Self‐Assembled Monolayer Interface with Reconstructed Hydrogen‐Bond Network for Enhanced CO₂ Electroreduction

CO₂ electrolysis is a promising approach to reduce CO₂ emissions while achieving high-value multi-carbon (C₂₊) products. Except for the key role of electrocatalyst for electrochemical CO₂ reduction reaction (CO₂RR), Reaction microenvironment is another critical factor influencing catalytic performance for these catalysts. Herein, a self-assembled monolayer (SAM) is proposed with reconstructed hydrogen-bond network to form an efficient three-phase interface that admins mass transport and ion-electron transfer. This approach is realized by co-assembly of the fluorinated SAM (F-SAM) and siloxane on commercial Cu catalyst (Cu@F-Si composite catalyst). Molecular dynamics simulations (MDS) and interfacial species analysis show that the F-SAM effectively facilitates CO₂ mass transport, while the siloxane hydrogen bond network maintains an ideal H⁺/e^- transfer pathway. Combined with density functional theory (DFT) calculations, this strategy reveals the mechanism by which optimizing *H/*CO coverage enhances C₂₊ product selectivity. Ultimately, the Cu@F-Si catalyst maintains a high current density of 502.5 mA cm^-2 with over 85% C₂₊ Faradaic efficiency (FE) and operates stably for more than 100 h at ≈300 mA cm^-2. This interface engineering strategy offers a promising solution for improving the efficiency of CO₂RR, with broader applications in multiphase catalytic systems.