Stability and oxygen transport property of La0.8Sr0.2Cr0.5Fe0.5O3 -δ

Wei He, Hua Huang, Ming Chen, Jian-Feng Gao, Chu-Sheng Chen

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The stability of La0.8Sr0.2Cr0.5Fe 0.5O3 -δ (LSCrF) in reducing atmosphere was investigated by examining the extent of its reaction with hydrogen at elevated temperature. LSCrF powder exposed to diluted hydrogen was found to loss a weight of only ~ 0.5%, corresponding to the formation of oxygen vacancies in the lattice. LSCrF powder exposed to flowing concentrated hydrogen for 30 h was found to decompose partially. The decomposition oxygen partial pressure of LSCrF at 950 °C was estimated to be 6.3 × 10- 28 atm from thermodynamic calculations. The stability of LSCrF under an oxygen chemical potential gradient was also examined by exposing a disk-shaped dense sample to air at one side and to reducing atmosphere (CO) at the other side at elevated temperatures. A thin, porous layer was found to form on the CO side surface. An oxygen permeation flux of 2.5 × 10- 7 mol cm- 2 s- 1 was observed at 950 °C under given air/CO gradient. The occurrence of oxygen permeation revealed the presence of mixed oxygen ionic and electronic conductivity. The oxygen ionic conductivity was estimated to be ~ 0.01 S/cm at 950 °C. © 2014 Elsevier B.V.
Original languageEnglish
JournalSolid State Ionics
Volume260
Pages (from-to)86-89
ISSN0167-2738
DOIs
Publication statusPublished - 2014

Keywords

  • Stability
  • Oxygen permeation
  • Oxygen ionic conductivity
  • Convergence of numerical methods
  • Hydrogen
  • Ionic conductivity
  • Oxygen permeable membranes
  • Chemical potential gradient
  • Electronic conductivity
  • Oxygen partial pressure
  • Oxygen transport properties
  • Oxygen-permeation flux
  • Thermodynamic calculations
  • Oxygen

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