Charge-Asymmetric Dual-Cu Sites in a Metal-Organic Framework Direct CO₂ Electroreduction to Ethanol

The selective electrochemical CO₂ reduction reaction (CO₂RR) to ethanol is constrained by copper's intrinsic kinetic preference for the ethylene-forming *CO→*COH pathway over the ethanol-selective *CO→*CHO route. Conventional solutions break this preference by introducing extrinsic chemical heterogeneity. Herein, we report an approach to generating electronic asymmetry in a homometallic system. The in-situ construction of a chemically bonded interface between a binuclear Cu-MOF and copper foil (cf) induces electron transfer, transforming symmetric Cu dimers into cooperative, charge-asymmetric dual sites. These sites function as a kinetic gate, raising the barrier for *CO→*COH while lowering it for *CO→*CHO to direct selectivity toward ethanol, as confirmed by in-situ spectroscopy and DFT. The findings indicate that interfacial electron redistribution can provide a straightforward means to encode functional asymmetry in homometallic electrocatalysts and to modulate multistep reaction pathways.