Turning copper into an efficient and stable CO evolution catalyst beyond noble metals.

Using renewable electricity to convert CO into CO offers a sustainable route to produce a versatile intermediate to synthesize various chemicals and fuels. For economic CO-to-CO conversion at scale, however, there exists a trade-off between selectivity and activity, necessitating the delicate design of efficient catalysts to hit the sweet spot. We demonstrate here that copper co-alloyed with isolated antimony and palladium atoms can efficiently activate and convert CO molecules into CO. This trimetallic single-atom alloy catalyst (CuSbPd) achieves an outstanding CO selectivity of 100% (±1.5%) at -402 mA cm and a high activity up to -1 A cm in a neutral electrolyte, surpassing numerous state-of-the-art noble metal catalysts. Moreover, it exhibits long-term stability over 528 h at -100 mA cm with an FE above 95%. Operando spectroscopy and theoretical simulation provide explicit evidence for the charge redistribution between Sb/Pd additions and Cu base, demonstrating that Sb and Pd single atoms synergistically shift the electronic structure of Cu for CO production and suppress hydrogen evolution. Additionally, the collaborative interactions enhance the overall stability of the catalyst. These results showcase that Sb/Pd-doped Cu can steadily carry out efficient CO electrolysis under mild conditions, challenging the monopoly of noble metals in large-scale CO-to-CO conversion.