Abstract: A semiconductor photoelectrode includes a conductive or insulating substrate having a moth-eye structure on a surface; a semiconductor thin film disposed on a surface having the moth-eye structure of the substrate; a catalyst layer disposed on the semiconductor thin film; and a reflection layer disposed on a surface opposite to the surface having the moth-eye structure of the substrate.

Abstract: A porous electrode-supported electrolyte membrane used in a gas phase reduction device for reducing carbon dioxide includes an electrolyte membrane and a porous reduction electrode bonded to the electrolyte membrane, and a surface of a hole of the porous reduction electrode is coated with a conductive first plating film.

Abstract: There is provided an electrolyte membrane that is disposed between an electrolytic solution in an oxidation tank and a reduction electrode in a reduction tank to be in contact with both the electrolytic solution and the reduction electrode and is used in a carbon dioxide reduction device which performs a carbon dioxide reduction reaction by bringing carbon dioxide into direct contact with the reduction electrode, the electrolyte membrane including: a water-repellent film on a part of a surface which is in contact with the electrolytic solution.

Abstract: A carbon dioxide reduction device includes: an oxidation electrode that receives light from the outside; an oxidation bath that holds an electrolytic solution in which the oxidation electrode is immersed; an electrolyte membrane that constitutes a part of one surface of the oxidation bath excluding a surface on which the light is incident; a reduction electrode that is connected to the electrolyte membrane; a reduction unit in which the reduction electrode is disposed and to which a gas containing carbon dioxide is supplied from the outside; and a blower that generates an airflow toward the reduction electrode inside the reduction unit. The reduction electrode has a plate shape, and one surface of the reduction electrode is in contact with the electrolyte membrane.

Abstract: Improvement in the efficiency of carbon dioxide reduction reaction is achieved. A gas supply unit having a plurality of pores is established in a lower portion of a reduction chamber, and carbon dioxide is supplied as bubbles into an aqueous solution. This can elevate a concentration of carbon dioxide dissolved in the aqueous solution without stirring the aqueous solution using a stirring bar, and render the concentration uniform in the aqueous solution. Therefore, the efficiency of reduction reaction of carbon dioxide in a reduction electrode can be improved.

Abstract: A porous electrode-supported electrolyte membrane according to the present embodiment includes an electrolyte membrane and a porous reduction electrode directly bonded onto the electrolyte membrane, in which the porous reduction electrode has an average pore diameter of 1 ?m or more. In a step of bonding the electrolyte membrane and the porous reduction electrode, pressure is applied while heat is applied so that the electrolyte membrane is prevented from swelling.

Abstract: A gas phase reduction device for carbon dioxide is a gas phase reduction device for carbon dioxide that exerts a catalytic function by light irradiation to generate oxidation-reduction reaction. The gas phase reduction device includes an oxidation tank in which an aqueous solution is put, a reduction tank to which carbon dioxide is supplied, a semiconductor photoelectrode installed in the aqueous solution, and a porous electrode-supported electrolyte membrane that is a joint body of an electrolyte membrane and a porous reduction electrode, the porous electrode-supported electrolyte membrane being installed between the oxidation tank and the reduction tank with the electrolyte membrane facing the oxidation tank and the porous reduction electrode facing the reduction tank.

Abstract: Provided is a semiconductor photoelectrode that exhibits a catalytic function with light irradiation to cause an oxidation-reduction reaction. The semiconductor photoelectrode includes: a conductive or insulating substrate; a semiconductor thin film disposed on the surface of the substrate; a catalyst layer disposed on the surface of the semiconductor thin film; a light transmission layer disposed in a lattice shape on the surface of the catalyst layer; and a protective layer disposed to cover the rear surface of the substrate and the side surfaces of the substrate and the semiconductor thin film. The semiconductor photoelectrode having another configuration includes a second semiconductor thin film disposed between the semiconductor thin film and the catalyst layer.

Abstract: A carbon dioxide gas-phase reduction apparatus includes: an oxidation tank including an oxidation electrode; a reduction tank which is adjacent to the oxidation tank and into which carbon dioxide is supplied when the inside of the reduction tank is empty; and a porous reduction electrode-supporting electrolyte membrane disposed between the oxidation tank and the reduction tank. The porous reduction electrode-supporting electrolyte membrane is a joint body obtained by joining a porous reduction electrode formed by dispersing a first electrolyte membrane inside voids and a second electrolyte membrane. The second electrolyte membrane is disposed on the oxidation tank side. The porous reduction electrode is disposed on the reduction tank side, connected to the oxidation electrode by a conducting wire, and performs a reduction reaction with the carbon dioxide in the reduction tank by electrons flowing through the conducting wire.

Abstract: A semiconductor photoelectrode includes a conductive or insulating substrate, a semiconductor thin film disposed on a surface of substrate and having an uneven structure on the surface, a catalytic layer disposed along the uneven structure on the surface of semiconductor thin film, and a protective layer disposed to cover a back surface of substrate and side surfaces of substrate and semiconductor thin film.

