Designed synthesis of unique ZnS@CdS@Cd0.5Zn0.5S-MoS2 hollow nanospheres for efficient visible-light-driven H2 evolution

Abstract

Solar-driven photocatalytic water-splitting for H₂ production holds great promise to alleviate the growing energy and environmental crisis. Nevertheless, it is still challenging up to now to develop noble-metal-free photocatalysts which are efficient for the H₂ evolution reaction (HER). In this work, based on the ion-exchange and alloying reactions between Zn and Cd ions in liquids, a template-assisted ion-exchange strategy combined with subsequent electrostatic assembly process was employed to prepare uniform ZnS@CdS@Cd_0.5Zn_0.5S-MoS₂ hollow nanospheres for the first time. Under visible-light irradiation (λ > 420 nm), the ZnS@CdS@Cd_0.5Zn_0.5S-MoS₂ hybrid exhibits an optimal HER activity of 50.65 mmol h⁻¹ g⁻¹, which is 20 times more than that of its Pt-decorated ZnS@CdS@Cd_0.5Zn_0.5S counterpart and superior to that of most CdS-based photocatalysts ever reported. Moreover, the ZnS@CdS@Cd_0.5Zn_0.5S-MoS₂ hybrid exhibits good stability for the long-term HER. The outstanding HER capability of ZnS@CdS@Cd_0.5Zn_0.5S-MoS₂ could be attributed to the dramatically facilitated separation of charge carriers, abundant active sites from the defect-rich 1T/2H MoS₂ few-layered nanosheets, and enhanced light-harvesting of the hollow nanostructure. The findings indicated here could benefit the exploitation of high-performance photocatalysts for promising solar-to-fuel applications.