▎ 摘　　要

NOVELTY - The preparation of nitrogen-doped graphene quantum dots, involves (A) using graphite rods as anode and cathode, immersing in aqueous solution of 0.05-0.5 mol/L ammonium sulfate and carrying out constant potential electrolysis at 4-10 V in electrolytic cell, and expanding graphite layer on anode and cathode surfaces, (B) adding aqueous ammonia to electrolytic cell, the molar ratio of ammonium sulfate and aqueous ammonia is (1-14):1, controlling working voltage of step (A) for 60-180 minutes, suction filtering electrolyte in electrolytic cell to obtain pale yellow filtrate, stirring light yellow filtrate and heating to remove excess ammonia, (C) dialyzing filtrate with molecular weight of 3000-12000 Da to neutral at room temperature, removing excess salt ions to obtain graphene quantum dots dispersion and freeze-drying graphene quantum dots dispersion. USE - Preparation of nitrogen-doped graphene quantum dots used for supercapacitor electrode material and for fluorescence detection. ADVANTAGE - The method enables preparation of nitrogen-doped graphene quantum dots with uniform size and increased stability by simple and easy process.