Abstract: An object of the present disclosure is to provide a simple, compact optical switch with low power consumption.

Abstract: An objective of the present disclosure is to provide an optical coupler and an optical switch capable of achieving stable optical characteristics with low power consumption and more economical efficiency with respect to external factors.

Abstract: Provided are a photocatalyst electrode for oxygen generation exhibiting a satisfactory onset potential, and a module including this photocatalyst electrode. The photocatalyst electrode for oxygen generation includes a current collector layer; a photocatalyst on the current collector layer; and a promoter supported on at least a portion of the photocatalyst, in which the promoter contains a first metal oxide having an oxygen generation overvoltage of 0.4 V or lower, and a second metal oxide having an oxygen generation overvoltage of higher than 0.4 V.

Abstract: Provided is a method for producing a photocatalyst electrode for water decomposition that exhibits excellent detachability between the substrate and the photocatalyst layer and exhibits high photocurrent density. The method for producing a photocatalyst electrode for water decomposition of the invention includes: a metal layer forming step of forming a metal layer on one surface of a first substrate by a vapor phase film-forming method or a liquid phase film-forming method; a photocatalyst layer forming step of forming a photocatalyst layer by subjecting the metal layer to at least one treatment selected from an oxidation treatment, a nitriding treatment, a sulfurization treatment, or a selenization treatment; a current collecting layer forming step of forming a current collecting layer on a surface of the photocatalyst layer, the surface being on the opposite side of the first substrate; and a detachment step of detaching the first substrate from the photocatalyst layer.

Abstract: The present invention provides a photocatalyst for water splitting which includes barium niobium oxynitride and exhibits excellent water splitting performance and a production method for the same, and a water splitting photoelectrode. The photocatalyst for water splitting of the present invention is a photocatalyst for water splitting including: an optical semiconductor and a promoter supported by the optical semiconductor, in which the optical semiconductor includes barium niobium oxynitride, and the promoter includes at least one substance selected from a group consisting of cobalt oxides and metallic cobalt.

Abstract: Provided are a photocatalyst electrode for oxygen generation exhibiting a satisfactory onset potential, and a module including this photocatalyst electrode. The photocatalyst electrode for oxygen generation includes a current collector layer; a photocatalyst on the current collector layer; and a promoter supported on at least a portion of the photocatalyst, in which the promoter contains a first metal oxide having an oxygen generation overvoltage of 0.4 V or lower, and a second metal oxide having an oxygen generation overvoltage of higher than 0.4 V.

Abstract: Provided is a method for producing a photocatalyst electrode for water decomposition that exhibits excellent detachability between the substrate and the photocatalyst layer and exhibits high photocurrent density. The method for producing a photocatalyst electrode for water decomposition of the invention includes: a metal layer forming step of forming a metal layer on one surface of a first substrate by a vapor phase film-forming method or a liquid phase film-forming method; a photocatalyst layer forming step of forming a photocatalyst layer by subjecting the metal layer to at least one treatment selected from an oxidation treatment, a nitriding treatment, a sulfurization treatment, or a selenization treatment; a current collecting layer forming step of forming a current collecting layer on a surface of the photocatalyst layer, the surface being on the opposite side of the first substrate; and a detachment step of detaching the first substrate from the photocatalyst layer.

Abstract: The present invention is to provide a photocatalyst electrode for water decomposition exhibiting a high photocurrent density and having reduced dark current. The photocatalyst electrode for water decomposition of the present invention has a photocatalyst layer and a current collector layer that is formed by a vapor deposition method and is disposed on the photocatalyst layer.

Abstract: The present invention provides a photocatalyst for water splitting which includes barium niobium oxynitride and exhibits excellent water splitting performance and a production method for the same, and a water splitting photoelectrode. The photocatalyst for water splitting of the present invention is a photocatalyst for water splitting including: an optical semiconductor and a promoter supported by the optical semiconductor, in which the optical semiconductor includes barium niobium oxynitride, and the promoter includes at least one substance selected from a group consisting of cobalt oxides and metallic cobalt.