A process for preparing a catalytic material of an electrode for electrochemical reduction reactions, said material comprising an active phase based on at least one group VIB metal and an electrically conductive support, which process is carried out according to at least the following steps:

a) bringing water into contact with said electrically conductive support,
b) bringing said wet support into contact with at least one metallic acid hydrate comprising at least one group VIB metal, of which the melting point of said metallic acid hydrate is between 20° C. and 100° C., the weight ratio of said metallic acid to said electrically conductive support being between 0.1 and 4,
c) heating, with stirring, to a temperature between the melting point of said metallic acid hydrate and 100° C.,
d) carrying out a sulfurization step at a temperature of between 100° C. and 600° C.

A device for catalytic conversion of carbon dioxide (CO.sub.2) includes a substrate having a surface, an array of conductive projections supported by the substrate and extending outward from the surface of the substrate, each conductive projection of the array of conductive projections having a semiconductor composition, and a plurality of nanoparticles disposed over the array of conductive projections, each nanoparticle of the plurality of nanoparticles being configured for the catalytic conversion of carbon dioxide (CO.sub.2). Each nanoparticle of the plurality of nanoparticles includes a metal sulfide, the metal sulfide including a d-block metal.

A device for catalytic conversion of carbon dioxide (CO.sub.2) includes a substrate having a surface, an array of conductive projections supported by the substrate and extending outward from the surface of the substrate, each conductive projection of the array of conductive projections having a semiconductor composition, and a plurality of nanoparticles disposed over the array of conductive projections, each nanoparticle of the plurality of nanoparticles being configured for the catalytic conversion of carbon dioxide (CO.sub.2). Each nanoparticle of the plurality of nanoparticles includes a metal sulfide, the metal sulfide including a d-block metal.

In a first implementation, a method for exfoliation of graphene flakes from a graphite sample includes compressing a graphite sample in an electrochemical reactor and applying a voltage between the graphite sample and an electrode in the electrochemical cell.

An electrode for an electrochemical reaction bath has a base body, an active side which is configured to come into contact with the reaction bath, and a passive side which is configured to come into contact with at least one electrical conductor. The passive side includes a doped carbon coating that is preferably less than 5 μm in thickness. Preferably the doped carbon coating is a doped polycrystalline diamond coating in sp.sup.3 configuration and is doped with boron.

A photoelectrochemical cell includes a cathode with a front and back cathode surface, an anode with front and back anode surfaces, a conductive connector between the cathode and the anode, and an optical waveguide configured to direct sunlight to the back surfaces of the cathode and anode. The cathode is adapted for photoelectric generation of electrons at the back cathode surface and electrolytic generation of hydrogen at the front cathode surface. Similarly, the anode is adapted for photoelectric generation of electrons at the back anode surface and electrolytic generation of oxygen at the front anode surface. The photoelectrochemical cell may also include a waveguide optical concentrator coupled to the waveguide.

A photoelectrochemical cell includes a cathode with a front and back cathode surface, an anode with front and back anode surfaces, a conductive connector between the cathode and the anode, and an optical waveguide configured to direct sunlight to the back surfaces of the cathode and anode. The cathode is adapted for photoelectric generation of electrons at the back cathode surface and electrolytic generation of hydrogen at the front cathode surface. Similarly, the anode is adapted for photoelectric generation of electrons at the back anode surface and electrolytic generation of oxygen at the front anode surface. The photoelectrochemical cell may also include a waveguide optical concentrator coupled to the waveguide.

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.

The present invention relates to a method for easily producing nanoparticles by expansion, explosion, vaporization, condensation and cooling of plasma in a liquid by means of heat resistance and, more particularly, to a method for preparing a silicon nanocomposite dispersion having a uniform carbon layer coated on the surface of silicon of which at least one area is connected to a silicon carbide formed by reacting a carbon in liquid (C) during expansion, explosion, vaporization, condensation and cooling, and applied products thereof.