Confined Intermediates Boost C2+ Selectivity in CO₂ Electroreduction

Addressing the efficient electrochemical conversion of CO₂ (CO₂RR) into valuable multicarbon (C2+) products necessitates innovative strategies to boost carbon (C1) intermediate coupling on catalyst surfaces. In this work, we introduce a surface-confinement strategy on Cu₂O nanoparticles by long alkyl chain grafting to create a spatially confined environment, impeding C1 intermediate detachment and promoting C-C coupling in the CO₂RR. The optimized C12-Cu₂O sample exhibits a Faradaic efficiency (FE) over 63.0% for C₂H₄, more than double the yield of pristine Cu₂O (FE = 25.7%). In situ ATR-FTIR spectroscopy provides direct evidence of rapid C1 intermediate enrichment and restricted diffusion within the surface-confined environment. Molecular dynamics simulations further support these findings by identifying a prolonged residency time that is proportionate to the alkyl chain length, thereby maximizing C2+ selectivity. This surface-confinement approach marks a previously overlooked but immensely promising paradigm in the catalyst design for the CO₂RR.