▎ 摘　　要

NOVELTY - Graphite and sodium nitrite are stirred with concentrated sulfuric acid and potassium permanganate, diluted with deionized water, neutralized, and washed, to obtain yellow viscous liquid. Viscous liquid is stirred, washed, centrifuged, concentrated and dialyzed. Obtained reaction mixture is added to ethanol, mixed with phthalonitrile, and dried, to obtain three-dimensional cobalt phthalocyanine/surfactant/graphene hydrogel. Hydrogel is washed with ultrapure water, and reacted, to obtain three-dimensional nitrogen-doped graphene/cobalt oxide nanocomposite material. USE - Preparation of three-dimensional nitrogen-doped graphene/cobalt oxide nanocomposite material. ADVANTAGE - The three-dimensional nitrogen-doped graphene/cobalt oxide nanocomposite material having improved electrochemical property is prepared. DETAILED DESCRIPTION - 1 g Graphite and 7.5 g sodium nitrite are added in 2 L round-bottom beaker, mechanically stirred, 300 mL concentrated sulfuric acid is slowly added, stirred for 0.5 hour, 40 g potassium permanganate is added, and mechanically stirred for 5 days. 1 L deionized water is added to the obtained mixture, diluted, 60 ml hydrogen peroxide having concentration of 30% is dripped, neutralized, centrifuged at 1000 rpm for 1 minute, supernatant was removed, and washed with deionized water, to obtain yellow viscous liquid. The viscous liquid is stirred at 4000 rpm for 10 minutes, washed with deionized water, centrifuged, coarse impurities are removed, concentrated, centrifuged at 6000 rpm for 1 minute, and dialyzed to remove small molecules. Obtained reaction mixture is added to 5 mg/mL ethanol, phthalonitrile is added, mixed, cobalt acetate and surfactant are added, ultrasonically dispersed for 2 hours, poured into polytetrafluoroethylene autoclave, and dried at 180 degrees C for 24 hours, to obtain three-dimensional cobalt phthalocyanine/surfactant/graphene hydrogel. Hydrogel is washed with ultrapure water, ethanol is completely removed, freeze-dried, calcined at 600-800 degrees C for 2 hours, nitrogen is introduced, and reacted, to obtain three-dimensional nitrogen-doped graphene/cobalt oxide nanocomposite material. The surfactant is cetyltrimethylammonium bromide and/or PluronicF12 (RTM: poloxamer).