Construction double electric field of sulphur vacancies as medium ZnS/Bi₂S₃-PVDF self-supported recoverable piezoelectric film photocatalyst for enhanced photocatalytic performance

When internally polarized by mechanical energy, piezoelectric materials can establish polarization electric field and provide driving force for separating photogenerated carriers. Herein, S vacancies are introduced as an intermediate to make metal ions form coordination bond with F^- on PVDF (polyvinylidene fluoride) surface, and the built-in electric field is intimately related to polarized electric field. We successfully synthesized ZnS/Bi₂S₃-PVDF film photocatalyst containing S vacancies (ZnS-V_S/Bi₂S₃-PVDF). Polarized electric field on PVDF caused by ultrasonic cavitation and built-in electric field formed between ZnS-V_S/Bi₂S₃ heterojunction structure are beneficial to interfacial charge transferring. Theoretical calculation simulation demonstrate that the synergistic effect of the double electric fields is propitious to inhibit the recombination of carriers. The hydrogen evolution rate of ZnS-V_S/Bi₂S₃-PVDF reaches 10.07 mmol h⁻¹g⁻¹. Moreover, it has excellent reversibility and facile recovery capacity. This work provides new platform for photocatalytic reduction of hydrogen evolution and is expected to contribute to clean energy production.