Cu–O–In Bridge Engineering in Cu ₂ O/In ₂ O ₃ Nanowires for Efficient CO ₂ ‐to‐CO Electroreduction

ABSTRACT Although modulating the d‐band center (ε _d ) is an effective strategy to improve electrocatalytic activity, precise regulation of ε _d for CO ₂ electroreduction to CO remains a substantial challenge. Here, we report a heterostructured catalyst consisting of In ₂ O ₃ ‐incorporated 3D nanowire copper foam (Cu ₂ O/In ₂ O ₃ @CF), with tunable ε _d via Cu–O–In bridges for efficient electrocatalytic CO ₂ reduction (eCO ₂ R) to CO. The optimized Cu ₂ O/In ₂ O ₃ @CF delivers impressive CO Faradaic efficiency (FE _CO ) exceeding 90% over a broad potential range from −0.47 to −0.87 V ( vs . reversible hydrogen electrode, RHE), with a peak FE _CO of 95.8% at −0.67 V (vs. RHE), and a high production rate of 1035.3 µmol cm ⁻² h ⁻¹ , along with stable operation for over 130 h. In situ Raman and Fourier transform infrared spectroscopy (FTIR) analyses combined with density functional theory (DFT) calculations reveal that the formation of Cu ₂ O/In ₂ O ₃ heterointerface with Cu–O–In bridge facilitates charge redistribution, upshifting the ε _d of Cu sites and downshifting that of In sites, thereby optimizing the adsorption‐desorption energies of reaction intermediates during eCO ₂ R. This synergistic design of oxide‐oxide heterointerface with an interconnected 1D nanowires architecture offers an innovative strategy for enhancing eCO ₂ R performance.