及びＺｒをドープしたＴａ３Ｎ５、ＣａＴａＯ２Ｎ、ＳｒＴａＯ２Ｎ、ＢａＴａＯ２Ｎ、ＬａＴａＯＮ２、ＬａＭｇ１／３Ｔａ２／３Ｏ２Ｎ、Ｙ２Ｔａ２Ｏ５Ｎ２、ＧａＮ、ＭｇをドープしたＧａＮ、Ｇｅ３Ｎ４、Ｚｎ１＋ｘＧｅＮ２Ｏｘ、Ｇａ１−ｘＺｎｘＮ１−ｘＯｘ（ｘは、０〜１の数値を表す。）等のオキシナイトライド若しくはナイトライド化合物；ＺｎＳ、Ｃｕ、Ｎｉ、ＰｂをドープしたＺｎＳ、ＡｇをドープしたＣｄＳ、ＣｄｘＺｎ１−ｘＳ（ｘは、０〜１の数値を表す。）、ＮａＩｎＳ２、ＡｇＩｎＺｎ７Ｓ９、Ｃｕ０．０９Ｉｎ０．０９Ｚｎ１．８２Ｓ２、Ｃｕ０．２５Ａｇ０．２５Ｉｎ０．５ＺｎＳ２、Ｃｕ２ＺｎＳｎＳ４等、および、ＣｕＩｎＳ２、ＣｕＧａＳ２、Ｃｕ（Ｇａ，Ｉｎ）Ｓ２、ＣｕＧａ３Ｓ５、Ｃｕ（Ｇａ，Ｉｎ）３Ｓ５、ＣｕＧａ５Ｓ８、Ｃｕ（Ｇａ，Ｉｎ）５Ｓ８、ＡｇＧａＳ２、（Ｃｕ，Ａｇ）（Ｇａ，Ｉｎ）Ｓ２、（Ｃｕ，Ａｇ）（Ｇａ，Ｉｎ）３Ｓ５等、一般式ＡＢｘＳｙ（ｘ＝１＋２ｖ、ｙ＝２＋３ｖ、０．５≦ｖ≦２)（ここでＡ＝Ｃｕ、Ａｇ、もしくは（Ｃｕ，Ａｇ）；Ｂ＝Ｇａ、Ｉｎ、Ａｌ、（Ｇａ，Ｉｎ）、（Ｉｎ，Ａｌ）、（Ｇａ，Ａｌ）、もしくは（Ｇａ，Ｉｎ，Ａｌ）で表されるサルファイド化合物；Ｓｍ２Ｔｉ２Ｏ５Ｓ２などのオキシサルファイド化合物；Ｌａ、Ｉｎを含むオキシサルファイド化合物（Ｃｈｅｍｉｓｔｒｙ Ｌｅｔｔｅｒｓ ２００７、 ３６、 ８５４−８５５）；Ｌａ５Ｔｉ２ＡｇＯ７Ｓ５やＬａ５Ｔｉ２ＣｕＯ７Ｓ５、Ｌａ５Ｔｉ２（Ａｇ，Ｃｕ）Ｏ７Ｓ５、Ｓｃ、Ｍｇ、Ｃａ、Ｇａ、Ａｌ等をドープしたＬａ５Ｔｉ２ＣｕＳ５Ｏ７等のオキシサルファイド化合物；ＣｕＧａＳｅ２、Ｃｕ（Ｉｎ，Ｇａ）Ｓｅ２、ＣｕＧａ３Ｓｅ５、Ｃｕ（Ｉｎ，Ｇａ）３Ｓｅ５、ＣｕＧａ５Ｓｅ８、Ｃｕ（Ｉｎ，Ｇａ）５Ｓｅ８、ＣｕＧａ（Ｓ，Ｓｅ）２、ＣｕＩｎ（Ｓ，Ｓｅ）２、Ｃｕ（Ｉｎ，Ｇａ）（Ｓ，Ｓｅ）２、ＣｕＧａ３（Ｓ，Ｓｅ）５、ＣｕＩｎ３（Ｓ，Ｓｅ）５、Ｃｕ（Ｉｎ，Ｇａ）３（Ｓ，Ｓｅ）５、ＣｕＧａ５（Ｓ，Ｓｅ）８、ＣｕＩｎ５（Ｓ，Ｓｅ）８、Ｃｕ（Ｇａ，Ｉｎ）（Ｓ，Ｓｅ）８等、一般式ＡＢｘＣｙ（ｘ＝１＋２ｖ、ｙ＝２＋３ｖ、０．５≦ｖ≦２）（ここでＡ＝Ｃｕ、Ａｇ、もしくは（Ｃｕ，Ａｇ）；Ｂ＝Ｇａ、Ｉｎ、Ａｌ、（Ｇａ，Ｉｎ）、（Ｉｎ，Ａｌ）、（Ｇａ，Ａｌ）、もしくは（Ｇａ，Ｉｎ，Ａｌ）；Ｃ＝Ｓｅもしくは（Ｓ，Ｓｅ）で表されるセレナイド化合物；等を例示することができる。中でも、ＲｈをドープしたＳｒＴｉＯ３、Ｌａ、Ｒｈ等を共ドープしたＳｒＴｉＯ３、Ｌａ５Ｔｉ２ＣｕＯ７Ｓ５、Ｓｃ、Ｍｇ、Ｃａ、Ｇａ、Ａｌ等をドープしたＬａ５Ｔｉ２ＣｕＳ５Ｏ７、Ｃｕ（Ｉｎ，Ｇａ）Ｓｅ２が好ましく、Ｌａ、Ｒｈを共ドープしたＳｒＴｉＯ３、ＳｃをドープしたＬａ５Ｔｉ２ＣｕＳ５Ｏ７がより好ましい。
1.1.1. Photocatalyst particles for hydrogen generation The photocatalyst particles 1a for hydrogen generation may be particles made of a material that catalyzes the reduction reaction of water or hydrogen ions. Examples of such materials include SrTiO 3 that can be doped with Cr, Sb, Ta, Rh, La, and the like, and oxides such as La 2 Ti 2 O 7 and SnNb 2 O 6 that can be doped with Cr, Fe, and the like; LaTiO 2 N, TaON, Ta 3 N 5 , Mg, and Ta 3 N 5, CaTaO 2 N doped with Zr, SrTaO 2 N, BaTaO 2 N, LaTaON 2, LaMg 1 / 3Ta 2/3 O 2 N, Y 2 Ta GaN doped with 2 O 5 N 2 , GaN, Mg, Ge 3 N 4 , Zn 1 + x GeN 2 O x , Ga 1-x Zn x N 1-x O x (x represents a numerical value of 0 to 1. Oxynitride or nitride compound such as ZnS, Cu, Ni, Pb doped ZnS, Ag doped CdS, Cd x Zn 1-x S (x is a number from 0 to 1) Value)), NaInS 2 , AgInZn 7 S 9 , Cu 0.09 In 0.09 Zn 1.82 S 2 , Cu 0.25 Ag 0.25 In 0.5 ZnS 2 , Cu 2 ZnSnS 4, etc. And CuInS 2 , CuGaS 2 , Cu (Ga, In) S 2 , CuGa 3 S 5 , Cu (Ga, In) 3 S 5 , CuGa 5 S 8 , Cu (Ga, In) 5 S 8 , AgGaS 2 , General formula AB x S y (x = 1 + 2v, y = 2 + 3v, 0.5 ≦ v ≦ 2), such as (Cu, Ag) (Ga, In) S 2 , (Cu, Ag) (Ga, In) 3 S 5 (Where A = Cu, Ag, or (Cu, Ag); B = Ga, In, Al, (Ga, In), (In, Al), (Ga, Al), or (Ga, In, Al) sulfide compound represented by); Sm Oxysulfide compounds such as Ti 2 O 5 S 2; La , oxysulfide compound containing In (Chemistry Letters 2007, 36, 854-855); La 5 Ti 2 AgO 7 S 5 and La 5 Ti 2 CuO 7 S 5 , Oxysulfide compounds such as La 5 Ti 2 CuS 5 O 7 doped with La 5 Ti 2 (Ag, Cu) O 7 S 5 , Sc, Mg, Ca, Ga, Al, etc .; CuGaSe 2 , Cu (In, Ga) Se 2 , CuGa 3 Se 5 , Cu (In, Ga) 3 Se 5 , CuGa 5 Se 8 , Cu (In, Ga) 5 Se 8 , CuGa (S, Se) 2 , CuIn (S, Se) 2 , Cu (In, Ga) (S, Se) 2 , CuGa 3 (S, Se) 5 , CuIn 3 (S, Se) 5 , Cu (In , Ga) 3 (S, Se) 5 , CuGa 5 (S, Se) 8 , CuIn 5 (S, Se) 8 , Cu (Ga, In) (S, Se) 8, and other general formulas AB x C y ( x = 1 + 2v, y = 2 + 3v, 0.5 ≦ v ≦ 2) (where A = Cu, Ag, or (Cu, Ag); B = Ga, In, Al, (Ga, In), (In, Al) ), (Ga, Al), or (Ga, In, Al); a selenide compound represented by C = Se or (S, Se); and the like. Among them, SrTiO 3 doped with Rh, La, Rh, etc. Co-doped SrTiO 3 , La 5 Ti 2 CuO 7 S 5 , Sc, Mg, Ca, Ga, Al etc. doped La 5 Ti 2 CuS 5 O 7 , Cu (In, Ga) Se 2 are preferred, La, SrTiO 3 were co-doped with Rh, La 5 Ti 2 CuS 5 O 7 doped with Sc is more preferred.
水素発生用光触媒粒子１ａの粒子径（二次粒子径を含む）は、後述するコンタクト層と接触しつつ十分な光吸収を達成できる大きさであればよく、下限が、例えば１０ｎｍ以上、好ましくは２０ｎｍ以上、より好ましくは５０ｎｍ以上であり、上限が、例えば１００μｍ以下、好ましくは１０μｍ以下、より好ましくは５μｍ以下である。 The particle diameter (including the secondary particle diameter) of the hydrogen generating photocatalyst particle 1a may be a size that can achieve sufficient light absorption while being in contact with a contact layer described later, and the lower limit is, for example, 10 nm or more, preferably It is 20 nm or more, More preferably, it is 50 nm or more, and an upper limit is 100 micrometers or less, for example, Preferably it is 10 micrometers or less, More preferably, it is 5 micrometers or less.
水素発生用光触媒粒子１ａには、必要に応じて助触媒（不図示）が担持される。具体的にはＰｔ、Ｐｄ、Ｒｈ、Ｒｕ、Ｎｉ、Ａｕ、Ｆｅ、ＮｉＯ、ＲｕＯ２、ＭｏＳ２、Ｍｏ３Ｓ４、Ｃｒ２Ｏ３で被覆されコアシェル構造をとったＰｔ、Ｒｈ、Ｒｕ、Ａｕ、及びＣｒ‐Ｒｈ酸化物等を例示することができる。中でもＰｔ、Ｒｕ、Ｎｉ、ＮｉＯ、Ｃｒ２Ｏ３で被覆されコアシェル構造をとったＰｔ、Ｒｈ、Ｒｕ、Ａｕ、及びＣｒ‐Ｒｈ酸化物が好ましく、Ｃｒ２Ｏ３で被覆されコアシェル構造をとったＲｕ、およびＲｕがより好ましい。 A cocatalyst (not shown) is supported on the hydrogen generating photocatalyst particles 1a as necessary. Specifically, Pt, Rh, Ru, Au coated with Pt, Pd, Rh, Ru, Ni, Au, Fe, NiO, RuO 2 , MoS 2 , Mo 3 S 4 , Cr 2 O 3 and having a core-shell structure. And Cr—Rh oxide. Among them, Pt, Rh, Ru, Au, and Cr—Rh oxide coated with Pt, Ru, Ni, NiO, Cr 2 O 3 and having a core-shell structure are preferable, and coated with Cr 2 O 3 to have a core-shell structure. Ru and Ru are more preferable.
光触媒粒子層１において、水素発生用光触媒粒子１ａは、１質量％以上９９質量％以下含まれていることが好ましい。下限がより好ましくは５質量％以上、特に好ましくは２０質量％以上であり、上限がより好ましくは９５質量％以下、特に好ましくは８０質量％以下である。光触媒粒子層１における水素発生用光触媒粒子１ａの含有量をこの範囲内とすることで、光触媒積層体の水分解活性を一層優れたものとすることができる。 In the photocatalyst particle layer 1, the hydrogen generating photocatalyst particles 1a are preferably contained in an amount of 1% by mass to 99% by mass. The lower limit is more preferably 5% by mass or more, particularly preferably 20% by mass or more, and the upper limit is more preferably 95% by mass or less, and particularly preferably 80% by mass or less. By setting the content of the photocatalyst particles 1a for generating hydrogen in the photocatalyst particle layer 1 within this range, the water splitting activity of the photocatalyst laminate can be further improved.
１．１．２．酸素発生用光触媒粒子
酸素発生用光触媒粒子１ｂは、水若しくは水酸化物イオンの酸化反応を触媒する材料からなる粒子であればよい。そのような材料としては、Ｃｒ、Ｎｉ、Ｓｂ、Ｎｂ、Ｔｈ、Ｓｂ等をドープし得るＴｉＯ２やＷＯ３、Ｂｉ２ＷＯ６、Ｂｉ２ＭｏＯ６、Ｉｎ２Ｏ３（ＺｎＯ）３、ＰｂＢｉ２Ｎｂ２Ｏ９、ＢｉＶＯ４、Ｍｏ及びＷをドープしたＢｉＶＯ４、Ａｇ３ＶＯ４、ＡｇＬｉ１／３Ｔｉ２／３Ｏ２、ＡｇＬｉ１／３Ｓｎ２／３Ｏ２等の酸化物；ＬａＴｉＯ２Ｎ、ＣａＮｂＯ２Ｎ、ＳｒＮｂＯ２Ｎ、ＢａＮｂＯ２Ｎ、ＬａＮｂＯＮ２、ＴａＯＮ、Ｔａ３Ｎ５、Ｍｇ及びＺｒをドープしたＴａ３Ｎ５、ＣａＴａＯ２Ｎ、ＳｒＴａＯ２Ｎ、ＢａＴａＯ２Ｎ、ＬａＴａＯＮ２、ＬａＭｇ１／３Ｔａ２／３Ｏ２Ｎ、Ｙ２Ｔａ２Ｏ５Ｎ２、ＧａＮ、ＭｇをドープしたＧａＮ、Ｇｅ３Ｎ４、Ｚｎ１＋ｘＧｅＮ２Ｏｘ、Ｇａ１−ｘＺｎｘＮ１−ｘＯｘ（ｘは、０〜１の数値を表す。）等のオキシナイトライド若しくはナイトライド化合物；Ｓｍ２Ｔｉ２Ｏ５Ｓ２、Ｌａ５Ｔｉ２ＡｇＯ７Ｓ５等のオキシサルファイド化合物；等を例示することができる。中でも、ＢｉＶＯ４、Ｍｏ及び／又はＷをドープしたＢｉＶＯ４、ＬａＴｉＯ２Ｎ、ＢａＮｂＯ２Ｎ、ＣａＮｂＯ２Ｎ、ＳｒＮｂＯ２Ｎ、ＢａＴａＯ２Ｎ、Ｔａ３Ｎ５が好ましく、ＢｉＶＯ４、ＭｏをドープしたＢｉＶＯ４、ＬａＴｉＯ２Ｎ、Ｔａ３Ｎ５がより好ましい。
1.1.2. Oxygen Generation Photocatalyst Particles The oxygen generation photocatalyst particles 1b may be particles made of a material that catalyzes an oxidation reaction of water or hydroxide ions. Examples of such materials include TiO 2 , WO 3 , Bi 2 WO 6 , Bi 2 MoO 6 , In 2 O 3 (ZnO) 3, and PbBi 2 that can be doped with Cr, Ni, Sb, Nb, Th, Sb, and the like. nb 2 O 9, BiVO 4, BiVO doped with Mo and W 4, Ag 3 VO 4, AgLi 1/3 Ti 2/3 O 2, AgLi oxides such as 1/3 Sn 2/3 O 2; LaTiO 2 N, CaNbO 2 N, SrNbO 2 N, BaNbO 2 N, LaNbON 2 , TaON, Ta 3 N 5 , Mg and Zr doped Ta 3 N 5 , CaTaO 2 N, SrTaO 2 N, BaTaO 2 N, LaTaON 2 , LaMg 1 / 3Ta 2/3 O 2 N , Y 2 Ta 2 O 5 N 2, GaN, GaN doped with Mg, Ge 3 N 4, Zn 1 + x G eN 2 O x, Ga 1- x Zn x N 1-x O x (x represents a numerical value of 0 to 1.) oxynitride or nitride compounds such as; Sm 2 Ti 2 O 5 S 2, La Examples thereof include oxysulfide compounds such as 5 Ti 2 AgO 7 S 5 ; Among them, BiVO 4, BiVO doped with Mo and / or W 4, LaTiO 2 N, BaNbO 2 N, CaNbO 2 N, SrNbO 2 N, BaTaO 2 N, the Ta 3 N 5 preferably doped BiVO 4, Mo BiVO 4 , LaTiO 2 N, and Ta 3 N 5 are more preferable.
酸素発生用光触媒粒子１ｂの粒子径（二次粒子径を含む）は、後述するコンタクト層と接触しつつ十分な光吸収を達成できる大きさであればよく、下限が、例えば１０ｎｍ以上、好ましくは２０ｎｍ以上、より好ましくは５０ｎｍ以上であり、上限が、例えば１００μｍ以下、好ましくは１０μｍ以下、より好ましくは５μｍ以下である。 The particle size (including the secondary particle size) of the oxygen-generating photocatalyst particle 1b may be a size that can achieve sufficient light absorption while in contact with a contact layer described later, and the lower limit is, for example, 10 nm or more, preferably It is 20 nm or more, More preferably, it is 50 nm or more, and an upper limit is 100 micrometers or less, for example, Preferably it is 10 micrometers or less, More preferably, it is 5 micrometers or less.
酸素発生用光触媒粒子１ｂには、必要に応じて助触媒（不図示）が担持される。具体的にはＩｒＯ２、ＰｔＯ２、ＲｕＯ２、Ｃｏ−Ｐｉ（リン酸水溶液中で析出させたコバルト酸化物；Kanan, M. W.; Nocera, D. G. Science 2008, 321, 1072-1075）、ＦｅＯＯＨ、ＮｉＯＯＨ、ＣｏＯ、Ｃｏ３Ｏ４、およびＣｏＯｘ（さまざまな酸化数のコバルトを含むコバルト酸化物混合物）、ＭｎＯ、Ｍｎ３Ｏ４、およびＭｎＯｘ（さまざまな酸化数のマンガンを含むマンガン酸化物混合物）、ＳｒＣｏＯ３、ＬａＮｉＯ３、ＬａＣｏＯ３等を例示することができる。 A cocatalyst (not shown) is supported on the oxygen-generating photocatalyst particles 1b as necessary. Specifically (cobalt oxide was precipitated with aqueous phosphoric acid in; Kanan, MW; Nocera, DG Science 2008, 321, 1072-1075) IrO 2, PtO 2, RuO 2, Co-Pi is, FeOOH, NiOOH, CoO, Co 3 O 4 , and CoOx (cobalt oxide mixture containing cobalt with various oxidation numbers), MnO, Mn 3 O 4 , and MnOx (mixture of manganese oxide containing manganese with various oxidation numbers), SrCoO 3 , LaNiO 3 , LaCoO 3 and the like.
光触媒粒子層１において、酸素発生用光触媒粒子１ｂは、１質量％以上９９質量％以下含まれていることが好ましい。下限がより好ましくは５質量％以上、特に好ましくは２０質量％以上であり、上限がより好ましくは９５質量％以下、特に好ましくは８０質量％以下である。光触媒粒子層１における酸素発生用光触媒粒子１ｂの含有量をこの範囲内とすることで、一層優れた水分解活性を有する光触媒積層体とすることができる。 In the photocatalyst particle layer 1, the oxygen generating photocatalyst particle 1b is preferably contained in an amount of 1% by mass to 99% by mass. The lower limit is more preferably 5% by mass or more, particularly preferably 20% by mass or more, and the upper limit is more preferably 95% by mass or less, and particularly preferably 80% by mass or less. By setting the content of the photocatalyst particles 1b for oxygen generation in the photocatalyst particle layer 1 within this range, a photocatalyst laminate having further excellent water splitting activity can be obtained.
１．１．３．光触媒粒子層
光触媒粒子層１において水素発生用光触媒粒子１ａと酸素発生用光触媒粒子１ｂとは互いに分散されている。なお、ここでいう「互いに分散」している状態は、すでに説明したとおりである。
1.1.3. Photocatalyst Particle Layer In the photocatalyst particle layer 1, the hydrogen generating photocatalyst particles 1a and the oxygen generating photocatalyst particles 1b are dispersed with each other. The state of “dispersed from each other” here is as described above.
