▎ 摘　　要

NOVELTY - Preparing an aqueous-phase of nitrogen-doped graphene (NG), comprises mixing graphene oxide aqueous turbid liquid (0.5-5 mg/ml) and a solid urea, and dissolving the mixture, transferring the mixture into a stainless steel reaction kettle, placing the reaction kettle in an oven for performing constant-temperature hydrothermal reaction, naturally cooling into room temperature, taking out the sample, soaking or dialyzing the sample by secondary de-ionized water for removing the unreacted urea and freeze-drying the sample. USE - The method is useful for preparing the aqueous-phase of nitrogen-doped graphene (NG). ADVANTAGE - The method can realize effective reduction of the graphene oxide and the control of the doping ratio of the nitrogen in the product by regulating and controlling the reaction temperature, the time and the ratio of the reactants etc. DETAILED DESCRIPTION - Preparing an aqueous-phase of nitrogen-doped graphene (NG), comprises mixing a raw material graphene oxide aqueous turbid liquid (0.5-5 mg/ml) and a solid urea, where the mass ratio of the graphene oxide to the urea is 1-0.01, and dissolving the mixture, transferring the mixture into a stainless steel reaction kettle, placing the reaction kettle in an oven for performing constant-temperature hydrothermal reaction, where the reaction temperature is 150-200 degrees C and reaction time is 5-20 hours, naturally cooling into room temperature, taking out the sample, soaking or dialyzing the sample by secondary de-ionized water for removing the unreacted urea and freeze-drying the sample for obtaining nitrogen-doped graphene, where the doping amount of the nitrogen is 2.05-8.47%, and the specific surface area of the nitrogen is 450-550 m2/g.