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.