光触媒粒子層の厚みについては薄くすることが好ましい。特に、光触媒粒子層１とコンタクト層２との積層方向における光触媒粒子１ａ、１ｂの積層数が１以上５０以下であることが好ましい。より好ましくは１以上３０以下、さらに好ましくは１以上２０以下、さらに好ましくは１以上１０以下、特に好ましくは１以上３以下である。このようにすることで、受光可能な光触媒粒子１ａ、１ｂがコンタクト層２と接触することとなり、光触媒粒子層１の厚みが薄くなるとともに、光触媒粒子間の抵抗を低下させることができ、水分解活性を一層向上させることができる。
尚、光触媒粒子１ａ、１ｂの積層数については、例えば、光触媒積層体の断面をＳＥＭ−ＥＤＸで観察する、或いは光学顕微鏡、触針式段差計等によって特定することが可能である。
It is preferable to reduce the thickness of the photocatalyst particle layer. In particular, the number of photocatalyst particles 1a and 1b in the stacking direction of the photocatalyst particle layer 1 and the contact layer 2 is preferably 1 or more and 50 or less. More preferably, it is 1-30, More preferably, it is 1-20, More preferably, it is 1-10, Most preferably, it is 1-3. By doing in this way, the photocatalyst particles 1a and 1b that can receive light come into contact with the contact layer 2, the thickness of the photocatalyst particle layer 1 is reduced, the resistance between the photocatalyst particles can be reduced, and water decomposition The activity can be further improved.
In addition, about the number of lamination | stacking of the photocatalyst particle | grains 1a and 1b, it is possible to observe the cross section of a photocatalyst laminated body with SEM-EDX, or to specify with an optical microscope, a stylus type step meter, etc., for example.
光触媒粒子層１に含まれる水素発生用光触媒粒子１ａと酸素発生用光触媒粒子１ｂとは、互いにバンドレベルがマッチしていることが好ましい。これにより、粒子間の電荷移動を一層促進することができる。尚、「バンドレベルがマッチしている」とは、水素発生用光触媒粒子および酸素発生用光触媒の、水分解反応にかかわるバンド、および光触媒粒子同士のキャリア相殺にかかわるバンドとが、図２に示したような順位で相対することを意味する。具体的には、エネルギー準位の高い順に、水素発生用光触媒の水素生成反応にかかわるバンド（Ａ）、酸素発生用光触媒のキャリア相殺にかかわるバンド（Ｂ）、水素発生用光触媒のキャリア相殺にかかわるバンド（Ｃ）、酸素発生用光触媒の酸素生成反応にかかわるバンド（Ｄ）、の順に位置し、酸素発生用光触媒のキャリア相殺にかかわるバンド（Ｂ）の電子が、効率よく水素発生用光触媒のキャリア相殺にかかわるバンド（Ｃ）へ移動できることを意味している。ここで、水分解反応にかかわるバンドは、光触媒粒子の価電子帯、伝導帯、もしくは不純物準位のいずれかである。
バンドレベルがマッチしている水素発生用光触媒粒子１ａと酸素発生用光触媒粒子１ｂの組み合わせとしては、例えば、Ｌａ、Ｒｈが共ドープされたＳｒＴｉＯ３とＢｉＶＯ４との組み合わせ；ＢａＴａＯ２ＮとＷＯ３との組み合わせ；Ｌａ５Ｔｉ２ＣｕＯ７Ｓ５とＢａＴａＯ２Ｎの組み合わせ等がある。
It is preferable that the hydrogen generation photocatalyst particles 1a and the oxygen generation photocatalyst particles 1b included in the photocatalyst particle layer 1 have the same band level. Thereby, the charge transfer between the particles can be further promoted. Incidentally, “the band level is matched” means that the band related to water splitting of the photocatalyst particles for hydrogen generation and the photocatalyst for oxygen generation and the band related to carrier offset between the photocatalyst particles are shown in FIG. It means to be opposite in the order. Specifically, the band (A) related to the hydrogen generation reaction of the hydrogen generation photocatalyst, the band (B) related to the carrier offset of the oxygen generation photocatalyst, and the carrier offset of the hydrogen generation photocatalyst in descending order of energy level. The electrons of the band (B), which is located in the order of the band (C) and the band (D) related to the oxygen generation reaction of the oxygen generating photocatalyst, and the carrier canceling of the oxygen generating photocatalyst are efficiently supported by the carrier of the hydrogen generating photocatalyst. This means that it is possible to move to the band (C) involved in cancellation. Here, the band involved in the water splitting reaction is one of the valence band, the conduction band, or the impurity level of the photocatalyst particles.
Examples of the combination of the hydrogen generating photocatalyst particle 1a and the oxygen generating photocatalyst particle 1b having matching band levels include a combination of SrTiO 3 and BiVO 4 co-doped with La and Rh; BaTaO 2 N and WO 3 A combination of La 5 Ti 2 CuO 7 S 5 and BaTaO 2 N.
光触媒粒子層１の表面（最外層から数えて１層目）に占める水素発生用光触媒粒子１ａの面積と酸素発生用光触媒粒子１ｂの面積との面積比は、水素発生用光触媒粒子１ａの面積と酸素発生用光触媒粒子１ｂの面積との合計を１００％として、水素発生用光触媒粒子の面積が１％以上９９％以下であることが好ましく、５％以上９５％以下であることがより好ましく、２０％以上８０％以下であることが特に好ましく、３３％以上６７％以下であることが最も好ましい。光触媒粒子層１における水素発生用光触媒粒子の面積比をこの範囲内とすることで、光触媒積層体の水分解活性を一層優れたものとすることができる。なお、ここでいう面積は光触媒粒子層の面方向における光触媒粒子の被覆面積である。被覆面積は、光触媒積層体を上面方向よりSEM、SEM-EDX等で観察し、画像内における光触媒粒子の面積を求めることにより求められる。 The area ratio of the area of the photocatalyst particles 1a for hydrogen generation to the area of the photocatalyst particles 1b for oxygen generation occupying the surface of the photocatalyst particle layer 1 (the first layer counted from the outermost layer) is the area of the photocatalyst particles 1a for hydrogen generation. The total area of the oxygen generating photocatalyst particles 1b is 100%, and the area of the hydrogen generating photocatalyst particles is preferably 1% or more and 99% or less, more preferably 5% or more and 95% or less, It is particularly preferably from 80% to 80%, most preferably from 33% to 67%. By making the area ratio of the photocatalyst particles for hydrogen generation in the photocatalyst particle layer 1 within this range, the water splitting activity of the photocatalyst laminate can be further improved. In addition, the area here is the covering area of the photocatalyst particles in the surface direction of the photocatalyst particle layer. The coating area is determined by observing the photocatalyst laminate from the top surface direction with SEM, SEM-EDX, etc., and determining the area of the photocatalyst particles in the image.
１．１．３．コンタクト層
コンタクト層２は、水素発生用光触媒粒子１ａ及び酸素発生用光触媒粒子１ｂよりも相対的に大きな電子伝導性を有する層である。尚、コンタクト層２は上記した光触媒粒子による水分解反応を阻害しない材料からなる。コンタクト層２を構成する材料としては、水素発生用光触媒粒子１ａ及び酸素発生用光触媒粒子１ｂよりも相対的に大きな電子伝導性を有する半導体や良導体が挙げられ、具体的には、Ａｇ、Ａｕ、Ｃ、Ｃｕ、Ｃｄ、Ｃｏ、Ｃｒ、Ｆｅ、Ｇａ、Ｇｅ、Ｈｇ、Ｉｒ、Ｉｎ、Ｍｎ、Ｍｏ、Ｎｂ、Ｐｂ、Ｒｕ、Ｒｅ、Ｒｈ、Ｓｎ、Ｓｂ、Ｔａ、Ｔｉ、Ｖ、Ｗ、或いはこれらの合金；Ｉｎ２Ｏ３−Ｇａ２Ｏ３−ＺｎＯ（ＩＧＺＯ）、ＩｎドープＳｎＯ２（ＩＴＯ）、ＦドープＳｎＯ２（ＦＴＯ）、ＳｂドープＳｎＯ２等の酸化物半導体、ＧａＮ、ＴｉＮ等の窒化物半導体、グラフェン、フラーレン、カーボンナノチューブ、グラファイトカーボン、カーボンブラック等の炭素系導電材等を例示することができる。中でもＩｒ、Ａｕ、Ｒｈ、Ｓｎ、Ｔｉが好ましく、Ａｕ、Ｒｈがより好ましい。
なお、コンタクト層は前記導電材が薄膜状になった状態でもよいし、導電性微粒子の集合体が層を形成したものでもよい。
1.1.3. Contact layer The contact layer 2 is a layer having relatively higher electron conductivity than the photocatalyst particles 1a for hydrogen generation and the photocatalyst particles 1b for oxygen generation. The contact layer 2 is made of a material that does not inhibit the water splitting reaction by the photocatalyst particles. Examples of the material constituting the contact layer 2 include semiconductors and good conductors having relatively higher electronic conductivity than the hydrogen generating photocatalyst particles 1a and the oxygen generating photocatalyst particles 1b. Specifically, Ag, Au, C, Cu, Cd, Co, Cr, Fe, Ga, Ge, Hg, Ir, In, Mn, Mo, Nb, Pb, Ru, Re, Rh, Sn, Sb, Ta, Ti, V, W, or these Alloys of In 2 O 3 —Ga 2 O 3 —ZnO (IGZO), In doped SnO 2 (ITO), F doped SnO 2 (FTO), oxide semiconductors such as Sb doped SnO 2 , and nitriding of GaN, TiN, etc. Examples thereof include carbon-based conductive materials such as physical semiconductors, graphene, fullerenes, carbon nanotubes, graphite carbon, and carbon black. Of these, Ir, Au, Rh, Sn, and Ti are preferable, and Au and Rh are more preferable.
The contact layer may be a state in which the conductive material is in a thin film shape, or may be a layer in which an aggregate of conductive fine particles forms a layer.
コンタクト層２は、光触媒粒子層１の、光が入射される一面側とは反対側を被覆している。ここで、コンタクト層２は光触媒粒子層１の表面形状に沿って設けられていることが好ましい。このような形態とすることで、光触媒粒子層１における光触媒粒子１ａ、１ｂとコンタクト層２とが密着する、すなわち、接触面積が大きくなることとなる結果、光触媒粒子１ａ、１ｂ間の電荷移動が促進され、光水分解活性を一層向上させることができる。また、光触媒粒子層１とコンタクト層２とを強固に結合させることができ、コンタクト層２から光触媒粒子１ａ、１ｂが容易に脱落してしまう等といったことも防止できる。 The contact layer 2 covers the side of the photocatalyst particle layer 1 opposite to the side on which light is incident. Here, the contact layer 2 is preferably provided along the surface shape of the photocatalyst particle layer 1. By adopting such a form, the photocatalyst particles 1a and 1b and the contact layer 2 in the photocatalyst particle layer 1 are in close contact, that is, the contact area is increased. As a result, charge transfer between the photocatalyst particles 1a and 1b is caused. It is promoted, and the photohydrolysis activity can be further improved. Further, the photocatalyst particle layer 1 and the contact layer 2 can be firmly bonded, and the photocatalyst particles 1a and 1b can be prevented from easily falling off from the contact layer 2.
或いは、本発明に係る光触媒積層体においては、水素発生用光触媒粒子１ａの一部、及び、酸素発生用光触媒粒子１ｂの一部が、コンタクト層２に埋没していることが好ましい。なお、ここでいう埋没とは、固定の一態様である。また、本発明に係る光触媒積層体においては、コンタクト層内に粒子全体が埋没した光触媒粒子が存在していても良いが、このような全体が埋没した粒子については、上記した光触媒粒子層を構成する光触媒粒子１ａ、１ｂからは除外するものとする。 Alternatively, in the photocatalyst laminate according to the present invention, it is preferable that a part of the hydrogen generating photocatalyst particles 1 a and a part of the oxygen generating photocatalyst particles 1 b are buried in the contact layer 2. In addition, burying here is an aspect of fixation. Further, in the photocatalyst laminate according to the present invention, the photocatalyst particles in which the entire particles are buried may be present in the contact layer. It is excluded from the photocatalyst particles 1a and 1b.
光触媒積層体１０においてコンタクト層２はシート状である。コンタクト層２の厚みについては特に限定されるものではない。薄膜状のような極めて薄い層であっても良いし、板状のような厚い層であっても良い。本発明においては、コンタクト層２の厚みを増大させるほど、コンタクト層２の強度が増す。例えば、コンタクト層２の厚みを増大させることで、コンタクト層２が独立して取り扱うことができる程度の強度を有するのであれば、後述する基材３ｂを設けることなく、光触媒積層体を構成することも可能である。
後述する基材３ｂを設けない場合、コンタクト層の厚みは、下限が好ましくは５μｍ以上、より好ましくは２０μｍ以上であり、さらに好ましくは５０μｍ以上であり、上限が好ましくは１ｍｍ以下、より好ましくは５００μｍ以下、さらに好ましくは１００μｍ以下である。
一方、後述する基材３ｂを設ける場合、コンタクト層の厚みは、下限が好ましくは０．３ｎｍ以上、より好ましくは１ｎｍ以上、さらに好ましくは１０ｎｍ以上であり、上限が好ましくは１００μｍ以下、より好ましくは５０μｍ以下、さらに好ましくは１０μｍ以下である。
In the photocatalyst laminate 10, the contact layer 2 has a sheet shape. The thickness of the contact layer 2 is not particularly limited. An extremely thin layer such as a thin film may be used, or a thick layer such as a plate may be used. In the present invention, the strength of the contact layer 2 increases as the thickness of the contact layer 2 increases. For example, if the contact layer 2 has a strength that can be handled independently by increasing the thickness of the contact layer 2, the photocatalyst laminate can be formed without providing the substrate 3 b described later. Is also possible.
When the substrate 3b described later is not provided, the lower limit of the thickness of the contact layer is preferably 5 μm or more, more preferably 20 μm or more, still more preferably 50 μm or more, and the upper limit is preferably 1 mm or less, more preferably 500 μm. Hereinafter, it is more preferably 100 μm or less.
On the other hand, when the substrate 3b described later is provided, the lower limit of the thickness of the contact layer is preferably 0.3 nm or more, more preferably 1 nm or more, still more preferably 10 nm or more, and the upper limit is preferably 100 μm or less, more preferably. It is 50 μm or less, more preferably 10 μm or less.
なお、コンタクト層は複数の導電材料からなっていてもよく、複層構成となっていてもよい。たとえば光触媒粒子層の表面形状に沿ってごく薄いＡｕ、Ｒｈ等の層を設け、その上にＴｉ等を積層したり、カーボンテープを設けたりしてもよい。 The contact layer may be made of a plurality of conductive materials and may have a multilayer structure. For example, a very thin layer of Au, Rh or the like may be provided along the surface shape of the photocatalyst particle layer, and Ti or the like may be laminated thereon, or a carbon tape may be provided.
このように、光触媒積層体１０においては、シート状のコンタクト層２の同一表面側に水素発生用光触媒粒子１ａと酸素発生用光触媒粒子１ｂとが互いに分散されて直接固定されている。このような構成を有する光触媒積層体１０において光照射による水分解反応時の電荷の移動について説明する。 Thus, in the photocatalyst laminate 10, the hydrogen generating photocatalyst particles 1a and the oxygen generating photocatalyst particles 1b are dispersed and fixed directly on the same surface side of the sheet-like contact layer 2. In the photocatalyst laminate 10 having such a configuration, the movement of charges during the water splitting reaction by light irradiation will be described.
図３に示すように、光触媒積層体１０において、コンタクト層２と接触する水素発生用光触媒粒子１ａは、その表面に光が照射されることによって粒子中に電子と正孔とを生ずる。ここで水素発生用光触媒粒子１ａは水の還元反応を触媒するものであるため、粒子中に生じた電子が水（プロトン）の還元反応に利用され、水を分解して水素を発生させる。また、粒子中に生じた正孔はコンタクト層２に到達し得る。
一方、光触媒積層体１０において、コンタクト層２と接触する酸素発生用光触媒粒子１ｂは、その表面に光が照射されることによって粒子中に電子と正孔とを生ずる。ここで酸素発生用光触媒粒子１ｂは水の酸化反応を触媒するものであるため、粒子中に生じた正孔が水の酸化反応に利用され、水を分解して酸素を発生させる。また、粒子中に生じた電子はコンタクト層２に到達し得る。
ここで、本発明では光触媒積層体１０において水素発生用光触媒粒子１ａと酸素発生用光触媒粒子１ｂとが互いに分散されていることから、光触媒粒子層１において光触媒粒子１ａ、１ｂが互いに隣接して存在する部分を複数有する。このような部分において、光触媒粒子１ａ、１ｂからコンタクト層２に到達した上記の正孔及び電子はコンタクト層２内で結合し打ち消し合う。すなわち、水素発生用光触媒粒子１ａにて生じた正孔が再度水素発生用光触媒粒子１ａにて生じた電子と結合することを抑制でき、且つ、酸素発生用光触媒粒子１ｂにて生じた電子が再度酸素発生用光触媒粒子１ｂにて生じた正孔と結合することを抑制することができる。それゆえ、本発明によれば、従来よりも高い水分解活性を奏する光触媒積層体１０を提供することができる。
水素発生用光触媒粒子と酸素発生用光触媒粒子が同一面上に設置されることによって、イオン勾配の影響を緩和することができる。水分解反応は、
4H2O + 4e- → 2H2 + 4OH- (水素生成光触媒粒子上での反応)
4OH- → O2 + 2H2O ＋ 4e- (酸素生成光触媒粒子上での反応)
もしくは
4H+ + 4e- → 2H2 (水素生成光触媒粒子上での反応)
2H2O → 4H+ + O2 + 4e- (酸素生成光触媒粒子上での反応)
に示すように、Ｈ＋イオンもしくはＯＨ−イオンが水素生成光触媒粒子と酸素生成光触媒粒子間を移動することによって進行する。この移動が滞ってイオン勾配が生じると、反応は
4H2O + 4e- → 2H2 + 4OH- (水素生成光触媒粒子上での反応)
2H2O → 4H+ + O2 + 4e- (酸素生成光触媒粒子上での反応)
のようになり、電解電圧が拡大するため反応が起きにくくなる。本発明のように水素発生用光触媒粒子と酸素発生用光触媒粒子を同一面上に設置することによって、反応サイトを近接させることができるため、このイオン勾配の影響を緩和し、反応を促進することができる。
As shown in FIG. 3, in the photocatalyst laminate 10, the hydrogen generating photocatalyst particles 1 a that are in contact with the contact layer 2 generate electrons and holes in the particles when the surface is irradiated with light. Here, since the photocatalyst particles 1a for hydrogen generation catalyze the reduction reaction of water, electrons generated in the particles are used for the reduction reaction of water (proton), and decomposes water to generate hydrogen. In addition, holes generated in the particles can reach the contact layer 2.
On the other hand, in the photocatalyst laminate 10, the oxygen-generating photocatalyst particles 1 b that are in contact with the contact layer 2 generate electrons and holes in the particles when the surface is irradiated with light. Here, since the oxygen-generating photocatalyst particles 1b catalyze the oxidation reaction of water, the holes generated in the particles are used for the oxidation reaction of water and decompose water to generate oxygen. In addition, electrons generated in the particles can reach the contact layer 2.
Here, in the present invention, since the photocatalyst particles 1a for hydrogen generation and the photocatalyst particles 1b for oxygen generation are dispersed with each other in the photocatalyst laminate 10, the photocatalyst particles 1a and 1b exist adjacent to each other in the photocatalyst particle layer 1. It has a plurality of parts to do. In such a portion, the holes and electrons that have reached the contact layer 2 from the photocatalyst particles 1a and 1b are combined and canceled in the contact layer 2. That is, it is possible to prevent the holes generated in the hydrogen generating photocatalyst particles 1a from being combined with the electrons generated in the hydrogen generating photocatalyst particles 1a again, and the electrons generated in the oxygen generating photocatalyst particles 1b again. Bonding with holes generated in the oxygen generating photocatalyst particles 1b can be suppressed. Therefore, according to the present invention, it is possible to provide the photocatalyst laminate 10 that exhibits higher water splitting activity than before.
By setting the photocatalyst particles for hydrogen generation and the photocatalyst particles for oxygen generation on the same plane, the influence of the ion gradient can be mitigated. Water splitting reaction
4H 2 O + 4e - → 2H 2 + 4OH - ( reaction on the hydrogen generation photocatalyst particles)
4OH - → O 2 + 2H 2 O + 4e - ( reaction on oxygen product photocatalyst particles)
Or
4H + + 4e - → 2H 2 ( reaction on the hydrogen generation photocatalyst particles)
2H 2 O → 4H + + O 2 + 4e - ( reaction on oxygen product photocatalyst particles)
As shown in FIG. 4, the H + ions or OH − ions travel by moving between the hydrogen-generating photocatalyst particles and the oxygen-generating photocatalyst particles. If this movement is delayed and an ion gradient occurs, the reaction
4H 2 O + 4e - → 2H 2 + 4OH - ( reaction on the hydrogen generation photocatalyst particles)
2H 2 O → 4H + + O 2 + 4e - ( reaction on oxygen product photocatalyst particles)
As a result, the electrolysis voltage is increased and the reaction is less likely to occur. By installing the photocatalyst particles for hydrogen generation and the photocatalyst particles for oxygen generation on the same surface as in the present invention, the reaction sites can be brought close to each other, so that the influence of this ion gradient is mitigated and the reaction is promoted. Can do.
