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

Abstract

As an approach to combat the increasing emissions of carbon dioxide in the last 50 years, the sequestration of carbon dioxide gas in ionic liquids has become an attractive research area. Ionic liquids can be made that possess incredibly high molar absorption and specificity characteristics for carbon dioxide. Their high carbon dioxide solubility and specificity combined with their high inherent electrical conductivity also creates an ideal medium for the electrochemical reduction of carbon dioxide. Herein, a lesser studied ionic liquid, 1-ethyl-3-methylimidazolium trifluoroacetate, was used as both an effective carbon dioxide capture material and subsequently as an electrochemical matrix with water for the direct reduction of carbon dioxide into formate at indium, tin, and lead electrodes in good yield (ca. 3 mg h(-1) cm(-2)).

Overpotentials and Faraday Efficiencies in CO2 Electrocatalysis–the Impact of 1‐Ethyl‐3‐Methylimidazolium Trifluoromethanesulfonate

“…[8][9][10][11][12] Improving the catalytic activity of the electrodes is recently complemented by testing the cocatalytic abilities of ionic liquids (ILs) as new electrolytes for CO 2 electrocatalysis. [13][14][15][16][17][18][19][20][21] The major conclusion implies the use of ILs, especially those featuring imidazolium cations, to be benefi cial in terms of (i) lowering the overpotential for the CO 2 reduction, (ii) inhibiting the hydrogen evolution reaction (HER), and (iii) increasing the selectivity for CO formation. As a matter of fact, the concentrations of ILs in the corresponding solutions span from as low as millimolar all the way to neat ILs.…”

Reduction of Carbon Dioxide to Formate at Low Overpotential Using a Superbase Ionic Liquid

“…[11] This change in product selectivity was also shown by Watkins and Bocarsly, where formate was produced in [C 2 mim][TFA] using Pb and Sn working electrodes. [12] Therein, no evidence was found for a [C 2 mim] + -CO 2 complex;[13] however, the RTIL was thought to stabilize intermediates in formate production.…”

Achieving Both High Selectivity and Current Density for CO2 Reduction to Formate on Nanoporous Tin Foam Electrocatalysts

“…KCl) were used as counter and reference electrodes, respectively, which was determined to be very stable although the potential changed systematically. [22] The working electrode was the well-prepared tin foam electrode. All of the experiments were carried out under room temperature and atmospheric pressure.…”