Electrochemical reduction of CO2 (CO2RR) to CO using renewable electricity offers a sustainable route for producing a versatile intermediate. This study demonstrates that a trimetallic single-atom alloy catalyst (Cu92Sb5Pd3) efficiently converts CO2 into CO with 100% (±1.5%) CO selectivity at -402 mA cm⁻² and high activity up to -1 A cm⁻² in a neutral electrolyte. It exhibits long-term stability (528 h) at -100 mA cm⁻² with a Faradaic efficiency (FE) for CO above 95%. Operando spectroscopy and theoretical simulations reveal synergistic effects of Sb and Pd single atoms in modifying Cu's electronic structure, favoring CO production and suppressing hydrogen evolution, while enhancing catalyst stability. This challenges the dominance of noble metals in large-scale CO2-to-CO conversion.
