▎ 摘　　要

NOVELTY - Preparation of graphene quantum dot includes making graphite oxide by modified Hummer method, mixing the natural flake graphite with a strong acid solution, adding potassium nitrate, reacting, adding distilled water, reacting, filtering or centrifugal washing the graphite oxide system, and vacuum drying to obtain graphite oxide solid; dispersing the solid graphite oxide in water to form graphite oxide suspension, centrifuging, discarding the lower precipitate, taking the upper layer suspension, adding hydrochloric acid solution in the upper layer suspension, centrifuging, discarding the supernatant, adding deionized water, and storing; and taking the synthesized graphite oxide solution and ultrasonically treating, adding alkali solution, stirring, baking, reacting, cooling, filtering to obtain a quantum dot solution, dialyzing microporous membrane in deionized water, and obtaining high concentration dark brown graphene quantum dot solution. USE - Method for preparing graphene quantum dot. ADVANTAGE - The method is fast and simple. DETAILED DESCRIPTION - Preparation of graphene quantum dot comprises: (A) making graphite oxide by modified Hummer method, where mass ratio of strong acid to graphite is 15-50 ml/g, mixing the natural flake graphite with a strong acid solution, adding potassium nitrate, where the mass ratio of potassium nitrate and graphite is 1-2:1, adding a strong oxidant in a water bath at 0-20 degrees C, where the mass ratio of the strong oxidizing agent to graphite is 2-6:1, raising the temperature to 40-70 degrees C to react for 1-3 hours, the ratio of the volume of distilled water to the graphite is 30-80 ml/g, adding distilled water, reacting for 10-30 minutes at 75-95 degrees C, ending the oxidation reaction, filtering or centrifugal washing the graphite oxide system, where the pH of the system is 5-7, and vacuum drying at 40-80 degrees C to obtain graphite oxide solid; (B) dispersing the solid graphite oxide in water to form graphite oxide suspension having a mass concentration of 2-7 mg/ml, low-speed centrifuging at 500 revolutions/minute, discarding the lower precipitate, taking the upper layer suspension, adding 100 ml of one-tenth hydrochloric acid solution in the upper layer suspension for 0.5 hour, centrifuging at 12000 revolutions/minute, each time for 10 minutes, discarding the supernatant up to pH 7, adding deionized water to dissolve the lower layer precipitate, and storing; and (C) taking the synthesized graphite oxide solution and ultrasonically treating, adding alkali solution, adjusting pH to 10-11, stirring and transferring 100 ml PTFE, putting in the oven, baking, after finishing reaction, cooling to room temperature, using the microporous film pressure filtering to obtain a quantum dot solution, dialyzing microporous membrane in deionized water for 24 hours at 500 Da, and obtaining high concentration dark brown graphene quantum dot solution.