Interfacial proton-electron donor synergy enables sustainable oxime electrosynthesis via dual-path reduction.

The electrosynthesis of value-added organonitrogen chemicals offers a promising strategy to address the anthropogenic unbalance of global nitrogen cycle. The challenge lies the dynamic asynchrony between proton and electron transfer at electrocatalytic interface, resulting in low Faradaic efficiency (FE) and selectivity. Here, we engineer a synergistic proton-electron donor interface by integrating protonated polyaniline with graphite sheets (p-PANI - GS), enabling dual-path reduction of nitrate (NO3-) to *NH2OH, i.e., spontaneous chemical reduction and enhanced electrocatalytic reduction. When coupled with cyclohexanone, this configuration delivers a high cyclohexanone oxime (C6H11NO) productivity of 67.1 µmol h-1 cm-2 with 69.9% FE, while maintaining robust stability across pH of 3.0 - 11.0. Mechanistic investigations unveil that autonomous proton donation synergizes with hetero-interfacial electron redistribution to achieve concerted proton-electron delivery at catalytic sites. Such donor synergy accelerates proton-coupled electron transfer kinetics and stabilizes *NH2OH intermediates in NO3- reduction, thereby steering selectivity toward C6H11NO. Additionally, the solar-driven system and machine learning prediction support the practical extensibility of this oxime electrosynthesis strategy. Our work pioneers an atomic-scale interface engineering framework enabling sustainable value-added oxime electrosynthesis.