Different Local Structures of Mo and Nb Polyhedra in the Oxide-Ion-Conducting Hexagonal Perovskite-Related Oxide Ba3MoNbO8.5 Revealed by 95Mo and 93Nb NMR Measurements
Different Local Structures of Mo and Nb Polyhedra in the Oxide-Ion-Conducting Hexagonal Perovskite-Related Oxide Ba3MoNbO8.5 Revealed by 95Mo and 93Nb NMR Measurements
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95Mo 和 93Nb NMR 测量揭示了氧化物离子传导六方钙钛矿相关氧化物 Ba3MoNbO8.5 中 Mo 和 Nb 多面体的不同局域结构
DOI：
10.1021/acs.jpcc.2c03429
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
Yashima Masatomo
中科院分区：
文献类型：
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作者：
Tansho Masataka;Goto Atsushi;Ohki Shinobu;Mogami Yuuki;Sakuda Yuichi;Yasui Yuta;Murakami Taito;Fujii Kotaro;Iijima Takahiro;Yashima Masatomo
氧化物离子导体Ba3MoNbO8.5、氧化物离子和质子导体Ba 7 Nb 4 MoO 20以及它们的相关氧化物由于它们的高离子导电性而成为重要的材料组。这些材料的离子传导层的结构尚未澄清，因为它们的复杂结构和难以区分Mo和Nb。在这项研究中，我们分别检测95 Mo和93 Nb的固态核磁共振（NMR）测量直接观察高氧离子导体Ba3MoNbO8.5中的Mo和Nb的配位。结果表明，93 Nb和95 Mo的显峰数不同。对于93 Nb NMR的两个化学位移，较强的峰归因于导电层中的NbO 6八面体，而较弱的峰归因于导电层中的NbO 4四面体或非导电层中的NbO 6八面体。富钼样品的~（95）Mo NMR谱中出现了四个峰。一个峰归因于在非导电层中的MoO 6八面体。其他三个峰归因于导电层的解释，只有分配其中的一个或两个到MoO 5多面体，推测在离子传导中发挥重要作用。据推测，这些是第一个结果支持MoO 5在氧化物离子导体的离子导电层中的存在，并且Mo可能在离子导电中起重要作用。目前的工作表明，通过NMR分析Mo-O和Nb-O多面体的局部结构是理解离子导电性质的重要工具，因为它提供了与元素无关的信息。因此，它有望有助于进一步发展的氧化物离子导体。
The oxide-ion conductor Ba3MoNbO8.5, the oxide-ion and proton conductor Ba7Nb4MoO20, and their related oxides are important groups of materials because of their high ionic conductivity. The structure of the ion-conducting layer of these materials has not been clarified because of their complex structure and the difficulty in distinguishing between Mo and Nb. In this study, we separately detected95Mo and93Nb by solid-state nuclear magnetic resonance (NMR) measurements to directly observe the Mo and Nb coordination in the high-oxide-ion conductor Ba3MoNbO8.5. The results showed that the number of revealed peaks was different for93Nb and95Mo. For the two chemical shifts from93Nb NMR, the more intense peak was attributed to a NbO6octahedron in the conducting layer, while the less intense peak was ascribed to a NbO4tetrahedron in the conducting layer or a NbO6octahedron in the nonconducting layer. Four peaks were observed in the95Mo NMR of the95Mo-enriched sample. One peak was attributed to the MoO6octahedron in the nonconducting layer. The other three peaks attributed to the conducting layer were only interpreted by assigning either one or two of them to the MoO5polyhedra, which are speculated to play an important role in ionic conduction. Presumably, these are the first results supporting the presence of MoO5in the ion-conducting layer of oxide-ion conductors, and Mo likely plays an important role in ionic conduction. The present work has demonstrated that the analysis of the local structure of Mo–O and Nb–O polyhedra by NMR is an important tool for understanding the nature of ionic conduction because it provides element-independent information. It is therefore expected to contribute to the further development of oxide-ion conductors.