Abstract: A photocatalytic member comprises a base and a photocatalytic layer fixed on the base. The photocatalytic layer comprises first photocatalyst particles being visible light responsive photocatalyst particles for hydrogen generation, second photocatalyst particles being visible light responsive photocatalyst particles for oxygen generation, and conductive particles which are provided between the first photocatalyst particle and the second photocatalyst particle, have Fermi level at a negative position relative to an electronic energy level at the upper end of the valence band of the first photocatalyst particle and at a positive position relative to an electronic energy level at the bottom end of the conduction band of the second photocatalyst particle, and are able to store an electron and a hole. In the photocatalytic layer, the conductive particles are located to be coupled to both the first photocatalyst particles and the second photocatalyst particles.

Abstract: Disclosed are metal nitride photocatalyst particles and/or metal oxynitride photocatalyst particles having high dispersibility. The metal nitride photocatalyst particles and/or metal oxynitride photocatalyst particles having high dispersibility can be obtained by containing metal nitride photocatalyst particles and/or metal oxynitride photocatalyst particles, which are capable of splitting water under visible light irradiation, and a phosphoric acid polymer that is adsorbed on the surface of the particles. Further, because these particles have high photocatalytic activity under visible light irradiation, splitting water by using these particles can generate hydrogen and/or oxygen with high efficiency.

Abstract: A photocatalytic member comprises a base and a photocatalytic layer fixed on the base. The photocatalytic layer comprises first photocatalyst particles being visible light responsive photocatalyst particles for hydrogen generation, second photocatalyst particles being visible light responsive photocatalyst particles for oxygen generation, and conductive particles which are provided between the first photocatalyst particle and the second photocatalyst particle, have Fermi level at a negative position relative to an electronic energy level at the upper end of the valence band of the first photocatalyst particle and at a positive position relative to an electronic energy level at the bottom end of the conduction band of the second photocatalyst particle, and are able to store an electron and a hole. In the photocatalytic layer, the conductive particles are located to be coupled to both the first photocatalyst particles and the second photocatalyst particles.

Abstract: Disclosed are metal nitride photoctalyst particles and/or metal oxynitride photocatalyst particles having high dispersibility. The metal nitride photoctalyst particles and/or metal oxynitride photocatalyst particles having high dispersibility can be obtained by containing metal nitride photoctalyst particles and/or metal oxynitride photocatalyst particles, which are capable of splitting water under visible light irradiation, and a phosphoric acid polymer that is adsorbed on the surface of the particles. Further, because these particles have high photocatalytic activity under visible light irradiation, splitting water by using these particles can generate hydrogen and/or oxygen with high efficiency.

Abstract: Disclosed is a visible light responsive photocatalyst that simultaneously realizes high crystallinity and refinement of primary particles. Also disclosed is a photocatalyst composed of secondary particles that have a high porosity and are aggregates of fine primary particles. Rhodium-doped strontium titanate that is a visible light responsive photocatalyst of the present invention has a primary particle diameter of not more than 70 nm and has a absorbance at a wavelength of 570 nm of not less than 0.6 and a absorbance at a wavelength of 1800 nm of not more than 0.7, each absorbance determining by measuring a diffuse reflection spectrum, the rhodium-doped strontium titanate having a high water-splitting activity as a photocatalyst.

Abstract: Disclosed is a visible light responsive photocatalytic member having a substrate covered with photocatalyst particles which are capable of generating hydrogen, wherein the said particles are made so as to be compatible in both high crystallinity and refining of the primary particles thereof. The photocatalytic member of the present invention is the visible light responsive photocatalytic member having the primary particle diameter thereof of 100 nm or less, wherein a photocatalytic layer containing the photocatalyst particles, which are capable of generating hydrogen, is immobilized on the substrate. More preferably, the said material has pores with the size of 10 to 200 nm inclusive among the photocatalyst particles. With this, water decomposition with a high photocatalytic activity under visible light irradiation can be realized.

Abstract: Disclosed is a method for producing metal oxide particles having high crystallinity and a small primary particle diameter. The method for producing the metal oxide particles according to the present invention comprises: a step of providing an aqueous dispersion comprising a water-soluble transition metal complex and water-dispersible organic polymer particles, wherein the water-soluble transition metal complex comprises one transition metal ion selected from a titanium ion, a tantalum ion, and a niobium ion; as well as a hydrophobic complexing agent and a hydrophilic complexing agent both being coordinated with the transition metal ion; drying the aqueous dispersion to produce a dried body; and firing the dried body.

Abstract: Disclosed is a composite photocatalyst comprising photocatalyst particles for hydrogen generation and photocatalyst particles for oxygen generation that possess a high activity level of splitting water under visible light irradiation. Also disclosed is a photocatalytic member comprising a composite photocatalyst-containing photocatalytic layer fixed on a substrate. The composite photocatalyst comprises visible light responsive photocatalyst particles for hydrogen generation having a primary particle diameter of not more than 100 nm and visible light responsive photocatalyst particles for oxygen generation, the visible light responsive photocatalyst particles for hydrogen generation being in contact with the visible light responsive photocatalyst particles for oxygen generation.

Abstract: Disclosed is a visible light responsive photocatalyst that simultaneously realizes high crystallinity and refinement of primary particles. Also disclosed is a photocatalyst composed of secondary particles that have a high porosity and are aggregates of fine primary particles. Rhodium-doped strontium titanate that is a visible light responsive photocatalyst of the present invention has a primary particle diameter of not more than 70 nm and has a absorbance at a wavelength of 570 nm of not less than 0.6 and a absorbance at a wavelength of 1800 nm of not more than 0.7, each absorbance determining by measuring a diffuse reflection spectrum, the rhodium-doped strontium titanate having a high water-splitting activity as a photocatalyst.