Construction of a Bi2S3/Bi0.5Na0.5TiO3 Composite Catalyst with S Vacancies for Efficient Piezo-Photocatalytic Hydrogen Production.

ABSTRACT

Photocatalytic hydrogen production with low environmental and economic costs is expected to be a powerful means to alleviate energy and environmental problems. However, how to inhibit the rapid recombination of photogenerated carriers is a challenge that photocatalytic hydrogen production has to face. In this study, the coupling of the piezoelectric effect and vacancy engineering into the photocatalytic reaction process synergistically promoted carrier separation, thereby promoting the improvement of hydrogen production performance. Specifically, the novel dual piezoelectric Bi2S3/Bi0.5Na0.5TiO3 (BS-12/BNT) piezo-photocatalyst rich in S vacancies was synthesized by an impregnation method. The hydrogen generation rate of 5% BS-12/BNT under the combined impact of light and ultrasound was up to 1019.39 µmol/g/h, which is 9.5 times higher than that of pure BNT. Various characterization analyses have confirmed that the piezoelectric-photocatalytic activity of BS/BNT composite materials is significantly improved, mainly due to the introduction of S vacancies and piezoelectric fields, which enhance the absorption of sunlight, reduce interface resistance, and so raise the photogenerated carriers' separation efficiency. In addition, the stability of BS/BNT is significantly better than that of the previously synthesized catalysts. Finally, according to the results of XPS, UV-vis, and ESR, the active groups and possible electron transfer paths generated during the piezoelectric-photocatalytic hydrogen production process were studied. This work presents a new approach to promote hydrogen production performance through the synergistic effect of the piezoelectric effect and S vacancies.