▎ 摘　　要

NOVELTY - Preparation of graphene comprises adding natural graphene, persulfate, and phosphorus pentoxide to concentrated sulfuric acid; stirring and reacting to obtain pre-oxidized graphene; sequentially adding pre-oxidized graphene, nitrate, and potassium permanganate to concentrated sulfuric acid; reacting to obtain oxidized graphene; dissolving oxidized graphene in alcohol to form solution; ultrasonically dispersing; reacting for 4-48 hours in sealing environment at 120-220 degrees C; centrifugally washing until pH is 6.5-7.5; and drying in vacuum. USE - Preparation of graphene. ADVANTAGE - The method does not adopt any reducing agent; instead, it reduces oxidized graphene by self-reducing ability of solvent. It is low cost, produces few pollution, and suitable for large-scale industrial production. DETAILED DESCRIPTION - Preparation of graphene comprises adding natural graphene, persulfate and phosphorus pentoxide to concentrated sulfuric acid; stirring for 4-10 hours at 60-90 degrees C; adding deionized water with stirring to cool at 20-28 degrees C; filtering and washing suspension with deionized water until pH is 6.5-7.5; drying in vacuum to obtain pre-oxidized graphene; sequentially adding pre-oxidized graphene, nitrate, and potassium permanganate to concentrated sulfuric acid; bathing with ice while stirring for 1-3 hours; raising temperature at 30-40 degrees C; stirring for 2-4 hours; adding warm water at 60-80 degrees C; raising temperature at 70-100 degrees C and maintaining at 10-40 minutes; diluting with warm water at 60-80 degrees C; sequentially adding hydrogen peroxide and diluted hydrochloric acid; centrifugally washing until pH is 6.5-7.5; drying in vacuum to obtain oxidized graphene; dissolving oxidized graphene in alcohol to make 0.1-1 mg/ml oxidized graphene solution; ultrasonically dispersing; reacting for 4-48 hours in sealing environment at 120-220 degrees C; centrifugally washing until pH is 6.5-7.5; and drying in vacuum to obtain blank graphene powder.