Synergistic piezophototronic and plasmonic effects in Pt-Pd/BiVO4 composites for enhanced tetracycline degradation

Piezo-photocatalysis has emerged as a promising strategy for environmental remediation, particularly in addressing persistent organic pollutants such as antibiotics. However, its practical implementation faces two critical challenges: (1) rapid recombination of photogenerated electron-hole pairs and (2) insufficient active sites for surface redox reactions. To overcome these limitations, we developed an innovative piezo-photocatalytic system composed of ultrathin BiVO4 nanosheets decorated with bimetallic Pt-Pd alloy nanoparticles (Pt-Pd/BiVO4) for efficient tetracycline (TC) degradation. As an efficient combination of photocatalysis and piezocatalysis, the built-in polarization field generated by the piezoelectric effect of BiVO4 catalysts could serve as a powerful driving force for the separation and migration of photoexcited charges. Simultaneously, the Pt-Pd nanoparticles enhance catalytic performance through (i) localized surface plasmon resonance (LSPR)-induced hot electron generation and (ii) optimized charge transfer pathways due to their superior electrical conductivity. Under simultaneous ultrasonic vibration and visible light illumination, the PPB-0.5 composites achieves an outstanding TC degradation rate constant (k = 0.071 min−1), representing a 3.54-fold enhancement compared to pure BiVO4. Furthermore, the degradation efficiency remains nearly 90 % after four cycles, highlighting the system's stability. The result reveal that the synergistic coupling of photocatalysis, piezoelectric polarization and plasmonic excitation significantly promotes the generation of reactive oxygen species (ROS), particularly ·OH and ·O2- radicals, which play a dominant role in TC degradation. This work not only provides fundamental insights into piezo-photo-plasmonic coupling effects but also offers a viable design strategy for developing robust hybrid catalysts for wastewater treatment applications.