Jardón-Álvarez Daniel, Kahn Nitzan, Houben Lothar, Leskes Michal
Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel.
Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel.
J Phys Chem Lett. 2021 Mar 25;12(11):2964-2969. doi: 10.1021/acs.jpclett.1c00221. Epub 2021 Mar 17.
Comprehending the oxygen vacancy distribution in oxide ion conductors requires structural insights over various length scales: from the local coordination preferences to the possible formation of agglomerates comprising a large number of vacancies. In Y-doped ceria, Y NMR enables differentiation of yttrium sites by quantification of the oxygen vacancies in their first coordination sphere. Because of the extremely low sensitivity of Y, longer-range information was so far not available from NMR. Herein, we utilize metal ion-based dynamic nuclear polarization, where polarization from Gd(III) dopants provides large sensitivity enhancements homogeneously throughout the bulk of the sample. This enables following Y-Y homonuclear dipolar correlations and probing the local distribution of yttrium sites, which show no evidence of the formation of oxygen vacancy rich regions. The presented approach can provide valuable structural insights for designing oxide ion conductors.
从局部配位偏好到可能形成的包含大量空位的团聚体。在钇掺杂二氧化铈中，Y核磁共振能够通过量化其第一配位球中的氧空位来区分钇位点。由于Y的灵敏度极低，到目前为止，核磁共振无法提供更远距离的信息。在此，我们利用基于金属离子的动态核极化，其中来自Gd(III)掺杂剂的极化在整个样品体积中均匀地提供了大幅的灵敏度增强。这使得能够追踪Y-Y同核偶极相关性并探测钇位点的局部分布，结果表明没有富氧空位区域形成的迹象。所提出的方法可为设计氧化物离子导体提供有价值的结构见解。
