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Influence of Temperature on the Performance of Gas Diffusion Electrodes in the CO 2 Reduction Reaction
Author(s) -
Löwe Armin,
Rieg Carolin,
Hierlemann Tim,
Salas Nicolas,
Kopljar Dennis,
Wagner Norbert,
Klemm Elias
Publication year - 2019
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.201900872
Subject(s) - faraday efficiency , electrolysis , hydrogen , diffusion , current density , electrode , formate , analytical chemistry (journal) , materials science , electrochemistry , thermodynamics , current (fluid) , chemistry , oxide , agglomerate , gaseous diffusion , electrolyte , metallurgy , composite material , catalysis , chromatography , organic chemistry , physics , quantum mechanics
A detailed investigation of the influence of operating temperature on the electrochemical reduction of CO 2 to formate at tin oxide loaded gas diffusion electrodes (GDEs). Ambient pressure electrolysis is performed between 20 and 70 °C with a focus on maximizing current density and energy efficiency while maintaining an average formate faradaic efficiency of at least 80 %. The best performance is achieved at a temperature of 50 °C, which allows a current density of 1000 mA cm −2 . Lower or higher temperatures both show an increased hydrogen evolution at said current density. Further investigation of CO 2 transport limitation revealed a minimum at 50 °C, which is explained by the opposing influence of temperature on CO 2 diffusion coefficients and solubility. This explanation is supported by an estimate of the current density at which hydrogen evolution starts to increase based on the flooded agglomerate model. Long‐term operation for 24 h also revealed an optimum temperature of 50 °C, which helps to suppress the increasing rate of hydrogen evolution and with that a mechanical degradation of the GDE.