Methods of making catalyst electrodes comprising sputtering at least Pt and Ir onto nanostructured whiskers to provide multiple alternating layers comprising, respectively in any order, at least Pt and Ir. In some exemplary embodiments, catalyst electrodes described, or made as described, herein are anode catalyst, and in other exemplary embodiments cathode catalyst. Catalysts electrodes are useful, for example, in generating H.sub.2 and O.sub.2 from water.

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.

A device for performing electrolysis of water is disclosed. The device comprising: a semiconductor structure comprising a surface and an electron guiding layer below said surface, the electron guiding layer of the semiconductor structure being configured to guide electron movement in a plane parallel to the surface, the electron guiding layer of the semiconductor structure comprising an InGaN quantum well or a heterojunction, the heterojunction being a junction between AlN material and GaN material or between AlGaN material and GaN material; at least one metal cathode arranged on the surface of the semiconductor structure; and at least one photoanode arranged on the surface of the semiconductor structure, wherein the at least one photoanode comprises a plurality of quantum dots of In.sub.xGa.sub.(1−x)N material, wherein 0.4≤x≤1. A system comprising such device is also disclosed.

A device for performing electrolysis of water is disclosed. The device comprising: a semiconductor structure comprising a surface and an electron guiding layer below said surface, the electron guiding layer of the semiconductor structure being configured to guide electron movement in a plane parallel to the surface, the electron guiding layer of the semiconductor structure comprising an InGaN quantum well or a heterojunction, the heterojunction being a junction between AlN material and GaN material or between AlGaN material and GaN material; at least one metal cathode arranged on the surface of the semiconductor structure; and at least one photoanode arranged on the surface of the semiconductor structure, wherein the at least one photoanode comprises a plurality of quantum dots of In.sub.xGa.sub.(1−x)N material, wherein 0.4≤x≤1. A system comprising such device is also disclosed.

The present application relates to a method for manufacturing a photoelectrode, the method comprising steps of impregnating a first transition metal oxide capable of performing photoreaction in an electrolyte, applying a voltage onto the electrolyte to generate an electrochemical oxidation reaction on the surface of the first transition metal oxide, and forming a second transition metal oxide thin film on the surface of the first transition metal oxide by irradiating light onto the first transition metal oxide at the same time as the step of applying the voltage.

The present application relates to a method for manufacturing a photoelectrode, the method comprising steps of impregnating a first transition metal oxide capable of performing photoreaction in an electrolyte, applying a voltage onto the electrolyte to generate an electrochemical oxidation reaction on the surface of the first transition metal oxide, and forming a second transition metal oxide thin film on the surface of the first transition metal oxide by irradiating light onto the first transition metal oxide at the same time as the step of applying the voltage.

The invention pertains to a method for efficiently spitting water into hydrogen and oxygen using a nanocomposite that includes ((BiVO.sub.4).sub.x—(TiO.sub.2).sub.1-x, wherein x ranges from 0.08 to 0.12, and optionally silver nanoparticles; methods for making a nanocomposite used in this method by a simple solvothermal method; and to photoanodes and photoelectrochemical cells and devices containing the nanocomposites.

The invention pertains to a method for efficiently spitting water into hydrogen and oxygen using a nanocomposite that includes ((BiVO.sub.4).sub.x—(TiO.sub.2).sub.1-x, wherein x ranges from 0.08 to 0.12, and optionally silver nanoparticles; methods for making a nanocomposite used in this method by a simple solvothermal method; and to photoanodes and photoelectrochemical cells and devices containing the nanocomposites.

A device for performing electrolysis of water is disclosed. The device may include a semiconductor structure with a surface and an electron guiding layer below said surface, the electron guiding layer of the semiconductor structure being configured to guide electron movement in a plane parallel to the surface. The electron guiding layer of the semiconductor structure may include an InGaN quantum well or a heterojunction, the heterojunction being a junction between AlN material and GaN material or between AlGaN material and GaN material and at least one metal cathode arranged on the surface of the semiconductor structure. The device may further include at least one photoanode arranged on the surface of the semiconductor structure, wherein the at least one photoanode may include a plurality of quantum dots of In.sub.xGa.sub.(1-x)N material, wherein 0.4≤x≤1. A system including such a device is also disclosed.

A device for performing electrolysis of water is disclosed. The device may include a semiconductor structure with a surface and an electron guiding layer below said surface, the electron guiding layer of the semiconductor structure being configured to guide electron movement in a plane parallel to the surface. The electron guiding layer of the semiconductor structure may include an InGaN quantum well or a heterojunction, the heterojunction being a junction between AlN material and GaN material or between AlGaN material and GaN material and at least one metal cathode arranged on the surface of the semiconductor structure. The device may further include at least one photoanode arranged on the surface of the semiconductor structure, wherein the at least one photoanode may include a plurality of quantum dots of In.sub.xGa.sub.(1-x)N material, wherein 0.4≤x≤1. A system including such a device is also disclosed.