▎ 摘　　要

NOVELTY - Preparation of a graphene oxide comprises adding (g) graphite powder (0.8-1.2) and sodium nitrate (0.3-0.7) in 20-30 mL sulfuric acid, cooling to lower than 4 degrees C, and starting ultrasonic oscillation; adding potassium permanganate (2-6), reacting for 1-12 hours, moving the mixed solution in a water bath of 30-45 degrees C, reacting for 0.5-2 hours, and mechanically stirring during a medium temperature reaction; and gradually dropping the mixed solution in 80-100 mL deionized water at 0-10 degrees C, and scattering the graphite oxide in deionized water for carrying out ultrasound for 0.5-2 hours. USE - Method for the synthesis of graphene oxide (claimed) used as a reinforcement of a composite material for preparing graphene oxide based composite material used for transparent electrode, a super capacitor, a hydrogen storage material, a chemical/biological sensor, and a thin film transistor. ADVANTAGE - The method uses ultrasonic assisted Hummers, thus it is convenient, fast, inexpensive, and improves space of the graphite oxide layer. The graphene oxide based composite material has high strength mechanical property and paper-shaped slices. DETAILED DESCRIPTION - Preparation of a graphene oxide comprises: (A) adding (g) graphite powder (0.8-1.2) and sodium nitrate (0.3-0.7) in 20-30 mL of 98 vol.% sulfuric acid to obtain a mixed solution, cooling to lower than 4 degrees C, and starting ultrasonic oscillation; (B) after 0.5-6 hours, slowly adding potassium permanganate (2-6) in the mixed solution, closing the ultrasonic oscillation, stirring, keeping the temperature at 4-15 degrees C, reacting for 1-12 hours, moving the mixed solution in a water bath of 30-45 degrees C, reacting for 0.5-2 hours, and mechanically stirring during a medium temperature reaction; and (C) gradually dropping the mixed solution in 80-100 mL deionized water at 0-10 degrees C, placing the mixed solution in a water bath at 95 degrees C to preserve heat for 15-60 minutes, mechanical stirring, adding 60-80 mL deionized water after the high temperature reaction for stopping the reaction, adding 15 mL of 20 vol.% hydrogen peroxide after 5-25 minutes for removing metallic oxide, adding 40 mL of 10 vol.% hydrochloric acid after reacting for 5-25 minutes, low speed centrifugal washing until the pH of supernatant liquor of the last centrifuging is 7, scattering the graphite oxide in deionized water for carrying out ultrasound for 0.5-2 hours for removing graphite oxide, and taking the supernatant liquor after the centrifuging to obtain the turbid liquid of graphene oxide.