Selective CO-to-acetate electroreduction via intermediate adsorption tuning on ordered Cu–Pd sites

Electrochemical reduction of carbon monoxide (CO) has recently emerged as a potential approach for obtaining high-value, multicarbon products such as acetate, while the activity and selectivity for prodution of acetate have remained low. Herein, we develop an atomically ordered copper–palladium intermetallic compound (CuPd) composed of a high density of Cu–Pd pairs that feature as catalytic sites to enrich surface *CO coverage, stabilize ethenone as a key acetate path intermediate and inhibit the hydrogen evolution reaction, thus substantially promoting acetate formation. The CuPd electrocatalyst enables a high Faradaic efficiency of 70 ± 5% for CO-to-acetate electroreduction and a high acetate partial current density of 425 mA cm−2. Under membrane electrode assembly conditions, the CuPd electrocatalyst demonstrated a 500 h CO-to-acetate conversion at 500 mA cm−2 with a stable acetate Faradaic efficiency of ~50%. Electrocatalytic CO reduction presents a route to low-temperature acetate production, but activity and efficiency remain below practical levels. Here, the authors present an intermetallic compound with stable, atomically ordered Cu–Pd pairs that facilitates an acetate pathway and delivers 70% Faradaic efficiency at 425 mA cm−2.