Piezoelectric effect achieves efficient carriers’ spatial separation and enhanced photocatalytic H2 evolution of UiO-66-NH2@CdS by transforming charge transfer mechanism

Abstract

The internal electric field induced by piezoelectric effect can optimize the transport pathway of photogenerated charge in photocatalysis. We constructed an effcient piezoelectric photocatalytic heterojunction UiO-66-NH2@CdS and achieved a shift in the charge transfer mechanism through the piezoelectric effect, resulting in excellent photocatalytic H2 evolution performance. The optimal heterojunction under the ultrasonic environment exhibited 2028.48 μmol·g−1·h−1 photocatalytic H2 evolution performance, roughly four times better than no-ultrasound condition. Because of the piezoelectric polarization of UiO-66-NH2, the photogenerated carrier transport mechanism was changed from type Ⅱ to the more favorable Z-scheme for charge separation. Meanwhile, the built-in electric field caused by the piezoelectric effect can act as a powerful driving force for charge separation, achieving high charge separation efficiency and promoting the utilization of photogenerated electrons. This work would provide a fresh perspective for MOF-based piezoelectric photocatalysts and have implications for the design of efficient Z-scheme heterojunctions.