Cu-O-In Bridge Engineering in Cu₂O/In₂O₃ Nanowires for Efficient CO₂-to-CO Electroreduction

Although modulating the d-band center (ε_d) is an effective strategy to improve electrocatalytic activity, precise regulation of ε_d for CO₂ electroreduction to CO remains a substantial challenge. Here, we report a heterostructured catalyst consisting of In₂O₃-incorporated 3D nanowire copper foam (Cu₂O/In₂O₃@CF), with tunable ε_d via Cu-O-In bridges for efficient electrocatalytic CO₂ reduction (eCO₂R) to CO. The optimized Cu₂O/In₂O₃@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 Cu₂O/In₂O₃ 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 eCO₂R. This synergistic design of oxide-oxide heterointerface with an interconnected 1D nanowires architecture offers an innovative strategy for enhancing eCO₂R performance.