Switching CO-to-Acetate Electroreduction on Cu Atomic Ensembles.

The electrocatalytic reaction pathway is highly dependent on the intrinsic structure of the catalyst. CO/CO electroreduction has recently emerged as a potential approach for obtaining C products, but it is challenging to achieve high selectivity for a single C product. Herein, we develop a Cu atomic ensemble that satisfies the appropriate site distance and coordination environment required for electrocatalytic CO-to-acetate conversion, which shows outstanding overall performance with an acetate Faradaic efficiency of 70.2% with a partial current density of 225 mA cm and a formation rate of 2.1 mmol h cm. Moreover, a single-pass CO conversion rate of 91% and remarkable stability can be also obtained. Detailed experimental and theoretical investigations confirm the significant advantages of the Cu atomic ensembles in optimizing C-C coupling, stabilizing key ketene intermediate (*CCO), and inhibiting the *HOCCOH intermediate, which can switch the CO reduction pathway from the ethanol/ethylene on the conventional metallic Cu site to the acetate on the Cu atomic ensembles.