Enhanced hydrogen evolution activity by modifying SrBi4Ti4O15 with Pd as a piezo-photocatalyst

Abstract

The synergistic coupling of piezoelectric catalysis and photocatalysis can significantly enhance hydrogen production efficiency. However, due to the limited charge carrier separation efficiency and scarce active sites in existing piezo-photocatalytic materials, developing high-performance catalysts with both high piezo- and photo-responses remains a key challenge. In this study, palladium nanocrystals (Pd-NCs) have been deposited on the surface of SrBi₄Ti₄O₁₅ (SBTO), resulting in the successful construction of an efficient hydrogen evolution catalyst based on the synergistic effect of piezo-photocatalysis. Under simultaneous illumination and ultrasound, SBTO-Pd-10% exhibited a hydrogen evolution rate of 27.6 mmol g⁻¹ h⁻¹, which is much higher than that under illumination (1.94 mmol g⁻¹ h⁻¹) or ultrasound (18.2 mmol g⁻¹ h⁻¹). More importantly, this represents an eleven-fold enhancement relative to pure SBTO. The enhanced performance can be attributed to the incorporation of Pd-NCs, which extends the visible light absorption spectrum of the SBTO–Pd composite, improves conductivity, and introduces additional catalytic sites, thereby promoting efficient charge carrier separation. Additionally, the ultrasonic effect induced an internal piezoelectric field that further inhibited photogenerated carrier recombination, resulting in significantly enhanced performance. This study reveals the synergistic catalytic mechanism of a coupled piezo-photocatalytic system, which provides a feasible pathway for the future design of highly efficient hydrogen production catalysts.