Synergistic mechanical nanostructuring and peroxymonosulfate activation enable superior piezocatalysis

Piezocatalysis facilitates the transduction of mechanical energy into chemical redox processes, but its practical application is hindered by intrinsically low catalytic efficiency and complex catalyst fabrication. Herein, we employ high-energy ball milling (HBM) to convert bulk lead-free Sr_0.5Ba_0.5Nb₂O₆ (SBN) ceramics into nanoscale piezocatalysts (SBN-HBM) with enhanced activity, and integrate them with peroxymonosulfate (PMS) activation to promote reactive oxygen species generation, thereby boosting overall catalytic performance. HBM refines grain size from the microscale to ~240 nm and introduces abundant oxygen vacancies, enhancing both piezoelectric polarization and surface reactivity. Under mechanical excitation, the integrated SBN-HBM/PMS system triggers synergistic oxidation featuring hydroxyl radicals (•OH), sulfate radicals (SO₄ •-), and piezo-induced holes, resulting in markedly accelerated degradation kinetics (e.g., k = 0.520 min^-1 for methyl orange, 0.356 min^-1 for tetracycline) and achieving > 99% bacterial inactivation. Experimental results and theoretical analyses reveal that defect-polarization coupling critically governs carrier separation dynamics and facilitates efficient redox reactions. This work offers a green and scalable strategy for transforming bulk piezoceramics into highly efficient piezocatalysts for decentralized wastewater treatment.