钙钛矿型混合导体透氧膜材料的制备和性能研究

发布时间：2018-03-05 13:34

  本文选题：钙钛矿结构材料　切入点：Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3-δ)　出处：《合肥工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：钙钛矿型陶瓷材料具有良好的催化活性,电化学特性等,在纯氧生产、电池电极材料,以及化工催化领域都有着良好的应用前景。对于面向实际应用的透氧膜材料来说,提高膜材料的透氧量和解决低氧分压气氛中膜稳定性等是其实现工业化应用的关键。为此,需解决提高材料的透氧量和性能稳定性等问题。影响陶瓷膜性能的因素较多,例如膜材料的组成、微观结构,膜的表面修饰等。本论文对Ba0.5Sr0.5Co0.8Fe0.2O3-δ陶瓷膜的制备工艺、微观结构及性能等进行研究,并考察表面修饰对Ba0.5Sr0.5Co0.8Fe0.2O3-δ膜材料的透氧性能的影响,此外,还考察了Sc和Cr掺杂对BaFeO3材料电性能和透氧性能等的影响,以探索新型的无Co透氧膜材料的制备。全文所得主要结论如下：(1) 通过甘氨酸-硝酸盐法,在900℃以上煅烧前驱体粉末,可以获得具有钙钛矿结构的BaFeO3粉体。并在不同的温度下烧结制备了烧结体材料,测得1000℃、1050℃和1100℃烧结所得烧结体在900℃的透氧量分别为0.81 ml·cm-2·min-1、1.13 ml·cm-2·min-1和1.56 ml·cm-2·min-1。1000℃、1050℃和1100℃烧结所得Ba0.5Sr0.5Co0.8Fe0.2O3-δ烧结体在400-800℃的平均热膨胀系数分别为14.34×10-6K-1,15.46x10-6K-1,15.34×10-6K-1。(2) 通过硝酸浸蚀对BSCF透氧膜表面进行修饰处理,使膜表面由原来的致密状态变得粗糙不平,增加了膜的比表面积,有利于表面氧交换反应的进行。且发现延长硝酸浸蚀时间会加强酸蚀的反应,膜表面会变得更加粗糙不平。对表面修饰过膜片的透氧率测试表明,经硝酸浸蚀20min后膜片的透氧量提高了1.6-4.5倍,而经硝酸浸蚀10min后膜片的透氧量提高了1.4-3.8倍,这可能是由于膜表面的粗糙水平不同造成。(3) 采用甘氨酸-硝酸盐法制备了BaFe1-yNyO3-δ(N=Sc、Cr, y=0、0.05、0.1、0.15)粉体,并制备相应的透氧膜材料。XRD表明,BaFeO3-δ材料在室温下是六方相,少量Sc的掺杂可使材料在室温下转变为立方结构,少量Cr的掺杂也促进BaFeO3-δ氧化物在室温下转变为立方相。电导率和透氧量的测试结果表明,少量Sc和Cr的掺杂会提高BaFeO3-δ的电导率和透氧量。BaFe0.95Sc0.05O3-□在450℃时电导率可达7.2S-cm-1,约是BaFeO3-δ材料的60倍; BaFe0.95Cr0.05O3-δ在450℃时电导率最大值分别为4.8 s·cm-1,约是BaFeO3-δ材料的40倍；且BaFe0.95Sc0.05O3-δ具有最大的透氧量,在900℃时达到0.66 ml·cm-2·min-1。
[Abstract]:Perovskite ceramic materials have good catalytic activity and electrochemical characteristics, and have a good application prospect in pure oxygen production, battery electrode materials and chemical catalytic field. Improving the oxygen permeability of membrane materials and solving the stability of membrane in low oxygen partial pressure atmosphere are the key to realize the industrial application. Therefore, it is necessary to solve the problems such as improving the oxygen permeability and property stability of the materials. There are many factors that affect the properties of ceramic membranes. For example, the composition, microstructure and surface modification of Ba0.5Sr0.5Co0.8Fe0.2O3- 未 ceramic films were studied in this paper. The effects of surface modification on the oxygen permeability of Ba0.5Sr0.5Co0.8Fe0.2O3- 未 films were investigated. The effects of SC and Cr doping on the electrical properties and oxygen permeability of BaFeO3 materials were also investigated in order to explore the preparation of new Co free oxygen permeable membrane materials. The main conclusions obtained in this paper are as follows: 1) by glycine nitrate method. The BaFeO3 powder with perovskite structure can be obtained by calcining the precursor powder above 900 鈩，

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