▎ 摘　　要

NOVELTY - A metal catalyst is deposited on a clean substrate, to form metal thin film. The metal thin film is etched, to form nano patterned metal catalyst particles, and to obtain graphical metal catalyst particles. The substrate, a carbon source and reducing gas are supplied to reactor and processed at 300-1100 degrees C, to obtain graphene quantum dots on nano metal catalyst particles. The graphene quantum dots-attached substrate is cooled. The metal catalyst particles are completely dissolved, and graphene quantum dots are separated from substrate and purified, to obtain graphene quantum dots. USE - Preparation of size-controlled graphene quantum dots (claimed). ADVANTAGE - The method enables preparation of size-controlled graphene quantum dots with high yield by economical method. DETAILED DESCRIPTION - A metal catalyst is deposited on a clean substrate, to form metal thin film with thickness of less than 50 nm. The metal thin film is etched, to form nano patterned metal catalyst particles, and to obtain graphical metal catalyst particles with size of less than 60 nm. The substrate is placed in chamber of chemical vapor deposition reactor, and a carbon source and reducing gas are supplied to reactor and processed at 300-1100 degrees C, to obtain graphene quantum dots on nano metal catalyst particles and 1-3 single atomic layers of graphene quantum dots are formed. The graphene quantum dots-attached substrate is cooled to room temperature in reducing atmosphere, and the substrate is removed. The metal catalyst particles are completely dissolved, and graphene quantum dots are separated from substrate. The solution of graphene quantum dots is suspended, separated and purified, to obtain graphene quantum dots.