Synthesis and efficient visible light photocatalytic H2 evolution of a metal-free g-C3N4/graphene quantum dots hybrid photocatalyst

Abstract

In this work, we report a systematic study of the relationship between photocatalytic properties of hydrogen evolution and structures and morphologies of g-C3N4 prepared by different precursors (urea, melamine and dicyandiamide). The photocatalytic performances of H2 production are affected by the method and degree of polymerization, the degree of protonation, and the morphology of g-C3N4 prepared by different precursors. Furthermore, a novel metal-free N-GQDs/g-C3N4 catalyst was designed and synthesized, which shows much better photocatalytic activity for H2 evolution from water splitting than that of g-C3N4 due to the unique and multiple roles of N-GQDs. A mechanism is put forth to explain the roles of N-GQDs and the detailed enhancement of photocatalytic performance of the N-GQDs/g-C3N4.