１．２．第２実施形態
図４に、第２実施形態に係る本発明の光触媒積層体２０を概略的に示す。光触媒積層体２０はコンタクト層２の光触媒粒子層１とは反対側の表面に基材３ｂを備える点で、光触媒積層体１０とは異なる。
1.2. Second Embodiment FIG. 4 schematically shows a photocatalyst laminate 20 of the present invention according to a second embodiment. The photocatalyst laminate 20 is different from the photocatalyst laminate 10 in that the substrate 3b is provided on the surface of the contact layer 2 opposite to the photocatalyst particle layer 1.
光触媒積層体２０において用いられる基材３ｂの形状については特に限定されるものではない。基材３ｂは酸性、中性、塩基性の水中で安定であり、光触媒１によって酸化されない材料であれば材質についても特に限定されるものではない。具体的には、ガラス、ムライト、アルミナ等のセラミックやチタン、銅、スズ、鉄、ステンレス等の金属・合金等の無機基材；耐薬品性コーティングを施したメタクリル樹脂、アクリル樹脂、ウレタン樹脂、フェノール樹脂、メラミン樹脂、ユリア樹脂、ポリエステル樹脂、ポリカーボネート樹脂、フッ素樹脂、ポリエチレン、ポリプロピレン、ポリスチレン、ポリアミド、ポリアセタール、ポリ塩化ビニル、ポリ塩化ビニリデン等の有機基材；炭素繊維;紙、竹、木材等の天然基材；を用いることができる。 The shape of the base material 3b used in the photocatalyst laminate 20 is not particularly limited. The substrate 3b is not particularly limited as long as it is a material that is stable in acidic, neutral, and basic water and is not oxidized by the photocatalyst 1. Specifically, ceramics such as glass, mullite, and alumina, and inorganic substrates such as metals, alloys such as titanium, copper, tin, iron, and stainless steel; methacrylic resin, acrylic resin, urethane resin with chemical-resistant coating, Organic base materials such as phenol resin, melamine resin, urea resin, polyester resin, polycarbonate resin, fluororesin, polyethylene, polypropylene, polystyrene, polyamide, polyacetal, polyvinyl chloride, polyvinylidene chloride; carbon fiber; paper, bamboo, wood, etc. Natural base materials can be used.
光触媒積層体２０は、基材３ｂを備えることによって強度が増大するため、取り扱い性に一層優れる。基材３ｂの形状を適宜変更することによって、様々な用途・箇所に用いることが可能である。基材３ｂの厚さは特に限定されないが、１μｍ以上、１００ｍｍ以下である。 Since the strength of the photocatalyst laminate 20 is increased by providing the base material 3b, the photocatalyst laminate 20 is further excellent in handleability. By changing the shape of the base material 3b as appropriate, it can be used in various applications and locations. Although the thickness of the base material 3b is not specifically limited, It is 1 micrometer or more and 100 mm or less.
尚、上記説明では、光触媒積層体を光水分解反応を触媒する用途に用いられるものとして説明したが、本発明の光触媒積層体の用途はこれに限られるものではない。例えば、光二酸化炭素還元を触媒する用途や光を利用して有害な有機化合物、菌、悪臭物質や無機化合物（アンモニウムイオン、アンモニア、硝酸イオン、亜硝酸イオン等）を無害化するための環境浄化、抗菌・殺菌、脱臭、防汚シート等として用いることもできる。 In the above description, the photocatalyst laminate is described as being used for catalyzing the photohydrolysis reaction, but the use of the photocatalyst laminate of the present invention is not limited thereto. For example, applications that catalyze the reduction of photocarbon dioxide and environmental purification using light to detoxify harmful organic compounds, bacteria, malodorous substances and inorganic compounds (ammonium ions, ammonia, nitrate ions, nitrite ions, etc.) It can also be used as antibacterial / sterilizing, deodorizing, antifouling sheets and the like.
２．光触媒積層体の製造方法
本発明に係る光触媒積層体は、以下に説明する製造方法によって容易に製造することができる。すなわち、水素発生用光触媒粒子と酸素発生用光触媒粒子とを混合して混合物を得る工程と、水素発生用光触媒粒子と酸素発生用光触媒粒子とがシート状のコンタクト層の同一表面と接触するように、コンタクト層の表面に混合物を固定する工程と、を備える、光触媒積層体の製造方法である。
2. Manufacturing method of photocatalyst laminated body The photocatalyst laminated body which concerns on this invention can be easily manufactured with the manufacturing method demonstrated below. That is, a step of mixing the hydrogen generating photocatalyst particles and the oxygen generating photocatalyst particles to obtain a mixture, and the hydrogen generating photocatalyst particles and the oxygen generating photocatalyst particles are in contact with the same surface of the sheet-like contact layer. And a step of fixing the mixture on the surface of the contact layer.
２．１．光触媒積層体１０の製造方法（１）
図５に光触媒積層体１０を製造する方法の流れを概略的に示す。以下、図５を参照しつつ、光触媒積層体１０の製造方法の一例について説明する。
2.1. Method for producing photocatalyst laminate 10 (1)
FIG. 5 schematically shows a flow of a method for producing the photocatalyst laminate 10. Hereinafter, an example of a method for producing the photocatalyst laminate 10 will be described with reference to FIG.
２．１．１．混合物を得る工程
光触媒積層体１０を製造するに際しては、まず水素発生用光触媒粒子１ａと酸素発生用光触媒粒子１ｂとを用意し（図５（Ａ））、用意した光触媒粒子１ａ、１ｂを混合して混合物１ｃを得る（図５（Ｂ））。混合物１ｃにおける光触媒粒子１ａ、１ｂの混合比については上述した通りである。光触媒粒子１ａ、１ｂの混合手段については特に限定されるものではなく、光触媒粒子１ａ、１ｂを互いに均一に分散させるように混合可能な手段であれば良い。例えば、スターラ、ミキサ、ボールミル等を用いて機械的エネルギーを付与しながら乾式又は湿式にて混合することができる。或いは、超音波ホモジナイザー等を用いて湿式にて分散混合してもよい。
2.1.1. Step of obtaining a mixture In producing the photocatalyst laminate 10, first, the hydrogen generating photocatalyst particles 1a and the oxygen generating photocatalyst particles 1b are prepared (FIG. 5A), and the prepared photocatalyst particles 1a and 1b are mixed. Thus, a mixture 1c is obtained (FIG. 5B). The mixing ratio of the photocatalyst particles 1a and 1b in the mixture 1c is as described above. The means for mixing the photocatalyst particles 1a and 1b is not particularly limited as long as the means can be mixed so that the photocatalyst particles 1a and 1b are uniformly dispersed. For example, it can be mixed dry or wet while applying mechanical energy using a stirrer, mixer, ball mill or the like. Alternatively, it may be dispersed and mixed in a wet manner using an ultrasonic homogenizer or the like.
２．１．２．混合物を固定する工程
次に、混合物１ｃとコンタクト層２の表面とを固定する（図５（Ｃ））。具体的には、シート状のコンタクト層２の同一表面側において、水素発生用光触媒粒子１ａ及び酸素発生用光触媒粒子１ｂがコンタクト層２と接触するように、コンタクト層２の表面と混合物１ｃとを固定する。固定された混合物１ｃによって光触媒粒子層１が形成される。混合物１ｃとコンタクト層２とを固定する方法については特に限定されるものではない。例えば、（１）乾式混合により得られた混合物１ｃをシート状のコンタクト層２の表面に載置・積層した後でプレスする、（２）湿式混合により得られた混合物１ｃを含むスラリーをシート状のコンタクト層２の表面に塗布・乾燥した後で適宜プレスする、（３）表面を均した混合物１ｃの表面にシート状のコンタクト層２を載置・積層した後でプレスする、（４）表面を均した混合物１ｃの表面にコンタクト層２を構成する材料を蒸着、スパッタリング、塗布等により堆積して混合物１ｃの表面にシート状のコンタクト層２を積層・固定する、等の方法によって混合物１ｃをコンタクト層２の表面に固定できる。尚、プレスにより、光触媒粒子層１の表面形状に沿ってコンタクト層２を設けることができる。或いは、光触媒粒子の一部をコンタクト層に埋没させることができる。これにより、光触媒粒子層１とコンタクト層２との密着性が向上する。また、蒸着、スパッタリング、塗布等によりコンタクト層を積層・固定した場合も、光触媒粒子層１の隙間にコンタクト層２を構成する材料が侵入する結果、光触媒粒子１ａ、１ｂとコンタクト層２とが密着する。このように、光触媒粒子層１とコンタクト層２とを密着させることで、光触媒粒子１ａ、１ｂ間の電荷移動が促進され、光水分解活性を一層向上させることができる。また、光触媒粒子層１とコンタクト層２とを強固に結合させることができ、コンタクト層２から光触媒粒子１ａ、１ｂが容易に脱落してしまう等といったことも防止できる。
2.1.2. Step of Fixing Mixture Next, the mixture 1c and the surface of the contact layer 2 are fixed (FIG. 5C). Specifically, on the same surface side of the sheet-like contact layer 2, the surface of the contact layer 2 and the mixture 1c are placed so that the hydrogen-generating photocatalyst particles 1a and the oxygen-generating photocatalyst particles 1b are in contact with the contact layer 2. Fix it. The photocatalyst particle layer 1 is formed by the fixed mixture 1c. The method for fixing the mixture 1c and the contact layer 2 is not particularly limited. For example, (1) the mixture 1c obtained by dry mixing is placed on the surface of the sheet-like contact layer 2 and then pressed, and (2) slurry containing the mixture 1c obtained by wet mixing is formed into a sheet. (3) The sheet-like contact layer 2 is placed on and laminated on the surface of the mixture 1c having a uniform surface, and then pressed. (4) The surface The material constituting the contact layer 2 is deposited by vapor deposition, sputtering, coating, etc. on the surface of the mixture 1c obtained by leveling, and the sheet-like contact layer 2 is laminated and fixed on the surface of the mixture 1c. It can be fixed to the surface of the contact layer 2. In addition, the contact layer 2 can be provided along the surface shape of the photocatalyst particle layer 1 by pressing. Alternatively, part of the photocatalyst particles can be buried in the contact layer. Thereby, the adhesiveness between the photocatalyst particle layer 1 and the contact layer 2 is improved. In addition, even when the contact layer is laminated and fixed by vapor deposition, sputtering, coating, etc., the photocatalyst particles 1a, 1b and the contact layer 2 are in close contact with each other as a result of the material constituting the contact layer 2 entering the gaps between the photocatalyst particle layers 1. To do. As described above, by bringing the photocatalyst particle layer 1 and the contact layer 2 into close contact with each other, the charge transfer between the photocatalyst particles 1a and 1b is promoted, and the photohydrolysis activity can be further improved. Further, the photocatalyst particle layer 1 and the contact layer 2 can be firmly bonded, and the photocatalyst particles 1a and 1b can be prevented from easily falling off from the contact layer 2.
２．１．３．不要な光触媒粒子を除去する工程
上述のようにして光触媒粒子層１をコンタクト層２の表面に固定することで光触媒積層体が得られ、これをそのまま水分解反応に用いることができる。ただし、本発明においては、光触媒積層体の光触媒粒子層はできるだけ薄いほうが好ましい。そのため、混合物１ｃをコンタクト層２に固定した後で、コンタクト層２と接触していない光触媒粒子１ａ、１ｂの少なくとも一部を除去することが好ましい（図５（Ｄ））。コンタクト層２と接触していない光触媒粒子１ａ、１ｂは硬い粒子間で多くの隙間を有しつつ固定されている一方、コンタクト層２と接触している光触媒粒子１ａ、１ｂは光触媒粒子同士だけでなく、コンタクト層２にも固定されることとなる。それゆえ、例えば、コンタクト層２に固定された光触媒粒子１ａ、１ｂはそのまま残しつつ、超音波洗浄等によって光触媒粒子層１からコンタクト層２と接触していない光触媒粒子１ａ、１ｂの少なくとも一部を容易に除去することができる。
2.1.3. Step of Removing Unnecessary Photocatalyst Particles A photocatalyst laminate is obtained by fixing the photocatalyst particle layer 1 to the surface of the contact layer 2 as described above, and this can be used as it is for the water splitting reaction. However, in the present invention, the photocatalyst particle layer of the photocatalyst laminate is preferably as thin as possible. Therefore, after fixing the mixture 1c to the contact layer 2, it is preferable to remove at least a part of the photocatalyst particles 1a and 1b that are not in contact with the contact layer 2 (FIG. 5D). The photocatalyst particles 1a and 1b not in contact with the contact layer 2 are fixed with many gaps between hard particles, while the photocatalyst particles 1a and 1b in contact with the contact layer 2 are only photocatalyst particles. Instead, it is also fixed to the contact layer 2. Therefore, for example, while leaving the photocatalyst particles 1a and 1b fixed to the contact layer 2 as they are, at least a part of the photocatalyst particles 1a and 1b that are not in contact with the contact layer 2 from the photocatalyst particle layer 1 by ultrasonic cleaning or the like. It can be easily removed.
以上のようにして、光触媒積層体１０を容易に製造することができる。 As described above, the photocatalyst laminate 10 can be easily manufactured.
尚、コンタクト層２の表面と混合物１ｃとを固定する場合、混合物１ｃとコンタクト層を接触させる前、後、もしくは前後にコンタクト層２、混合物１ｃ、もしくはコンタクト層２及び混合物１ｃの両方を加熱炉、ホットプレート等で加熱することで、コンタクト層２の表面において、より強固に光触媒粒子１ａ、１ｂを固定することができる。これにより、界面抵抗を低減することができ、一層優れた光分解活性を有する光触媒積層体を得ることができる。加熱温度としては、好ましくは下限が２００℃（４７３Ｋ）以上であり、上限が５５０℃（８２３Ｋ）以下である。より好ましくは、下限が２５０℃（５２３Ｋ）以上、上限が４００℃（６７３Ｋ）以下である。後述する光触媒積層体１０の製造方法（２）や光触媒積層体２０の製造方法においても同様である。 When the surface of the contact layer 2 and the mixture 1c are fixed, the contact layer 2, the mixture 1c, or both the contact layer 2 and the mixture 1c are heated before, after, or before and after contacting the mixture 1c with the contact layer. The photocatalyst particles 1a and 1b can be more firmly fixed on the surface of the contact layer 2 by heating with a hot plate or the like. Thereby, interface resistance can be reduced and the photocatalyst laminated body which has the further outstanding photolytic activity can be obtained. As for the heating temperature, the lower limit is preferably 200 ° C. (473 K) or higher, and the upper limit is 550 ° C. (823 K) or lower. More preferably, the lower limit is 250 ° C. (523 K) or more and the upper limit is 400 ° C. (673 K) or less. The same applies to the method (2) for producing the photocatalyst laminate 10 and the method for producing the photocatalyst laminate 20 described later.
２．２．光触媒積層体１０の製造方法（２）
或いは、以下のような製造方法であっても、光触媒積層体１０を容易に製造することができる。図６に光触媒積層体１０を製造する方法の流れを概略的に示す。以下、図６を参照しつつ、光触媒積層体１０の製造方法の一例について説明する。
2.2. Method for producing photocatalyst laminate 10 (2)
Or even if it is the following manufacturing methods, the photocatalyst laminated body 10 can be manufactured easily. FIG. 6 schematically shows a flow of a method for producing the photocatalyst laminate 10. Hereinafter, an example of a method for producing the photocatalyst laminate 10 will be described with reference to FIG.
２．２．１．混合物を得る工程
まず、水素発生用光触媒粒子１ａと酸素発生用光触媒粒子１ｂとを混合して混合物１ｃを得る（図６（Ａ）、（Ｂ））。光触媒粒子１ａ、１ｂの混合については上述した通りである。
2.2.1. Step of Obtaining Mixture First, the hydrogen generating photocatalyst particles 1a and the oxygen generating photocatalyst particles 1b are mixed to obtain a mixture 1c (FIGS. 6A and 6B). The mixing of the photocatalyst particles 1a and 1b is as described above.
２．２．２．光触媒粒子層を形成する工程
次に、混合物１ｃを第１基材３ａ上に積層して第１基材３ａ上に光触媒粒子層１を形成する（図６（Ｃ））。例えば、乾式にて混合された混合物１ｃを第１基材３ａ上に載置して表面を均すことで、第１基材３ａ上に光触媒粒子層１を積層できる。或いは、湿式にて混合された混合物１ｃを含むスラリーを第１基材３ａ上に塗布・乾燥することによっても第１基材３ａ上に光触媒粒子層１を積層できる。
2.2.2. Step of Forming Photocatalyst Particle Layer Next, the mixture 1c is laminated on the first substrate 3a to form the photocatalyst particle layer 1 on the first substrate 3a (FIG. 6C). For example, the photocatalyst particle layer 1 can be laminated on the first substrate 3a by placing the mixture 1c mixed in a dry manner on the first substrate 3a and leveling the surface. Or the photocatalyst particle layer 1 can be laminated | stacked on the 1st base material 3a also by apply | coating and drying the slurry containing the mixture 1c mixed by the wet on the 1st base material 3a.
２．２．３．コンタクト層を固定する工程
次に、光触媒粒子層１の第１基材３ａとは反対側とシート状のコンタクト層２とを固定して第１積層体５を得る（図６（Ｄ））。光触媒粒子層１の表面とコンタクト層２とを固定する方法としては特に限定されるものではない。例えば、（１）シート状のコンタクト層２を光触媒粒子層１の表面に載置・積層した後でプレスする、（２）光触媒粒子層１の表面にコンタクト層２を構成し得る材料を物理蒸着法（真空蒸着、スパッタリングなど）、化学蒸着法（化学気相成長法など）、電解めっき法、無電解めっき法、塗布法などによって積層・固定する、等の方法によって光触媒粒子層１の表面とコンタクト層２とを固定することができる。
尚、強度の高い光触媒積層体１０を得る場合、コンタクト層２の厚みを大きくすることが好ましい。そのため、真空蒸着法、スパッタリング法等によってコンタクト層２を積層・固定する場合は、堆積時間を光触媒にダメージのない範囲で長時間とすることが好ましい。この場合のコンタクト層２の厚みについては上述した通りである。また、コンタクト層２形成前後の加熱処理については上述のとおりである。
2.2.3. Step of Fixing Contact Layer Next, the opposite side of the photocatalyst particle layer 1 from the first substrate 3a and the sheet-like contact layer 2 are fixed to obtain a first laminate 5 (FIG. 6D). The method for fixing the surface of the photocatalyst particle layer 1 and the contact layer 2 is not particularly limited. For example, (1) a sheet-like contact layer 2 is placed on and laminated on the surface of the photocatalyst particle layer 1 and then pressed. (2) Physical vapor deposition of a material that can form the contact layer 2 on the surface of the photocatalyst particle layer 1 The surface of the photocatalyst particle layer 1 is deposited and fixed by a method (vacuum vapor deposition, sputtering, etc.), chemical vapor deposition method (chemical vapor deposition method, etc.), electrolytic plating method, electroless plating method, coating method, etc. The contact layer 2 can be fixed.
In addition, when obtaining the photocatalyst laminated body 10 with high intensity | strength, it is preferable to enlarge the thickness of the contact layer 2. As shown in FIG. Therefore, when the contact layer 2 is laminated and fixed by a vacuum deposition method, a sputtering method, or the like, it is preferable to set the deposition time to a long time within a range where the photocatalyst is not damaged. The thickness of the contact layer 2 in this case is as described above. The heat treatment before and after the formation of the contact layer 2 is as described above.
２．２．４．第１基材を除去する工程
最後に、第１積層体５から第１基材３ａを除去する（図６（Ｅ））。この場合、光触媒粒子層１においてコンタクト層２に固定されていない光触媒粒子１ａ、１ｂの少なくとも一部を第１基材３ａとともに容易に除去することができる。或いは、第１基材３ａを除去した後で、超音波洗浄等によって不要な光触媒粒子をさらに除去してもよい。
2.2.4. Step of removing first base material Finally, the first base material 3a is removed from the first laminate 5 (FIG. 6E). In this case, at least a part of the photocatalyst particles 1a and 1b not fixed to the contact layer 2 in the photocatalyst particle layer 1 can be easily removed together with the first base material 3a. Alternatively, unnecessary photocatalyst particles may be further removed by ultrasonic cleaning or the like after removing the first substrate 3a.
以上のような方法であっても、光触媒積層体１０を容易に製造することができる。 Even if it is the above methods, the photocatalyst laminated body 10 can be manufactured easily.
２．３．光触媒積層体２０の製造方法
図７に光触媒積層体２０を製造する方法の流れを概略的に示す。以下、図７を参照しつつ、光触媒積層体２０の製造方法の一例について説明する。
2.3. Method for Producing Photocatalyst Laminate 20 FIG. 7 schematically shows a flow of a method for producing the photocatalyst laminate 20. Hereinafter, an example of a method for producing the photocatalyst laminate 20 will be described with reference to FIG.
