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格子动力学可以触发固体氧离子导体中低温氧气的移动性
Werner Paulus1, Helmut Schober, Stefan Eibl
1Sciences Chimiques de Rennes, UMR 6226 CNRS-Université de Rennes1, Inorganic Materials: Soft Chemistry and Reactivity of Solids, Campus de Beaulieu, F-35042 Rennes, France. werner.paulus@univ-rennes1.fr
Journal of the American Chemical Society
|November 7, 2008
概括
铁氧化物 (SrFeO(2.5)) 由于晶格动态而表现出显著的低温氧气流动性,与铁氧化物 (CaFeO(2.5) 不同. 这一发现为设计先进的氧离子导体提供了新的途径.
科学领域:
- 材料科学 材料科学 材料科学
- 固态化学 固态化学
- 无机化学 无机化学 有机化学
背景情况:
- 铁氧化物 (SrFeO ((2.5)) 和氧化物 (SrCoO ((2.5)) 在室温下可逆地间接氧气,形成立方矿.
- 铁氧化 (CaFeO(2.5)) 需要极端的氧化条件,突出了氧气流动性的显著差异.
研究的目的:
- 为了阐明SrFeO中与CaFeO中相比,SrFeO中明显的低温氧气流动性的原因,与CaFeO相比,SrFeO中明显的低温氧气流动性的原因.
- 调查格子动态在促进缺氧矿中氧气扩散中的作用.
主要方法:
- 使用 (18) O/(16) O. 的温度依赖氧同位素交换实验.
- 不弹性中子散射 (INS) 研究.
- 开始 (密度函数理论) 分子动态计算.
主要成果:
- 在SrFeO ((x) 下600 K.的自由氧流动性得到证实.
- 低温氧气流动性与特定的低能格子模式有关.
- 在SrFeO ((3-x) 中增强的,用声子辅助的氧气扩散,归因于顶点氧原子的Fe-O-Fe键减弱.
结论:
- 格子动态显著影响缺氧矿的氧气流动性,特别是那些有棕色米勒岩结构的矿.
- 动态触发的现象,如语音辅助扩散,使氧化物离子容易迁移.
- 这些发现为设计和定制低温氧离子导体提供了新的概念.
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