David PASQUIER (a), Ziad BITAR (a,b), Antoine FECANT (a), Sylvie CHARDON (b), Emmanuelle TRELA-BAUDOT (a)
a) IFPEN, Rond-point de l’échangeur de Solaize, BP3, 69360 Solaize, France
b) Université Joseph Fourier-Grenoble 1-UMR-5250, BP53, 38041 Grenoble, France
Corresponding author email: firstname.lastname@example.org
One of the major challenges of this century is undoubtedly reducing the atmospheric emissions of carbon dioxide. Therefore, over the past decades, CO2 capture and storage (CCS) technologies have received increasing attention. Nowadays, the conversion and utilization of CO2 is being considered as an attractive solution to assist in solving CO2 issues. An effective utilization of CO2 as a storage medium for renewable energy could be achieved by an electrochemical approach. Several metal electrodes have proven their efficiency to selectively reduce CO2 into formic acid, at relatively high overpotential. On indium electrodes, the potential required to reduce CO2 to HCOO- is much less negative than other metals (Pb, Cd, Bi and Tl) . Formic acid could be either selectively dissociated into hydrogen and CO2 with the appropriate catalyst or used in a Direct Formic Acid Fuel Cell (DFAFC) to recover energy in an electrical form .
However, the electrocatalytic reduction of CO2 in aqueous media at bulk metal electrodes suffers from several hindrances. An essential problem is the hydrogen evolution reaction which prevails over the CO2 reduction especially in acidic solutions. Owing to the low solubility of CO2 in aqueous media under ambient conditions, the reaction rates and current densities are limited by mass transfer on solid electrodes . In addition, the low specific surface area of these electrodes and their deactivation due to surface poisoning, are the major factors limiting their utilization in an electrochemical process. Several studies have been published showing that gas diffusion electrodes (GDE) could be a solution to increase the current density .
In this communication, we will focus on indium-loaded GDE (GDE/In), their preparation and physical characterization, as well as their redox properties. We will present the electrocatalytic performance of these GDE in a designed electrolysis cell allowing a controlled flow of CO2 through the GDE. We will compare the electrochemical behavior of GDE/In and indium foil for the CO2 reduction according to several criteria: current density, selectivity for formic acid and resistance to impurities.
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