２．３．１．混合物を得る工程
まず、水素発生用光触媒粒子１ａと酸素発生用光触媒粒子１ｂとを混合して混合物１ｃを得る（図７（Ａ）、（Ｂ））。光触媒粒子１ａ、１ｂの混合については上述した通りである。
2.3.1. Step of Obtaining Mixture First, the hydrogen generating photocatalyst particles 1a and the oxygen generating photocatalyst particles 1b are mixed to obtain a mixture 1c (FIGS. 7A and 7B). The mixing of the photocatalyst particles 1a and 1b is as described above.
２．３．２．光触媒粒子層を形成する工程
次に、混合物１ｃを第１基材３ａ上に積層して第１基材３ａ上に光触媒粒子層１を形成する（図７（Ｃ））。具体的な方法については上述した通りである。
2.3.2. Step of Forming Photocatalyst Particle Layer Next, the mixture 1c is laminated on the first substrate 3a to form the photocatalyst particle layer 1 on the first substrate 3a (FIG. 7C). The specific method is as described above.
２．３．３．コンタクト層を固定する工程
次に、光触媒粒子層１の第１基材３ａとは反対側とシート状のコンタクト層２とを固定して第１積層体５を得る（図７（Ｄ））。具体的な方法については上述した通りである。
尚、光触媒積層体２０は、後述の第２基材３ｂを備えているため、コンタクト層２を薄くすることが可能である。そのため、短時間の物理蒸着法（真空蒸着、スパッタリングなど）による堆積によって薄膜状のコンタクト層２を光触媒粒子層１の表面に積層・固定することが好ましい。この場合のコンタクト層２の厚みについては上述した通りである。
2.3.3. Step of Fixing Contact Layer Next, the opposite side of the photocatalyst particle layer 1 from the first substrate 3a and the sheet-like contact layer 2 are fixed to obtain a first laminate 5 (FIG. 7D). The specific method is as described above.
In addition, since the photocatalyst laminated body 20 is provided with the below-mentioned 2nd base material 3b, it is possible to make the contact layer 2 thin. Therefore, it is preferable to laminate and fix the thin contact layer 2 on the surface of the photocatalyst particle layer 1 by deposition by a short time physical vapor deposition method (vacuum vapor deposition, sputtering, etc.). The thickness of the contact layer 2 in this case is as described above.
２．３．４．第２基材を固定する工程
次に、コンタクト層２の光触媒粒子層１とは反対側と第２基材３ｂとを固定して第２積層体１５を得る（図７（Ｅ））。例えば、第２基材３ｂとコンタクト層２とを接着剤を介して貼り合わせることによって、第２積層体１５を得ることができる。
2.3.4. Step of fixing the second base material Next, the opposite side of the contact layer 2 from the photocatalyst particle layer 1 and the second base material 3b are fixed to obtain a second laminated body 15 (FIG. 7E). For example, the 2nd laminated body 15 can be obtained by bonding the 2nd base material 3b and the contact layer 2 through an adhesive agent.
２．３．５．第１基材を除去する工程
最後に、第１積層体５から第１基材３ａを除去する（図７（Ｆ））。第１基材３ａを除去した後で、不要な光触媒粒子１ａ、１ｂをさらに除去してもよい。
2.3.5. Step of removing first base material Finally, the first base material 3a is removed from the first laminate 5 (FIG. 7F). After removing the first substrate 3a, unnecessary photocatalyst particles 1a and 1b may be further removed.
以上のようにして、光触媒積層体２０を容易に製造することができる。 As described above, the photocatalyst laminate 20 can be easily manufactured.
尚、製造した光触媒積層体１０又は２０に、さらに助触媒を担持させてもよい。例えば、助触媒源を含む溶液内に光触媒積層体１０又は２０を設置したうえで、光触媒粒子層に対して光照射を行う光電析法よって、光触媒積層体に助触媒を担持することができる。尚、光触媒粒子１ａ、１ｂに既に助触媒が担持されている場合でも、光触媒積層体１０又は２０とした後で、さらに助触媒を担持させることが可能である。例えば、所定の助触媒を担持した光触媒粒子１ａ、１ｂを用いて光触媒積層体１０又は２０を得た後で、当該光触媒積層体１０又は２０に対して、上記所定の助触媒とは異なる種類の助触媒を担持させることも可能である。
また、助触媒の担持方法としては、上述の光電析法のほか、触媒担持に一般的に用いられる吸着法、インシピエント・ウェトネス(incipient wetness）法、ポアフィリング法、蒸発乾固法、噴霧法（担体に助触媒成分を含む溶液を噴霧する方法）などを含むいわゆる含浸法やイオン交換法を用いることができる。
The produced photocatalyst laminate 10 or 20 may further support a promoter. For example, after the photocatalyst laminate 10 or 20 is installed in a solution containing a cocatalyst source, the cocatalyst can be supported on the photocatalyst laminate by a photodeposition method in which the photocatalyst particle layer is irradiated with light. Even when the cocatalyst is already supported on the photocatalyst particles 1a and 1b, the cocatalyst can be further supported after the photocatalyst laminate 10 or 20 is formed. For example, after obtaining the photocatalyst laminate 10 or 20 using the photocatalyst particles 1a and 1b carrying a predetermined promoter, the photocatalyst laminate 10 or 20 is of a kind different from the predetermined promoter. It is also possible to carry a promoter.
In addition to the photodeposition method described above, the cocatalyst loading method includes an adsorption method, an incipient wetness method, a pore filling method, an evaporation to dryness method, and a spray method (commonly used for catalyst loading). A so-called impregnation method or ion exchange method including a method of spraying a solution containing a promoter component on a support) can be used.
また、混合物を固定する工程において、コンタクト層の混合物による被覆率は、水素発生用光触媒粒子と酸素発生用光触媒粒子の面積の合計を１００％として、水素発生用光触媒粒子による被覆率を１％以上９９％以下とすることが好ましく、５％以上９５％以下とすることがより好ましく、２０％以上８０％以下とすることが特に好ましく、３３％以上６７％以下とすることが最も好ましい。なお、被覆率は、光触媒積層体を上面方向よりSEM、SEM-EDX等で観察し、画像内における光触媒粒子の面積を求めることにより求められる。 In the step of fixing the mixture, the coverage of the contact layer with the mixture is 100% of the total area of the hydrogen generating photocatalyst particles and the oxygen generating photocatalyst particles, and the coverage with the hydrogen generating photocatalyst particles is 1% or more. It is preferably 99% or less, more preferably 5% or more and 95% or less, particularly preferably 20% or more and 80% or less, and most preferably 33% or more and 67% or less. The coverage is obtained by observing the photocatalyst laminate from the upper surface direction with SEM, SEM-EDX or the like, and determining the area of the photocatalyst particles in the image.
３．光触媒モジュール
本発明に係る光触媒モジュールは、上記光触媒積層体を有する光触媒モジュールであって、水素及び酸素を分離する分離装置をさらに備えることを特徴とする。分離装置としては水素及び酸素から水素を分離する水素分離装置、並びに、水素及び酸素から酸素を分離する酸素分離装置のいずれであってもよい。当該水素及び酸素から水素を分離する、水素分離装置がより好ましい。
3. Photocatalyst module The photocatalyst module according to the present invention is a photocatalyst module having the photocatalyst laminate, further comprising a separation device for separating hydrogen and oxygen. The separation device may be any one of a hydrogen separation device that separates hydrogen from hydrogen and oxygen, and an oxygen separation device that separates oxygen from hydrogen and oxygen. A hydrogen separator that separates hydrogen from the hydrogen and oxygen is more preferable.
特に、本発明に係る光触媒モジュールは、上記の分離装置として、本発明に係る光触媒積層体によって発生する水素及び酸素による爆発を回避しうる分離装置が好ましい。 In particular, the photocatalyst module according to the present invention is preferably a separator capable of avoiding an explosion caused by hydrogen and oxygen generated by the photocatalyst laminate according to the present invention as the above-described separator.
本発明では、光触媒積層体においてコンタクト層の同一表面側において、複数の水素発生用光触媒粒子の少なくとも一部と複数の酸素発生用光触媒粒子の少なくとも一部とが、コンタクト層と接触している。このような光触媒積層体を用いて光水分解反応を行った場合、コンタクト層の同一表面側において水素及び酸素の双方を含む混合ガスが発生することとなる。よって、光触媒モジュールに、混合ガスの爆発を回避しつつ水素を分離する水素分離装置を備えさせることで、安全性に一層優れる光触媒モジュールとすることができる。 In the present invention, on the same surface side of the contact layer in the photocatalyst laminate, at least some of the plurality of hydrogen generating photocatalyst particles and at least some of the plurality of oxygen generating photocatalyst particles are in contact with the contact layer. When the photohydrolysis reaction is performed using such a photocatalyst laminate, a mixed gas containing both hydrogen and oxygen is generated on the same surface side of the contact layer. Therefore, by providing the photocatalyst module with a hydrogen separator that separates hydrogen while avoiding the explosion of the mixed gas, the photocatalyst module can be further improved in safety.
水素分離装置に備えられる爆発を回避可能な機構は、特に限定されないが、不活性な希釈ガスを用いる機構（例えば、Ｊ．Ｆｉｒｅ Ｓｃｉｅｎｃｅｓ １９８５、３、２４５参照）、水中で分離する機構、及び隙間径が小さい細隙材と分子篩膜とを接続する機構が挙げられる。 There are no particular limitations on the mechanism provided in the hydrogen separator that can avoid explosion, but a mechanism that uses an inert diluent gas (see, for example, J. Fire Sciences 1985, 3, 245), a mechanism that separates in water, and a gap A mechanism for connecting a slit material having a small diameter and a molecular sieve membrane is mentioned.
３．１．不活性な希釈ガスを用いる機構
不活性な希釈ガスを用いる機構では、モジュール内の水素濃度及び酸素濃度を低下させて、水素及び酸素を含む混合ガスを爆発範囲外のガスとすることで、爆発を回避可能である。不活性な希釈ガスとしては、窒素、アルゴン、ヘリウム、空気、およびＣ３Ｆ８、Ｃ４Ｆ１０等のハロゲン化炭化水素等が挙げられる。
3.1. Mechanism using inert diluent gas In the mechanism using inert diluent gas, the hydrogen concentration and oxygen concentration in the module are reduced, and the mixed gas containing hydrogen and oxygen is made out of the explosion range. Can be avoided. Examples of the inert diluent gas include nitrogen, argon, helium, air, and halogenated hydrocarbons such as C3F8 and C4F10.
３．２．水中で分離する機構
水中で分離する機構では、光触媒の水分解反応によって水中に供給された水素及び酸素を、水中にて直接分離処理することで、爆発を回避可能である。例えば、水中に分子篩膜を接触或いは浸漬し、当該水中に供給された水素及び酸素のうち水素を、当該分子篩膜から優先的に透過させることで、爆発を回避しつつ水素を分離できる。なお、水には、電解質等の可溶成分が溶解しても、光触媒以外の不溶成分が存在していてもよい。分子篩膜の形態については後述する。
3.2. Mechanism for separating in water In the mechanism for separating in water, explosion can be avoided by directly separating hydrogen and oxygen supplied into water by water splitting reaction of the photocatalyst in water. For example, hydrogen can be separated while avoiding an explosion by contacting or immersing the molecular sieve membrane in water and preferentially permeating hydrogen from hydrogen and oxygen supplied into the water from the molecular sieve membrane. In addition, even if soluble components, such as an electrolyte, melt | dissolve in water, insoluble components other than a photocatalyst may exist. The form of the molecular sieve membrane will be described later.
３．３．隙間径が小さい細隙材と分子篩膜とを接続する機構
隙間径が小さい細隙材と分子篩膜とを接続する機構では、水素及び酸素を含む混合ガスが流通する流路を細隙とすることで、爆発を回避可能である。具体的には、水素及び酸素を含む混合ガスの消炎直径は３１０μｍであることが知られている（爆発防止実用便覧、サイエンスフォーラム（１９８３））ので、分子篩膜で分離するまでの混合ガスが流通する流路を、直径３１０μｍ以下の細隙とすることによって、爆発を回避可能である。
3.3. Mechanism for connecting a slit material with a small gap diameter and a molecular sieve membrane In a mechanism for connecting a slit material with a small gap diameter and a molecular sieve membrane, the flow path through which a mixed gas containing hydrogen and oxygen flows is made a slit. It is possible to avoid the explosion. Specifically, it is known that the flame extinguishing diameter of the mixed gas containing hydrogen and oxygen is 310 μm (Explosion Prevention Practical Handbook, Science Forum (1983)), so the mixed gas is circulated until it is separated by the molecular sieve membrane. Explosion can be avoided by making the flow path to be a slit having a diameter of 310 μm or less.
なお、本発明において「細隙」とは、酸素ガス及び／又は水素ガスが流通可能な細い流路を意味し、「細隙材」とは、細隙を有する部材を意味し、「隙間径」とは、細隙材に存在する細隙の径を意味する。 In the present invention, “slit” means a narrow flow path through which oxygen gas and / or hydrogen gas can flow, and “slit material” means a member having a slit, and “gap diameter”. "" Means the diameter of the slit existing in the slit material.
細隙と分子篩膜とを接続するためには、分子篩膜は、細隙材の少なくとも外側又は内側を覆っていたらよい。分子篩膜が細隙材の少なくとも外側又は内側を覆う形態としては、特に限定はされないが、分子篩膜が細隙材の表面に直接接触する形態、及び分子篩膜が何らかの部材を介して細隙材の表面を覆っている形態が挙げられる。 In order to connect the slit and the molecular sieve membrane, the molecular sieve membrane may cover at least the outer side or the inner side of the slit material. The form in which the molecular sieve membrane covers at least the outer side or the inner side of the slit material is not particularly limited, but the form in which the molecular sieve membrane is in direct contact with the surface of the slit material, and the molecular sieve membrane is formed on the slit material through some member. The form which covers the surface is mentioned.
分子篩膜は、細隙材の少なくとも外側又は内側を覆っているので、細隙材の細隙へと供給された水素及び酸素を含む混合ガスのうち、水素は分子篩膜を容易に透過する一方で、酸素等は分子篩膜を透過し難く細隙材内に留まる。これにより、細隙材内の混合ガスから、水素を選択的に分離することができる。この場合の分子篩膜は、分子篩能によって分子を選択的に透過させる膜であり、酸素よりも水素の透過度が大きな膜であって、水素ガスと酸素ガスが水となる反応（２Ｈ２＋Ｏ２→２Ｈ２Ｏ）を触媒しない材質で構成されているか、前記反応を触媒するとしても水素-酸素混合ガスが接触する表面が反応を触媒しない材料で被覆されていればよい。具体的には、特に限定されないが、ゼオライト膜、シリカ膜、炭素膜、パラジウム合金膜、及び高分子膜、並びにこれらの組み合わせであることが挙げられる。 Since the molecular sieve membrane covers at least the outer side or the inner side of the slit material, among the mixed gas containing hydrogen and oxygen supplied to the slit of the slit material, hydrogen easily permeates the molecular sieve membrane. Oxygen and the like hardly permeate the molecular sieve membrane and remain in the slit material. Thereby, hydrogen can be selectively separated from the mixed gas in the slit material. The molecular sieving membrane in this case is a membrane that selectively permeates molecules by molecular sieving ability, and is a membrane having a hydrogen permeability higher than oxygen, and a reaction in which hydrogen gas and oxygen gas become water (2H 2 + O 2 → 2H 2 O) may be formed of a material that does not catalyze, or even if the reaction is catalyzed, the surface in contact with the hydrogen-oxygen mixed gas may be coated with a material that does not catalyze the reaction. Specific examples include, but are not limited to, zeolite membranes, silica membranes, carbon membranes, palladium alloy membranes, polymer membranes, and combinations thereof.
細隙材としては、特に限定されないが、隔壁により仕切られた互いに略平行な複数の流路を有するハニカム構造体、及びマイクロリアクターが挙げられる。細隙材を構成する材質は、特に限定されないが、水素ガスと酸素ガスが水となる反応（２Ｈ２＋Ｏ２→２Ｈ２Ｏ）を触媒しない材質で構成されているか、前記反応を触媒するとしても、水素-酸素混合ガスに接する表面が触媒しない材料で被覆されていればよく、具体的にはガラス、セラミックス、金属、カーボン成形体、及び樹脂が挙げられる。 The slit material is not particularly limited, and examples thereof include a honeycomb structure having a plurality of substantially parallel flow paths partitioned by partition walls, and a microreactor. As the material constituting the slit material is not particularly limited, either hydrogen gas and oxygen gas are reacted to be a water (2H 2 + O 2 → 2H 2 O) is composed of a material which does not catalyze, catalyzing the reaction However, the surface in contact with the hydrogen-oxygen mixed gas only needs to be coated with a material that does not catalyze, and specific examples include glass, ceramics, metal, carbon molded body, and resin.
水素分離装置は、分子篩膜を用いた膜分離装置以外にも、圧力スイング吸着装置や温度スイング吸着装置等の吸着分離装置等の「ガス分離・精製技術、東レリサーチセンター（２００７）」に記載された装置を用いることができる。 The hydrogen separator is described in “Gas Separation / Purification Technology, Toray Research Center (2007)” such as a pressure swing adsorption device and a temperature swing adsorption device in addition to a membrane separation device using a molecular sieve membrane. Can be used.
なお、モジュールのうち、より爆発を避けたい部分には、フレームアレスタ（火災が発生した場合に大きな火災延焼や、爆発を防止する安全装置）等の消炎機能をもつ部材を組み合わせて用いてもよい。 It should be noted that a part of the module that wants to avoid explosion may be used in combination with a member having a flame extinguishing function such as a flame arrester (a safety device that prevents a large fire spread or explosion in the event of a fire). .
４．水素製造方法
本発明に係る水素製造法は、光触媒積層体によって水素及び酸素を発生させる発生ステップと、発生ステップにおいて発生した水素及び酸素を分離する分離ステップとを備える。
4). Hydrogen production method The hydrogen production method according to the present invention includes a generation step of generating hydrogen and oxygen by the photocatalyst laminate, and a separation step of separating hydrogen and oxygen generated in the generation step.
４．１．発生ステップ
発生ステップは、光触媒積層体の光触媒粒子層に、水或いは水溶液等を接触させるとともに光を照射し、水分解反応を生じさせることによって水素及び酸素を発生させるステップである。ここでいう光は太陽光、人工光（蛍光灯、UV灯、LED、水銀ランプ、キセノンランプ、メタルハライドランプ、ナトリウムランプ、ハロゲンランプなど）のいずれでもよく、波長 １８０〜１０００ｎｍ、放射照度１μＷ／ｍ２以上のものを指す。水分解反応の詳細については上述の通りであり、ここでは説明を省略する。尚、発生ステップにおいては、光照射の放射照度は１ｍＷ／ｍ２以上、反応温度は０℃以上、圧力は０．１ｋＰａ（絶対圧）以上とすることが望ましい。なお、水温をできるだけ高温（例えば、４０℃以上１００℃未満）とすることによって、水分解反応を促進することができる。
4.1. Generation Step The generation step is a step of generating hydrogen and oxygen by bringing water or an aqueous solution or the like into contact with the photocatalyst particle layer of the photocatalyst laminate and irradiating light to cause a water splitting reaction. The light here may be any of sunlight, artificial light (fluorescent lamp, UV lamp, LED, mercury lamp, xenon lamp, metal halide lamp, sodium lamp, halogen lamp, etc.), wavelength 180 to 1000 nm, irradiance 1 μW / m It refers to two or more. The details of the water splitting reaction are as described above, and a description thereof is omitted here. In the generation step, it is desirable that the irradiance of light irradiation is 1 mW / m 2 or more, the reaction temperature is 0 ° C. or more, and the pressure is 0.1 kPa (absolute pressure) or more. In addition, water splitting reaction can be accelerated | stimulated by making water temperature as high as possible (for example, 40 degreeC or more and less than 100 degreeC).
４．２．分離ステップ
分離ステップは、発生ステップにおいて発生した水素及び酸素を分離するステップであれば、どのような形態であってもよい。特に、発生ステップにおいて発生した水素及び酸素の爆発を回避しつつ、当該水素及び酸素から水素を分離するステップとすることが好ましい。これにより、一層安全に水素を製造することができる。例えば、上述したような、不活性な希釈ガスを用いる機構、水中で分離する機構、及び隙間径が小さい細隙材と分子篩膜とを接続する機構等を用いて、爆発を回避しつつ分離ステップを行うことができる。
4.2. Separation step The separation step may take any form as long as it is a step of separating hydrogen and oxygen generated in the generation step. In particular, it is preferable to separate hydrogen from hydrogen and oxygen while avoiding explosion of hydrogen and oxygen generated in the generation step. Thereby, hydrogen can be produced more safely. For example, a separation step while avoiding an explosion using a mechanism using an inert diluent gas, a mechanism for separating in water, a mechanism for connecting a slit material having a small gap diameter and a molecular sieve membrane, etc., as described above. It can be performed.
以下、実施例により本発明をさらに具体的に説明するが、本発明は、その要旨を超えない限り、以下の実施例により制限されるものではない。 EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not restrict | limited by a following example, unless the summary is exceeded.
