Enhancing hydrogen evolution reaction performance of ZnIn2S4-Based single atom catalysts via surface vacancies and interlayer charge transfer

The development of efficient single atom catalysts (SACs) for the hydrogen evolution reaction (HER) is crucial for advancing clean energy technologies. In this study, we investigate the effects of surface vacancies on the HER performance of ZnIn₂S₄ monolayers using first-principles calculations. Our findings show that introducing sulfur vacancies (S_v) and indium vacancies (In_v) triggers interlayer charge transfer, resulting in charge redistribution around metal atoms and modifying the catalytic behavior of ZnIn₂S₄-based SACs. Notably, Pt/ZnIn₂S₄ exhibited outstanding HER activity with a ΔG_H∗ of 0.02 eV, in excellent agreement with experimental reports. Furthermore, Ir/ZnIn₂S₄-Sv and Ir/ZnIn₂S₄-In_v also demonstrated superior catalytic performance with a ΔG_H∗ of 0 eV, indicating their potential as highly effective HER SACs. This study underscores the crucial role of interlayer charge transfer in modulating catalytic activity and offers valuable insights for the design of novel and efficient SACs for sustainable hydrogen production.