▎ 摘　　要

NOVELTY - Preparing graphene/metal oxide nanocomposite powder comprises e.g. taking and mixing graphite with strong oxidizing acid and nitrate mixture and then cooling, adding potassium-containing strong oxidizer, raising the temperature and then continuously stirring to obtain the mixed liquid, placing the obtained mixed liquid in a warm water bath, continuously reacting the mixture, adding hot water to make the system to boil and then keeping, adding hydrogen peroxide and then stirring the mixture until it is completely dissolved and then washing with water, and filtering the mixture. USE - The method is useful for preparing graphene/metal oxide nanocomposite powder (claimed), which is useful for catalyst. ADVANTAGE - The method is capable of simply, conveniently and economically preparing the graphene/metal oxide nanocomposite powder with less energy consumption and without toxicity in an eco-friendly manner. DETAILED DESCRIPTION - Preparing graphene/metal oxide nanocomposite powder comprises taking and mixing graphite with strong oxidizing acid and nitrate mixture and then cooling to -5 degrees C to 0 degrees C, adding potassium-containing strong oxidizer, raising the temperature to 0-60 degrees C and then continuously stirring for 24-48 hours to obtain the mixed liquid, placing the obtained mixed liquid in a warm water bath at 10-500 degrees C, continuously reacting the mixture for 40-60 minutes, adding hot water to make the system to boil and then keeping for 20-40 minutes, adding hydrogen peroxide and then stirring the mixture until it is completely dissolved and then washing with water, filtering the mixture, drying the filter cake to obtain the oxidized graphite, where the mass ratio of the: graphite and strong oxidizing acid is 1:(0.025-5); graphite and nitrate is 1:(0.2-8), graphite and potassium-containing strong oxidant is 1:(0.1-4); and graphite and hydrogen peroxide is 1:(0.125-4), the strong oxidizing acid is concentrated sulfuric acid or perchloric acid, the potassium-containing strong oxidant is potassium permanganate or potassium perchlorate, and nitrate is sodium nitrate, potassium nitrate, magnesium nitrate, calcium nitrate or aluminum nitrate, dissolving the oxidized graphite mother liquor to obtain the graphite oxide under ultrasonic frequency of 100-2000 W for 0.5-12 hours to obtain the graphene oxide solution, purifying the graphite oxide dilute mother liquor to obtain the graphene oxide solution in the centrifugal machine rotating number of 3000-10000 revolutions per minute, centrifuging the liquid and collecting an upper layer using a collecting device for underground leaching solution and then freezing and drying to obtain the graphene oxide powder, performing oxidization of graphite/metal oxide nanocomposite powder, dissolving metal in a solvent and then placing in a supercritical reactor using gas until the pressure is 2-7 MPa, raising the temperature to the reaction kettle to a supercritical state and then reacting for 0.5-4 hours, releasing the gas in the kettle and then cooling, filtering the kettle liquid, and drying the resulting precipitate to obtain the graphene/metal oxide nanometer composite material nanometer composite material powder, where the mass ratio of the oxidized graphite and metal oxide nanocomposite powder is 1:(0.005-10), the metal is a metal nitride, metal compound or metal chloride, and the gas is carbon dioxide, argon, nitrogen, neon or hydrogen, the solvent is water, ethanol, acetone, diethyl ether, chloroform, benzene, toluene, ethylbenzene, ethylene glycol, glycerol, tetrahydrofuran, N,N-dimethyl formamide, halogenated hydrocarbon, methyl acetate, ethyl acetate, carbon tetrachloride, aliphatic hydrocarbon, aromatic hydrocarbon, organic chloride, ethylenediamine or carbon disulfide.