１．水素発生用光触媒粒子の作製
ＳｒＴｉＯ３の合成は、従来法である固相合成法にて合成した。すなわちＳｒＣＯ３（関東化学製、９９．９％）１．００ｇ、ＴｉＯ２（関東化学製、ルチル型９９．０％）０．５３０ｇを混合し、１３７３Ｋで１０時間加熱した。得られたＳｒＴｉＯ３ １．８３５ｇを、空気中１２７３Ｋで１２時間焼成した直後のＬａ２Ｏ３（関東化学製 ９９．９９％）０．０６５２ｇおよびＲｈ２Ｏ３（関東化学製 ９９．９％）０．０５０８ｇとエタノール中で混合し、１３７３Ｋで６時間、空気中で加熱してＳｒＴｉＯ３：Ｌａ／Ｒｈを得た。得られたＳｒＴｉＯ３：Ｌａ／Ｒｈの粒子径は１００−７００ｎｍであった。
1. Preparation of photocatalyst particles for hydrogen generation SrTiO 3 was synthesized by a solid phase synthesis method which is a conventional method. That is, 1.00 g of SrCO 3 (manufactured by Kanto Chemical, 99.9%) and 0.530 g of TiO 2 (manufactured by Kanto Chemical, rutile type 99.0%) were mixed and heated at 1373 K for 10 hours. 0.0652 g of La 2 O 3 (99.9% manufactured by Kanto Chemical) and Rh 2 O 3 (99.9% manufactured by Kanto Chemical) immediately after calcining 1.835 g of the obtained SrTiO 3 at 1273 K in air for 12 hours 0.0508 g and ethanol were mixed and heated in air at 1373 K for 6 hours to obtain SrTiO 3 : La / Rh. The particle diameter of the obtained SrTiO 3 : La / Rh was 100-700 nm.
２．酸素発生用光触媒粒子の作製
ＢｉＶＯ４は０．４８５ｇのＢｉ（ＮＯ３）３・５Ｈ２Ｏ（和光純薬社製、９９．９％）、および０．０９１０ｇのＶ２Ｏ５（和光純薬社製、９９．９％）を５０ｍＬの０．７５ｍｏｌ／Ｌの硝酸水溶液中で４８時間、室温で撹拌することにより合成した。得られたＢｉＶＯ４粉末はろ過、洗浄してのち乾燥した。以上のようにして得られたＢｉＶＯ４粒子（粒子径２００〜４０００ｎｍ）を酸素発生用光触媒粒子とした。
2. Preparation of photocatalyst particles for oxygen generation BiVO 4 was 0.485 g of Bi (NO 3 ) 3 .5H 2 O (manufactured by Wako Pure Chemical Industries, 99.9%), and 0.0910 g of V 2 O 5 (Wako Pure Chemical Industries, Ltd.). (99.9%) was synthesized by stirring in 50 mL of a 0.75 mol / L nitric acid aqueous solution for 48 hours at room temperature. The obtained BiVO 4 powder was filtered, washed and dried. BiVO 4 particles (particle diameter 200 to 4000 nm) obtained as described above were used as photocatalyst particles for oxygen generation.
３．水分解反応活性の評価
（比較例１）
０．０１ｇの水素発生用光触媒粒子ＳｒＴｉＯ３：Ｌａ／Ｒｈと０．０１ｇの酸素発生用光触媒粒子を０．２ｕｍｏｌのＲｕＣｌ３を含む希硫酸水溶液中（ｐＨ３．５）４０ｍｌに懸濁し、脱気したのち、攪拌しつつ、３００Ｗキセノンランプ（λ＞４２０ｎｍ）を光源として１０時間（水分解速度が一定となるまで）光を照射し、水素発生用光触媒粒子１ａと酸素発生用光触媒粒子１ｂとの混合物を得た。回収した混合粉末を図８に示すように、溶液（硫酸にてｐＨを３．５に調整した硫酸水溶液）４０ｍｌに添加し、超音波処理により分散させて光触媒スラリー１ｄを得た。当該光触媒スラリー１ｄを閉鎖循環系評価装置に設置し、脱気したのち、攪拌しつつ、３００Ｗキセノンランプ（λ＞４２０ｎｍ）を光源として光を照射し、水分解反応活性を評価した。結果を下記表１に示す。
なお、ここで水分解反応活性を面積当たりで比較するため、ガス生成速度（μｍｏｌ／ｈ）を反応器内の有効照射面積で除して評価した。
3. Evaluation of water splitting reaction activity (Comparative Example 1)
0.01 g of hydrogen generating photocatalyst particles SrTiO 3 : La / Rh and 0.01 g of oxygen generating photocatalyst particles were suspended in 40 ml of dilute sulfuric acid aqueous solution (pH 3.5) containing 0.2 umol of RuCl 3 and deaerated. After that, while stirring, light is irradiated for 10 hours (until the water decomposition rate becomes constant) using a 300 W xenon lamp (λ> 420 nm) as a light source, and the hydrogen generating photocatalyst particles 1a and the oxygen generating photocatalyst particles 1b are irradiated. A mixture was obtained. As shown in FIG. 8, the recovered mixed powder was added to 40 ml of a solution (a sulfuric acid aqueous solution whose pH was adjusted to 3.5 with sulfuric acid) and dispersed by ultrasonic treatment to obtain a photocatalyst slurry 1d. The photocatalyst slurry 1d was placed in a closed circulation system evaluation apparatus, degassed, and irradiated with light using a 300 W xenon lamp (λ> 420 nm) as a light source while stirring to evaluate water splitting reaction activity. The results are shown in Table 1 below.
Here, in order to compare the water splitting reaction activity per area, the gas generation rate (μmol / h) was divided by the effective irradiation area in the reactor and evaluated.
（比較例２）
図９に示すように、水素発生用光触媒粒子１ａと酸素発生用光触媒粒子１ｂとを、質量比１：１でイソプロパノール中に懸濁して混合物１ｃとし、当該混合物１ｃをガラスからなる第１基材上３ａに積層して光触媒粒子層１を形成し、当該光触媒粒子層１の上に両面テープ（株式会社ニトムズ、ハンディカット多用途両面テープ、J1330）からなる第２基材３ｂ（厚み０．２３ｍｍ）を接合した。その後、第１基材３ａを除去し、第２基材３ｃの表面に光触媒粒子が固定された光触媒積層体５０を得た。得られた光触媒積層体を溶液（硫酸にてｐＨを３．５に調整した硫酸水溶液）４０ｍｌ中に設置し、３００Ｗキセノンランプ（λ＞４２０ｎｍ）を光源として、光触媒粒子層１に光を照射し、水分解反応活性を評価した。結果を下記表１に示す。
(Comparative Example 2)
As shown in FIG. 9, the hydrogen generating photocatalyst particles 1a and the oxygen generating photocatalyst particles 1b are suspended in isopropanol at a mass ratio of 1: 1 to form a mixture 1c, and the mixture 1c is made of glass. A photocatalyst particle layer 1 is formed by laminating the upper 3a, and a second base material 3b (thickness 0.23 mm) made of a double-sided tape (Nitoms Co., Ltd., handy cut versatile double-sided tape, J1330) is formed on the photocatalyst particle layer 1. ). Then, the 1st base material 3a was removed and the photocatalyst laminated body 50 by which the photocatalyst particle was fixed to the surface of the 2nd base material 3c was obtained. The obtained photocatalyst laminate was placed in 40 ml of a solution (sulfuric acid aqueous solution adjusted to pH 3.5 with sulfuric acid), and a photocatalyst particle layer 1 was irradiated with light using a 300 W xenon lamp (λ> 420 nm) as a light source. The water splitting reaction activity was evaluated. The results are shown in Table 1 below.
（実施例１）
図１０に示す方法で光触媒積層体を作製した。すなわち、水素発生用光触媒粒子１ａとしてＳｒＴｉＯ３：Ｌａ／Ｒｈと酸素発生用光触媒粒子１ｂとしてＢｉＶＯ４とを、質量比１：１でイソプロパノール中に懸濁して混合物１ｃとし、当該混合物１ｃをガラスからなる第１基材上３ａに積層し、第１基材３ａ上に光触媒粒子層１を形成した。次に、光触媒粒子層１の表面に金を真空蒸着により積層し、光触媒粒子層１の表面に厚み１μｍのコンタクト層２を固定した。次に、コンタクト層２の表面にカーボンテープ（日新ＥＭ株式会社製カーボン両面テープ（不織布基材）およびガラスからなる第２基材３ｂ（厚み０．５５ｍｍ）を接着した後、第２基材３ｂと第１基材３ａとを引き剥がした後、蒸留水中で超音波処理することによって、第１基材３ａとともに不要な光触媒粒子１ａ、１ｂを除去した。得られた光触媒積層体を０．３５ｕｍｏｌのＲｕＣｌ３を含む（硫酸にてｐＨを３．５に調整した硫酸水溶液）４０ｍｌ中に設置し、３００Ｗキセノンランプ（λ＞４２０ｎｍ）を光源として、光触媒粒子層１に１０時間（水素生成速度が一定となるまで）光を照射し、光触媒積層体にＲｕ助触媒を担持し、光触媒粒子層１を構成する光触媒粒子を水素発生用光触媒粒子１ａ’及び酸素発生用光触媒粒子１ｂ’とした。得られた光触媒積層体を溶液（硫酸にてｐＨを３．５に調整した硫酸水溶液）４０ｍｌ中に設置し、これを閉鎖循環系評価装置に設置し、脱気したのち、３００Ｗキセノンランプ（λ＞４２０ｎｍ）を光源として、温度２８８Ｋ、圧力０．０５ａｔｍの条件下で、光触媒粒子層１に光を照射し、生成ガスをガスクロマトグラフ分析装置により検出することで水分解反応活性を評価した。結果を下記表１に示す。
Example 1
A photocatalyst laminate was produced by the method shown in FIG. That is, SrTiO 3 : La / Rh as hydrogen generating photocatalyst particles 1a and BiVO 4 as oxygen generating photocatalyst particles 1b are suspended in isopropanol at a mass ratio of 1: 1 to form a mixture 1c, and the mixture 1c is made of glass. Then, the photocatalyst particle layer 1 was formed on the first base material 3a. Next, gold was laminated on the surface of the photocatalyst particle layer 1 by vacuum vapor deposition, and the contact layer 2 having a thickness of 1 μm was fixed to the surface of the photocatalyst particle layer 1. Next, after adhering a carbon tape (a carbon double-sided tape (nonwoven fabric base material) manufactured by Nissin EM Co., Ltd.) and a glass-made second base material 3b (thickness 0.55 mm) to the surface of the contact layer 2, the second base material After peeling off 3b and the 1st base material 3a, the unnecessary photocatalyst particle | grains 1a and 1b were removed with the 1st base material 3a by ultrasonically treating in distilled water. Installed in 40 ml containing 35 umol of RuCl 3 (sulfuric acid aqueous solution adjusted to pH 3.5 with sulfuric acid), using a 300 W xenon lamp (λ> 420 nm) as a light source for 10 hours (hydrogen generation rate) The photocatalyst layer is supported on the photocatalyst laminate, and the photocatalyst particles constituting the photocatalyst particle layer 1 are converted into hydrogen generating photocatalyst particles 1a ′ and oxygen generating photocatalyst particles 1b. The obtained photocatalyst laminate was placed in 40 ml of a solution (sulfuric acid aqueous solution adjusted to pH 3.5 with sulfuric acid), placed in a closed circulation system evaluation device, degassed, and then 300 W Using a xenon lamp (λ> 420 nm) as a light source, the photocatalyst particle layer 1 is irradiated with light under the conditions of a temperature of 288 K and a pressure of 0.05 atm, and the generated gas is detected by a gas chromatograph analyzer, thereby promoting water splitting reaction activity. The results are shown in Table 1 below.
（実施例２）
光触媒積層体水分解反応活性を評価する際、溶液のｐＨを６．８とした以外には実施例１と同様に実施した。結果を下記表１に示す。
(Example 2)
When evaluating the photocatalyst laminate water splitting reaction activity, the same procedure as in Example 1 was performed except that the pH of the solution was 6.8. The results are shown in Table 1 below.
（実施例３）
光触媒粒子層１の表面に真空蒸着する元素を金のかわりにＲｈにしたほかは、実施例１と同様の手法で光触媒積層体を得たのち、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表１に示す。
(Example 3)
A photocatalyst laminate was obtained in the same manner as in Example 1 except that the element to be vacuum deposited on the surface of the photocatalyst particle layer 1 was changed to Rh instead of gold. evaluated. The results are shown in Table 1 below.
（実施例４）
光触媒粒子層１の表面に真空蒸着する元素を金のかわりにＮｉにしたほかは、実施例１と同様の手法で光触媒積層体を得たのち水分解反応活性を評価した。結果を下記表１に示す。
Example 4
Except that the element to be vacuum-deposited on the surface of the photocatalyst particle layer 1 was Ni instead of gold, a photocatalyst laminate was obtained in the same manner as in Example 1, and the water splitting reaction activity was evaluated. The results are shown in Table 1 below.
（実施例５）
光触媒粒子層１の表面に真空蒸着する元素を金のかわりにＡｌにしたほかは、実施例１と同様の手法で光触媒積層体を得たのち水分解反応活性を評価した。結果を下記表１に示す。
(Example 5)
Except that the element to be vacuum-deposited on the surface of the photocatalyst particle layer 1 was Al instead of gold, a photocatalyst laminate was obtained in the same manner as in Example 1, and then the water splitting reaction activity was evaluated. The results are shown in Table 1 below.
表１に示す通り、実施例１に係る光触媒積層体を用いた場合、比較例１及び２と比べて、水分解活性が飛躍的に向上した。すなわち、シート状のコンタクト層と、コンタクト層の表面に固定された光触媒粒子層と、を備え、光触媒粒子層において、複数の水素発生用光触媒粒子と複数の酸素発生用光触媒粒子とが互いに分散されており、コンタクト層の同一表面側において、複数の水素発生用光触媒粒子の少なくとも一部と複数の酸素発生用光触媒粒子の少なくとも一部とが、コンタクト層と接触している、光触媒積層体により、水分解活性を従来よりも向上できることが分かった。
他方、コンタクト層の種類については、Ａｕだけではなく、Ｒｈ、Ｎｉでも良好な水分解活性を与えることがわかった。さらに、Ａｌでは酸素の生成は観測されなかったものの、水素生成については良好な生成速度が観測された。本結果より、コンタクト層としてはＡｕ以外にも、良好な導電性を持つものであれば好適に使用することが可能であることが明らかである。
As shown in Table 1, when the photocatalyst laminate according to Example 1 was used, the water splitting activity was dramatically improved as compared with Comparative Examples 1 and 2. That is, a sheet-like contact layer and a photocatalyst particle layer fixed on the surface of the contact layer are provided, and in the photocatalyst particle layer, a plurality of hydrogen generating photocatalyst particles and a plurality of oxygen generating photocatalyst particles are dispersed with each other. And at the same surface side of the contact layer, at least a part of the plurality of hydrogen generating photocatalyst particles and at least a part of the plurality of oxygen generating photocatalyst particles are in contact with the contact layer, It was found that the water splitting activity can be improved than before.
On the other hand, regarding the type of contact layer, it was found that not only Au but also Rh and Ni give good water splitting activity. Furthermore, although no oxygen was observed in Al, a good production rate was observed for hydrogen generation. From this result, it is apparent that the contact layer can be suitably used as long as it has good conductivity other than Au.
４．ｐＨ依存性
従来の光触媒分散体や光触媒積層体においては、ｐＨの変化によって水分解活性が低下するという問題があった。以下、溶液における硫酸量または水酸化ナトリウム量を調整してｐＨを２．５〜７．５まで変化させ、各ｐＨの水溶液に対して、実施例１に係る光触媒積層体２０を用いて上述の条件と同様にして水分解反応を行い、水分解活性のｐＨ依存性を確認した。結果を図１１に示す。
4). pH Dependence Conventional photocatalyst dispersions and photocatalyst laminates have a problem in that water splitting activity decreases due to changes in pH. Hereinafter, the amount of sulfuric acid or sodium hydroxide in the solution is adjusted to change the pH from 2.5 to 7.5, and the aqueous solution of each pH is used for the above-mentioned using the photocatalyst laminate 20 according to Example 1. A water splitting reaction was performed in the same manner as the conditions, and the pH dependence of the water splitting activity was confirmed. The results are shown in FIG.
図１１に示す結果から明らかなように、実施例１に係る光触媒積層体２０を用いた場合、水分解活性は、ｐＨの変化に関わらず高い活性を維持することが分かった。 As is clear from the results shown in FIG. 11, it was found that when the photocatalyst laminate 20 according to Example 1 was used, the water splitting activity maintained high activity regardless of the change in pH.
５．積層体の被覆率
実施例１にかかわる光触媒積層体のＳＥＭ観察およびＳＥＭ−ＥＤＸマッピング結果を図１２に示した。ＳＥＭ観察およびＳＥＭ−ＥＤＸマッピングでは上方より観察することで、光触媒粒子層の光照射面側の表面の形態や構成元素の比率を観察することができる。図１２ （Ａ）のｃ）−ｅ）のＥＤＸマッピングに示す通り、Ｂｉ、Ｓｒ、Ａｕの面積比はほぼＢｉ：Ｓｒ：Ａｕ＝３：５：２程度であった。すなわち、積層体表面の水素発生用光触媒（ＳｒＴｉＯ３：Ｌａ／Ｒｈ）と酸素発生用光触媒（ＢｉＶＯ４）の面積比は５：３であり、水素発生用光触媒粒子と酸素発生用光触媒粒子との合計を１００％として、水素発生用光触媒粒子によるコンタクト層の被覆率は 約６０％であった。
5. Coverage of Laminate SEM observation and SEM-EDX mapping result of the photocatalyst laminate relating to Example 1 are shown in FIG. By observing from above in SEM observation and SEM-EDX mapping, it is possible to observe the form of the surface on the light irradiation surface side of the photocatalyst particle layer and the ratio of constituent elements. As shown in the EDX mapping of c) -e) in FIG. 12A, the area ratio of Bi, Sr, and Au was approximately Bi: Sr: Au = 3: 5: 2. That is, the area ratio of the hydrogen generation photocatalyst (SrTiO 3 : La / Rh) and the oxygen generation photocatalyst (BiVO 4 ) on the surface of the laminate is 5: 3, and the hydrogen generation photocatalyst particles and the oxygen generation photocatalyst particles The total coverage was 100%, and the coverage of the contact layer with the hydrogen generating photocatalyst particles was about 60%.
６．積層体の粒子積層数
ＳＥＭ観察およびＳＥＭ−ＥＤＸマッピングでは断面方向より観察することで、光触媒粒子層の積層方向の形態や構成元素の比率を観察することができる。図１２（Ｂ）のａ）、ｂ） の粒子形態およびｃ）−ｅ）のＥＤＸマッピングより解析したところ、積層方向の粒子数は、ＳｒＴｉＯ３：Ｌａ／Ｒｈで８−２８個程度、ＢｉＶＯ４で１−２２個程度であった。このことから、光触媒積層体の積層方向の粒子数は、５０個程度以下が適切であることが明らかである。
6). The number of stacked particles in the layered body In SEM observation and SEM-EDX mapping, the form in the stacking direction of the photocatalyst particle layer and the ratio of constituent elements can be observed by observing from the cross-sectional direction. When analyzed from the particle morphology of a) and b) of FIG. 12B and the EDX mapping of c) -e), the number of particles in the stacking direction was about 8-28 in SrTiO 3 : La / Rh, BiVO 4 About 1-22. From this, it is clear that the number of particles in the stacking direction of the photocatalyst stack is appropriately about 50 or less.
上記の通り、特定の水素発生用光触媒と酸素発生用光触媒とを用いた場合において、シート状のコンタクト層と、コンタクト層の表面に固定された光触媒粒子層と、を備え、光触媒粒子層において、複数の水素発生用光触媒粒子と複数の酸素発生用光触媒粒子とが互いに分散されており、コンタクト層の同一表面側において、複数の水素発生用光触媒粒子の少なくとも一部と複数の酸素発生用光触媒粒子の少なくとも一部とが、コンタクト層と接触している、光触媒積層体を所定条件で作製することにより、従来よりも優れた水分解活性を有する光触媒積層体が得られた。 As described above, in the case of using a specific hydrogen generating photocatalyst and an oxygen generating photocatalyst, the sheet-like contact layer, and a photocatalyst particle layer fixed to the surface of the contact layer, The plurality of hydrogen generating photocatalyst particles and the plurality of oxygen generating photocatalyst particles are dispersed from each other, and at least a part of the plurality of hydrogen generating photocatalyst particles and the plurality of oxygen generating photocatalyst particles are disposed on the same surface side of the contact layer. By producing a photocatalyst laminate in which at least a part of the photocatalyst is in contact with the contact layer under predetermined conditions, a photocatalyst laminate having a water splitting activity superior to that of the prior art was obtained.
以下、（Ｉ）光触媒積層体の作製条件の最適化、（ＩＩ）水素発生用光触媒や酸素発生用光触媒の種類を変更させても同様の効果が奏されること、等について確認した。 Hereinafter, it was confirmed that (I) optimization of the production conditions of the photocatalyst laminate, (II) that the same effect can be achieved even if the type of the photocatalyst for hydrogen generation or the oxygen generation is changed.
