Enhancing *CO coverage on Sm-Cu2O via 4f-3d orbital hybridization for highly efficient electrochemical CO2 reduction to C2H4

The electrocatalytic conversion of CO2 into valuable chemical feedstocks using renewable electricity offers a compelling strategy for closing the carbon loop. While copper-based materials are effective in catalyzing CO2 to C2+ products, the instability of Cu+ species, which tend to reduce to Cu0 at cathodic potentials during CO2 reduction, poses a significant challenge. Here, we report the development of Sm-Cu2O and investigate the influence of f-d orbital hybridization on the CO2 reduction reaction (CO2RR). Supported by density functional theory (DFT) calculations, our experimental results demonstrate that hybridization between Sm3+ 4f and Cu+ 3d orbitals not only improves the adsorption of *CO intermediates and increases CO coverage to stabilize Cu+ but also facilitates CO2 activation and lowers the energy barriers for C-C coupling. Notably, Sm-Cu2O achieves a Faradaic efficiency for C2H4 that is 38% higher than that of undoped Cu2O. Additionally, it sustains its catalytic activity over an extended operational period exceeding 7 hours, compared to merely 2 hours for the undoped sample. This research highlights the potential of f-d orbital hybridization in enhancing the efficacy of copper-based catalysts for CO2RR, pointing towards a promising direction for the development of durable, high-performance electrocatalysts for sustainable chemical synthesis.