▎ 摘　　要

NOVELTY - Preparing graphene involves under ice water bath condition, mixing the graphite and sodium nitrate, adding sulfuric acid and heating, adding potassium permanganate, raising temperature, and adding de-ionized water, warm water and hydrogen peroxide, stirring, ultrasonically dispersing to obtain oxidized graphite; dissolving the graphite in de-ionized water to prepare a graphene oxide water solution; mixing thiourea, soluble strong base and de-ionized water to obtain reducing agent solution; and mixing reducing agent solution and graphene oxide water solution to obtain graphene powder. USE - For preparing graphene (claimed). ADVANTAGE - The method prepares is simple, fast and easy to operate, has mild reaction condition, and has no special requirement to the equipment. DETAILED DESCRIPTION - Preparing graphene involves under ice water bath condition, mixing the graphite and sodium nitrate at mass ratio of 1:0.4-0.6, then adding 98% sulfuric acid, where mass ratio of sulfuric acid and the graphite is 30-40 ml:1 g, continuously stirring at speed of 100-200 rotation/minute for 15-30 minutes; then heating the mixed liquid using water bath at not greater than 10 degrees C, adding potassium permanganate, where mass ratio of potassium permanganate and graphite is 4-6:1, continuously stirring for 1-2 hours, raising water bath temperature at 30-40 degrees C for 1-3 hours and reacting, and then adding de-ionized water, continuously stirring for 15-30 minutes, then adding 30-35 degrees C warm water and 20-30% hydrogen peroxide, where the volume ratio of the sulfuric acid, deionized water, warm water and hydrogen peroxide is 1:0.5-1:2-2.5:0.4-0.6, continuously stirring for 10-20 minutes, ultrasonically dispersing the solution for 15-30 minutes, filtering, washing to obtain oxidized graphite; dissolving the oxidized graphite in de-ionized water to prepare a graphene oxide water solution; mixing thiourea or carbohydrazide, soluble strong base and de-ionized water at stirring speed of 30-50 rotation per minute to obtain reducing agent solution, where mass ratio of thiourea, de-ionized water, and soluble strong alkali is 30-50 ml:1 g:2-4 g; and mixing reducing agent solution and graphene oxide water solution by stirring at speed of 100-200 rotation per minute in 85-100 degrees C the water bath, continuously stirring and reacting for 5-10 hours and filtering, washing the filtering the product by using ethanol and de-ionized water, and drying to obtain graphene powder.