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

Abstract

Copper-based electrocatalysts effectively produce multicarbon (C₂₊ ) compounds during the electrochemical CO₂ reduction (CO₂ RR). 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 FE_C2+ ≈ 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 CO₂ RR. 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.