Defect engineering for enhancing the piezoelectric catalytic activity of Bi₂S₃ for hydrogen production

Piezocatalysis has emerged as a promising strategy for sustainable hydrogen production, yet its efficiency remains limited by insufficient charge separation and sluggish surface reactions. In this study, we demonstrate that introducing sulfur vacancies into bismuth sulfide (Bi₂S₃) significantly enhances its piezocatalytic performance for hydrogen evolution. DFT calculations revealed that sulfur vacancies induce asymmetric Bi-S bond contraction and adjacent bond elongation, and the redistribution of electron density produces local dipole moments, thus improving the piezoelectric response of Bi₂S₃. Moreover, it is further established that there is an obvious structure-activity relationship between the crystal structure and piezoelectric catalytic efficiency. This work provides a defect-engineering approach for designing high-performance piezoelectric catalysts for clean energy applications.