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Examination of gas-diffusion electrodes applied in CO2 electrolysis employing electrochemical impedance spectroscopy (EIS)

Bienen, Fabian and Kopljar, Dennis and Wagner, Norbert and Löwe, Armin and Klemm, Elias and Friedrich, Kaspar Andreas (2019) Examination of gas-diffusion electrodes applied in CO2 electrolysis employing electrochemical impedance spectroscopy (EIS). Sofia Electrochemical Days (SED) 2019, Sofia, Bulgarien.

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Closing the anthropogenic carbon cycle is one of the major challenges for the present mankind. Low-temperature electrochemical reduction of carbon dioxide to useful chemicals can contribute to the solution of this problem by changing the role of CO2 from harmful waste into a valuable feedstock. The electrolyzer can be operated with renewable energy and CO2 taken from concentrated off-gas of industrial plants. One of the main challenges of this process is to bring gaseous CO2 in contact with the catalyst and the aqueous phase to maintain high space-time-yields. By applying porous gas-diffusion electrodes (GDEs) instead of plane electrodes the triple-phase-boundary - reaction zone – and gas transport are significantly enhanced. Electrochemical impedance spectroscopy is a powerful tool to analyze the nature and velocity of single processes occurring at the microscopic level in electrochemical devices. These insights provide valuable information for a specific optimization of electrodes regarding electrochemical performance and long-term stability. However, there is a lack of knowledge which processes are displayed in the impedance spectrum during alkaline CO2 electrolysis on GDEs. This work focusses on the identification of these processes shown in the impedance spectrum by changing experimental parameters e.g. temperature, CO2 partial pressure & current density and analyzing the obtained response in the spectrum. As it is exemplary shown in Fig. 1 the shape of the impedance spectrum dramatically changes depending on the supplied gas mixture at the GDE. Compared to the absence of CO2 where hydrogen evolution prevails, two additional processes become visible for a pure CO2 gas feed which can be associated to the CO2 reduction reaction.

Item URL in elib:https://elib.dlr.de/129871/
Document Type:Conference or Workshop Item (Speech)
Title:Examination of gas-diffusion electrodes applied in CO2 electrolysis employing electrochemical impedance spectroscopy (EIS)
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Bienen, FabianFabian.Bienen (at) dlr.dehttps://orcid.org/0000-0002-4660-8826
Kopljar, DennisDennis.Kopljar (at) dlr.dehttps://orcid.org/0000-0002-2228-2016
Wagner, NorbertNorbert.Wagner (at) dlr.dehttps://orcid.org/0000-0002-2596-8689
Löwe, Arminarmin.loewe (at) itc.uni-stuttgart.deUNSPECIFIED
Klemm, Eliaselias.klemm (at) itc.uni-stuttgart.deUNSPECIFIED
Friedrich, Kaspar AndreasAndreas.Friedrich (at) dlr.deUNSPECIFIED
Date:17 October 2019
Refereed publication:No
Open Access:No
Gold Open Access:No
In ISI Web of Science:No
Keywords:GDE CO2 Reduktion Impedanzspektroskopie Formiat
Event Title:Sofia Electrochemical Days (SED) 2019
Event Location:Sofia, Bulgarien
Event Type:international Conference
Organizer:Bulgarische Akademie der Wissenschaften
HGF - Research field:Energy
HGF - Program:Storage and Cross-linked Infrastructures
HGF - Program Themes:Electrochemical Energy Storage
DLR - Research area:Energy
DLR - Program:E SP - Energy Storage
DLR - Research theme (Project):E - Electrochemical Prcesses (Batteries)
Location: Stuttgart
Institutes and Institutions:Institute of Engineering Thermodynamics > Electrochemical Energy Technology
Deposited By: Wagner, Dr.rer.nat. Norbert
Deposited On:18 Nov 2019 15:14
Last Modified:18 Nov 2019 15:14

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