Lussier Joey A, Szkop Kevin M, Sharma Arzoo Z, Wiebe Christopher R, Bieringer Mario
Department of Chemistry, University of Manitoba , Winnipeg, Manitoba R3T 2N2, Canada.
Manitoba Institute for Materials, University of Manitoba , Winnipeg, Manitoba R3T 2N2, Canada.
Inorg Chem. 2016 Mar 7;55(5):2381-9. doi: 10.1021/acs.inorgchem.5b02746. Epub 2016 Feb 15.
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.
YPrO₃₊δ体系是一个近乎理想的模型体系，可用于研究氧化物离子导体相关相中氧化物缺陷的产生和湮灭，在固体氧化物燃料电池中作为固态电解质具有潜在应用价值。本文报道了纯相YPrO₃₊δ（0≤δ≤0.46）的形成、结构、高温反应性和磁化率。通过粉末X射线原位衍射实验研究了YPrO₃₊δ体系的拓扑还原和氧化过程，结果表明整个系列均为方铁锰矿结构（空间群：Ia3̅）。中子和X射线数据相结合清楚地显示了氧的吸收和去除。该研究详细描绘了Y(3+)/Pr(3+)/Pr(4+)亚晶格随氧化还原化学变化的演变情况。氧化时，观察到阳离子位点分裂，位于（(1)/4, (1)/4, (1)/4）位置的阳离子沿体对角线迁移至（x, x, x）位置。任何超过YPrO₃.0的氧位于额外的16c位点，而不会使原始的48e位点空出。原位X射线衍射数据和热重分析表明，从YPrO₃到YPrO₃.46的所有组成在低温（低于425℃）下都具有可逆的拓扑氧化还原反应活性。利用磁化率研究进一步确定镨的氧化态。立方晶胞参数与氧含量之间的线性关系使得可以直接从X射线衍射数据确定氧化学计量比。本文报道的不同合成策略根据YPrO₃₊δ相的结构细节和反应性进行了合理化分析，并为这些功能材料的定向合成提供了指导。
