Charge Migration in CdS/NiS Schottky junction composites for benzylalcohol oxidation coupled with hydrogen production

Abstract

Photosynthesis of organic compounds in coupling with promoted hydrogen evolution are hot spots in energy and environmental science. Here, we have fabricated CdS/NiS composites by two-step hydrothermal method for the highly selective oxidation of benzyl alcohol (BA) to benzaldehyde (BAD) in coupling with highly efficient hydrogen evolution. This efficient bifunctional catalyst is proposed to promote the separation of photoexcited electrons (e-) and holes (h+). The optimized 1% CdS/NiS composition exhibited the highest H2 evolution rate of 6.7 mmolg-1h-1 and a simultaneous BAD generation rate of 5.8 mmolg-1h-1 under visible light irradiation, which are respectively 2.5 and 3 times higher than those of pure CdS. Furthermore, ESR measurement result and DFT calculations suggest that NiS decoration promotes the charge separation, thereby enhancing the efficiency of the overall photocatalytic process. This work provides an effective strategy for integrated productions of organic synthesis and energy conversion.