Polarization-assisted dual-vacancy catalyst enables sustainable water purification via accelerated interfacial redox dynamics.

The intrinsic bottleneck of conventional Fenton catalysis lies in sluggish electron transfer and unsustainable redox dynamics. Herein, we engineer defective BiVO4 (VvoBVO) with adjacent vanadium-oxygen dual vacancies to integrate lattice-defect engineering with piezoelectric polarization, significantly boosting Fe-mediated Fenton redox reactions. Combined experiments and theoretical results reveal that synchronous dual vacancies induce defect dipoles, amplifying the piezoelectric response and providing interfacial sites for interactions with Fe species and H2O2 adsorption. Under mechanical stimulation, defect-polarization coupling drives directional charge redistribution from the catalyst lattice to reactive Fe species and H2O2, thereby accelerating Fe3+ reduction and continuous generation of hydroxyl radicals. Consequently, the VvoBVO-based Fenton system achieves nearly complete degradation of 2,4-dichlorophenol (kobs = 0.17 min-1, 30 min), alongside excellent cycling stability and pollutant mineralization. Such a mechanism was further applied to a hydraulic-turbulence-driven reactor for energy-saving wastewater treatment, realizing efficient pollutant removal and simultaneous mechanical-to-electrical energy harvesting (∼0.97 W). This work establishes an effective approach in Fenton catalysis via interfacing defect engineering with piezoelectric polarization, contributing to highly potent and long-term viable water environmental remediation.