Effect of Preparation Conditions on the Polymorphism and Transport Properties of La6–xMoO12−δ (0 ≤ x ≤ 0.8)
Effect of Preparation Conditions on the Polymorphism and Transport Properties of La6–xMoO12−δ (0 ≤ x ≤ 0.8)
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DOI：
10.1021/acs.chemmater.7b02481
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发表时间：
2017-08
影响因子：
8.6
通讯作者：
Adrián López-Vergara;J. M. Porras-Vázquez;A. Infantes-Molina;J. Canales-Vázquez;A. Cabeza;E. R. Losilla;D. Marrero-López
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文献类型：
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作者：
Adrián López-Vergara;J. M. Porras-Vázquez;A. Infantes-Molina;J. Canales-Vázquez;A. Cabeza;E. R. Losilla;D. Marrero-López
在这项工作中，La 6-xMoO 12 −δ（0 ≤ x ≤ 0.8）材料作为一种新的陶瓷质子导体进行了研究。根据合成过程中应用的冷却速率，获得具有菱面体和立方结构的不同多晶相。这些材料已经通过不同的技术进行了彻底的表征，包括X射线粉末衍射，透射电子显微镜和X射线光谱，以充分了解样品的结构特征。在干/湿气体（N2，O2，和5%H2-Ar）的热重分析和阻抗谱证实了在低温下的质子导电性的存在。在还原气氛下，材料是混合的离子-电子导体。在最快的冷却速率下制备的样品具有立方结构和较高的n型电子电导率相比，在较慢的冷却速率下制备的菱面体结构。
In this work, La6–xMoO12−δ (0 ≤ x ≤ 0.8) materials are investigated as a new family of ceramic proton conductors. Different polymorphic phases with rhombohedral and cubic structure are obtained, depending on the cooling rate applied during the synthesis process. The materials have been thoroughly characterized by different techniques, including X-ray powder diffraction, transmission electron microscopy, and X-ray photospectroscopy in order to fully understand the structural features of the samples. Thermogravimetric analysis and impedance spectroscopy in dry/wet gases (N2, O2, and 5% H2–Ar) confirmed the existence of proton conductivity at low temperature. Under a reducing atmosphere, the materials are mixed ionic-electronic conductors. The sample prepared at the fastest cooling rate exhibits cubic structure and higher n-type electronic conductivity compared to those prepared at a slower cooling rate with rhombohedral structure.