Single-atom RhS bond on defective CdZnS for enhanced photocatalytic hydrogen production

Abstract

It is highly necessary but challenging to modify sulfides at the atomic scale to boost the separation of electron-hole pairs for enhanced photocatalytic performance. In this regard, single Rh atoms (Rh₁) are assembled on CdZnS support with S vacancy defects (def-CZS) through RhS bond, creating a highly efficient photocatalyst. The optimized Rh₁/def-CZS achieves an outstanding hydrogen evolution activity (30,512 μmol h⁻¹ g⁻¹), 4.32 and 3.34 folds enhancement that of CZS and def-CZS, respectively. The defective CZS support provides abundant S vacancy defects for Rh atom anchoring, where Rh bonds with neighboring S atoms (RhS). Theoretical calculations suggest that Rh can not only act as new H generation-release sites, but also optimize electron distribution around S defects simultaneously through the RhS bond, facilitating the separation of electron-hole pairs. Furthermore, in line with DFT results, in situ Raman confirms Rh (RhH) and electron-rich S atoms (SH) two main sites for proton reduction during hydrogen evolution.