７．水素発生用光触媒の調製
７．１．Ｌａ５Ｔｉ２ＣｕＳ５Ｏ７：Ｓｃ の調製
用いた原料は下記の通り。
Ｌａ２Ｏ３：関東化学社製、純度９９．９９％
Ｌａ２Ｓ３：高純度化学研究所社製、純度９９．９％
Ｃｕ２Ｓ：高純度化学研究所社製、純度９９％
ＴｉＯ２：レアメタリック社製、ルチル型、純度９９．９９％
Ｓｃ２Ｏ３：（実施例１〜９）関東化学社製、９９．９５％
Ｓ：高純度化学研究社製、硫黄粉末、純度９９．９９％
7). Preparation of photocatalyst for hydrogen generation 7.1. Preparation of La 5 Ti 2 CuS 5 O 7 : Sc The raw materials used are as follows.
La 2 O 3 : manufactured by Kanto Chemical Co., Inc., purity 99.99%
La 2 S 3 : manufactured by Kojundo Chemical Laboratory Co., Ltd., purity 99.9%
Cu 2 S: High purity chemical laboratory company, purity 99%
TiO 2 : manufactured by Rare Metallic, rutile type, purity 99.99%
Sc 2 O 3 : (Examples 1 to 9) manufactured by Kanto Chemical Co., 99.95%
S: High purity chemical research company make, sulfur powder, purity 99.99%
Ｌａ５Ｔｉ２ＣｕＳ５Ｏ７：Ｓｃは、「Physical Chemistry Chemical Physics，2012，14, 15475」に記載の方法に準拠し、固相反応法で調製した。具体的な調製方法を下記する。 La 5 Ti 2 CuS 5 O 7 : Sc was prepared by a solid phase reaction method in accordance with the method described in “Physical Chemistry Chemical Physics, 2012, 14, 15475”. A specific preparation method is described below.
卓上型グローブボックス（株式会社美和製作所社製 １ＡＤＢ−３ＭＫＨ−ＤＭＳ型）中で、上記各原料を、モル比でＬａ２Ｏ３：Ｌａ２Ｓ３：Ｃｕ２Ｓ：ＴｉＯ２：Ｓｃ２Ｏ３：Ｓ＝１．０：１．５：０．５：１．９８：０．０１：０．２５となるようにアルミナ乳鉢で混合し、Ｔｉ原子及びＳｃ原子の合計に対するＳｃ原子の原子百分率で１．０％の混合物を得た。前記混合物を石英管に封入して真空封管した後に電気炉で加熱した。このとき、２００℃（４７３Ｋ）までは９分、４００℃（６７３Ｋ）までは１時間４０分、１０００℃（１２７３Ｋ）までは５０時間かけて昇温し、１０００℃（１２７３Ｋ）で４８時間保持した。その後、５００℃（７７３Ｋ）まで１２時間３０分間かけて冷却し、その後、室温まで自然冷却した。得られた塊の外縁部から目視で不純物相を取り除き、アルミナ乳鉢で粉砕してＬａ５Ｔｉ２ＣｕＳ５Ｏ７：Ｓｃ（Ｓｃ０．１％品）粉末を得た。 In a tabletop glove box (1ADB-3MKH-DMS type manufactured by Miwa Seisakusho Co., Ltd.), the above raw materials are mixed in a molar ratio of La 2 O 3 : La 2 S 3 : Cu 2 S: TiO 2 : Sc 2 O 3. : S = 1.0: 1.5: 0.5: 1.98: 0.01: 0.25 mixed in an alumina mortar, and the atomic percentage of Sc atoms with respect to the total of Ti atoms and Sc atoms A 1.0% mixture was obtained. The mixture was sealed in a quartz tube, vacuum sealed and then heated in an electric furnace. At this time, the temperature was raised to 200 ° C. (473 K) for 9 minutes, to 400 ° C. (673 K) for 1 hour 40 minutes, to 1000 ° C. (1273 K) over 50 hours, and maintained at 1000 ° C. (1273 K) for 48 hours. . Then, it cooled to 500 degreeC (773K) over 12 hours and 30 minutes, and cooled naturally to room temperature after that. The impurity phase was visually removed from the outer edge of the obtained lump, and pulverized with an alumina mortar to obtain La 5 Ti 2 CuS 5 O 7 : Sc (Sc 0.1% product) powder.
７．２．Ｐｔ／Ｌａ５Ｔｉ２ＣｕＳ５Ｏ７：Ｓｃの調製
Ｌａ５Ｔｉ２ＣｕＳ５Ｏ７：Ｓｃ（０．５ｇ）をＨ２ＰｔＣｌ６（田中貴金属社製、Ｌａ５Ｔｉ２ＣｕＳ５Ｏ７：Ｓｃに対してＰｔとして０．１‐０．４ｗｔ％）の１０ｖｏｌ％のメタノール水溶液に懸濁し、閉鎖循環系装置を用い、空気の非存在下で可視光（λ＞４２０ｎｍ）を４時間照射しＰｔ（ＩＶ）を金属Ｐｔに光還元した。Ｐｔの析出の後、生成物を蒸留水でよく洗浄し、４０℃で１２時間真空乾燥させた。
7.2. Preparation of Pt / La 5 Ti 2 CuS 5 O 7 : Sc La 5 Ti 2 CuS 5 O 7 : Sc (0.5 g) was changed to H 2 PtCl 6 (La 5 Ti 2 CuS 5 O 7 : Sc, manufactured by Tanaka Kikinzoku Co., Ltd.) Pt was suspended in a 10 vol% methanol aqueous solution of 0.1-0.4 wt% as Pt, and irradiated with visible light (λ> 420 nm) for 4 hours in the absence of air using a closed circulation system. (IV) was photoreduced to metal Pt. After precipitation of Pt, the product was thoroughly washed with distilled water and vacuum dried at 40 ° C. for 12 hours.
７．３．ＲｈＣｒＯｘ／Ｌａ５Ｔｉ２ＣｕＳ５Ｏ７：Ｓｃの調製
Ｌａ５Ｔｉ２ＣｕＳ５Ｏ７：Ｓｃ（０．５ｇ）を、Ｒｈ（ＮＯ３）３（田中貴金属社製、Ｌａ５Ｔｉ２ＣｕＳ５Ｏ７：Ｓｃに対してＲｈとして０．２ｗｔ％）、Ｃｒ（ＮＯ３）３・９Ｈ２０（田中貴金属社製、Ｌａ５Ｔｉ２ＣｕＳ５Ｏ７：Ｓｃに対してＣｒとして０．３ｗｔ％）を含む３−４ｍＬ水溶液に懸濁し、磁性坩堝内、ウォーターバス上で、ガラス棒で撹枠しながら溶媒を蒸発乾燥させた。その後Ｎ２気流中３５０℃で焼成した。
7.3. RhCrOx / La 5 Ti 2 CuS 5 O 7: Preparation of Sc La 5 Ti 2 CuS 5 O 7: Sc a (0.5g), Rh (NO 3 ) 3 ( Tanaka Kikinzoku Co., La 5 Ti 2 CuS 5 O 7: 0.2 wt% as Rh relative Sc), Cr (NO 3) 3 · 9H 2 0 ( Tanaka Kikinzoku Co., La 5 Ti 2 CuS 5 O 7: 0.3wt% as Cr with respect to Sc) The solvent was evaporated and dried while stirring with a glass rod in a magnetic crucible and on a water bath. Then, it was fired at 350 ° C. in a N 2 stream.
８．酸素発生用光触媒の調製
８．１．ＢｉＶＯ４：Ｍｏの調製
用いた原料は下記の通り：
Ｂｉ２Ｏ３：関東化学社製、純度９８．０％
ＮＨ４ＶＯ３：関東化学社製、純度９９．０％
ＭｏＯ３：関東化学社製、純度９９．５％
8). Preparation of photocatalyst for oxygen generation 8.1. Preparation of BiVO 4 : Mo The raw materials used are as follows:
Bi 2 O 3 : manufactured by Kanto Chemical Co., Inc., purity 98.0%
NH 4 VO 3 : manufactured by Kanto Chemical Co., Inc., purity 99.0%
MoO 3 : manufactured by Kanto Chemical Co., Inc., purity 99.5%
Ｂｉ／Ｖ／Ｍｏ＝１．００／０．９９５／０．００５（ｍｏｌ比）になるように、Ｂｉ２Ｏ３（６．９８９ｇ）、ＮＨ４ＶＯ３（３．４９２ｇ）およびＭｏＯ３（０．０２１６ｇ）をメノウ自動乳鉢で２時間混合した。得られた混合物をアルミナ製坩堝に入れて、電気炉にて大気中９００℃で５時間焼成した。焼成後、室温まで放冷させた後、解砕した。なお、以上のｍｏｌ比は仕込み量を表す。 Bi 2 O 3 (6.989 g), NH 4 VO 3 (3.492 g) and MoO 3 (0 so that Bi / V / Mo = 1.00 / 0.995 / 0.005 (mol ratio). 0.0216 g) was mixed in an agate automatic mortar for 2 hours. The obtained mixture was put in an alumina crucible and baked in an electric furnace at 900 ° C. for 5 hours. After firing, the mixture was allowed to cool to room temperature and then crushed. In addition, the above mol ratio represents preparation amount.
その後、遊星型ボールミルを用いて湿式粉砕した。ボールミリングした手順は、容積の１２ｍＬジルコニア製のポットにφ３ｍｍのジルコニア製ビーズを１００個入れ、調製済みのＭｏドープＢｉＶＯ４を０．５ｇ入れた。５ｍＬの純水を添加し、８００ｒｐｍで２時間粉砕した。粉砕後、遠心分離機で粉末を回収し、真空乾燥機で４０度、５時間乾燥した後、回収し、ＢｉＶＯ４：Ｍｏを得た。 Thereafter, wet pulverization was performed using a planetary ball mill. In the ball milling procedure, 100 zirconia beads having a diameter of 3 mm were placed in a 12 mL zirconia pot having a volume, and 0.5 g of the prepared Mo-doped BiVO 4 was placed. 5 mL of pure water was added and pulverized at 800 rpm for 2 hours. After the pulverization, the powder was recovered with a centrifugal separator, dried at 40 ° C. for 5 hours with a vacuum dryer, and then recovered to obtain BiVO 4 : Mo.
８．２．ＣｏＯｘ／ＢｉＶＯ４：Ｍｏ の調製
ＢｉＶＯ４：Ｍｏ粉末０．５ｇを磁性るつぼにいれ、ＣｏＯを０．５ｗｔ％になるように、Ｃｏ（ＮＯ３）２（和光純薬社製、９９．５％）を磁性るつぼに添加し、純水を少々入れた。超音波でＢｉＶＯ４：Ｍｏ粉末を十分に懸濁した後、湯浴で蒸発乾燥した。最後に、電気炉で、大気中３００℃で２時間焼成し、ＣｏＯｘ／ＢｉＶＯ４：Ｍｏを得た。
8.2. Preparation of CoO x / BiVO 4 : Mo BiVO 4 : Mo powder (0.5 g) was placed in a magnetic crucible, and Co (NO 3 ) 2 (Wako Pure Chemical Industries, 99.5) was added so that CoO might be 0.5 wt%. %) Was added to the magnetic crucible and a little pure water was added. The BiVO 4 : Mo powder was sufficiently suspended with ultrasonic waves and then evaporated to dryness in a hot water bath. Finally, it was calcined in the atmosphere at 300 ° C. for 2 hours to obtain CoOx / BiVO 4 : Mo.
８．３．ＣｏＯｘ／ＬａＴｉＯ２Ｎの調製
ＣｏＯｘが担持されたＬａＴｉＯ２Ｎは以下の手順で合成した。
まずＬａＴｉＯ２Ｎの前駆体となるＬａ２Ｔｉ２Ｏ７を以下手順で合成した。空気中１２７３Ｋで１０時間焼成した直後のＬａ２Ｏ３（和光純薬工業株式会社製、９９．９９％）２．６８４１ g、ＴｉＯ２（関東化学株式会社製、ルチル型９９．９％）１．３１５９ｇ、及びＮａＣｌ（和光純薬工業株式会社製、９９．５％）９．６２８５ｇを混合し、１４２３Ｋで５時間加熱した。このとき、１４２３Ｋまでは１１５分かけて昇温し、１４２３Ｋで５時間保持した。その後、１０７３Ｋまで３５０分かけて冷却し、その後、室温まで自然冷却した。得られた試料は十分な量の蒸留水で洗浄し、３４３Ｋで乾燥してＬａ２Ｔｉ２Ｏ７を得た。
8.3. CoO x / LaTiO 2 N LaTiO 2 N to prepare CoO x is carried in was synthesized by the following procedure.
First, La 2 Ti 2 O 7 as a precursor of LaTiO 2 N was synthesized by the following procedure. La 2 O 3 (Wako Pure Chemical Industries, Ltd., 99.99%) 2.6684 g, TiO 2 (Kanto Chemical Co., Ltd., Rutile type 99.9%) 1 immediately after firing in air at 1273K for 10 hours 1 3159 g and NaCl (99.5%, manufactured by Wako Pure Chemical Industries, Ltd.) 9.6285 g were mixed and heated at 1423K for 5 hours. At this time, the temperature was raised to 1423K over 115 minutes, and the temperature was maintained at 1423K for 5 hours. Then, it cooled to 1073K over 350 minutes, and cooled naturally to room temperature after that. The obtained sample was washed with a sufficient amount of distilled water and dried at 343K to obtain La 2 Ti 2 O 7 .
つぎに得られたＬａ２Ｔｉ２Ｏ７（１．００ｇ）を石英ウールに包みアンモニアを流通させた管状炉内で、１２２３Ｋで１５時間加熱した。このとき、１２２３Ｋまでは９５分かけて昇温し、１２２３Ｋで１５時間保持した。その後、室温まで自然冷却してＬａＴｉＯ２Ｎを得た。 Next, La 2 Ti 2 O 7 (1.00 g) obtained was wrapped in quartz wool and heated at 1223 K for 15 hours in a tubular furnace in which ammonia was circulated. At this time, the temperature was raised to 1223K over 95 minutes and held at 1223K for 15 hours. Then, to obtain a LaTiO 2 N was naturally cooled to room temperature.
得られたＬａＴｉＯ２Ｎ（０．２ｇ）をＣｏ（ＮＯ３）２・６Ｈ２Ｏ（和光純薬工業株式会社製、９９．５％、ＬａＴｉＯ２Ｎに対してＣｏとして２．０ｗｔ％）を含む３−４ｍＬの水溶液に懸濁し、磁性蒸発皿内、ウォーターバス上で、ガラス棒で撹枠しながら溶媒を蒸発乾燥させた。その後、試料をアルミナボートに載せアンモニアを流通させた管状炉内で、９７３Ｋで１時間加熱した。このとき、９７３Ｋまでは７０分かけて昇温し、９７３Ｋで１時間保持した。その後、室温まで自然冷却して、ＣｏＯｘが担持されたＬａＴｉＯ２Ｎ（ＣｏＯｘ／ＬａＴｉＯ２Ｎ、ＣｏＯｘ／ＬＴＯＮ）を得た。 The resulting LaTiO 2 N (0.2g) and Co (NO 3) 2 · 6H 2 O ( Wako Pure Chemical Industries, Ltd., 99.5%, 2.0wt% as Co relative LaTiO 2 N) and It was suspended in a 3-4 mL aqueous solution, and the solvent was evaporated to dryness in a magnetic evaporating dish and on a water bath while stirring with a glass rod. Thereafter, the sample was placed on an alumina boat and heated at 973 K for 1 hour in a tubular furnace in which ammonia was circulated. At this time, the temperature was increased to 973K over 70 minutes and maintained at 973K for 1 hour. Then naturally cooled to room temperature to obtain LaTiO the CoO x is supported 2 N (CoO x / LaTiO 2 N, CoO x / LTON) a.
８．４．ＣｏＯｘ／Ｔａ３Ｎ５の調製
ＣｏＯｘが担持されたＴａ３Ｎ５は以下の手順で合成した。Ｔａ２Ｏ５（レアメタリック社製、９９．９９％）１．００ｇを石英ウールに包みアンモニアを流通させた（３００ｍＬ／ｍｉｎ）管状炉内で、１１２３Ｋで２０時間加熱した。このとき、１１２３Ｋまでは８５分かけて昇温し、１１２３Ｋで２０時間保持した。その後、室温まで自然冷却してＴａ３Ｎ５を得た。
8.4. Ta 3 N 5 to prepare CoO x is carried in CoO x / Ta 3 N 5 was synthesized by the following procedure. In a tubular furnace in which 1.00 g of Ta 2 O 5 (manufactured by Rare Metallic, 99.99%) was wrapped in quartz wool and ammonia was circulated (300 mL / min), it was heated at 1123 K for 20 hours. At this time, the temperature was raised to 1123K over 85 minutes and held at 1123K for 20 hours. Then, to obtain a Ta 3 N 5 was naturally cooled to room temperature.
得られたＴａ３Ｎ５（０．１〜０．２５ｇ）をＣｏ（ＮＯ３）２・６Ｈ２Ｏ（和光純薬工業株式会社製、９９．５％、Ｔａ３Ｎ５に対してＣｏとして２．０ｗｔ％）を含む３−４ｍＬの水溶液に懸濁し、磁性蒸発皿内、ウォーターバス上でガラス棒で撹枠しながら溶媒を蒸発乾燥させた。その後、試料をアルミナボートに載せアンモニアを流通させた（２００ｍＬ／ｍｉｎ）管状炉内で、９２３Ｋで１時間加熱した。このとき、９２３Ｋまでは６５分かけて昇温し、９２３Ｋで１時間保持した。その後、室温まで自然冷却して、ＣｏＯｘが担持されたＴａ３Ｎ５を得た。 The resulting Ta 3 N 5 (0.1~0.25g) the Co (NO 3) 2 · 6H 2 O ( Wako Pure Chemical Industries, Ltd., 99.5%, as Co relative to Ta 3 N 5 The solution was suspended in 3-4 mL of an aqueous solution containing 2.0 wt%, and the solvent was evaporated and dried in a magnetic evaporating dish on a water bath while stirring with a glass rod. Thereafter, the sample was placed on an alumina boat and heated at 923 K for 1 hour in a tubular furnace in which ammonia was circulated (200 mL / min). At this time, the temperature was increased to 923K over 65 minutes and held at 923K for 1 hour. Thereafter, it was naturally cooled to room temperature to obtain Ta 3 N 5 on which CoO x was supported.
９．水分解反応活性の評価
９．１．Ｍｏ添加効果の確認
（実施例６）
酸素発生用光触媒粒子１ｂとしてＢｉＶＯ４：Ｍｏを使用し、助触媒前駆体であるＲｕＣｌ３の含有量を０．２μｍｏｌとしたほかは、実施例１と同様の手法で積層体を得た後、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表２に示す。
9. Evaluation of water splitting reaction activity 9.1. Confirmation of Mo addition effect (Example 6)
After using BiVO 4 : Mo as the oxygen-generating photocatalyst particles 1b and setting the content of RuCl 3 as the promoter precursor to 0.2 μmol, a laminate was obtained in the same manner as in Example 1, Water splitting reaction activity was evaluated by the same method as in Example 2. The results are shown in Table 2 below.
表２に示す結果から明らかなように、酸素発生用光触媒においてＭｏを添加することによって、助触媒であるＲｕ量を減少させたとしても、水分解活性が向上することが分かった。 As is clear from the results shown in Table 2, it was found that by adding Mo in the photocatalyst for oxygen generation, the water splitting activity is improved even if the amount of Ru as a co-catalyst is reduced.
９．２．光触媒積層体作製時の加熱温度の影響
（実施例７）
実施例６において、実施例１の手法に沿って光触媒積層体を作製する際、真空蒸着によるＡｕの積層後、且つ、カーボンテープの接着前に、加熱温度４７３Ｋで２０分保持したほかは、実施例６と同様の手法で積層体を得た後、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表３に示す。
9.2. Effect of heating temperature on preparation of photocatalyst laminate (Example 7)
In Example 6, when producing the photocatalyst laminate in accordance with the method of Example 1, after holding the Au by vacuum deposition and before bonding the carbon tape, it was carried out for 20 minutes at a heating temperature of 473K. After obtaining a laminated body by the method similar to Example 6, water splitting reaction activity was evaluated by the same method as Example 2. FIG. The results are shown in Table 3 below.
（実施例８）
加熱保持温度を５７３Ｋとしたほかは、実施例７と同様の手法で積層体を得た後、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表３に示す。
(Example 8)
Except that the heating and holding temperature was 573 K, a laminate was obtained in the same manner as in Example 7, and then the water splitting reaction activity was evaluated in the same manner as in Example 2. The results are shown in Table 3 below.
（実施例９）
加熱保持温度を６７３Ｋとしたほかは、実施例７と同様の手法で積層体を得た後、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表３に示す。
Example 9
Except that the heating and holding temperature was 673 K, a laminate was obtained in the same manner as in Example 7, and then the water splitting reaction activity was evaluated in the same manner as in Example 2. The results are shown in Table 3 below.
