Facet engineering enables efficient H2O2 piezo-synthesis and self-activation for decentralized water purification

Piezo-catalytic self-Fenton is a promising strategy for chemical-free decentralized water purification but suffers from sluggish H2O2 generation and activation kinetics. Herein, we designed a bifunctional piezo-catalyst (Cu2WS4) with spatially separated H2O2 generation and activation sites on dedicated facets. Results demonstrate that the piezoelectric field aligns with facet-specific intrinsic fields in Cu2WS4, synergistically boosting directional charge migration, which directs two-electron oxygen reduction reaction to Cu-W bridge sites on {001} facets and water oxidation reaction to Cu_top sites on {101} facets, achieving a high H2O2 production rate of 892.2 µmol g−1 h−1. Notably, the Cu-W heteronuclear dual-coordination architecture enables the H2O2 produced to be sustainably activated in-situ to hydroxyl radicals (·OH). Meanwhile, sulfur-bridged electron shuttle accelerates the CuII/CuI redox cycle, sustaining continuous H2O2 activation for ·OH generation and efficient removal of various refractory pollutants. This work offers a promising approach for reagent-free technologies that harvest ambient mechanical energy for decentralized water purification. A bifunctional Cu2WS4 piezocatalyst with facet-separated sites enables self-Fenton water purification, efficiently producing H2O2 and activating it in situ to remove refractory pollutants.