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

Abstract

AbstractMolecular modifications have shown tremendous potential in boosting the electrochemical CO2 reduction (CO2RR) 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., *CO2 and *CO). Here, report that a diethanolamine (DEA)‐modified Cu catalyst can reduce CO2 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 CO2 and the following C–C coupling processes during the CO2RR‐to‐ethylene process. Molecular dynamics simulations suggest that the molecules distant from the Cu site have a CO2 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.