Electrocatalytic activities of La0.6Ca0.4CoO 3 and La0.6Ca0.4CoO3-carbon composites toward the oxygen reduction reaction in concentrated alkaline electrolytes

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DOIResolve DOI: http://doi.org/10.1149/1.3560170
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TypeArticle
Journal titleJournal of the Electrochemical Society
ISSN0013-4651
Volume158
Issue5
PagesA597A604
SubjectAlkaline electrolytes; Alkaline media; Alkaline solutions; Brunauer emmett tellers; Carbon composites; Carbon support; Electrocatalytic activity; Electrocatalytic properties; Electron transfer; Electron transfer pathways; Exchange current densities; High activity; Kinetic currents; Oxygen reduction reaction; Rechargeable battery; Rotating ring-disk electrode techniques; Synergetic effect; Tafel slopes; Calcium; Carbon carbon composites; Cobalt compounds; Electrolytes; Electrolytic reduction; Electron transitions; Gas adsorption; Nanocomposite films; Oxygen; Perovskite; Potassium hydroxide; Rate constants; X ray diffraction; High resolution transmission electron microscopy
AbstractPerovskites exhibit high activities toward oxygen reduction reaction (ORR) in alkaline media, which are the promising candidates for air-cathode in zinc-air rechargeable batteries. Among them, La0.6Ca 0.4CoO3-C was reported with high ORR activities in alkaline solutions. However, the functioning of carbon support towards ORR was rare studied. In this study, La0.6Ca0.4CoO3 powder was prepared and characterized by X-ray diffraction, high-resolution transmission electron microscopy, and the Brunauer Emmett Teller gas adsorption technique. The electrocatalytic properties of La0.6Ca 0.4CoO3 (LCCO) and La0.6Ca 0.4CoO3-carbon composite (LCCO-C) layers towards the ORR were comparatively studied using the rotating ring-disk electrode technique in 1, 4, and 6 M KOH electrolytes to reveal the functioning of carbon. The Koutecky-Levich theory and Tafel slope analysis were applied to acquire the overall electron transfer number and kinetic parameters, such as kinetic currents, rate constants, and exchange current densities. The overall electron transfer number was measured to be almost 4 for both LCCO and LCCO-C. A synergetic effect toward the ORR was observed when carbon was present in the LCCO layer, explained by an assumed 22-electron transfer pathway. The ORR activities and kinetics of LCCO-C were better than LCCO, and the synergetic effect (2 2-electron transfer pathway) is proposed as one possible reason. © 2011 The Electrochemical Society.
Publication date
LanguageEnglish
AffiliationNational Research Council Canada (NRC-CNRC); NRC Institute for Fuel Cell Innovation (IFCI-IIPC)
Peer reviewedYes
NPARC number21271080
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Record identifierc009b3bd-9f6c-4619-be2f-b920a9df3c75
Record created2014-03-24
Record modified2016-05-09
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