▎ 摘　　要

NOVELTY - A method for preparing large graphene, involves (S1) dissolving potassium persulfate in concentrated sulfuric acid to prepare solution (a), putting the graphite into solution (a), and stirring to obtain mixed solution (b), (S2) putting the mixed solution (b) into a microwave reactor for microwave hydrothermal oxidation intercalation stripping, (S3) taking out the mixed solution, adding distilled water, diluting the unreacted concentrated sulfuric acid to expand and exfoliate, and centrifuging to obtain graphene solution (I) and expandable graphite suspension, (S4) washing the expandable graphite, irradiating the expandable graphite to obtain expanded graphite, (S5) adding the expanded graphite to the mixed solvent for further intercalation and dispersion, reacting to obtain mixed solution (c), and (S6) ultrasonically processing the mixed solution (c), and centrifuging to obtain suspension to obtain graphene solution (II), and drying to obtain graphene. USE - Method for preparing large graphene used in medicine, composite material, super capacitor, and sewage purification application. ADVANTAGE - The preparation efficiency of graphene prepared by the general redox method is increased by more than 40%. The method enables quick preparation of graphene with excellent crystallization performance, thickness of 17 layers, high raw material cost, complex reaction device, strict reaction condition, high energy consumption, long time, high yield, high quality, and small diameter. The size of the graphene sheet is 125 mum. The graphene has small structural defect and high quality. DETAILED DESCRIPTION - A method for preparing large graphene, involves (S1) weighing a certain amount of potassium persulfate, dissolving in concentrated sulfuric acid to prepare solution (a), putting the graphite into solution (a), and stirring uniformly to obtain mixed solution (b), (S2) putting the mixed solution (b) into a microwave reactor for microwave hydrothermal oxidation intercalation stripping, controlling the reaction temperature at 50-80degrees Celsius, heating rate at 1-3degrees Celsius/second and heat preservation time for 5-15 minutes, (S3) taking out the mixed solution (b) after the reaction in the step (S2), adding distilled water of 1-2 times of volume of the solution, diluting the unreacted concentrated sulfuric acid to expand and exfoliate, and centrifuging after finishing the reaction to obtain graphene solution (I) and expandable graphite suspension, (S4) repeatedly washing the expandable graphite to neutral after drying, irradiating the expandable graphite after drying with microwave fluidization under the protective atmosphere microwave for 5-50 seconds to obtain expanded graphite, (S5) adding the expanded graphite to the mixed solvent prepared by ethanolamine and N,N-dimethylformamide for further intercalation and dispersion, reacting under the microwave hydrothermal condition at 100-200degreesC for 30-120 minutes to obtain mixed solution (c), and (S6) ultrasonically processing the mixed solution (c) for 30-90 minutes to achieve sufficient exfoliation of the graphene, and centrifuging to obtain suspension to obtain graphene solution (II), and drying to obtain graphene.