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Title: Oxygen trapping and cation site-splitting in Y(2₋x)PrxO3+δ (0.0≤x<2.0 and δ≤1.0)

Here we discuss the reduction and oxidation of the solid solution Y(2₋x)PrxO3+δ (0.0≤x<2.0 and δ≤1.0) with an emphasis in our investigation on potential solid state electrolyte applications in solid oxide fuel cells. The fully reduced solid solution Y2₋xPrxO3 (0.0≤x<2.0) crystallizes in the bixbyite structure ($$^{Ia\bar{3}}$$). The oxidized solid solution Y2₋xPrxO3+δ (0.0≤x<1.4) forms bixbyite phases ($$^{Ia\bar{3}}$$) whereas Y2₋xPrxO3+δ (1.4≤x<2) compositions form fully disordered defect fluorite structures ($$^{Fm\bar{3}ms}$$) with variable oxide defect concentrations. The two cation positions are investigated in detail using synchrotron powder X-ray and time of flight neutron diffraction data. In the bixbyite structures the 8c cation site splits into the 16c cation site and the 24d cation position migrates toward the ideal fluorite coordination upon oxidation. Reductive in-situ diffraction experiments reveal the co-existence of the fluorite and bixbyite structure only in a narrow temperature range. During oxidation of the bixbyite phase a new 16c oxide anion site is populated. Finally, the impact of the 16c oxide site population on the cation sublattice is being discussed.
Authors:
 [1] ;  [2] ;  [2] ;  [1]
  1. Univ. of Manitoba, Winnipeg, MB (Canada). Dept. of Chemistry; Univ. of Manitoba, Winnipeg, MB (Canada). Manitoba Inst. for Materials
  2. Univ. of Manitoba, Winnipeg, MB (Canada). Dept. of Chemistry
Publication Date:
OSTI Identifier:
1322362
DOE Contract Number:
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 242; Journal Issue: P2
Publisher:
Elsevier
Research Org:
Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
ENGLISH
Subject:
Solid state electrolytes; Oxide ion conductors; Bixbyite; Fluorite; Powder neutron diffraction; Powder x-ray diffraction; High-temperature in-situ diffraction; Cation site-splitting; Yttrium praseodymium oxide