Construction of heterojunctions between ReS2 and twin crystal ZnxCd1−xS for boosting solar hydrogen evolution

Abstract

Facilitating charge separation as well as surface redox reactions is considered to be an efficient way to improve semiconductor-based photocatalytic hydrogen generation. In this study, we developed a highly active and reliable photocatalyst, ReS₂/T-ZCS, by anchoring nanoflower-like ReS₂ particles on the surface of host chalcogenide nanotwins (Zn_0.5Cd_0.5S). By virtue of the in-built driving force from the homojunction with a type-II staggered band alignment in twin crystal Zn_0.5Cd_0.5S (T-ZCS) and heterojunctions between T-ZCS and ReS₂ on the surface of the photocatalyst, a substantially improved charge separation and transfer property were achieved. Hence, the twin crystal Zn_0.5Cd_0.5S decorated nanoflower-like ReS₂ exhibits a significantly improved photocatalytic H₂ evolution rate of 112.10 mmol g⁻¹ h⁻¹ and the corresponding apparent quantum efficiency reaches 32.65% at 420 nm, which is 31 times larger than that of pure phase Zn_0.5Cd_0.5S. Our work not only couples the merits of homojunctions and heterojunctions to promote solar energy conversion, but also expands applications of the transition metal dichalcogenide (TMD) family in electrocatalysis, photothermal-catalysis and energy storage.