Abstract: Included are an oxidation electrode that is formed in a film state on a transparent substrate and receives light from the outside, an oxidation bath that holds an electrolytic solution in which the oxidation electrode is immersed, a reduction electrode, a reduction bath that holds the electrolytic solution, in which the reduction electrode is immersed and which is subjected to bubbling with carbon dioxide from the outside, an electrolyte membrane that is disposed between the oxidation bath and the reduction bath and divides the electrolytic solution into an oxidation side and a reduction side, and a thermoelectric element including a heat absorbing plate that faces the transparent substrate, receives light transmitted through the transparent substrate, and converts the light into heat, including a heat radiation plate that faces the heat absorbing plate and radiates the heat of the heat absorbing plate, including thermoelectric materials interposed between the heat absorbing plate and the heat radiation plate

Abstract: A semiconductor device includes a semiconductor layer, which is disposed on the surface of a substrate and causing an oxidation reaction and a reduction reaction when irradiated with light, an oxidation catalyst layer, which is disposed on part of the surface of the semiconductor layer, forms along with the semiconductor layer a Schottky junction, and oxidizes an oxidation target substance, a reduction catalyst layer, which is disposed on part of the surface of the semiconductor layer where the oxidation catalyst layer is not disposed so as to be separated from the oxidation catalyst layer, forms along with the semiconductor layer an ohmic junction, and reduces a reduction target substance, and an insulation layer, which is disposed on the entirety of the surface of the semiconductor layer where none of the oxidation catalyst layer and the reduction catalyst layer is disposed so as to be in contact with the oxidation catalyst layer and the reduction catalyst layer.

Abstract: The nitride semiconductor photocatalytic thin film of the present embodiment is a nitride semiconductor photocatalytic thin film that exhibits a catalytic function to cause a redox reaction by light irradiation. The nitride semiconductor photocatalytic thin film includes: a conductive substrate; a semiconductor thin film disposed on a surface of the conductive substrate; a first catalyst layer that forms an ohmic junction on a portion of a surface of the semiconductor thin film; a second catalyst layer that forms a Schottky junction on a portion of the surface of the semiconductor thin film, and a protective layer disposed to cover a back surface of the conductive substrate and side surfaces of the conductive substrate and the semiconductor thin film. The substrate and the semiconductor thin film include a same element and have a same crystal structure.

Abstract: A gas phase reduction apparatus of carbon dioxide includes an oxidation chamber that includes an oxidation electrode; a reduction chamber that is adjacent to the oxidation chamber and receives supplied carbon dioxide; and a porous electrode-supporting electrolyte membrane that is placed between the oxidation chamber and the reduction chamber. The porous electrode-supporting electrolyte membrane is a joined body including a porous reduction electrode joined to an electrolyte membrane. The electrolyte membrane is placed on the oxidation chamber side. The porous reduction electrode is placed on the reduction chamber side and configured to reduce the carbon dioxide by electrons from the oxidation electrode connected via a conductor.

Abstract: A semiconductor photoelectrode that is to be located in an aqueous solution to cause a decomposition reaction of the aqueous solution upon being irradiated with light, the semiconductor photoelectrode including: a semiconductor layer that is formed on an insulative or conductive substrate and is provided with a plurality of protrusion structures that protrude in one direction that is opposite a direction in which the substrate is located; a catalyst layer that is continuously laminated on the surface of the semiconductor layer; and a wire that is electrically connected to the semiconductor layer.

Abstract: A gas-phase reduction device for carbon dioxide includes: an oxidation chamber containing an oxidation electrode; a reduction chamber to which carbon dioxide is supplied; a gas reduction sheet that has an ion exchange membrane and a reduction electrode laminated together therein and that is disposed between the oxidation chamber and the reduction chamber with the ion exchange membrane facing the oxidation chamber and the reduction electrode facing the reduction chamber; a conducting wire that connects the oxidation electrode and the reduction electrode; and a heat source that surrounds the reduction chamber.

Abstract: To improve the efficiency of a reduction reaction. A power source applies a voltage to an oxidation electrode immersed in an aqueous solution in an oxidation tank and a reduction electrode immersed in an aqueous solution in a reduction tank, the voltage having a voltage value that changes with a predetermined cycle to be a voltage value at which ions can be desorbed from a surface of the oxidation electrode and a surface of the reduction electrode during one cycle of the voltage change. The frequency of the voltage is set within a range of 10 Hz to 1 kHz.

Abstract: A carbon dioxide gas phase reduction device includes an oxidation tank including an oxidation electrode, a reduction tank to which carbon dioxide is supplied, an intermediate tank that is disposed between the oxidation tank and the reduction tank and capable of pouring and discharging an electrolytic solution, an ion exchange membrane disposed between the oxidation tank and the intermediate tank, a gas reduction sheet in which an ion exchange membrane and a reduction electrode are laminated and which is disposed between the reduction tank and the intermediate tank with the ion exchange membrane facing the intermediate tank and the reduction electrode facing the reduction tank, and a conducting wire connecting the oxidation electrode to the reduction electrode.

Abstract: A method for producing a nitride semiconductor photoelectrode includes: a first step of forming an n-type gallium nitride layer on an electrically insulative or conductive substrate; a second step of forming an indium gallium nitride layer on the n-type gallium nitride layer; a third step of forming a p-type nickel oxide layer on the indium gallium nitride layer; and a fourth step of subjecting a nitride semiconductor in which the p-type nickel oxide layer has been formed to heat treatment.

Abstract: Provided is a semiconductor photoelectrode which maintains a light energy conversion efficiency for a long time. In the semiconductor photoelectrode, using a conductive substrate including a III-V group compound semiconductor, a semiconductor thin film including a III-V group compound semiconductor having a photocatalytic function is disposed on the substrate, and an oxygen generation co-catalyst layer having an oxygen generation co-catalytic function for the semiconductor thin film is disposed on the semiconductor thin film. Between the semiconductor thin film and the oxygen generation co-catalyst layer, a semiconductor thin film including a III-V group compound semiconductor having a lattice constant smaller than that of the semiconductor thin film in a plane perpendicular to a crystal growth direction is disposed.