▎ 摘　　要

NOVELTY - Preparing a graphene and polyoxometalate composite material by electrochemical reduction involves: 1) preparing graphene oxide: in the presence of strong acid and a strong oxidizer, oxidizing a raw material graphite into graphite oxide, further ultrasonically stripping the graphite oxide for obtaining graphene oxide, 2) preparing a mixed solution of the graphene oxide and polyoxometalate, 3) electrochemically reducing the graphene oxide by polyoxometalate, and 4) separating the graphene and polyoxometalate composite material. USE - For preparing a graphene and polyoxometalate composite material by electrochemical reduction (claimed) which is used in catalytic electrode material, lithium ion battery and electrochemical capacitor. ADVANTAGE - During the reduction process, the polyoxometalate can be spontaneously adsorbed to the surface of the generated graphene for forming a graphene and polyoxometalate composite material. The composite material prepared by the method is a powder material with porous structure, which has potential application value in catalytic electrode material, lithium ion battery and electrochemical capacitor. The method uses a multi-metallic oxygen cluster solution, and does not add other supporting electrolyte. DETAILED DESCRIPTION - Preparing a graphene and polyoxometalate composite material by electrochemical reduction involves: 1) preparing graphene oxide: in the presence of strong acid and a strong oxidizer, oxidizing a raw material graphite into graphite oxide, further ultrasonically stripping the graphite oxide for obtaining graphene oxide; 2) preparing a mixed solution of the graphene oxide and polyoxometalate: adding an aqueous solution of polyoxometalate into an aqueous suspension of the graphene oxide, ultrasonically stirring for 1-2 hours for obtaining a mixed solution of the graphene oxide and the polyoxometalate; during the whole process, adding into ice for cooling, where the concentration of the graphene oxide in the mixed solution is 0.5-2 mg/ml, and the concentration of the polyoxometalate is 10-50 mM; 3) electrochemically reducing the graphene oxide by the polyoxometalate: selecting the peak tail potential of the reversible cathode peak of the polyoxometalate used in the mixed solution of step (2) as an electrochemical reduction potential, under the conditions of stirring speed of 1000-1500 revolutions per minute (rpm) and nitrogen (N2) flow rate of 0.5-1.2 l/minute, reducing the mixed solution of step (2) for 0.3-5 hours at a constant potential; 4) separating the graphene and polyoxometalate composite material: taking the reduced mixed solution, stirring in the air for 2-4 hours at room temperature until the mixed solution is changed from blue to colorless turbid liquid; consequently, extracting and filtering the turbid liquid by an organic filter membrane of 200-300 nm, washing by a polar solvent (5-20 ml) for removing the unabsorbed polyoxometalate, when there is no filtrate effluent, dispersing the filter cake in a volatile non-polar solvent (5-50 ml) for obtaining a black powder with bulk volume after naturally volatilizing the non-polar solvent, then drying the black powder in a vacuum drying oven for completely removing the adsorbed solvent for preparing the graphene and polyoxometalate composite material. DESCRIPTION OF DRAWING(S) - The figure shows an electrochemical reduction for producing graphene and multi-metallic oxygen cluster compound material.