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Physical and electrochemical characterization of catalysts for oxygen reduction in fuel cells

Christenn, Claudia und Schulze, Mathias und Friedrich, Kaspar Andreas (2006) Physical and electrochemical characterization of catalysts for oxygen reduction in fuel cells. 2. Workshop of the network "Efficient Oxygen Reduction for the Electrochemical Energy Conversion", 2006-04-06 - 2006-04-07, Ulm, Deutschland.

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Kurzfassung

In low temperature fuel cells the oxygen reduction reaction (ORR) at the cathode has an important influence on the losses of the conversion from chemical to electrical energy. Especially for the reaction kinetic the catalyst is the crucial factor, while the structure of the electrodes is important for catalyst utilization, efficient mass transport, and durability of the cell. In particular, the cathode catalysts currently used are associated with major cell efficiency losses because of the kinetic limitation of the oxygen reduction reaction. To solve this problem a better understanding of key steps in the oxygen reduction process on commonly used cathode catalysts as well as of alternative catalysts is required. For this purpose physical and electrochemical methods are used to characterize the catalysts. Besides the V-i-characteristics and the electrochemical impedance spectroscopy as electrochemical methods, the surface science analysis methods for the physical characterization are very helpful tools. Surface science analytical methods such as x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) provide important insight into the structural and chemical properties of the electrodes. In order to perform a complete surface science analysis of the catalysts it is not sufficient to investigate freshly prepared catalysts, but also necessary to study the catalysts after operation in fuel cells or after electrochemical treatment. Comparing the catalysts before and after the electrochemical stressing the alterations of the catalysts can be determined. The electrochemical characterization by V-i-characteristics yields basic information about the performance of the electrodes and about the kinetics of the oxygen reduction reaction. Unfortunately, this information is not very detailed and insufficient for a distinct assessment of the catalysts. In order to achieve more detailed understanding electrochemical impedance spectroscopy and the ex-situ methods have to be combined. The results of combined investigations of different cathode catalysts will be presented. The catalysts were characterized by polarization curves, electrochemical impedance spectra and physically by surface analysis methods.

elib-URL des Eintrags:https://elib.dlr.de/45715/
Dokumentart:Konferenzbeitrag (Vortrag)
Titel:Physical and electrochemical characterization of catalysts for oxygen reduction in fuel cells
Autoren:
AutorenInstitution oder E-Mail-AdresseAutoren-ORCID-iDORCID Put Code
Christenn, ClaudiaNICHT SPEZIFIZIERTNICHT SPEZIFIZIERTNICHT SPEZIFIZIERT
Schulze, MathiasNICHT SPEZIFIZIERTNICHT SPEZIFIZIERTNICHT SPEZIFIZIERT
Friedrich, Kaspar AndreasNICHT SPEZIFIZIERTNICHT SPEZIFIZIERTNICHT SPEZIFIZIERT
Datum:7 April 2006
Open Access:Nein
Gold Open Access:Nein
In SCOPUS:Nein
In ISI Web of Science:Nein
Stichwörter:Cathode catalyst, Physical characterization, Electrochemical characterization, Pt-alloy, Ruthenium selenides, Methanol, Fuel cell
Veranstaltungstitel:2. Workshop of the network "Efficient Oxygen Reduction for the Electrochemical Energy Conversion"
Veranstaltungsort:Ulm, Deutschland
Veranstaltungsart:nationale Konferenz
Veranstaltungsdatum:2006-04-06 - 2006-04-07
Veranstalter :Zentrum für Sonnenenergie- und Wasserstoff-Forschung (ZSW)
HGF - Forschungsbereich:Energie
HGF - Programm:Rationelle Energieumwandlung (alt)
HGF - Programmthema:E BZ - Brennstoffzellen (alt)
DLR - Schwerpunkt:Energie
DLR - Forschungsgebiet:E BZ - Brennstoffzellen
DLR - Teilgebiet (Projekt, Vorhaben):E - Membran-Brennstoffzellen (alt)
Standort: Stuttgart
Institute & Einrichtungen:Institut für Technische Thermodynamik > Elektrochemische Energietechnik
Hinterlegt von: Christenn, Claudia
Hinterlegt am:05 Dez 2006
Letzte Änderung:27 Apr 2009 13:16

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