Boosting Electrocatalytic Ethylene Epoxidation by Single Atom Modulation.

The electrochemical synthesis of ethylene oxide (EO) using ethylene and water under ambient conditions presents a low-carbon alternative to existing industrial production process. Yet, the electrocatalytic ethylene epoxidation route is currently hindered by largely insufficient activity, EO selectivity, and long-term stability. Here we report a single atom Ru-doped hollandite structure KIr4O8 (KIrRuO) nanowire catalyst for efficient EO production via a chloride-mediated ethylene epoxidation process. The KIrRuO catalyst exhibits an EO partial current density up to 0.7 A cm-2 and an EO yield as high as 92.0 %. The impressive electrocatalytic performance towards ethylene epoxidation is ascribed to the modulation of electronic structures of adjacent Ir sites by single Ru atoms, which stabilizes the *CH2CH2OH intermediate and facilitates the formation of active Cl2 species during the generation of 2-chloroethanol, the precursor of EO. This work provides a single atom modulation strategy for improving the reactivity of adjacent metal sites in heterogeneous electrocatalysts.