▎ 摘　　要

NOVELTY - Ultra-small blue-green double-emitting nitrogen- and chlorine-doped graphene quantum dot is claimed. The graphene quantum dot contains nitrogen and chlorine, the doping amount of nitrogen is 2-5.4 atm%, the doping amount of chlorine is 1-2.16 atm%, and the graphene quantum dot particle size distribution is 0.8-5 nm. USE - Used as ultra-small blue-green double-emitting nitrogen- and chlorine-doped graphene quantum dot. ADVANTAGE - The quantum dot: has simple preparation process; and is suitable for large scale industrial production. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing graphene quantum dot comprising (i) mixing 2 mmol citric acid and 1-4 mmol 1,2,4-triaminobenzene dihydrochloride respectively, dissolving in 10-20 ml deionized water, stirring at 25 degrees C for 30 minutes, transferring the mixed solution to a Teflon-lined reaction vessel, and reacting at 190-210 degrees C for 6-60 hours and naturally cooling to room temperature to obtain nitrogen and chlorine co-doped graphene quantum dot, and (ii) placing the crude product of nitrogen and chlorine co-doped graphene quantum dot obtained in step (i) in a dialysis bag having a molecular weight cutoff of 3500 Da, carrying out dialysis for 24-48 hours, and then placing in a dialysis bag with a molecular weight cut off of 3000 Da for 12-24 hours, removing the obtained dialysate using a rotary evaporator to remove residual solvent to obtain concentrated nitrogen and chlorine co-doped graphene quantum dot aqueous solution, placing the above solution in a solid state at -20 degrees C, and removing the residual solvent in a vacuum freeze-drying oven to obtain final product.