Controllable Engineering of ZnIn2S4 with sulfur vacancy as an efficient piezocatalyst toward H2 production

The identification of novel and efficient piezoelectric catalysts is crucial for practical applications. Utilizing Density Functional Theory (DFT) calculations, ZnIn₂S₄ (ZIS), possessing a non-central symmetric crystal structure, is identified as a promising piezoelectric material for piezocatalysis. Hierarchical ZIS nanosheets are synthesized through a facile hydrothermal method, and defect engineering is employed to enhance their activity. By optimizing the defect concentration, ZIS-300, with the optimal defect level, demonstrates the highest H₂ production rate of approximately 3164.67 µmo1^.g^-1.h^-1 under ultrasound, surpassing previously reported piezocatalysts. Furthermore, ZIS-300 exhibits good stability, maintaining its activity and structural integrity after five cycles. Detailed piezo-electrochemical analyses attribute the enhanced piezocatalytic performance to the introduction of sulfur vacancies, which create a shallow donor band facilitating charge carrier separation. This work contributes to a deeper understanding of designing high-performance piezocatalysts through theoretical calculations and defect engineering strategies.