Over 70 % Faradaic Efficiency for CO2 Electroreduction to Ethanol Enabled by Potassium Dopant-Tuned Interaction between Copper Sites and Intermediates

It is highly desired yet challenging to steer the CO2 electroreduction reaction (CO2ER) toward ethanol with high selectivity, for which the evolution of reaction intermediates on catalytically active sites holds the key. Herein, we report that K doping in Cu2Se nanosheets array on Cu foam serves as a versatile way to tune the interaction between Cu sites and reaction intermediates in CO2ER, enabling highly selective production of ethanol. As revealed by characterization and simulation, the electron transfer from K to Se can stabilize Cu-I species which facilitate the adsorption of linear *COL and bridge *COB intermediates to promote C-C coupling during CO2ER. As a result, the optimized K-11.2%-Cu2Se nanosheets array can catalyze CO2ER to ethanol as a single liquid product with high selectivity in a potential area from -0.6 to -1.2 V. Notably, it offers a Faradaic efficiency of 70.3 % for ethanol production at -0.8 V with as is stable for 130 h.