▎ 摘　　要

NOVELTY - Preparing chlorine doped graphene quantum dot comprises (i) producing highly active chlorine radicals under irradiation of ultraviolet light, and (ii) carrying out photochemical reaction of graphene quantum dots with chlorine radicals to obtain chlorine doped graphene quantum dot. USE - The method is useful for preparing chlorine doped graphene quantum dot. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for device for preparing chlorine doped graphene quantum dot comprising inert gas tanks, chlorine gas generators, photochemical reactors and UV lamps. The inert gas tank is connected to a chlorine gas generator. The chlorine gas generator is connected to the photochemical reactor. The UV lamp is located above the photochemical reactor.