title: Order/Disorder and in Situ Oxide Defect Control in the Bixbyite Phase YPrO3+δ (0 ≤ δ < 0.5).
abstract: The YPrO3+δ system is a nearly ideal model system for the investigation of oxide defect creation and annihilation in oxide ion conductor related phases with potential applications as solid state electrolytes in solid oxide fuel cells. The formation, structure, high temperature reactivity, and magnetic susceptibility of phase pure YPrO3+δ (0 ≤ δ ≤ 0.46) are reported. The topotactic reduction and oxidation of the YPrO3+δ system was investigated by powder X-ray in situ diffraction experiments and revealed bixbyite structures (space group: Ia3̅) throughout the series. Combined neutron and X-ray data clearly show oxygen uptake and removal. The research provides a detailed picture of the Y(3+)/Pr(3+)/Pr(4+) sublattice evolution in response to the redox chemistry. Upon oxidation, cation site splitting is observed where the cation in the ((1)/4, (1)/4, (1)/4) position migrates along the body diagonal to the (x, x, x) position. Any oxygen in excess of YPrO3.0 is located in the additional 16c site without depopulating the original 48e site. The in situ X-ray diffraction data and thermal gravimetric analysis have revealed the reversible topotactic redox reactivity at low temperatures (below 425 °C) for all compositions from YPrO3 to YPrO3.46. Magnetic susceptibility studies were utilized in order to further confirm praseodymium oxidation states. The linear relation between the cubic unit cell parameter and oxygen content allows for the straightforward determination of oxygen stoichiometry from X-ray diffraction data. The different synthesis strategies reported here are rationalized with the structural details and the reactivity of YPrO3+δ phases and provide guidelines for the targeted synthesis of these functional materials.
authors.affiliation: Department of Chemistry, University of Manitoba , Winnipeg, Manitoba R3T 2N2, Canada.|Manitoba Institute for Materials, University of Manitoba , Winnipeg, Manitoba R3T 2N2, Canada.
authors.forename: Joey A
authors.initials: JA
authors.lastname: Lussier
authors.affiliation: Department of Chemistry, University of Manitoba , Winnipeg, Manitoba R3T 2N2, Canada.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Szkop
authors.affiliation: Department of Chemistry, University of Manitoba , Winnipeg, Manitoba R3T 2N2, Canada.|Department of Chemistry, University of Winnipeg , Winnipeg, Manitoba R3B 2E9, Canada.
authors.forename: Arzoo Z
authors.initials: AZ
authors.lastname: Sharma
authors.affiliation: Department of Chemistry, University of Manitoba , Winnipeg, Manitoba R3T 2N2, Canada.|Department of Chemistry, University of Winnipeg , Winnipeg, Manitoba R3B 2E9, Canada.|Department of Physics and Astronomy, McMaster University , Hamilton, Ontario L8S 4M1, Canada.|Canadian Institute for Advanced Research , Toronto, Ontario M5G 1Z8, Canada.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Wiebe
authors.affiliation: Department of Chemistry, University of Manitoba , Winnipeg, Manitoba R3T 2N2, Canada.|Manitoba Institute for Materials, University of Manitoba , Winnipeg, Manitoba R3T 2N2, Canada.
authors.forename: Mario
authors.initials: M
authors.lastname: Bieringer