▎ 摘　　要

NOVELTY - Preparing graphene by combustion synthesis comprises e.g. (i) mixing extruded vermiculite powder and metal magnesium powder evenly, and placing them in a tube furnace, and warming for 2-6 hours, melting the magnesium powder and infiltrating to fill the pores of the vermiculite, and then naturally cooling to room temperature to obtain vermiculite/magnesium composite, (ii) mixing the vermiculite/magnesium composite and metal magnesium powder, adding it into a reactor to evacuate, and then passing carbon monoxide and/or carbon dioxide into the reactor, using local induction heating to ignite the combustion reaction of magnesium and gas, and cooling, and (iii) adding the reacted powder into hydrochloric acid solution to soak and stirring for 3-12 hours, and then washing with pure water until neutral, then adding it into the hydrofluoric acid solution for soaking and stirring for 10-20 hours, then washing it with pure water until neutral, and freeze-drying. USE - The graphene is useful in fields of catalyst supports, supercapacitors, and lithium battery electrode materials. ADVANTAGE - The method: utilizes expanded vermiculite as template for depositing graphene, which is cheap and easily available raw materials; has low price, and high reaction temperature. The prepared graphene has sheet shape and high electrical conductivity. DETAILED DESCRIPTION - Preparing graphene by combustion synthesis comprises (i) mixing extruded vermiculite powder and metal magnesium powder evenly according to the mass ratio of 4-12:0.8-2.8, and placing them in a tube furnace, raising the temperature to 660-800 ℃ under high-purity nitrogen or argon atmosphere, and warming for 2-6 hours, melting the magnesium powder and infiltrating to fill the pores of the vermiculite, and then naturally cooling to room temperature to obtain vermiculite/magnesium composite, (ii) mixing the vermiculite/magnesium composite and metal magnesium powder evenly in a mass ratio of 8-16:0.2-3, adding it into a reactor to evacuate, and then passing carbon monoxide and/or carbon dioxide into the reactor, using local induction heating to ignite the combustion reaction of magnesium and gas for 0.5-5 minutes, and cooling to room temperature after the reaction, and (iii) adding the reacted powder into hydrochloric acid solution to soak and stirring for 3-12 hours, and then washing with pure water until neutral, then adding it into the hydrofluoric acid solution for soaking and stirring for 10-20 hours, then washing it with pure water until neutral, and freeze-drying at 30 ℃ to obtain three-dimensional porous graphene.