Highly selective electrocatalytic reduction of carbon dioxide to carbon monoxide on silver electrode with aqueous ionic liquids

Abstract

In this study, the electrochemical reduction of carbon dioxide (CO2) was examined in a series of aqueous solutions of ionic liquids on metal (silver (Ag), copper, platinum and gold) catalyst cathode. The results indicated that Ag metal cathode in 1-butyl-3-methylimidazolium chloride (BMImCl) with 20wt.% water showed excellent synergy in electrochemical reduction of CO2 to carbon monoxide (CO) with extremely high selectivity (>99%) and efficiency, and with stable area specific activity (ca. 2.4mA·cm−2). The behavior of electrocatalytic reduction of CO2 to CO on Ag electrode in ionic liquids (ILs) was examined by cyclic voltammogram. The study revealed that the chloride containing IL could be the most effective candidate for reduction of CO2 to CO and for inhibiting the hydrogen evolution reaction probably due to the dominated water–anion and water–cation interactions in aqueous BMImCl.