Asymmetric Adsorption Site and Cu Vacancy Regulation in La–Cu Nanospheres to Promote CO ₂ Electroreduction Performance with Ultrahigh CH ₄ Selectivity

Abstract Electrochemical CO ₂ reduction to CH ₄ is extensively investigated. As the most deeply reduced C1 product, CH ₄ formation involves a kinetically sluggish eight‐electron transfer pathway, resulting in poor reaction selectivity. A carbon‐supported LaCu nanosphere catalyst with Cu vacancies (La _0.05 Cu _v1 @C) is reported here for efficient CO ₂ ‐to‐CH ₄ conversion. Experimental results demonstrate that the La _0.05 Cu _v1 @C material achieves a methane Faradaic efficiency (FE _CH4 ) of 73.3% at −1.6 V versus reversible hydrogen electrode (RHE), outperforming the control samples. Atomically dispersed La induces electron transfer, forming an asymmetric adsorption site to enhance CO ₂ adsorption and activation, while Cu vacancies optimize intermediate adsorption strength, suppressing C─C coupling and promoting hydrogenation pathways. La sites can also promote water dissociation to supply protons for subsequent methane formation. By synergizing defect engineering and heteroatom doping, this research establishes a new paradigm for developing selective copper‐based catalysts in methane activation systems.