Electrochemical reduction of nitrous oxide in 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid electrolyte

Abstract

An ionic liquid/organic solvent mixture was adopted as an electrolyte for the electrochemical reduction of N2O. The ionic liquid and organic solvent used for the electrolyte were 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) and propylene carbonate (PC), respectively. The use of [BMIM][BF4] in place of aqueous solutions improves the solubility of N2O and also avoids the hydrogen evolution reaction, which is the main side reaction in an aqueous solution. The low electrical conductivity and high viscosity of [BMIM][BF4], the main disadvantages in the context of electrochemical reactions, were compensated on introducing PC. The composition of the [BMIM][BF4]/PC was optimized considering both the electrical conductivity and N2O stability in the solution. For the optimized [BMIM][BF4]/PC, a high faradaic efficiency (>90%) was achieved for N2O reduction to N2. Keywords: N2O, Electrochemical reduction, Ionic liquid, Non-aqueous solution