A method of producing graphene sheets from coke or coal powder, comprising: (a) forming an intercalated coke or coal compound by electrochemical intercalation conducted in an intercalation reactor, which contains (i) a liquid solution electrolyte comprising an intercalating agent; (ii) a working electrode that contains the powder in ionic contact with the liquid electrolyte, wherein the coke or coal powder is selected from petroleum coke, coal-derived coke, meso-phase coke, synthetic coke, leonardite, lignite coal, or natural coal mineral powder; and (iii) a counter electrode in ionic contact with the electrolyte, and wherein a current is imposed upon the working electrode and the counter electrode for effecting electrochemical intercalation of the intercalating agent into the powder; and (b) exfoliating and separating graphene planes from the intercalated coke or coal compound using an ultrasonication, thermal shock exposure, mechanical shearing treatment, or a combination thereof to produce isolated graphene sheets.

A method for oxidizing water including fabricating a working electrode using an electrocatalyst, preparing an electrochemical cell by putting the working electrode, a counter electrode, and a reference electrode in an electrolyte, and performing an oxygen evolution reaction (OER) by applying an electrical potential between the working electrode and the counter electrode. The electrocatalyst includes a nickel-calcium-iron layered double hydroxide (NiCaFe-LDH) nanoparticle, the NiCaFe-LDH nanoparticle has a formula of [Fe.sub.x)NiCa(.sub.1-x](OH).sub.2(NO.sub.3).sub.x.nH.sub.2O, where: 0.2x0.4 and 0n2.5.

The present invention relates to a graphene material inlaid with single metal atoms, the preparation method thereof and its application of being used as the catalyst for the electroreduction of carbon dioxide. The graphene material inlaid with single metal atoms comprises single metal atoms and graphene; the single metal atoms are dispersed in the framework of the graphene; and the graphene is at least one selected from N doped graphene and N and S co-doped graphene. The material is used for the electrochemical reduction reaction of carbon dioxide, which significantly improves the utilization efficiency of the metal atoms and enhances the catalytic activity for the electroreduction of carbon dioxide, improves the catalytic stability, inhibits effectively the hydrogen evolution reaction, improves the selectivity for CO product, and broadens the electric potential window of reducing carbon dioxide to generate CO.

Photocatalytic device to dissociate an aqueous phase to product hydrogen gas, said device being set up in such a way that at least one photocatalytic system in contact with said aqueous phase can be irradiated by a light source to producethrough an oxidation reaction in said aqueous phaseoxygen gas, electrons and protons at a means of electron capture, said device comprising: a first zone comprising said aqueous phase, and a means for reducing said protons set up to carry out a reduction reaction on said protons by said electrons in order to generate hydrogen gas.
said device being characterised in that said means for proton reduction is a proton exchange interface with a front side facing said means of electron capture, and a back side, with only said back side of said proton exchange interface bearing at least one catalyst and/or at least one catalytic system.

A method of synthesizing three-dimensional (3D) reduced graphene oxide (RGO) foams embedded with water splitting nanocatalysts includes providing a first solution containing nickel (II) nitrate, a second solution containing iron (III) nitrate, and a graphene oxide (GO) aqueous suspension; mixing the GO aqueous suspension with the first solution and the second solution to form a GO-NiFe mixture; adjusting a pH value of the GO-NiFe mixture to be about 3.5; and performing hydrothermal reaction in the GO-NiFe mixture to form RGO-NiFe foams, wherein nanocatalysts containing Ni-Fi oxide particles are embedded in porous structures of the 3D RGO foams.

The present disclosure provides an electrode for an electrolysis device, which allows performance of a catalyst to be efficiently exhibited in an electrochemical reaction of reducing an electrolysis reactant to generate an electrolysis product material. Specifically, a carbon fiber that has a structure in which the carbon fiber contains a part of and/or a whole of a catalyst particle is used as a cathode electrode to greatly improve adherence force of the catalyst particle and enable efficient generation of an electrolysis product material.

The present invention relates to an electrochemical process for the reduction of molecular oxygen in alkaline solutions in the presence of nitrogen-doped carbon nanotubes, in which no hydrogen peroxide forms as a by-product of the reduction.