Design of Z-scheme WSSe–XS₂ (X = Zr and Hf) heterostructures as photocatalysts for efficient solar water splitting

Transition metal dichalcogenides (TMDs) have been extensively studied as efficient photocatalysts for water splitting. However, the utilization efficiency of photogenerated carriers remains a major limitation for their practical applications. An effective approach to address this issue is the construction of Z-scheme heterostructures. In this study, WSSe-XS₂ (X = Hf, Zr) heterostructures are constructed, and their stability, electronic structure, optical properties, photocatalytic performance, and solar hydrogen evolution efficiency are evaluated using first-principles calculations. The results demonstrate that all WSSe-XS₂ heterostructures are stable and exhibit a Z-type configuration. Moreover, band edge positions straddle the hydrogen and oxygen evolution potentials, indicating their potential as high-performance photocatalysts for water splitting. Further calculations show that all heterostructures exhibit excellent catalytic activity in both acidic and neutral solutions, along with promising solar hydrogen evolution efficiency. These theoretical predictions provide valuable insights for the future experimental synthesis of high-performance photocatalysts for water splitting.