Ceo₂/Cus Nanoplates Electroreduce Co₂ to Ethanol with Stabilized Cu⁺ Species

Copper-based electrocatalysts effectively produce multicarbon (C2+) compounds during the electrochemical CO2 reduction (CO2RR). However, big challenges still remain because of the chemically unstable active sites. Here, cerium is used as a self-sacrificing agent to stabilize the Cu+ of CuS, due to the facile Ce3+/Ce4+ redox. CeO2-modified CuS nanoplates achieve high ethanol selectivity, with FE up to 54% and FEC2+ approximate to 75% in a flow cell. Moreover, in situ Raman spectroscopy and in situ Fourier-transform infrared spectroscopy indicate that the stable Cu+ species promote C-C coupling step under CO2RR. Density functional theory calculations further reveal that the stronger *CO adsorption and lower C-C coupling energy, which is conducive to the selective generation of ethanol products. This work provides a facile strategy to convert CO2 into ethanol by retaining Cu+ species.