Atomically Isolated Cd Sites Boosting CO Electroreduction to C₂₊ Alcohols at Ampere-Level Current Densities

Herein, two Cu-based model electrocatalysts, Cu nanosheets modified with Cd single atoms (Cd-SACs@Cu NS) and unmodified Cu nanosheets (Cu NS), were rationally designed to investigate the C-C coupling to C₂₊ alcohols mechanisms in CORR. Compared to Cu NS, Cd-SACs@Cu NS exhibits a significantly enhanced Faradaic efficiency (FE) for C₂₊ alcohols of nearly 70% at an unprecedented current density of 1100 mA cm^-2 and maintains a higher FE (>50%) over a broad range of current densities (100-2100 mA cm^-2) under alkaline conditions in a flow cell. In situ characterizations and theoretical studies reveal that the enhanced selectivity toward C₂₊ alcohols on Cd-SACs@Cu NS is attributed to the improved H₂O dissociation at atomically dispersed Cd sites and enhanced CO adsorption on the paired Cu atoms adjacent to single Cd atoms. These effects synergistically facilitate the spillover of hydrogen atoms from Cd to Cu sites, thereby promoting the protonation at the β-carbon of *CH₂CHO, which leads to the selective formation of C₂₊ alcohols. In contrast, the unmodified Cu NS is prone to promoting the cleavage of the C─O bond, thereby facilitating the generation of C₂H₄.