▎ 摘　　要

NOVELTY - Preparing graphene quantum dots comprises (i) carrying out chemical vapor deposition of magnesium oxide as templating agent to prepare porous graphene, (ii) ultrasonic dispersing the porous graphene prepared in step (i) in mixed acid solution, heating, neutralizing with alkali and filtering to obtain filtrate, where the mixed acid solution includes sulfuric acid and nitric acid, and (iii) dialyzing the filtrate prepared in step (ii) to obtain final product. USE - The method is useful in preparation of graphene quantum dot (claimed). ADVANTAGE - The method: utilizes porous graphene having carbon atoms with high activity at the edge of the grain boundary, which disintegrates the porous graphene into graphene quantum dots; has less etching loss; produces controllable size of the graphene fragments by etching and thus increases the yield of graphene quantum dots; and has low cost compared with the existing technology. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for graphene quantum dots prepared by above method.