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

Abstract 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.