Highly efficient electrochemical reduction of CO2 into formic acid over lead dioxide in an ionic liquid–catholyte mixture

Abstract

The development of efficient electrocatalytic systems for CO₂ conversion with high current density and high Faradaic efficiency simultaneously is crucially important but challenging. Herein, we described the first study of the electrochemical reduction of CO₂ into HCOOH over commercial lead dioxide (PbO₂) as the electrode in ionic liquid (IL)-containing catholytes. It was found that 1-benzyl-3-methylimidazolium tetrafluoroborate ([Bzmim]BF₄) was the best IL to enhance the efficiency of the PbO₂ electrode in the electroreduction of CO₂ to HCOOH. In a ternary electrolyte consisting of [Bzmim]BF₄ (14.7 wt%), H₂O (11.7 wt%) and acetonitrile, the PbO₂ electrode showed an excellent performance in electroreduction of CO₂ into HCOOH with high Faradaic efficiency (95.5%) and very high current density (40.8 mA cm⁻²) simultaneously.