Cooperative CO₂-to-ethanol conversion via enriched intermediates at molecule–metal catalyst interfaces

Electrochemical conversion of CO₂ into liquid fuels, powered by renewable electricity, offers one means to address the need for the storage of intermittent renewable energy. Here we present a cooperative catalyst design of molecule–metal catalyst interfaces with the goal of producing a reaction-intermediate-rich local environment, which improves the electrosynthesis of ethanol from CO₂ and H₂O. We implement the strategy by functionalizing the copper surface with a family of porphyrin-based metallic complexes that catalyse CO₂ to CO. Using density functional theory calculations, and in situ Raman and operando X-ray absorption spectroscopies, we find that the high concentration of local CO facilitates carbon–carbon coupling and steers the reaction pathway towards ethanol. We report a CO₂-to-ethanol Faradaic efficiency of 41% and a partial current density of 124 mA cm⁻² at −0.82 V versus the reversible hydrogen electrode. We integrate the catalyst into a membrane electrode assembly-based system and achieve an overall energy efficiency of 13%.