Unraveling the piezoelectric field effect: [111]pc-oriented BiFeO3 single crystal as a catalytic booster for TiO2-based piezo-photocatalysis

This study investigates the role of a [111]pc-oriented piezoelectric BiFeO3 single-crystal substrate in enhancing the piezo-photocatalysis of a sputtered TiO2 thin film. Compared to an identical film on glass, the BiFeO3/TiO2 heterostructure exhibits a 2.07-fold higher degradation rate constant for ofloxacin under combined light and ultrasonic excitation. Direct evidence from in-situ EPR and KPFM reveals that the BiFeO3 substrate’s piezoelectric field drives efficient charge separation, leading to a ~4-fold enhancement in superoxide radical (•O2-) generation and significant surface electron accumulation, which are responsible for the superior activity.