Piezopotential-Driven Nitrogen Reduction for Sustainable Ammonia Synthesis via Metal-Piezoelectric Interfacial Coupling.

Ambient ammonia synthesis remains highly challenging due to the inertness of N2 and inefficient charge separation and interfacial reaction kinetics in current piezocatalytic systems. Herein, we report a metal-piezoelectric strategy by engineering amorphous Ru-coated ZnO nanorods to enable highly efficient piezocatalytic nitrogen reduction. The introduction of an optimized amorphous Ru-coated surface induces strong interfacial charge redistribution and establishes a built-in electric field, which synergistically enhances piezoelectric polarization and carrier dynamics. As a result, the optimized ZnO-NRs/10Ru exhibits a dramatically prolonged carrier lifetime (18 ns, an approximately ninefold increase) and the strongest piezoresponse among all samples. Piezo-induced charge separation generates reductive •H species that may facilitate the hydrogenation of adsorbed nitrogen species, accompanied by •OH formation through hole-mediated water oxidation. Under purely mechanical stimulation, ZnO-NRs/10Ru achieves an ammonia yield of 2007.06 µmol gcat -1 L-1 h-1, nearly twice that of pristine ZnO, with excellent structural stability and isotope-confirmed nitrogen origin. Finite-element simulations further demonstrate that the Ru-coated surface optimizes internal piezopotential distribution while maintaining efficient charge transfer across the ZnO/Ru interface. This work provides a general strategy for metal-modified piezoelectric catalysts toward sustainable ammonia synthesis and energy conversion applications.