Atomic Coordination Engineering of Sub-Nanometer Cu Clusters for Selective CO₂ Electroreduction to Multi-Carbon...

Electrochemical conversion of CO₂ to multi-carbon (C₂₊) alcohols remains a substantial challenge due to the competing ethylene pathway. Precisely tuning the bond energy of key intermediates plays an essential role in dictating the alcohol and ethylene pathway. Herein, we demonstrate that S and N coordinated Cu sub-nanometer clusters (Cu/SNC) can achieve targeted modulation of the bond energy (Cu─C, C─O, and Cu─O) of multiple key intermediates (*CO and *OCHCH₂), thus leading to preferential production of C₂₊ alcohols rather than ethylene. Notably, Cu/SNC exhibited a C₂₊ alcohols selectivity of 59.1% and a high alcohol-to-ethylene ratio of 7.21, which is 19 times larger than that without S and N coordination. Mechanistic studies reveal that N and S dopants individually facilitate CO₂ activation and lower the *CO adsorption energy barrier, synergistically steering the asymmetric C─C coupling pathway to promote C₂₊ species formation. Moreover, N and S co-coordination enables precise modulation of the adsorption behavior of oxygen-containing intermediates. This electronic restructuring weakens Cu─O interactions while strengthening the C─O bond, thereby preferentially stabilizing alcohol-forming pathways. This work provides a framework for precisely regulating the reaction pathway toward the highly selective electroreduction of CO₂ to C₂₊ alcohols.