Selective and Energy Efficient Electrocatalytic CO2-to-Ethanol Conversion through Anion Modulation

Ethanol, with its high market value and stable global demand, stands out as an attractive product of electrocatalytic CO₂ reduction. However, achieving high ethanol selectivity and energy efficiency at industrial current densities remains challenging. In this study, we employed a blended anion modulation strategy to enhance the selectivity and energy efficiency of CO₂-to-ethanol conversion. The Cu₂(OH)₃F pre-catalyst achieved Faradaic efficiencies of 50% and 93% for ethanol and C₂₊, respectively, at 700 mA cm⁻² in a blended electrolyte consisting of 2 M KOH and 1 M KCl. Comprehensive electrochemical tests, combined with in situ characterizations and theoretical analysis, revealed that chloride and hydroxide increased *CO coverage for efficient C─C coupling. Moreover, hydroxide stabilizes the *CHCOH intermediate through hydrogen bonding with the adsorbed hydroxide on the catalyst surface, while Cl synergistically enhances its reactivity by promoting water dissociation toward the ethanol pathway.