The influence of piezoelectric effect on the heterogeneous photocatalytic hydrogen production of strontium titanate nanoparticles

Highlights: • The piezoelectric effect has a profound influence on heterogeneous photocatalytic H₂ production. • The viscosity of sacrificial agents and positions of ultrasonic vibrators affect sonophotocatalytic H₂ production. • Pt nanoparticles prefer aggregating on the surface of STO nanoparticles by in situ sonophotocatalysis deposition. • The piezoelectric potential on the local surface inhibits photo-generated carriers' migration. Combining photocatalysis with the other physical-field is an efficient way to improve the performance of photocatalysis. The piezoelectric effect on the heterogeneous photocatalytic hydrogen production of SrTiO₃ (STO) nanoparticles was studied in this paper. It was found that the piezoelectric effect generated by the ultrasonic cavitation (sonophotocatalysis) had a profound influence on heterogeneous photocatalytic hydrogen production with or without sacrificial agents. Notably, the sonophotocatalytic hydrogen production of STO was related to the viscosity of sacrificial agents and the position of the ultrasonic vibrators. The mechanism of the performance changes by sonophotocatalysis was investigated by in-situ deposition Pt nanoparticles, which were found to aggregate obviously on STO nanoparticles' surface. Thus, ultrasonic cavitation would build a piezoelectric potential on the local surface of STO that would inhibit photo-generated carriers migrating to the surface.