Improved photocatalytic activity of BaTiO3/La2Ti2O7 heterojunction composites via piezoelectric-enhanced charge transfer

[Display omitted] •BaTiO3/La2Ti2O7 shows good piezoelectric potential under ultrasonic vibration.•The polarization electric field can regulate charge carriers at the interface.•Ultrasound vibration enhances the visible light activity of BaTiO3/La2Ti2O7. The separation efficiency of photogenerated carriers in photocatalysis is one of the key factors limiting the overall performance. The polarization field modification of piezoelectric materials is considered to be an effective strategy to regulate their photocatalytic performance. In this study, novel heterojunction photocatalysts that combine piezoelectric BaTiO3 nanorods and La2Ti2O7 nanosheets were synthesized and the polarization electric field promoted the bulk charge separation, while regulating the migration and separation of the carriers at the heterojunction interface. Under the combined action of visible light and ultrasonic, the piezo-photocatalytic degradation efficiency of CIP over BaTiO3/La2Ti2O7 composites increased by 24% and 12.5% compared with its photocatalytic and piezocatalytic degradation efficiency, respectively. Furthermore, the finite element simulation shows that BaTiO3/La2Ti2O7 heterojunctions have a stronger piezoelectric potential difference compared to pure BaTiO3. Our findings provide insights into the development of piezo-photocatalysts that can effectively degrade pollutants under visible light.