Surface Segregation in Solid Oxide Electrode Materials Occurring at Intermediate Temperatures
Surface Segregation in Solid Oxide Electrode Materials Occurring at Intermediate Temperatures
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中间温度下发生的固体氧化物电极材料的表面偏析
DOI：
10.1149/06602.0061ecst
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
J.A. Kilner
中科院分区：
文献类型：
--
作者：
J. Druce;H. Tellez;T. Ishihara;J.A. Kilner
组成元素和杂质的偏析影响固体氧化物电极材料的表面组成，并因此影响表面交换反应的速率。在这项工作中，我们比较偏析发生在400 ℃的Pr 0。5Sr0. 5CoO 3-δ（PSCO）和PrBaCo 2 O 5-δ（PBCO）。在低温下退火时，表面组成迅速变化，仅15分钟后二价阳离子就明显分离。PBCO含有Na杂质，其经历与Ba类似的偏析行为，在退火2小时后成为主要的表面阳离子。虽然这些材料中的阳离子迁移率与氧相比是缓慢的，但它足以在小时量级的时间尺度上引起表面组成的显著变化。
The segregation of constituent elements and impurities affects the surface composition of solid oxide electrode materials, and hence, the rate of the surface exchange reaction. In this work, we compare segregation occurring at 400 C in Pr0. 5Sr0. 5CoO3-δ (PSCO) and PrBaCo2O5-δ (PBCO). The surface composition changes rapidly on annealing at low temperature, with segregation of the divalent cation evident after just 15 minutes. The PBCO contained a Na impurity which undergoes similar segregation behavior to the Ba, becoming the dominant surface cation after 2 hours of annealing. Although cation mobility in these materials is slow compared to oxygen, it is sufficient to cause significant changes in surface composition on timescales of the order of hours.