▎ 摘　　要

NOVELTY - Preparation of graphene comprises mixing uniformly sodium nitrate, potassium permanganate and concentrated sulfuric acid in the ball-milling tank, adding graphite material, dry ice and zirconium dioxide grinding ball, ball-milling, rotating, adding ice block, and ball-milling; diluting a graphite suspension with deionized water, and adding hydrogen peroxide solution, stirring reaction, and ultrasonic processing; adding sodium hydroxide and composite reducing agent in graphene oxide suspension liquid, heating, stirring, and reacting; and filtering, washing, and drying to obtain the graphene. USE - Method for preparing graphene (claimed). ADVANTAGE - The method is simple, and has high efficiency, low cost and easy industrial production. DETAILED DESCRIPTION - Preparation of graphene comprises: (A) mixing uniformly sodium nitrate, potassium permanganate and concentrated sulfuric acid in the ball-milling tank, adding graphite material, dry ice and zirconium dioxide grinding ball, ball-milling for 2-3 hours, rotating at 250 revolutions/minute, adding ice block, and ball-milling for 1-2 hours to obtain a brown graphite suspension, where the sulfuric acid has a concentration of 98%, the graphite is natural crystalline flake graphite, and ratio of graphite, sodium nitrate, potassium permanganate, concentrated sulfuric acid and dry ice is 1 g:0.3-0.6 g:1.5-2 g:10-20 ml: 30-60 g, and the ice block is deionized water, freezing ice and adding ice to concentrated sulfuric acid at a mass ratio of 1-2:1; (B) diluting a graphite suspension with deionized water to 3-10 mg/ml, and adding hydrogen peroxide solution, stirring reaction at 90-95 degrees C water bath, then regulating pH value to 7-8 with sodium hydroxide solution, and ultrasonic processing for 1 hour, where the hydrogen peroxide solution concentration is 30 mass%, where the mass ratio of hydrogen peroxide to potassium permanganate 0.5-1:1, the ultrasonic frequency is 40 kHz, and power is 240 W; (C) adding sodium hydroxide and composite reducing agent in graphene oxide suspension liquid, heating, stirring, reacting for 3 hours, where composite reducing agent comprises hydrazine hydrate and thiourea dioxide at a mass ratio of 1:0.5-1; and (D) filtering the composite reducing agent, washing, and drying to obtain the graphene, where the mass ratio of the reducing agent to raw material graphite is 1-2:1, the reaction temperature is 93-98 degrees C, and the mass ratio of the sodium hydroxide to thiourea dioxide is 1:1.