Publications

Detailed Information

Active Reaction Sites for Oxygen Reduction in La0.9Sr0.1,MnO3/YSZ Electrodes

Cited 170 time in Web of Science Cited 177 time in Scopus
Authors

Lee, Hee Y.; Cho, Woo S.; Oh, Seung M.; Wiemhofer, H.-D.; Gopel, W.

Issue Date
1995-08
Publisher
Electrochemical Society
Citation
J. Electrochem. Soc., 142, 2659 (1995)
Abstract
Active reaction sites for 02 reduction in La0.~Sr01MnO3 electrode have been characterized by addressing the origin of
the cathodic polarization effects on this electrode material. Cathodic polarization (up to - 1.2 V vs. Pt reference electrode}
had several effects on O2 reduction kinetics. First, the O2 reduction rate was favorably increased when the perovskite
electrode was cathodically polarized. Second, in situ x-ray photoelectron spectroscopy results indicated that the Mn ions
are electrochemically reduced and concomitantly the oxygen stoichiometry decreases. Reduction of Mn ions was further
demonstrated in the cyclic voltammogram traced under nitrogen atmosphere. Third, hysteresis in cathodic currents was
observed in the cyclic voltammograms of the perovskite/YSZ/Pt system, and the hysteresis phenomena were more prominent
at higher O~ pressure. We interpreted these findings to mean that the internal and/or external surface oxide vacancies
participate in the O2 reduction reaction. However, it has been explained from the Po2-dependent hysteresis phenomena that,
even though those surface sites are active in the O2 reduction~ their activity is less than that of the three-phase boundary
sites since additional diffusional processes are required for the former sites. Consequently, the three-phase boundary sites
are the major reaction sites at lower O2 pressure, which leads to a small hysteresis. However, at higher 02 pressure, the
surface sites also participate in the reaction, resulting in a larger hysteresis.
ISSN
0013-4651
Language
English
URI
https://hdl.handle.net/10371/5636
DOI
https://doi.org/10.1149/1.2050070

https://doi.org/10.1149/1.2050070
Files in This Item:
Appears in Collections:

Altmetrics

Item View & Download Count

  • mendeley

Items in S-Space are protected by copyright, with all rights reserved, unless otherwise indicated.

Share