Catalytic chemical potential shift on the surface of nonstoichiometric oxides under non-equilibrium gas atmosphere

Keiji Yashiro, Shigenori Onuma, Maya Sase, Atsushi Kaimai, Takanori Otake, Hiroshige Matsumoto, Tatsuya Kawada, Junichiro Mizusaki

Research output: Contribution to journalConference articlepeer-review

3 Citations (Scopus)

Abstract

Perovskite-type oxide, La0.5Sr0.5CoO 3-δ, has large oxygen nonstoichiometry and high electrical conductivity with a large carrier concentration. The oxygen nonstoichiometry, δ, of dense La0.5Sr0.5CoO3-δ was measured in the stream of NOx-O2-N2 system at 873 to 1073 K by means of a thermogravimetric method. Small amounts of NO 2 caused large changes in oxygen nonstoichiometry. It seems probable that excessive amounts of oxygen can be incorporated into the bulk due to catalytic decomposition of NO2, and as a result, oxygen potential on the surface of the sample seems to be much higher than that of gaseous phase. EMF measurements for dense La0.6Sr0.4CoO 3-δ electrode also revealed that the oxygen potential is affected by NO2. Thus, the gas sensing mechanism of this oxide was found to relate to the change of the bulk property, especially oxygen nonstoichiometry.

Original languageEnglish
Pages (from-to)2411-2416
Number of pages6
JournalSolid State Ionics
Volume176
Issue number31-34
DOIs
Publication statusPublished - 2005 Oct 1
Event30th Symposium on Solid State Ionics in Japan -
Duration: 2004 Dec 12004 Dec 3

Keywords

  • Chemical potential shift
  • Lanthanum cobaltite
  • NO
  • Oxygen nonstoichiometry
  • Surface catalytic activity

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

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