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

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.