▎ 摘　　要

NOVELTY - Concentrated sulfuric acid is mixed with graphite powder and potassium permanganate to obtain mixture (I). To obtained mixture, hydrogen peroxide is added and stirred to obtain golden mixture. Obtained mixture is centrifuged and neutral precipitate is mixed with deionized water, stirred, frozen and lyophilized to obtain graphene oxide powder. Obtained powder is mixed with deionized water to obtain graphene oxide dispersion. Dispersion is mixed with reducing agent, added into electrode vial, heated and black solid is soaked in deionized water to obtain graphene hydrogel electrode. USE - Preparation of graphene hydrogel electrode (claimed). ADVANTAGE - The method efficiently provides graphene hydrogel electrode by simple method under mild reaction condition in short period of time. DETAILED DESCRIPTION - 20-30 ml 98% Concentrated sulfuric acid is added to a glass container, placed in an ice bath, stirred until the temperature dropped to 0-10 degrees C, and 1 g graphite powder is added and stirred for 2-4 hours at 100 rpm to obtain mixture containing graphite powder and 98% concentrated sulfuric acid. To the obtained mixture, 3-8 g potassium permanganate is added, stirred continuously for 2-4 hours at 100 rpm, heated and 140 mL deionized water is added. The obtained mixture is continuously stirred at 100 rpm, and the temperature is controlled at 90-95 degrees C to obtain mixture (I). To the obtained mixture (I), 10 ml 30% hydrogen peroxide is added, and stirred at 100 rpm for 10 minutes to obtain golden mixture. The obtained mixture is placed in a centrifuge bottle, centrifuged, and precipitate (I) and supernatant (I) are obtained. The precipitate (I) is mixed with 1-6% hydrochloric acid, stirred at 100 rpm for 5-30 minutes, and centrifuged to obtain supernatant (II) and precipitate (II). The supernatant (II) is mixed with 1-5 mol/L barium chloride solution to obtain white barium sulfate. The precipitate (II) is mixed with 1-6% dilute hydrochloric acid, stirred at 100 rpm for 5-30 minutes, and centrifuged to obtain supernatant (III) and precipitate (III). The supernatant (III) is mixed with 1-5 mol/L barium chloride solution, to obtain white barium sulfate. The precipitate (III) is mixed with 1-6% dilute hydrochloric acid, stirred at 100 rpm for 5-30 minutes, and centrifuged to obtain precipitate (IV) and supernatant (IV). The supernatant (IV) is added to a container, and mixed with 1-5 mol/L barium chloride solution to obtain white barium sulfate. The content of 1-6% hydrochloric acid is 60-100 mL. The obtained precipitate is mixed with 60 mL deionized water, centrifuged and the precipitate is mixed with 60 mL deionized water, stirred for 5-20 minutes, centrifuged, and neutral precipitate is collected. The resultant neutral precipitate is mixed with 60 mL deionized water, stirred at the speed of 100 rpm for 5-20 minutes, placed in vacuum freeze dryer, and lyophilized to obtain graphene oxide powder. The obtained graphene oxide powder is mixed with 0.25-1 L deionized water to obtain graphene oxide dispersion. The obtained dispersion is stirred at 50-150 rpm for 6-12 hours, and 0.5-4 g sodium sulfide or 0.5-4 g ascorbic acid as reducing agent is added to obtain mixture (II). The obtained mixture (II) is stirred at 50-150 rpm for 1-10 minutes, left still for 0.5-36 hours, and the mixture is poured into an electrode vial. The vial is then heated at 80-95 degrees C for 3-10 hours and black solid is removed and soaked in deionized water for 20 hours or more to obtain graphene hydrogel electrode.