High field O-17 NMR study of defects in doped zirconia and ceria
High field O-17 NMR study of defects in doped zirconia and ceria
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DOI：
10.1016/j.ssi.2010.04.024
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发表时间：
2011-06-16
影响因子：
3.2
通讯作者：
Maekawa, Hideki
中科院分区：
文献类型：
--
作者：
Ando, Mariko;Oikawa, Itaru;Maekawa, Hideki
用固体O-17魔角自旋（MAS）核磁共振（NMR）谱研究了CeO 2-Y2 O3（YDC）和Y2 O3-ZrO 2（YSZ）二元体系中氧离子的局域配位结构.观察到光谱的组成依赖性，并与以前的Y-89 MAS NMR结果进行了比较。YSZ的O-17 MAS NMR谱显示出具有重叠峰的线形，这不允许直接的峰分离。另一方面，YDC的O-17 MAS NMR显示出取决于氧位点的局部配位环境的清楚分辨的峰。通过峰分离，可以测定不同阳离子数的氧四面体O-T（4Ce）、O-T（3Ce +1 Y）和O-T（2Ce +2 Y）的相对含量。当Y含量低于25%时，以O-T（4Ce）为主，O-T（3Ce +1 Y）和O-T（2Ce +2 Y）次之。氧物种的分布偏离了随机分布的预期值。因此，考虑了氧物种的热力学稳定性，假设O-T（4Ce）、O-T（3Ce +1 Y）和O-T（2Ce +2 Y）之间的平衡常数。O-T（3Ce +1 Y）物种的优先减少重现了实验值。首次定量测定了YDC的氧位优先度。(C)2010 Elsevier B. V.保留所有权利。
The local coordination structure around oxygen ions in CeO2-Y2O3 (YDC) and Y2O3-ZrO2 (YSZ) binary has been investigated by solid-state O-17 magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy at high magnetic field of 21.8 T. Compositional dependence of the spectrum was observed and compared with the previous Y-89 MAS NMR results. The O-17 MAS NMR spectra of YSZ showed a line shape with overlapped peaks which did not allow straightforward peak separation. On the other hand, O-17 MAS NMR of YDC showed clearly resolved peaks depending on the local coordination environments of oxygen sites. By the peak separation, the relative amount of oxygen tetrahedra with different numbers of cations, O-T (4Ce), O-T(3Ce + 1Y) and O-T(2Ce + 2Y) can be determined. O-T(4Ce) was dominant compared to O-T(3Ce + 1Y) and O-T(2Ce + 2Y) at Y contents below 25%. The distribution of oxygen species deviated from a value expected from a random distribution. Therefore, the thermodynamic stability of oxygen species was considered, assuming an equilibrium constant between O-T(4Ce), O-T(3Ce + 1Y) and O-T(2Ce + 2Y). A preferential decrease of O-T(3Ce + 1Y) species was found to reproduce the experimental values. The degree of the oxygen sites preference on composition was quantitatively determined for YDC for the first time. (C) 2010 Elsevier B.V. All rights reserved.