Sustained Direct Electro-epoxidation of Ethylene via a Strain-Gradient CuO-Ag Interface.

Yu, Xifeng; Zhao, Yong; Liu, Sijia; Tian, Fayou; Zhang, Yinghua; Li, Hui; Yang, Siwen; Ren, Hao et al. · Nat Commun · 2026

basic_science · Level V

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Abstract

Direct electrochemical ethylene epoxidation using water as the oxygen source offers a sustainable alternative to conventional thermal processes, but practical implementation is constrained by insufficient ethylene adsorption and the inherent instability of the critical OO* intermediate. Here we show that a CuO/Ag catalyst engineered with coupled strain and electronic properties promotes exposure of metastable Ag(111) facets to strengthen ethylene adsorption and establishes a dual-reagent confinement system that enriches H<sub>2</sub>O and C<sub>2</sub>H<sub>4</sub> at respective interfacial domains. Characterization and simulation reveal that dynamic charge oscillations at the interface induce an electron flow from Ag to CuO, which facilitates C=C bond activation and stabilizes the OO* intermediate by suppressing O-O bond cleavage. In a membrane electrode assembly reactor, a stable ethylene oxide production rate of 345 μmol·cm<sup>-2</sup>·h<sup>-1</sup> is achieved at 50 mA·cm<sup>-2</sup> over 60 hours, with a Faradaic efficiency of 45.6% and a selectivity of 92.8%. This work validates interfacial strain and electronic properties as a viable strategy for sustainable electrified synthesis, as exemplified by the continuous direct epoxidation of ethylene.