Oxygen non-stoichiometry, redox thermodynamics, and structure of LaFe1 - xCoxO3 - δ

Mehdi Pishahang*, Egil Bakken, Svein Stølen, Christopher Ian Thomas, Paul Inge Dahl

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

11 Citations (Scopus)

Abstract

The oxygen non-stoichiometry and redox thermodynamic properties of the LaFe1 - xCoxO3 - δ system (x = 0.25 and 0.75) are studied. At low temperatures, the LaCoO3 and LaFeO3 systems show partial solid solubility. At 1,273 K (in air), both compounds are single phases and are orthorhombic and rhombohedral for x = 0.25 and 0.75, respectively. Thermogravimetry has been used to measure the oxygen non-stoichiometry versus oxygen partial pressure at three temperatures, 1,223, 1,273, and 1,323 K. Redox thermodynamic quantities are extracted directly from the oxygen non-stoichiometry curves. The extracted enthalpies of oxidation do not vary significantly with stoichiometry, and for x = 0.25 and 0.75, they are -640 ± 60 and -440 ± 60 kJ (mol O2)-1, respectively. Ideal solid solution thermodynamic models are used to analyze the redox mechanisms.

Original languageEnglish
Pages (from-to)869-878
Number of pages10
JournalIONICS
Volume19
Issue number6
DOIs
Publication statusPublished - Jun 2013
MoE publication typeA1 Journal article-refereed

Keywords

  • Oxygen non-stoichiometry
  • Perovskite
  • Redox thermodynamics

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