Oxophilicity-Controlled CO₂ Electroreduction to C₂₊ Alcohols over Lewis Acid Metal-Doped Cu^δ+ Catalysts

Abstract

Cu-based electrocatalysts have great potential for facilitating CO₂ reduction to produce energy-intensive fuels and chemicals. However, it remains challenging to obtain high product selectivity due to the inevitable strong competition among various pathways. Here, we propose a strategy to regulate the adsorption of oxygen-associated active species on Cu by introducing an oxophilic metal, which can effectively improve the selectivity of C₂₊ alcohols. Theoretical calculations manifested that doping of Lewis acid metal Al into Cu can affect the C-O bond and Cu-C bond breaking toward the selectively determining intermediate (shared by ethanol and ethylene), thus prioritizing the ethanol pathway. Experimentally, the Al-doped Cu catalyst exhibited an outstanding C₂₊ Faradaic efficiency (FE) of 84.5% with remarkable stability. In particular, the C₂₊ alcohol FE could reach 55.2% with a partial current density of 354.2 mA cm^-2 and a formation rate of 1066.8 μmol cm^-2 h^-1. A detailed experimental study revealed that Al doping improved the adsorption strength of active oxygen species on the Cu surface and stabilized the key intermediate *OC₂H₅, leading to high selectivity toward ethanol. Further investigation showed that this strategy could also be extended to other Lewis acid metals.