Spontaneous Symmetry Breaking via Metal-Triggered Surface Defect Engineering for Durable Piezocatalytic Hydrogen Evolution.

Abstract

Piezocatalysis, which converts ubiquitous mechanical energy into chemical fuels, offers a sustainable route for distributed hydrogen production. However, progress in this field has largely been limited to material-level studies, often characterized by weak polarization, insufficient active sites, and a lack of long-term device-level demonstrations. Here, we propose a metal-triggered surface defect strategy that integrates surface metal anchoring with defect formation to simultaneously enhance polarization and increase the density of active sites. Using Au-ZnSnO₃ as a model system, we demonstrate that Au anchoring spontaneously induces Zn vacancy formation, breaking surface symmetry and strengthening the piezoelectric response by more than fivefold. These synergistic effects result in a 3.7-fold enhancement in the hydrogen evolution rate, placing this material among the top-performing piezocatalysts. Crucially, integrating the catalyst into a custom-designed continuous-flow microreactor enables the first demonstration of ultra-long, device-level piezocatalytic hydrogen production for over 158 h, establishing a new benchmark for durability in this field. Experimental and theoretical analyses reveal that Au anchoring reduces the formation energy of Zn vacancies and optimizes hydrogen adsorption energetics, thereby achieving a balance between proton reduction and hydrogen desorption. This work establishes metal-triggered surface defect engineering as a promising design strategy that links structural symmetry with catalytic reactivity in mechanically driven energy conversion systems.