Enhanced CO2 Adsorption and Conversion in Diethanolamine‐Cu Interfaces Achieving Stable Neutral Ethylene Electrosynthesis

Abstract Molecular modifications have shown tremendous potential in boosting the electrochemical CO 2 reduction (CO 2 RR) to ethylene. However, the key mechanisms of modulation at the molecular level remain unclear, especially for the adsorption and activation of key intermediates (e.g., * CO 2 and * CO). Here, report that a diethanolamine (DEA)‐modified Cu catalyst can reduce CO 2 to ethylene with a faradaic efficiency of ≈50.5% with a partial current density of ≈155.7 mA cm −2 in the neutral conditions, which surpasses the Cu catalyst without molecular modification (≈28.5% and ≈95.6 mA cm −2 ). Density functional theory calculations demonstrate that DEA on the Cu surface boosts the adsorption and activation of CO 2 and the following C–C coupling processes during the CO 2 RR‐to‐ethylene process. Molecular dynamics simulations suggest that the molecules distant from the Cu site have a CO 2 enrichment effect. Operational stability achieved via the introduction of DEA molecules onto ketjen black, which then successively immobilized on the Cu nanoparticles and polytetrafluoroethylene electrodes to obtain a stable tripe‐phase boundary, realizing constant ethylene selectivity for 100 operating hours in a flow cell.