Efficient CO2 electroreduction to ethanol enabled by tip-curvature-induced local electric fields†

Abstract

Electrocatalytic reduction of CO₂ into multicarbon (C₂₊) products offers a promising pathway for CO₂ utilization. However, achieving high selectivity towards multicarbon alcohols, such as ethanol, remains a challenge. In this work, we present a novel CuO nanoflower catalyst with engineered tip curvature, achieving remarkable selectivity and efficiency in the electroreduction of CO₂ to ethanol. This catalyst exhibits an ethanol faradaic efficiency (FE_ethanol) of 47% and a formation rate of 320 μmol h⁻¹ cm⁻², with an overall C₂₊ product faradaic efficiency (FE_C2+) reaching ∼77.8%. We attribute this performance to the catalyst's sharp tip, which generates a strong local electric field, thereby accelerating CO₂ activation and facilitating C–C coupling for deep CO₂ reduction. In situ Raman spectroscopy reveals an increased *OH coverage under operating conditions, where the enhanced *OH adsorption facilitates the stabilization of *CHCOH intermediates through hydrogen bonding interaction, thus improving ethanol selectivity. Our findings demonstrate the pivotal role of local electric fields in altering reaction kinetics for CO₂ electroreduction, presenting a new avenue for catalyst design aiming at converting CO₂ to ethanol.