喷雾热分解法合成与电性能
(1. 山东理工大学 化学工程学院, 淄博 255049;
2. 上海交通大学 化学化工学院, 上海 200240)
摘 要: 用喷雾热分解法制备La0.6Sr0.4Co0.2Fe0.8O3-α(LSCF)超细粉体材料, 用扫描电镜和透射电镜研究粉体的形貌与粒度, 用X射线衍射仪研究粉体材料的晶相结构, 通过能谱仪研究其元素组成和掺杂性能, 用激光粒度分析仪分析粒度分布, 并测试其电性能。 结果表明： 喷雾热分解法合成的LSCF粉体材料粒子呈球形, 平均粒度3.13 μm, 超声喷雾在900 ℃热分解的产物能直接形成钙钛矿型晶相, 且经过1 100 ℃处理后结晶度更完整； 能谱仪分析显示喷雾热分解法直接制成的LSCF粉体掺杂均匀；粉体的粒度符合液滴粒子转变机理, 即1个产物粒子由1个液滴形成；当加入乙醇时, 粉体的粒度将减小, 但加入尿素、硝酸铵和柠檬酸时其粒度增加。 粉体的电导率峰值出现的位置为650 ℃。
关键字: 钙钛矿型复合氧化物；混合导体；喷雾热分解
and its electrical property
（1. School of Chemical Engineering,
Shandong University of Technology, Zibo 255049, China;
2. School of Chemistry and Chemical Technology,
Shanghai Jiao Tong University, Shanghai 200240, China）
Abstract: La0.6Sr0.4Co0.2Fe0.8O3-α (LSCF) ultrafine powders were synthesized through an ultrasonic spray pyrolysis process. The products were characterized by scanning electron microscopy and transmitted electron microscopy to observe the morphology, by X-ray diffractrometry to display the crystalline phase and by energy dispersive spectrometry to determine the elemental compositions and doping performance, and by laser particle size analyzer to analyze the particle size. Lastly, the conductivity of LSCF was tested. The results indicate that the prepared powders consist mainly of spherical particles with diameters of 3.13 μm. At the operating temperature of 900 ℃, a single perovskite crystalline phase may be formed, although the higher temperature favors the formation of perovskite structure. The energy dispersive spectrometer spectra show that the spray pyrolysis allows for the perfectly even-doping. The particle size can be adjusted by the parameters such as the concentration of precursor solution and additives. The particle size increases with increasing concentration of precursor solution and conforms to One-Droplet-One-Particle mechanism (ODOP). The particle size is decreased by addition of ethanol but increased when carbamide, ammonium nitrate or citric acid is used as the additive. Experimental result indicates that maximum conductivity occurs at 650 ℃, which is the expectation temperature for SOFC.
Key words: perovskite composite oxide; mixed conductor; spray pyrolysis
