The present invention utilizes an electrochemical catalyst which contains: a metal oxide that is composed of one or more compounds selected from among zirconium oxide, cerium oxide, yttrium oxide, gadolinium oxide, samarium oxide, cobalt oxide and scandium oxide; and a metal variant, which has a valence that is different from the valence of the metal that constitutes the metal oxide.

Provided is a photocathode structure including: a photocathode including silicon (Si); an intermediate layer formed on the photocathode, and including a silicon oxide (SiO.sub.x); and a protective layer foiled on the intermediate layer, and including a metal oxide, wherein the intermediate layer is a tunneling barrier configured to transfer charges from the photocathode to the protective layer by an electric field applied from an outside.

Provided is a photocathode structure including: a photocathode including silicon (Si); an intermediate layer formed on the photocathode, and including a silicon oxide (SiO.sub.x); and a protective layer foiled on the intermediate layer, and including a metal oxide, wherein the intermediate layer is a tunneling barrier configured to transfer charges from the photocathode to the protective layer by an electric field applied from an outside.

An electrode suitable for use as a cathode for the development of hydrogen in industrial electrolytic processes, equipped with a catalytic coating having an external layer containing ruthenium and selenium; and a method for the production of the same.

An electrode suitable for use as a cathode for the development of hydrogen in industrial electrolytic processes, equipped with a catalytic coating having an external layer containing ruthenium and selenium; and a method for the production of the same.

A tandem electrode for electrochemically reducing carbon dioxide is described. The electrode includes a first distinct catalyst layer and a second distinct catalyst layer. The first distinct catalyst layer is made of a C.sub.1 hydrocarbon or C.sub.2+ product selective catalyst and the second distinct catalyst layer is comprised of a CO selective catalyst. In one embodiment, the second distinct catalyst layer is concentrated at one end of the tandem electrode. In another embodiment, the tandem electrode also includes a microporous layer and a substrate layer.

A tandem electrode for electrochemically reducing carbon dioxide is described. The electrode includes a first distinct catalyst layer and a second distinct catalyst layer. The first distinct catalyst layer is made of a C.sub.1 hydrocarbon or C.sub.2+ product selective catalyst and the second distinct catalyst layer is comprised of a CO selective catalyst. In one embodiment, the second distinct catalyst layer is concentrated at one end of the tandem electrode. In another embodiment, the tandem electrode also includes a microporous layer and a substrate layer.

In this disclosure, a process of recycling acid, base and the salt reagents required in the Li recovery process is introduced. A membrane electrolysis cell which incorporates an oxygen depolarized cathode is implemented to generate the required chemicals onsite. The system can utilize a portion of the salar brine or other lithium-containing brine or solid waste to generate hydrochloric or sulfuric acid, sodium hydroxide and carbonate salts. Simultaneous generation of acid and base allows for taking advantage of both chemicals during the conventional Li recovery from brines and mineral rocks. The desalinated water can also be used for the washing steps on the recovery process or returned into the evaporation ponds. The method also can be used for the direct conversion of lithium salts to the high value LiOH product. The method does not produce any solid effluent which makes it easy-to-adopt for use in existing industrial Li recovery plants.

An object is to provide a methane synthesis device having as a whole a reduced size and a simplified configuration. A methane synthesis device 100 is composed of respective components from an end plate 2 at the leftmost side to an end plate 23 at the rightmost side and is compactly assembled by fastening plural bolts and nuts to bring these individual components into tightly contact with each other. The components may be divided into a Sabatier reaction unit of signs 3 to 9, a water electrolysis unit of signs 13 to 19, and other components. Hydrogen gas generated in the water electrolysis unit is mixed with carbon dioxide gas and supplied to the Sabatier reaction unit, and methane is synthesized in the Sabatier reaction unit. The size of the device is reduced as a whole and configuration is simplified by integrally stacking the water electrolysis unit, the Sabatier reaction unit, a carbon dioxide supplying unit, and a hydrogen gas supplying unit.

An object is to provide a methane synthesis device having as a whole a reduced size and a simplified configuration. A methane synthesis device 100 is composed of respective components from an end plate 2 at the leftmost side to an end plate 23 at the rightmost side and is compactly assembled by fastening plural bolts and nuts to bring these individual components into tightly contact with each other. The components may be divided into a Sabatier reaction unit of signs 3 to 9, a water electrolysis unit of signs 13 to 19, and other components. Hydrogen gas generated in the water electrolysis unit is mixed with carbon dioxide gas and supplied to the Sabatier reaction unit, and methane is synthesized in the Sabatier reaction unit. The size of the device is reduced as a whole and configuration is simplified by integrally stacking the water electrolysis unit, the Sabatier reaction unit, a carbon dioxide supplying unit, and a hydrogen gas supplying unit.