Oxygen-mediated formation of MoSx-doped hollow carbon dots for visible light-driven photocatalysis

Abstract

It is of great interest to modulate the photocatalytic activity of nanomaterials by varying their composition at the atomic scale and their nanostructure. Herein, we demonstrate a bottom-up approach for the synthesis of MoSx-doped hollow carbon dots ((MoS)HCDs) as a photocatalyst for the visible light-driven aerobic oxidative coupling of amines. The molecular oxygen-assisted solvothermal reaction of a MoS2 nanosheets/N-methyl-2-pyrrolidone dispersion provided (MoS)HCDs with a unique hollow interior of 6-7 nm as well as with doping of a large portion of pyridinic N atoms and MoSx. As compared to typical carbon dots not bearing hollow structures, the as-prepared (MoS)HCDs exhibited excellent photocatalytic activity in the oxidative coupling reactions of various amines under visible light irradiation at 25 degrees C. Mechanistic investigations suggested that doping with pyridinic N atoms and MoSx was responsible for the significantly improved photocatalytic activity of (MoS)HCDs in photocatalysis. The reaction mechanism of the oxidative coupling reactions of amines that were effectively promoted by (MoS)HCDs under visible light irradiation was also fully examined.