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.