▎ 摘　　要

Structure and photocatalytic activity of high quality graphene covered SiC powder (GCSP) composites as metal-free photocatalysts with different sizes and graphene layer numbers are investigated. The results indicate that the GCSP covered with 4-9 layers of graphene reveal outstanding photocatalytic activity enhancement among the other graphene layer numbers. Moreover, it is found that smaller particles have higher activity than the larger ones and more than 730% improvement is achieved by the GCSP derived from 0.5 mu m SiC powder relative to the pristine SiC powder, which is more than 6 times of that of photoreduced graphene oxide/SiC composite. Our results demonstrate that it is the high quality graphene and the perfect heterojunction interface between the graphene and SiC particles render the SiC/graphene core-shell heterojunction an outstanding photocatalytic activity, as well as potential for a low cost and metal-free photocatalyst.