Facile synthesis of defective ZnS–ZnO composite nanosheets for efficient piezocatalytic H ₂ production

A facile approach was developed for the synthesis of ultrathin ZnS-ZnO nanosheets. By simply manipulating the synthesis temperature, ZnS-ZnO composite nanosheets with sulfur vacancies were successfully obtained using ZnS(en)_0.5 as the precursor. The formation of the ZnS-ZnO composite leads to the creation of a heterojunction at the interface between the two materials, which enhances the separation of piezogenerated electrons and holes. Additionally, sulfur vacancies are concurrently introduced into the ZnS lattice during the heat treatment process. This defective ZnS with sulfur vacancies exhibits a narrowed bandgap and low excitation energy. Consequently, the defective ZnS-ZnO composite nanosheets demonstrate much higher piezocatalytic activity compared to ZnS and ZnO catalysts, surpassing the performance of most reported piezocatalysts. Furthermore, the ZnS-ZnO composite nanosheets maintain stability over five cycles of catalytic reactions. The study offers a promising approach for enhancing piezocatalytic performance for H₂ production.