（実施例１０）
加熱保持温度を７７３Ｋとしたほかは、実施例７と同様の手法で積層体を得た後、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表３に示す。
(Example 10)
Except that the heating and holding temperature was 773 K, a laminate was obtained by the same method as in Example 7, and then the water splitting reaction activity was evaluated by the same method as in Example 2. The results are shown in Table 3 below.
（実施例１１）
実施例６において、実施例１の手法に沿って光触媒積層体を作製する際、光触媒粒子層１へ真空蒸着によりＡｕを積層する前に、加熱温度５７３Ｋで２０分保持し、Ａｕ積層後の加熱を行わなかったほかは、実施例７と同様の手法で積層体を得た後、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表３に示す。
(Example 11)
In Example 6, when producing a photocatalyst laminate in accordance with the method of Example 1, before laminating Au to the photocatalyst particle layer 1 by vacuum deposition, the heating temperature was maintained at 573 K for 20 minutes, and heating after Au lamination was performed. Except not having performed, after obtaining the laminated body by the method similar to Example 7, water splitting reaction activity was evaluated by the same method as Example 2. FIG. The results are shown in Table 3 below.
表３に示す結果から明らかなように、光触媒積層体を作製する場合においては、光触媒粒子層とコンタクト層とを設けた後で加熱することによって、水分解活性がさらに向上することが分かった。特に、本実施例にて採用した材料においては、４７３Ｋ〜６７３Ｋで加熱を行った場合に、加熱を行わなかった場合よりも水分解活性が向上した。加熱によって光触媒粒子層がコンタクト層に密着させることができ、界面抵抗が低減されたためと考えられる。尚、加熱温度は用いる材料によって適宜決定できるものと考えられる。 As is clear from the results shown in Table 3, it was found that in the production of the photocatalyst laminate, the water splitting activity was further improved by heating after providing the photocatalyst particle layer and the contact layer. In particular, in the material employed in this example, when the heating was performed at 473 K to 673 K, the water splitting activity was improved as compared with the case where the heating was not performed. It is thought that the photocatalyst particle layer was brought into close contact with the contact layer by heating, and the interface resistance was reduced. In addition, it is thought that heating temperature can be determined suitably with the material to be used.
９．３．光触媒積層体作製時の加熱保持時間の影響
（実施例１２）
加熱保持時間を１０分としたほかは、実施例８と同様の手法で積層体を得た後、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表４に示す。
9.3. Effect of heating and holding time during production of photocatalyst laminate (Example 12)
Except for setting the heating and holding time to 10 minutes, a laminate was obtained by the same method as in Example 8, and then the water splitting reaction activity was evaluated by the same method as in Example 2. The results are shown in Table 4 below.
（実施例１３）
加熱保持時間を３０分としたほかは、実施例８と同様の手法で積層体を得た後、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表４に示す。
(Example 13)
Except for setting the heating and holding time to 30 minutes, a laminate was obtained in the same manner as in Example 8, and then the water splitting reaction activity was evaluated in the same manner as in Example 2. The results are shown in Table 4 below.
表４に示す結果から明らかなように、光触媒積層体の作製時の加熱保持時間を適切な時間に調整することで、水分解活性がさらに向上することが分かった。尚、本実施例では、加熱保持時間としては約２０分が最適であったが、光触媒粒子の種類や大きさ等によって、最適な時間は異なるものと考えられる。 As is clear from the results shown in Table 4, it was found that the water splitting activity was further improved by adjusting the heating and holding time during preparation of the photocatalyst laminate to an appropriate time. In this example, the optimum heating and holding time was about 20 minutes, but it is considered that the optimal time varies depending on the type and size of the photocatalyst particles.
９．４．助触媒担持量の影響
（実施例１４）
助触媒前駆体であるＲｕＣｌ３含有量を０μｍｏｌとしたほかは実施例８と同様の手法で積層体を得た後、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表５に示す。
9.4. Effect of the amount of promoter supported (Example 14)
A layered product was obtained in the same manner as in Example 8 except that the content of RuCl 3 as the cocatalyst precursor was changed to 0 μmol, and the water splitting reaction activity was evaluated in the same manner as in Example 2. The results are shown in Table 5 below.
（実施例１５）
助触媒前駆体であるＲｕＣｌ３含有量を０．１μｍｏｌとしたほかは実施例８と同様の手法で積層体を得た後、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表５に示す。
(Example 15)
A layered product was obtained in the same manner as in Example 8 except that the content of RuCl 3 as a cocatalyst precursor was 0.1 μmol, and then the water splitting reaction activity was evaluated in the same manner as in Example 2. The results are shown in Table 5 below.
（実施例１６）
助触媒前駆体であるＲｕＣｌ３含有量を０．３５μｍｏｌとしたほかは実施例８と同様の手法で積層体を得た後、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表５に示す。
(Example 16)
A layered product was obtained in the same manner as in Example 8 except that the content of RuCl 3 as a cocatalyst precursor was 0.35 μmol, and the water splitting reaction activity was evaluated in the same manner as in Example 2. The results are shown in Table 5 below.
表５に示す結果から明らかなように、助触媒の担持量が多過ぎても少な過ぎても、水分解活性が低下することが分かった。助触媒が多過ぎると、光触媒粒子による光吸収が阻害され、逆に水分解活性が低下したものと考えられる。尚、本実施例では、ＲｕＣｌ３量として０．１５〜０．２５μｍｏｌ程度とすると良好な結果が得られたが、最適範囲は光触媒粒子の種類や助触媒の種類によって適宜決定可能と考えられる。 As is clear from the results shown in Table 5, it was found that the water splitting activity was lowered when the amount of the promoter supported was too much or too little. If there are too many cocatalysts, light absorption by the photocatalyst particles is hindered, and conversely, water splitting activity is considered to have decreased. In this example, good results were obtained when the amount of RuCl 3 was about 0.15 to 0.25 μmol, but it is considered that the optimum range can be appropriately determined depending on the type of photocatalyst particles and the type of promoter.
９．５．助触媒の種類の影響
（実施例１７）
助触媒前駆体としてＲｕＣｌ３を０．２μｍｏｌ、Ｃｒ（ＮＯ３）３を０．１μｍｏｌ（Ｃｒ２Ｏ３として０．０５μｍｏｌ）添加したほかは実施例８と同様の手法で積層体を得た後、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表６に示す。
9.5. Effect of promoter type (Example 17)
After obtaining a laminate in the same manner as in Example 8, except that 0.2 μmol of RuCl 3 and 0.1 μmol of Cr (NO 3 ) 3 (0.05 μmol as Cr 2 O 3 ) were added as a cocatalyst precursor. The water splitting reaction activity was evaluated in the same manner as in Example 2. The results are shown in Table 6 below.
（実施例１８）
助触媒前駆体としてＲｕＣｌ３を０．２μｍｏｌ、Ｃｒ（ＮＯ３）３を０．２μｍｏｌ（Ｃｒ２Ｏ３として０．１μｍｏｌ）添加したほかは実施例８と同様の手法で積層体を得た後、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表６に示す。
(Example 18)
After obtaining a laminate in the same manner as in Example 8, except that 0.2 μmol of RuCl 3 and 0.2 μmol of Cr (NO 3 ) 3 (0.1 μmol as Cr 2 O 3 ) were added as the cocatalyst precursor. The water splitting reaction activity was evaluated in the same manner as in Example 2. The results are shown in Table 6 below.
（実施例１９）
助触媒前駆体としてＲｕＣｌ３を０．２μｍｏｌ、Ｃｒ（ＮＯ３）３を０．３μｍｏｌ（Ｃｒ２Ｏ３として０．１５μｍｏｌ）添加したほかは実施例８と同様の手法で積層体を得た後、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表６に示す。
(Example 19)
After obtaining a laminate in the same manner as in Example 8, except that 0.2 μmol of RuCl 3 and 0.3 μmol of Cr (NO 3 ) 3 (0.15 μmol as Cr 2 O 3 ) were added as a cocatalyst precursor. The water splitting reaction activity was evaluated in the same manner as in Example 2. The results are shown in Table 6 below.
（実施例２０）
助触媒前駆体としてＲｕＣｌ３を０．２μｍｏｌ、Ｃｒ（ＮＯ３）３を０．４μｍｏｌ（Ｃｒ２Ｏ３として０．２μｍｏｌ）添加したほかは実施例８と同様の手法で積層体を得た後、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表６に示す。
(Example 20)
After obtaining a laminate in the same manner as in Example 8, except that 0.2 μmol of RuCl 3 and 0.4 μmol of Cr (NO 3 ) 3 (0.2 μmol as Cr 2 O 3 ) were added as a cocatalyst precursor. The water splitting reaction activity was evaluated in the same manner as in Example 2. The results are shown in Table 6 below.
表６に示す結果から明らかなように、複数種類の助触媒を併用し、量比を最適化することによって、水分解活性をさらに向上できることが分かった。Ｃｒ２Ｏ３を逐次的に光電析することでＣｒ２Ｏ３膜がＲｕ助触媒上に形成され、副反応が抑制されるために活性が向上したと考えられる。尚、本実施例では、Ｃｒ２Ｏ３量として０．１〜０．２μｍｏｌ程度とすると良好な結果が得られたが、最適範囲は光触媒粒子の種類や組み合わせる助触媒の種類によって適宜決定可能と考えられる。 As is clear from the results shown in Table 6, it was found that the water splitting activity can be further improved by using a plurality of types of promoters together and optimizing the quantity ratio. Cr 2 O 3 to sequentially Cr 2 O 3 film by optical electrodeposition is formed on the Ru cocatalyst is believed that side reactions with improved activity to be inhibited. In this example, good results were obtained when the amount of Cr 2 O 3 was about 0.1 to 0.2 μmol, but the optimum range can be determined as appropriate depending on the type of photocatalyst particles and the type of cocatalyst to be combined. Conceivable.
９．６．水素発生用光触媒と酸素発生用光触媒との質量比の影響
（実施例２１）
水素発生用光触媒粒子１ａとしてＳｒＴｉＯ３：Ｌａ／Ｒｈと酸素発生用光触媒粒子１ｂとしてＢｉＶＯ４：Ｍｏとを、質量比で水素発生用：酸素発生用＝５：１で使用したほかは、実施例８と同様の手法で積層体を得た後、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表７に示す。
9.6. Example 21 Influence of Mass Ratio of Hydrogen Generation Photocatalyst and Oxygen Generation Photocatalyst
Except that SrTiO 3 : La / Rh was used as the photocatalyst particle 1a for hydrogen generation and BiVO 4 : Mo was used as the photocatalyst particle 1b for oxygen generation at a mass ratio of hydrogen generation: oxygen generation = 5: 1. After obtaining a laminate by the same method as in No. 8, water splitting reaction activity was evaluated by the same method as in Example 2. The results are shown in Table 7 below.
（実施例２２）
水素発生用光触媒粒子１ａとしてＳｒＴｉＯ３：Ｌａ／Ｒｈと酸素発生用光触媒粒子１ｂとしてＢｉＶＯ４：Ｍｏとを、質量比で水素発生用：酸素発生用＝２：１で使用したほかは、実施例８と同様の手法で積層体を得た後、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表７に示す。
(Example 22)
Except that SrTiO 3 : La / Rh was used as the hydrogen generating photocatalyst particle 1a and BiVO 4 : Mo was used as the oxygen generating photocatalyst particle 1b at a mass ratio of hydrogen generating: oxygen generating = 2: 1. After obtaining a laminate by the same method as in No. 8, water splitting reaction activity was evaluated by the same method as in Example 2. The results are shown in Table 7 below.
（実施例２３）
水素発生用光触媒粒子１ａとしてＳｒＴｉＯ３：Ｌａ／Ｒｈと酸素発生用光触媒粒子１ｂとしてＢｉＶＯ４：Ｍｏとを、質量比で水素発生用：酸素発生用＝１：２で使用したほかは、実施例８と同様の手法で積層体を得た後、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表７に示す。
(Example 23)
Except that SrTiO 3 : La / Rh was used as the photocatalyst particle 1a for hydrogen generation and BiVO 4 : Mo was used as the photocatalyst particle 1b for oxygen generation, and hydrogen generation: oxygen generation = 1: 2 in mass ratio. After obtaining a laminate by the same method as in No. 8, water splitting reaction activity was evaluated by the same method as in Example 2. The results are shown in Table 7 below.
（実施例２４）
水素発生用光触媒粒子１ａとしてＳｒＴｉＯ３：Ｌａ／Ｒｈと酸素発生用光触媒粒子１ｂとしてＢｉＶＯ４：Ｍｏとを、質量比で水素発生用：酸素発生用＝１：５で使用したほかは、実施例８と同様の手法で積層体を得た後、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表７に示す。
(Example 24)
Except that SrTiO 3 : La / Rh was used as the photocatalyst particle 1a for hydrogen generation and BiVO 4 : Mo was used as the photocatalyst particle 1b for oxygen generation at a mass ratio for hydrogen generation: oxygen generation = 1: 5. After obtaining a laminate by the same method as in No. 8, water splitting reaction activity was evaluated by the same method as in Example 2. The results are shown in Table 7 below.
表７に示す結果から明らかなように、水素発生用光触媒と酸素発生用光触媒との質量比には最適な値が存在することが分かった。なお、本実施例では、質量比１：１が最適であったが、光触媒粒子の種類や粒子サイズ、表面積、水素発生用助触媒と酸素発生用助触媒の活性比等によって、最適な比率は異なるものと考えられる。 As is clear from the results shown in Table 7, it was found that there was an optimum value for the mass ratio between the hydrogen generating photocatalyst and the oxygen generating photocatalyst. In this example, the mass ratio of 1: 1 was optimal. However, the optimal ratio depends on the type and particle size of the photocatalyst particles, the surface area, the activity ratio of the hydrogen generation promoter and the oxygen generation promoter, and the like. It is considered different.
９．７．蒸着法の影響
（実施例２５）
Ａｕ積層時に真空蒸着（ＴＶＥ）ではなく電子ビーム蒸着（ＥＢＥ）を４００℃で実施したほかは、実施例１８と同様の手法で積層体を得た後、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表８に示す。
9.7. Effect of evaporation method (Example 25)
A layered product was obtained in the same manner as in Example 18 except that electron beam evaporation (EBE) was performed at 400 ° C. instead of vacuum evaporation (TVE) when Au was laminated. Activity was evaluated. The results are shown in Table 8 below.
表８に示す結果から明らかなように、コンタクト層の蒸着法については特に制限がなく、光触媒粒子層にコンタクト層を適切に積層できる方法であれば、いずれの蒸着法を用いても所望の効果が奏されることが分かった。 As is apparent from the results shown in Table 8, there is no particular limitation on the contact layer deposition method, and any desired deposition effect can be used as long as the contact layer can be appropriately stacked on the photocatalyst particle layer. Was found to be played.
９．８．光水分解温度の影響
（実施例２６）
実施例２５で得られた光触媒積層体の水分解活性を評価するにあたり、ソーラーシミュレータ（朝日分光株式会社製、HAL-320、ＡＭ１．５、以下同様）を光源として用い、水温を２７９Ｋに調節したほかは実施例２と同様に水分解活性を評価した。結果を下記表９に示す。尚、光源としてＸｅランプを用いた場合とソーラーシミュレータを用いた場合とでは、光触媒の水分解活性が異なるものとなる。
9.8. Effect of photohydrolysis temperature (Example 26)
In evaluating the water splitting activity of the photocatalyst laminate obtained in Example 25, a solar simulator (manufactured by Asahi Spectroscopic Co., Ltd., HAL-320, AM1.5, the same applies below) was used as a light source, and the water temperature was adjusted to 279K. Otherwise, water splitting activity was evaluated in the same manner as in Example 2. The results are shown in Table 9 below. Note that the water splitting activity of the photocatalyst is different between the case where the Xe lamp is used as the light source and the case where the solar simulator is used.
（実施例２７）
水温を２９１Ｋに調節したほかは実施例２６と同様に水分解活性を評価した。結果を下記表９に示す。
(Example 27)
The water splitting activity was evaluated in the same manner as in Example 26 except that the water temperature was adjusted to 291K. The results are shown in Table 9 below.
（実施例２８）
水温を２９８Ｋに調節したほかは実施例２６と同様に水分解活性を評価した。結果を下記表９に示す。
(Example 28)
The water splitting activity was evaluated in the same manner as in Example 26 except that the water temperature was adjusted to 298K. The results are shown in Table 9 below.
（実施例２９）
水温を３０８Ｋに調節したほかは実施例２６と同様に水分解活性を評価した。結果を下記表９に示す。
(Example 29)
The water splitting activity was evaluated in the same manner as in Example 26 except that the water temperature was adjusted to 308K. The results are shown in Table 9 below.
（実施例３０）
水温を３１３Ｋに調節したほかは実施例２５と同様に水分解活性を評価した。結果を下記表９に示す。
(Example 30)
The water splitting activity was evaluated in the same manner as in Example 25 except that the water temperature was adjusted to 313K. The results are shown in Table 9 below.
（実施例３１）
水温を３１８Ｋに調節したほかは実施例２５と同様に水分解活性を評価した。結果を下記表９に示す。
(Example 31)
The water splitting activity was evaluated in the same manner as in Example 25 except that the water temperature was adjusted to 318K. The results are shown in Table 9 below.
（実施例３２）
実施例８で得られた光触媒積層体の水分解活性を評価するにあたり、ソーラーシミュレータを光源として用い、水温を２７９Ｋに調節したほかは実施例２と同様に水分解活性を評価した。結果を下記表１０に示す。
(Example 32)
In evaluating the water splitting activity of the photocatalyst laminate obtained in Example 8, the water splitting activity was evaluated in the same manner as in Example 2 except that the solar simulator was used as a light source and the water temperature was adjusted to 279K. The results are shown in Table 10 below.
（実施例３３）
水温を２８８Ｋに調節したほかは実施例３２と同様に水分解活性を評価した。結果を下記表１０に示す。
(Example 33)
The water splitting activity was evaluated in the same manner as in Example 32 except that the water temperature was adjusted to 288K. The results are shown in Table 10 below.
（実施例３４）
水温を２９７Ｋに調節したほかは実施例３２と同様に水分解活性を評価した。結果を下記表１０に示す。
(Example 34)
The water splitting activity was evaluated in the same manner as in Example 32 except that the water temperature was adjusted to 297K. The results are shown in Table 10 below.
（実施例３５）
水温を３０９Ｋに調節したほかは実施例３２と同様に水分解活性を評価した。結果を下記表１０に示す。
(Example 35)
The water splitting activity was evaluated in the same manner as in Example 32 except that the water temperature was adjusted to 309K. The results are shown in Table 10 below.
（実施例３６）
水温を３１５Ｋに調節したほかは実施例３２と同様に水分解活性を評価した。結果を下記表１０に示す。
(Example 36)
The water splitting activity was evaluated in the same manner as in Example 32 except that the water temperature was adjusted to 315K. The results are shown in Table 10 below.
表９、１０に示す結果から明らかなように、光水分解反応時の温度（水温）ができるだけ高いほうが、水分解活性が高くなることが分かった。本実施例では、特に３００Ｋを超える温度においては、水素発生量が１０μｍｏｌ／（ｈ・ｃｍ２）を超える高い水分解活性が得られた。例えば、本発明に係る光触媒積層体を備えた光触媒モジュールを高温環境（例えば、日中の屋外や、砂漠や、廃熱を利用可能な環境等）で稼働させることで、効率的に水分解反応を生じさせることができると考えられる。 As is clear from the results shown in Tables 9 and 10, it was found that the water splitting activity increases as the temperature (water temperature) during the photowater splitting reaction is as high as possible. In this example, particularly at a temperature exceeding 300 K, a high water splitting activity with a hydrogen generation amount exceeding 10 μmol / (h · cm 2 ) was obtained. For example, the photocatalyst module provided with the photocatalyst laminate according to the present invention is operated in a high temperature environment (for example, outdoors in the daytime, desert, environment where waste heat can be used, etc.), thereby efficiently performing the water splitting reaction. It is thought that can be caused.
９．９．異なる種類の光触媒粒子を用いた場合でも同様の効果が奏されることの確認
９．９．１．水素発生用光触媒粒子について
（比較例３）
０．１ｇの水素発生用光触媒粒子Ｌａ５Ｔｉ２ＣｕＳ５Ｏ７：Ｓｃと０．１ｇの酸素発生用光触媒粒子ＣｏＯｘ／ＢｉＶＯ４：Ｍｏを希硫酸水溶液中（ｐＨ３．５）２００ｍｌに懸濁し、脱気したのち、攪拌しつつ、３００Ｗキセノンランプ（λ＞４２０ｎｍ）を光源として２０時間（光を照射し、水分解反応活性を評価した。なお、ここで水分解反応活性を面積当たりで比較するため、ガス生成速度（μｍｏｌ／ｈ）を反応器内の有効照射面積で除して評価した。結果を下記表１１ に示す。
9.9. Confirmation that the same effect can be obtained even when different types of photocatalyst particles are used 9.9.1. About photocatalyst particles for hydrogen generation (Comparative Example 3)
0.1 g of hydrogen generating photocatalyst particles La 5 Ti 2 CuS 5 O 7 : Sc and 0.1 g of oxygen generating photocatalyst particles CoOx / BiVO 4 : Mo are suspended in 200 ml of dilute sulfuric acid aqueous solution (pH 3.5). After degassing, stirring was performed using a 300 W xenon lamp (λ> 420 nm) as a light source for 20 hours (light irradiation was performed to evaluate water splitting reaction activity. Here, water splitting reaction activity was compared per area. Therefore, the gas generation rate (μmol / h) was divided by the effective irradiation area in the reactor, and the results are shown in Table 11 below.
