Effect of A-site lanthanum doping on the CO2 tolerance of SrCo0.8Fe0.2O3-δ oxygen-transporting membranes
Effect of A-site lanthanum doping on the CO2 tolerance of SrCo0.8Fe0.2O3-δ oxygen-transporting membranes
复制标题
DOI：
10.1016/j.memsci.2013.02.051
复制
发表时间：
2013-06-15
影响因子：
9.5
通讯作者：
Feldhoff, Armin
中科院分区：
文献类型：
--
作者：
Klande, Tobias;Ravkina, Olga;Feldhoff, Armin
SrCo0.8Fe0.2O3-δ（SCF）钙钛矿被系统地掺杂，在A-位点上增加镧含量至60重量%，以研究对CO2耐受性的影响。采用溶胶-凝胶法制备了不同的粉体，并通过原位X射线衍射（XRD）和含CO2气氛中的长期氧渗透测量对材料进行了表征。用扫描电子显微镜（SEM）和透射电子显微镜（TEM）研究了显微结构。除了菱形La0.6Sr0.4Co0.8Fe0.2O3-δ（LSCF 6482）之外，所有粉末都表现出立方钙钛矿结构，然而，其在较高温度下显示出向立方钙钛矿结构的相变。掺杂20wt%的镧可显著提高材料对CO2的耐受性，掺杂60wt%的镧可使材料在CO2气氛中至少200 h保持稳定的透氧性能。在空气/氦气梯度中的氧渗透实验表明，随着镧含量的增加，氧渗透通量降低。CO2操作后的膜的微观结构分析表明，碳酸盐优先在膜的二氧化碳暴露的扫掠侧形成致密层。(C)2013 Elsevier B. V.保留所有权利。
The SrCo0.8Fe0.2O3-delta (SCF) perovskite was systematically doped with increasing lanthanum content up to 60 wt% on the A-site to investigate the effect on CO2 tolerance. Different powders were prepared by a sol-gel method and the materials were characterized by in-situ X-ray diffraction (XRD) and long-term oxygen permeation measurements in CO2-containing atmospheres. The microstructure was investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). All powders exhibit cubic perovskite structure except the rhombohedral La0.6Sr0.4Co0.8Fe0.2O3-delta (LSCF 6482), which however, shows a phase transition into cubic perovskite structure at higher temperature. By doping 20 wt% lanthanum, the tolerance against CO2 is considerably increased and doping with 60 wt% lanthanum resulted in a stable oxygen permeation performance in CO2 atmosphere for at least 200 h. Oxygen permeation experiments in an air/helium gradient showed that with increasing lanthanum content the oxygen permeation flux decreases. Microstructure analysis of the membranes after CO2 operation showed that the carbonate preferentially forms a dense layer at the carbon dioxide exposed sweep side of the membranes. (C) 2013 Elsevier B.V. All rights reserved.