Stabilizing Oxidation State of Cu via Ce Doping into La 2 CuO 4 for Enhanced Electroreduction of CO 2 to Multicarbon Products

Abstract Stabilizing oxidation state of Cu (Cu δ+ , δ > 0) sites is the key‐enabling issue for electrocatalytic carbon dioxide (CO 2 ) reduction reaction (eCO 2 RR) to multicarbon (C 2+ ) products. The present study addresses this challenge by introducing cerium (Ce) doping into La 2 CuO 4 . The Ce doping facilitates f – d orbital coupling between Ce 4 f and Cu 3 d orbitals, suppressing electron enrichment around Cu atoms by transferring electrons from Cu 3 d orbitals to Ce 4 f orbitals via a Cu−O−Ce chain. These changes modulate the electronic structure of Cu, reduce the distance between neighboring Cu atoms, optimize the binding energy of surface‐adsorbed CO (*CO), and lower the reaction energy barrier for *CO dimerization. As a result, the La 1.95 Ce 0.05 CuO 4 catalyst achieves a Faradaic efficiency up to 81% for C 2+ products and maintains high stability over 50 h operation. This work highlights the unique role of Ce doping in stabilizing Cu δ+ sites and hence enhancing C−C coupling, providing a pathway for designing efficient catalysts for eCO 2 RR.