▎ 摘　　要

NOVELTY - Preparing graphene with larger surface area comprises (i) adding concentrated sulfuric acid to mixture of expanded graphite and nitrate, stirring, maintaining temperature, stirring, adding potassium permanganate, stirring, adjusting temperature and stirring; (ii) raising temperature, adding hydrogen peroxide, adding deionized water for diluting acid solution, and releasing heat; (iii) carrying out ultrasonic treatment; (iv) settling the suspension liquid, removing supernatant, washing, and repeating settling process; (v) subjecting hydro-gel product to ultrasonic treatment; and (vi) reducing. USE - The method is useful for preparing graphene with larger surface area (claimed). ADVANTAGE - The method: performs graphene oxide sheet deposition and washing process, which is higher than that of natural crystalline flake graphite; utilizes artificial graphite powder as raw material; has high production yield of 95%; and is suitable for industrial mass production. DETAILED DESCRIPTION - Preparing graphene with larger surface area comprises (i) adding concentrated sulfuric acid to mixture of expanded graphite and nitrate, stirring uniformly, maintaining temperature at 22-28 degrees C, stirring for 15-30 minutes, then adding potassium permanganate, continuously preserving heat, stirring for 90-600 minutes, adjusting temperature to 40-50 degrees C, and maintaining temperature and stirring for 15-60 minutes, where the content of the expanded graphite is 22-30%, nitrate is 11-20%, and potassium permanganate is 50-65%, and the nitrate is sodium nitrate and/or potassium nitrate; (ii) raising the temperature to 90-100 degrees C, maintaining the temperature to heat for 15-120 minutes, adding 30-35 wt.% hydrogen peroxide, where adding 2-ml of hydrogen peroxide to each gram of expanded graphite, adding deionized water for diluting acid solution, and releasing heat, where the volume ratio of deionized water and initial solution is 2:1-3:1; (iii) carrying out ultrasonic treatment on the resulting solution under ultrasonic machine power of 100-1000 W and frequency of 10-5000 Hz for 5 minutes to 2 hours; (iv) settling the suspension liquid, removing the supernatant, adding hydrochloric acid for washing, then respectively using ethyl alcohol and deionized water for washing, and repeating the settling process until the solution is neutral to obtain hydro-gel product; (v) subjecting the neutral graphene oxide hydro-gel product to ultrasonic treatment under ultrasonic machine power of 100-1000 W and frequency of 10-5000 Hz for 5 minutes-2 hours; and (vi) using hydrazine hydrate as reducing agent for carrying out reduction process on hydro-gel solution at 90-100 degrees C for 200-400 minutes. An INDEPENDENT CLAIM is also included for the graphene with larger surface area prepared by the above mentioned method.