Piezoelectric Polarization and Sulfur Vacancy Enhanced Photocatalytic Hydrogen Evolution Performance of Bi2S3/ZnSn(OH)6 Piezo-photocatalyst

The combination of piezoelectric catalysis and photocatalysis could effectively enhance the carrier separation efficiency and further improve the hydrogen production activity. However, piezoelectric polarization always suffers from a low polarization strength, which severely restricts its actual applications. In this study, we successfully synthesized a novel sulfur vacancy-rich Bi₂S₃/ZnSn (OH)₆ (BS-12/ZSH) piezo-photocatalyst for hydrogen evolution through water splitting. Notably, the piezo-photocatalytic hydrogen generation rate of the 8% BS-12/ZSH catalyst (336.21 μmol/g/h) was superior to that of pristine ZSH (29.71 μmol/g/h) and BS-12 (21.66 μmol/g/h). In addition, the hydrogen generation for 8% BS-12/ZSH (336.21 μmol/g/h) under ultrasonic coupling illumination was significantly higher than that under single illumination (52.09 μmol/g/h) and ultrasound (121.90 μmol/g/h), owing to the cooperative interaction of the sulfur vacancy and piezoelectric field. Various characterization analyses confirmed that (1) the introduction of sulfur vacancies in BS-12 provided more active sites, (2) BS-12 with sulfur vacancies acted as a co-catalyst to accelerate the hydrogen production rate, and (3) the piezoelectric field eliminated the electrostatic shielding and offered an additional driving force, which effectively promoted the separation of electron-hole pairs. This research clearly reveals the synergistic effect between piezocatalysis and photocatalysis as well as offers a promising sight for the rational design of high-efficiency piezo-photocatalysts.