▎ 摘　　要

NOVELTY - Preparing nano-cobalt oxide graphene composite, comprises (i) dissolving surfactant in water, adding graphite, ultrasonicating, centrifuging and taking the supernatant; (ii) under stirring condition, adding cobalt salt into the supernatant, stirring to obtain a solution A; (iii) dissolving urea in water, to obtain urea aqueous solution, and then dropwise adding the solution of step (ii) into urea aqueous solution, cooling the resultant reaction, centrifuging, washing the resulting precipitate, and vacuum drying; then drying the resulting solid, heating and calcining. USE - The method is useful for preparing nano-cobalt oxide graphene composite (claimed). ADVANTAGE - The method has mild reaction conditions, and increases the catalytic performance of the graphene composite. DETAILED DESCRIPTION - Preparing nano-cobalt oxide graphene composite, comprises (i) dissolving surfactant in water, adding graphite, ultrasonicating for 10-50 hours, centrifuging at 4000-5000 revolutions per minute for 10-30 minutes, and taking the supernatant; where the surfactant is cetyl trimethyl ammonium bromide and dodecyl benzene sulfonate; the ratio of surfactant, water and graphite is 12 mmol: 100 ml: 1 g; and the graphite is natural flake graphite, natural graphite or graphite microspheres; (ii) under stirring condition, adding cobalt salt into the supernatant, stirring for 20-30 minutes, to obtain a solution A; where the cobalt salt is cobalt nitrate, cobalt chloride, cobalt acetate or cobalt sulfate, and the ratio of supernatant to cobalt salt is 10 mmol: 1 g; (iii) dissolving urea in water, to obtain 1-5 mol/l urea aqueous solution, and then dropwise adding the solution of step (ii) into urea aqueous solution at the rate of 0.5-5 ml/minute, transferring the resulting mixture into a temperature controlled autoclave at 90-180 degrees C for 5-15 hours, cooling the resultant reaction solution to room temperature, centrifuging at 6000-16000 revolutions per minute for 10-30 minutes, washing the resulting precipitate with water and ethanol, 3-5 times, and vacuum drying at 60-80 degrees C for 10-20 hours; the ratio of urea in urea aqueous solution and cobalt salt is 5:1; then drying the resulting solid in an inert gas e.g. nitrogen, and heating under the protection of argon or helium at a rate of 1 degrees C/minute, and calcining at 400-500 degrees C for 3-5 hours.