（比較例４）
水素発生用光触媒粒子としてＬａ５Ｔｉ２ＣｕＳ５Ｏ７：ＳｃのかわりにＲｈＣｒＯｘ／Ｌａ５Ｔｉ２ＣｕＳ５Ｏ７：Ｓｃを使用したほかは比較例３と同様に実施した。結果を下記表１１に示す。
(Comparative Example 4)
La 5 Ti 2 CuS 5 O 7 as a hydrogen-generating photocatalyst particles: RhCrOx instead of Sc / La 5 Ti 2 CuS 5 O 7: addition to using the Sc was carried out in the same manner as Comparative Example 3. The results are shown in Table 11 below.
（実施例３７）
水素発生用光触媒粒子１ａとしてＬａ５Ｔｉ２ＣｕＯ５Ｓ７：Ｓｃ、酸素発生用光触媒粒子１ｂとしてＣｏＯ／ＢｉＶＯ４：Ｍｏを質量比１：１でイソプロパノール中に懸濁して混合物１ｃとし、当該混合物１ｃをガラスからなる第１基材上３ａに積層し、第１基材３ａ上に光触媒粒子層１を形成した。次に、光触媒粒子層１の表面に金を真空蒸着により積層し、光触媒粒子層１の表面に厚み２μｍのコンタクト層２を固定した。次に、コンタクト層２の表面にカーボンテープ（日新ＥＭ株式会社製カーボン両面テープ（不織布基材）およびガラスからなる第２基材３ｂ（厚み０．５５ｍｍ）を接着した後、第２基材３ｂと第１基材３ａとを引き剥がした後、蒸留水中で超音波処理することによって、第１基材３ａとともに不要な光触媒粒子１ａ、１ｂを除去した。得られた光触媒積層体を純水２００ｍｌ中に設置し、３００Ｗキセノンランプ（λ＞４２０ｎｍ）を光源として、光触媒粒子層１に光を照射し、水分解反応活性を評価した。結果を下記表１１に示す。
(Example 37)
La 5 Ti 2 CuO 5 S 7 : Sc as the hydrogen generating photocatalyst particle 1 a and CoO / BiVO 4 : Mo as the oxygen generating photocatalyst particle 1 b in a mass ratio of 1: 1 in isopropanol to form a mixture 1 c, and the mixture 1c was laminated | stacked on the 1st base material 3a which consists of glass, and the photocatalyst particle layer 1 was formed on the 1st base material 3a. Next, gold was laminated on the surface of the photocatalyst particle layer 1 by vacuum deposition, and the contact layer 2 having a thickness of 2 μm was fixed to the surface of the photocatalyst particle layer 1. Next, after adhering a carbon tape (carbon double-sided tape (nonwoven fabric substrate) manufactured by Nissin EM Co., Ltd.) and glass to the surface of the contact layer 2, the second substrate 3b (thickness 0.55 mm) After peeling off 3b and the 1st base material 3a, the unnecessary photocatalyst particle | grains 1a and 1b were removed with the 1st base material 3a by ultrasonically treating in distilled water. The sample was placed in 200 ml, and a 300 W xenon lamp (λ> 420 nm) was used as a light source to irradiate the photocatalyst particle layer 1 to evaluate the water splitting reaction activity, and the results are shown in Table 11 below.
（実施例３８）
水素発生用光触媒粒子１ａとしてＰｔ／Ｌａ５Ｔｉ２ＣｕＯ５Ｓ７：Ｓｃを用いたほかは実施例３７と同様の手法で光触媒積層体を調製し、活性を評価した。結果を表１１に示す。
(Example 38)
A photocatalyst laminate was prepared in the same manner as in Example 37 except that Pt / La 5 Ti 2 CuO 5 S 7 : Sc was used as the photocatalyst particles 1a for hydrogen generation, and the activity was evaluated. The results are shown in Table 11.
（実施例３９）
水素発生用光触媒粒子１ａとしてＲｈＣｒＯｘ／Ｌａ５Ｔｉ２ＣｕＯ５Ｓ７：Ｓｃを用いたほかは実施例３７と同様の手法で光触媒積層体を調製し、活性を評価した。結果を表１１に示す。
(Example 39)
A photocatalyst laminate was prepared in the same manner as in Example 37 except that RhCrOx / La 5 Ti 2 CuO 5 S 7 : Sc was used as the hydrogen-generating photocatalyst particle 1a, and the activity was evaluated. The results are shown in Table 11.
表１１に示す結果から明らかなように、水素発生用光触媒粒子として上述した種類以外のものを用いた場合であっても、シート状のコンタクト層と、コンタクト層の表面に固定された光触媒粒子層と、を備え、光触媒粒子層において、複数の水素発生用光触媒粒子と複数の酸素発生用光触媒粒子とが互いに分散されており、コンタクト層の同一表面側において、複数の水素発生用光触媒粒子の少なくとも一部と複数の酸素発生用光触媒粒子の少なくとも一部とが、コンタクト層と接触している、光触媒積層体とすることで、コンタクト層を設けない場合と比較して、水分解活性を大きく向上させることができた。
尚、コンタクト層を設けずに光触媒粒子を単に成形しただけの場合は、光触媒粒子を水中に分散させた形態（比較例３、４）よりも、水分解活性がさらに低下することが自明である。
As is apparent from the results shown in Table 11, even when a hydrogen generation photocatalyst particle other than the above-mentioned types is used, a sheet-like contact layer and a photocatalyst particle layer fixed on the surface of the contact layer In the photocatalyst particle layer, the plurality of hydrogen generating photocatalyst particles and the plurality of oxygen generating photocatalyst particles are dispersed with each other, and at least one of the plurality of hydrogen generating photocatalyst particles on the same surface side of the contact layer. By making a photocatalyst laminate in which some and at least some of the plurality of photocatalyst particles for oxygen generation are in contact with the contact layer, the water splitting activity is greatly improved compared to the case where no contact layer is provided. I was able to.
In addition, when the photocatalyst particles are simply formed without providing the contact layer, it is obvious that the water splitting activity is further lowered as compared with the form in which the photocatalyst particles are dispersed in water (Comparative Examples 3 and 4). .
９．９．２．酸素発生用光触媒粒子について
（実施例４０）
酸素発生用光触媒粒子１ｂとしてＣｏＯｘ／Ｔａ３Ｎ５を使用し、助触媒前駆体であるＲｕＣｌ３の含有量を０．２μｍｏｌとしたほかは、実施例１と同様の手法で積層体を得た後、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表１２に示す。
9.9.2. Example of photocatalyst particles for oxygen generation (Example 40)
A laminate was obtained in the same manner as in Example 1 except that CoOx / Ta 3 N 5 was used as the photocatalyst particles 1b for oxygen generation and the content of RuCl 3 as the promoter precursor was 0.2 μmol. Thereafter, the water splitting reaction activity was evaluated in the same manner as in Example 2. The results are shown in Table 12 below.
（実施例４１）
酸素発生用光触媒粒子１ｂとしてＣｏＯｘ／ＬａＴｉＯ２Ｎを使用し、助触媒前駆体であるＲｕＣｌ３の含有量を０．２μｍｏｌとしたほかは、実施例１と同様の手法で積層体を得た後、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表１２に示す。
(Example 41)
After obtaining a laminate in the same manner as in Example 1 except that CoOx / LaTiO 2 N was used as the oxygen-generating photocatalyst particles 1b and the content of RuCl 3 as the promoter precursor was 0.2 μmol. The water splitting reaction activity was evaluated in the same manner as in Example 2. The results are shown in Table 12 below.
（比較例５）
酸素発生用光触媒粒子１ｂとしてＣｏＯｘ／ＬａＴｉＯ２Ｎを使用したこと以外は、比較例１と同様の手法で水分解反応活性を評価した。結果を下記表１２に示す。
(Comparative Example 5)
The water splitting reaction activity was evaluated in the same manner as in Comparative Example 1 except that CoOx / LaTiO 2 N was used as the oxygen-generating photocatalyst particles 1b. The results are shown in Table 12 below.
表１２に示す結果から明らかなように、酸素発生用光触媒粒子として上述した種類以外のものを用いた場合であっても、シート状のコンタクト層と、コンタクト層の表面に固定された光触媒粒子層と、を備え、光触媒粒子層において、複数の水素発生用光触媒粒子と複数の酸素発生用光触媒粒子とが互いに分散されており、コンタクト層の同一表面側において、複数の水素発生用光触媒粒子の少なくとも一部と複数の酸素発生用光触媒粒子の少なくとも一部とが、コンタクト層と接触している、光触媒積層体（実施例４０、４１）とすることで、コンタクト層を設けない場合（比較例５）と比較して、水分解活性を大きく向上させることができた。
尚、コンタクト層を設けずに光触媒粒子を単に成形しただけの場合は、光触媒粒子を水中に分散させた形態（比較例５）よりも、水分解活性がさらに低下することが自明である。
As is apparent from the results shown in Table 12, even when a photocatalyst particle for oxygen generation other than the above-mentioned types is used, a sheet-like contact layer and a photocatalyst particle layer fixed on the surface of the contact layer In the photocatalyst particle layer, the plurality of hydrogen generating photocatalyst particles and the plurality of oxygen generating photocatalyst particles are dispersed with each other, and at least one of the plurality of hydrogen generating photocatalyst particles on the same surface side of the contact layer. When a contact layer is not provided by using a photocatalyst laminate (Examples 40 and 41) in which part and at least some of the plurality of photocatalyst particles for oxygen generation are in contact with the contact layer (Comparative Example 5) Compared with), the water splitting activity was greatly improved.
In addition, when the photocatalyst particles are simply formed without providing the contact layer, it is obvious that the water splitting activity is further reduced as compared with the case where the photocatalyst particles are dispersed in water (Comparative Example 5).
９．１０．コンタクト層についての追加実験
（実施例４２）
光触媒粒子層１の表面に真空蒸着する元素を金のかわりにＴｉにしたほかは、実施例６と同様の手法で光触媒積層体を得たのち、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表１３に示す。
9.10. Additional experiment on contact layer (Example 42)
After obtaining the photocatalyst laminate by the same method as in Example 6 except that the element to be vacuum-deposited on the surface of the photocatalyst particle layer 1 is Ti instead of gold, the water splitting reaction activity is obtained by the same method as in Example 2. evaluated. The results are shown in Table 13 below.
（実施例４３）
光触媒粒子層１の表面に真空蒸着する元素を金のかわりにＳｎにしたほかは、実施例６と同様の手法で光触媒積層体を得たのち、実施例２と同じ手法で水分解反応活性を評価した。結果を下記表１３に示す。
(Example 43)
After obtaining the photocatalyst laminate by the same method as in Example 6 except that the element to be vacuum-deposited on the surface of the photocatalyst particle layer 1 is Sn instead of gold, the water splitting reaction activity is obtained by the same method as in Example 2. evaluated. The results are shown in Table 13 below.
表１３に示す結果から明らかなように、コンタクト層としてＴｉやＳｎを用いた場合であっても光水分解活性が得られることがわかった。特に、酸素発生用光触媒粒子の種類が若干異なるものの、コンタクト層を設けない比較例１、２と比べて、実施例４２、４３は良好な光水分解活性が得られた。本結果より、コンタクト層としてはＡｕ以外にも、良好な導電性を持つものであれば好適に使用することが可能であることが明らかである。 As is clear from the results shown in Table 13, it was found that photohydrolysis activity can be obtained even when Ti or Sn is used as the contact layer. In particular, although the types of photocatalyst particles for oxygen generation were slightly different, Examples 42 and 43 exhibited good photohydrolysis activity compared to Comparative Examples 1 and 2 in which no contact layer was provided. From this result, it is apparent that the contact layer can be suitably used as long as it has good conductivity other than Au.
本発明に係る光触媒積層体は、太陽光等を利用して水を分解し、水素及び／又は酸素を製造する際に好適に利用可能である。また、二酸化炭素の光還元による資源化にも利用可能である。或いは、有害な有機化合物及び無機化合物を無害化する空気浄化用途や水質浄化等に利用することもできる。 The photocatalyst laminate according to the present invention can be suitably used when water is decomposed using sunlight or the like to produce hydrogen and / or oxygen. It can also be used for recycling by photoreduction of carbon dioxide. Alternatively, it can also be used for air purification or water purification for detoxifying harmful organic compounds and inorganic compounds.
Claims (18)
前記光触媒粒子層において、複数の水素発生用光触媒粒子と複数の酸素発生用光触媒粒子とが互いに分散されており、
前記コンタクト層の同一表面側において、前記複数の水素発生用光触媒粒子の少なくとも一部と前記複数の酸素発生用光触媒粒子の少なくとも一部とが、前記コンタクト層と接触している、
光触媒積層体。 A sheet-like contact layer, and a photocatalyst particle layer fixed on the surface of the contact layer,
In the photocatalyst particle layer, a plurality of hydrogen generating photocatalyst particles and a plurality of oxygen generating photocatalyst particles are dispersed with each other.
On the same surface side of the contact layer, at least some of the plurality of hydrogen generation photocatalyst particles and at least some of the plurality of oxygen generation photocatalyst particles are in contact with the contact layer,
Photocatalyst laminate.
前記水素発生用光触媒粒子と前記酸素発生用光触媒粒子とがシート状のコンタクト層の同一表面と接触するように、該コンタクト層の表面と前記混合物とを固定する工程と、
を備える、
光触媒積層体の製造方法。 Mixing a photocatalyst particle for hydrogen generation and a photocatalyst particle for oxygen generation to obtain a mixture;
Fixing the surface of the contact layer and the mixture so that the photocatalyst particles for hydrogen generation and the photocatalyst particles for oxygen generation are in contact with the same surface of the sheet-like contact layer;
Comprising
A method for producing a photocatalyst laminate.
前記光触媒粒子層の前記第１基材とは反対側とシート状のコンタクト層とを固定して第１積層体を得る工程と、
前記第１積層体から前記第１基材を除去する工程と、
を備える、請求項７又は８に記載の製造方法。 Laminating the mixture on a first substrate to form a photocatalyst particle layer on the first substrate;
Fixing the opposite side of the photocatalyst particle layer to the first substrate and a sheet-like contact layer to obtain a first laminate;
Removing the first substrate from the first laminate;
The manufacturing method of Claim 7 or 8 provided with these.
前記光触媒粒子層の前記第１基材とは反対側とシート状のコンタクト層とを固定して第１積層体を得る工程と、
前記コンタクト層の前記光触媒粒子層とは反対側と第２基材とを固定して第２積層体を得る工程と、
前記第２積層体から前記第１基材を除去する工程と、
を備える、請求項７又は８に記載の製造方法。 Laminating the mixture on a first substrate to form a photocatalyst particle layer on the first substrate;
Fixing the opposite side of the photocatalyst particle layer to the first substrate and a sheet-like contact layer to obtain a first laminate;
Fixing the opposite side of the contact layer to the photocatalyst particle layer and the second base material to obtain a second laminate;
Removing the first substrate from the second laminate;
The manufacturing method of Claim 7 or 8 provided with these.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2017124344A (en) * | 2016-01-12 | 2017-07-20 | 松下 文夫 | Photocatalyst, production method of photocatalyst and oxidation reduction apparatus |
| CN107362792A (en) * | 2017-06-22 | 2017-11-21 | 江苏大学 | A kind of preparation method of strontium titanates/niobic acid tin composite nano materials |
| WO2018047694A1 (en) * | 2016-09-12 | 2018-03-15 | 信越化学工業株式会社 | Mixture of visible light-responsive photocatalytic titanium oxide fine particles, dispersion liquid thereof, method for producing dispersion liquid, photocatalyst thin film, and member having photocatalyst thin film on surface |
| WO2019239870A1 (en) * | 2018-06-13 | 2019-12-19 | シャープ株式会社 | Photocatalytic sheet |
| WO2020153080A1 (en) * | 2019-01-25 | 2020-07-30 | シャープ株式会社 | Photocatalytic sheet |
| JPWO2019244570A1 (en) * | 2018-06-22 | 2021-06-24 | シャープ株式会社 | Photocatalyst, photocatalyst cluster, photocatalyst dispersion system and method for producing photocatalyst |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110035822B (en) * | 2016-12-12 | 2020-03-17 | 富士胶片株式会社 | Photocatalyst electrode for oxygen generation, method for manufacturing photocatalyst electrode for oxygen generation, and module |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011131170A (en) * | 2009-12-24 | 2011-07-07 | Mitsubishi Chemicals Corp | Electrode for photolytic water decomposition reaction using photocatalyst |
| JP2012188683A (en) * | 2011-03-08 | 2012-10-04 | Mitsui Chemicals Inc | Gas generation apparatus, and gas generation method |
| WO2013133338A1 (en) * | 2012-03-08 | 2013-09-12 | 国立大学法人東京大学 | Electrode for photohydrolysis, and method for manufacturing same |
| WO2014046305A1 (en) * | 2012-09-21 | 2014-03-27 | Toto株式会社 | Composite photocatalyst, and photocatalyst material |
-
2015
- 2015-08-06 WO PCT/JP2015/072433 patent/WO2016039055A1/en active Application Filing
- 2015-08-06 JP JP2015155946A patent/JP2016059920A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011131170A (en) * | 2009-12-24 | 2011-07-07 | Mitsubishi Chemicals Corp | Electrode for photolytic water decomposition reaction using photocatalyst |
| JP2012188683A (en) * | 2011-03-08 | 2012-10-04 | Mitsui Chemicals Inc | Gas generation apparatus, and gas generation method |
| WO2013133338A1 (en) * | 2012-03-08 | 2013-09-12 | 国立大学法人東京大学 | Electrode for photohydrolysis, and method for manufacturing same |
| WO2014046305A1 (en) * | 2012-09-21 | 2014-03-27 | Toto株式会社 | Composite photocatalyst, and photocatalyst material |
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2017124344A (en) * | 2016-01-12 | 2017-07-20 | 松下 文夫 | Photocatalyst, production method of photocatalyst and oxidation reduction apparatus |
| US11059036B2 (en) | 2016-09-12 | 2021-07-13 | Shin-Etsu Chemical Co., Ltd. | Mixture of visible light-responsive photocatalytic titanium oxide fine particles, dispersion liquid thereof, method for producing dispersion liquid, photocatalyst thin film, and member having photocatalyst thin film on surface |
| WO2018047694A1 (en) * | 2016-09-12 | 2018-03-15 | 信越化学工業株式会社 | Mixture of visible light-responsive photocatalytic titanium oxide fine particles, dispersion liquid thereof, method for producing dispersion liquid, photocatalyst thin film, and member having photocatalyst thin film on surface |
| CN109789396A (en) * | 2016-09-12 | 2019-05-21 | 信越化学工业株式会社 | Visible light responsive photocatalytic titanium oxide microparticle mixture, its dispersion liquid, the manufacturing method of dispersion liquid, photocatalyst film and surface have photocatalyst film component |
| JPWO2018047694A1 (en) * | 2016-09-12 | 2019-06-24 | 信越化学工業株式会社 | Visible light responsive photocatalyst titanium oxide fine particle mixture, dispersion liquid thereof, method of producing dispersion liquid, photocatalyst thin film, and member having photocatalyst thin film on the surface |
| CN109789396B (en) * | 2016-09-12 | 2022-04-05 | 信越化学工业株式会社 | Visible light-responsive photocatalytic titanium oxide fine particle mixture, dispersion liquid thereof, method for producing dispersion liquid, photocatalyst thin film, and member having photocatalyst thin film on surface |
| CN107362792B (en) * | 2017-06-22 | 2020-02-21 | 江苏大学 | Preparation method of strontium titanate/tin niobate composite nano material |
| CN107362792A (en) * | 2017-06-22 | 2017-11-21 | 江苏大学 | A kind of preparation method of strontium titanates/niobic acid tin composite nano materials |
| WO2019239870A1 (en) * | 2018-06-13 | 2019-12-19 | シャープ株式会社 | Photocatalytic sheet |
| JPWO2019244570A1 (en) * | 2018-06-22 | 2021-06-24 | シャープ株式会社 | Photocatalyst, photocatalyst cluster, photocatalyst dispersion system and method for producing photocatalyst |
| JP7110342B2 (en) | 2018-06-22 | 2022-08-01 | シャープ株式会社 | Photocatalytic clusters and photocatalytic dispersion systems |
| WO2020153080A1 (en) * | 2019-01-25 | 2020-07-30 | シャープ株式会社 | Photocatalytic sheet |
| JPWO2020153080A1 (en) * | 2019-01-25 | 2021-11-25 | シャープ株式会社 | Photocatalyst sheet |
| JP7133040B2 (en) | 2019-01-25 | 2022-09-07 | シャープ株式会社 | photocatalyst sheet |
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