Catalytic nano-metal interfaces drive pH-universal CO₂-to-ethanol conversion.

Abstract

Renewably powered electrochemical CO₂ reduction (CO₂R) to alcohols presents a promising route to liquid fuels and chemicals. However, protonation of different intermediates often leads to mixed liquid and gas products, complicating separation and reducing economic feasibility. Here, we present a hydroxyl-affinity-tuning strategy that stabilizes hydroxyl-containing CO₂R intermediates away from interfacial water through constructing nano-metal interfaces, thereby favoring ethanol production. Theory-guided catalyst design directs nano-cobalt/Cu surfaces, delivering CO₂-to-ethanol Faradaic efficiencies (FE) of 62.17% and 45.32% under alkaline and acidic conditions, respectively, with ethanol partial current densities over ~300 mA cm^-2. In acidic media, the catalyst maintains ethanol production for 235 hours with an average FE of 44.74%. In situ spectroscopy and theoretical calculations reveal that nano-Co/Cu interfaces favor binding hydroxyl groups and thereby enriches C-OH species on the copper surface, redirects CO₂R pathways toward ethanol. This work provides a catalyst-centered strategy for designing interfacial architectures for selective alcohol synthesis. Future efforts should focus on translating this design principle into scalable systems for practical electrochemical CO₂ utilization.