Electron-Rich In ₂ O ₃ –Cu Interfaces Drive Selective and Stable CO ₂ Electroreduction

Metal–oxide interfaces can effectively steer CO2 electroreduction on copper, yet conventional supported catalysts suffer from severe interfacial degradation under operating potentials. Here, we report an inverse In2O3/Cu architecture that mitigates this limitation by anchoring highly dispersed In2O3 domains onto a porous Cu. Strong oxide–metal interactions stabilize the phase boundaries and generate an electron-rich interfacial Cu microenvironment. The optimized 5In2O3/Cu catalyst achieves a CO Faradaic efficiency of ∼95% and maintains stable operation for 90 h. In situ infrared spectroscopy combined with density functional theory reveals that the interface stabilizes a less-ordered interfacial water structure and provides dual active sites that suppress the hydrogen evolution reaction while lowering the *COOH formation barrier to 0.51 eV. These findings establish inverse catalyst design as an effective strategy for achieving both high selectivity and long-term stability in CO2RR.