A novel Nb₂O₅-doped SrCo_0.8Fe_0.2O_{3?span style='font-style: italic'>¦Ä} oxide with high permeability and stability for oxygen separation

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• 作者：Guangru Zhang ; Zhengkun Liu ; Na Zhu ; Wei Jiang ; Xueliang Dong ; Wanqin Jin ; ^{wqjin@njut.edu.cn}
• 关键词：Niobium oxide ; Perovskite ; Mixed conducting membrane ; Oxygen separation
• 刊名：Journal of Membrane Science
• 出版年：2012
• 出版时间：1 July, 2012
• 年：2012
• 卷：405-406
• 期：Complete
• 页码：300-309
• 全文大小：1728 K

文摘

A new series of Nb₂O₅-doped (0.5, 1, 3, 5, 10 and 15 wt. % ) SrCo_0.8Fe_0.2O_3?em>¦Ä (SCF) mixed conducting materials have been synthesized by the solid-state reaction method. The crystal structure, phase stability, oxygen desorption behavior, thermal expansion behavior, electrical conductivity and oxygen permeability of the prepared materials were systematically investigated. Doped Nb₂O₅ was completely incorporated into the SCF structure and effectively suppressed the coexisting orthorhombic phase in bulk cubic SCF and the perovskite-brownmillerite transition under low oxygen partial pressure. In situ high-temperature X-ray diffraction (HTXRD) also indicated good chemical and structure stability of the slightly doped Nb₂O₅ (0.5 wt. % ) at both 0.21 ¡Á 10⁵ and 1 ¡Á 10^? Pa oxygen partial pressures at high temperatures. Nb₂O₅ dissolved into the SCF lattice served to some extent to decrease the electrical conductivity and oxygen flux, and increase the thermal expansion. The grain size of the membranes were significantly suppressed by the doping of Nb₂O₅. In particular, SCFNb0.5 with the cubic perovskite structure has the smallest cell parameters, the lowest thermal expansion and the highest oxygen flux.