Catalytic Electrochemical Reduction of CO2 in Ionic Liquid EMIMBF3Cl

Abstract

A novel ionic liquid EMIMBF3Cl that contains a BF3Cl− anion has been synthesized. This is the first report of an ionic liquid with a BF3Cl− anion. It was found that CO2 gas can be dissolved and electrochemically reduced at ambient pressure, and room temperature in the ionic liquid EMIMBF3Cl. The reduction of CO2 occurred at a relatively less negative electrode potential of −1.8 V vs. silver wire, compared to previous reported values that are between −2.4 and −2.0 V. The reduction current density can be as high as ∼5.7 mA/cm2. The BF3Cl− anion may catalyze the CO2 reduction by forming a Lewis acid-base adduct BF3-CO2.

Roles of ion pairing on electroreduction of carbon dioxide based on imidazolium-based salts

“…À1.58 V was observed. Similar to those electrochemical behaviours of CO 2 in organic solvents with quaternary ammonium salts as supporting electrolytes, this irreversible reductive peak observed on Ag electrode can be ascribed to a chemically irreversible, one electron reduction of CO 2 to the radical anion CO 2 .À [13][14][15].…”

“…Experimental and molecular simulation studies focused on understanding the factors governing the high solubility of CO 2 in imidazoliumbased salts have found that the anion dominates the interactions with the CO 2 , with the cation playing a secondary role [25,26]. Instructed by these findings, many researchers attributed the catalytic effects of imidazolium-based salts towards CO 2 reduction to a Lewis acid-base interaction between CO 2 and anions of the imidazolium-based salts [14,15]. If this assumption is true, CO 2 electroreduction in the presence of an imidazolium-based salt should follow a CE-type mechanism.…”

“…In the salt 1-butyl-3-methyimidazolium tetrafluoroborate (BMIMBF 4 ), CO 2 was reduced on Ag electrode at À2.0 V (vs. Ag wire) at 50 C [13]. In 1-butyl-3-methylimidazolium acetate (BMIMAc) and 1-ethyl-3-methylimidazolium trifluorochloroborate (EMIMBF 3 Cl), the reduction potentials of CO 2 on Pt electrode were both found to be À1.8 V (vs. Ag wire) at room temperature [14,15]. However, there are few reports thus far that focus on the mechanistic study on CO 2 electroreduction catalyzed by imidazolium-based salts.…”

Organic molecules as mediators and catalysts for photocatalytic and electrocatalytic CO2reduction

“…37 The ionic conductivity of dry C 2 MIM-BF 3 Cl was 19.0 mS cm À1 at room temperature, and the CO 2 solubility was 0.52 AE 0.25 mass% at 1 atm and room temperature. It was suggested that the anion of C 2 MIM-BF 3 Cl might catalyze CO 2 reduction through an interaction with CO 2 as shown in Fig.…”

Direct Reduction of Carbon Dioxide to Formate in High‐Gas‐Capacity Ionic Liquids at Post‐Transition‐Metal Electrodes

“…[6] Snuffin et al have suggested that in the case of a BF 4 À anion it is the boron that can act as a Lewis acid for CO 2 binding [25] by substituting one fluorine for an oxygen bound carbon dioxide molecule. [6] Snuffin et al have suggested that in the case of a BF 4 À anion it is the boron that can act as a Lewis acid for CO 2 binding [25] by substituting one fluorine for an oxygen bound carbon dioxide molecule.…”