▎ 摘　　要

NOVELTY - The preparation method of graphene quantum dots, involves (1) washing and drying longan shell, carrying out high temperature carbonization under protective atmosphere, cleaning, drying and grinding to obtain carbon powder, (2) oxidizing obtained carbon powder by nitric acid and subjecting to suction filtration and drying to obtain black powder, (3) adding the obtained black powder to solvent of N,N-dimethylformamide, ultrasonically reacting the obtained suspension, hydrothermally reacting, cooling to room temperature and carrying out suction filtration. USE - Preparation of graphene quantum dots. ADVANTAGE - The method enables preparation of graphene quantum dots by simple, economical and environmentally-friendly process. DETAILED DESCRIPTION - Preparation of graphene quantum dots, involves (1) washing and drying longan shell, carrying out high temperature carbonization under protective atmosphere, cleaning, drying and grinding to obtain carbon powder, (2) oxidizing obtained carbon powder by nitric acid and subjecting to suction filtration and drying to obtain black powder, (3) adding the obtained black powder to a solvent of N,N-dimethylformamide, ultrasonically reacting the obtained suspension and transferring to high-temperature and high-pressure reactor for hydrothermal treatment, (4) cooling to room temperature, carrying out suction filtration to obtain resulting filtrate.