Theoretical calculations and controllable synthesis of MoSe2/CdS-CdSe with highly active sites for photocatalytic hydrogen evolution

Abstract

It is still of great practical significance to exploring low-cost and earth-abundant alternative materials as cocatalyst for photocatalytic hydrogen evolution. The density functional theory (DFT) calculations indicated that both the basal plane and the edge of mixed phase MoSe2 provide the highly catalytic activity for hydrogen evolution reaction (HER). Based on this, the mixed phase MoSe2 was designed as an excellent cocatalyst because of superior ability to receive electrons and optimal active sites for HER. Herein, the ternary (1T/2H) MoSe2/CdS-CdSe structure was prepared by a simple hydrothermal method. The hydrazine monohydrate as reductant helps to control 1T phase content of MoSe2, and the maximum content of 1T phase MoSe2 reaches 66.5%. The results showed that the H2 evolution rate of the optimized MoSe2/CdS-CdSe reached a value of 24.34 mmol h−1 g−1 and a high quantum efficiency (QE) of 28.5% at 500 nm. A volcano-like correlation has been presented for the first time to illustrate the effect of structures of MoSe2 on photocatalytic activity for HER, which provides the direction of design of MoSe2 cocatalyst.