Switching CO-to-Acetate\nElectroreduction on Cu Atomic\nEnsembles

The electrocatalytic reaction pathway is highly dependent\non the\nintrinsic structure of the catalyst. CO<sub>2</sub>/CO electroreduction\nhas recently emerged as a potential approach for obtaining C<sub>2+</sub> products, but it is challenging to achieve high selectivity for\na single C<sub>2+</sub> product. Herein, we develop a Cu atomic ensemble\nthat satisfies the appropriate site distance and coordination environment\nrequired for electrocatalytic CO-to-acetate conversion, which shows\noutstanding overall performance with an acetate Faradaic efficiency\nof 70.2% with a partial current density of 225 mA cm<sup>–2</sup> and a formation rate of 2.1 mmol h<sup>–1</sup> cm<sup>–2</sup>. Moreover, a single-pass CO conversion rate of 91% and remarkable\nstability can be also obtained. Detailed experimental and theoretical\ninvestigations confirm the significant advantages of the Cu atomic\nensembles in optimizing C–C coupling, stabilizing key ketene\nintermediate (*CCO), and inhibiting the *HOCCOH intermediate, which\ncan switch the CO reduction pathway from the ethanol/ethylene on the\nconventional metallic Cu site to the acetate on the Cu atomic ensembles.