Investigation of Mixed Conductor BaCo0.7Fe0.3−xYxO3−δ with High Oxygen Permeability

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• 作者：Hailei Zhao ; Nansheng Xu ; Yunfei Cheng ; Wenjing Wei ; Ning Chen ; Weizhong Ding ; Xionggang Lu ; Fushen Li
• 刊名：Journal of Physical Chemistry C
• 出版年：2010
• 出版时间：October 21, 2010
• 年：2010
• 卷：114
• 期：41
• 页码：17975-17981
• 全文大小：411K
• 年卷期：v.114,no.41(October 21, 2010)
• ISSN：1932-7455

文摘

Cubic BaCo_0.7Fe_0.3−xY_xO_3−δ (BCFY, x = 0.08−0.2) was prepared by the conventional solid state reaction route as oxygen permeation membranes. The effects of Y-doping on the crystal structure, electrical conductivity, and oxygen permeability are investigated, and the factors influencing the activation energy of oxygen migration are discussed from the viewpoints of metal−oxygen bonding energy and geometric lattice structure. Y-substitution decreases the electrical conductivity but increases the oxygen vacancy concentration of BCFY samples. Nevertheless, the oxygen permeability decreases with increasing Y-doping level. Both the strong Y−O bonding energy and the decreased critical radius (r_C) with Y-doping should be responsible for the increased activation energy. First principle calculation reveals that Y-doping results in the nonequivalent positions of the mobile oxygen ions and thus limits the oxygen ion diffusion passages. BaCo_0.7Fe_0.22Y_0.08O_3−δ membrane exhibits a high oxygen permeability of 1.73 mL min⁻¹ cm⁻² at 900 °C, thus being a promising candidate material for oxygen separation or POM applications.