Imidazolium Ions with an Alcohol Substituent for Enhanced Electrocatalytic Reduction of CO2.

Electrochemical reduction of CO2 to CO is an attractive process for carbon capture and energy regeneration. Imidazolium ionic liquids (IMILs) are promising electrolyte catalytically active additives for this important reaction. Herein, we report functionalizing the imidazolium ion with a propanol substituent at the N site can significantly enhance the catalytic activity of IMILs, causing a positive shift of the onset potential for the CO2 reduction by about 90 mV in an acetonitrile electrolyte. Theoretical calculations indicated that the propanol hydroxyl could bridge a local hydrogen-bonding chain as shortcut for proton transfer, leading to a dramatic decrease of the activation barrier for the catalytic reduction of CO2 in IMIL.