Interface-Regulated Orbital Coupling Enables Nucleophilic Carbon Assembly Pathways in Electrochemical CO₂ Conversion

Achieving selective and durable CO₂ electroreduction to ethanol remains challenging due to the instability of Cu oxidation states and inefficient C─C coupling. Here, we construct a Zn single-atom-Cu₂O hybrid catalyst, where atomically dispersed Zn atoms form a well-defined ZnO─Cu interface. The catalyst delivers a high ethanol Faradaic efficiency of 74.4% and operates stably for 200 h. Density functional theory and operando X-ray absorption spectroscopy reveal that an intrinsic orbital coupling between Zn4 s/4p and O 2p orbitals induces interfacial polarization. Under reaction conditions, this polarization stabilizes low-coordinated Cu⁺ sites and facilitates *CHO formation. This polarization enables a nucleophilic C─C coupling pathway that bypasses *CO dimerization, reducing the kinetic barrier for ethanol formation. The concept of interfacial orbital regulation demonstrated here provides a general strategy for steering multi-electron reactions and C─X bond formation in electrochemical carbon valorization.