溶胶-凝胶法制备La_(0．8)Sr_(0．2)CoO_3纳米材料及其气敏性能的研究

Synthesis of Nanometer La_(0.8)Sr_(0.2)CoO_3 by Sol-Gel Method and Its Sensitive Property for NO_2

以La(NO_3)_3·6H_2O、Sr(NO_3)_2、Co(NO_3)_2·6H_2O为原料,用EDTA络合溶胶-凝胶法制备La_(0.8)Sr_(0.2)CoO_3凝胶,在700℃、800℃、900℃煅烧,制得La_(0.8)Sr_(0.2)CoO_3粉体。用DTA、FT-IR、XRD、SEM等手段对制备过程、热分解机理及粉体的性能进行了研究。在700℃焙烧2 h得到La_(0.8)Sr_(0.2)CoO_3纯相纳米粉,颗粒呈球形。选取700℃焙烧2 h的La_(0.8)Sr_(0.2)CoO_3粉体制成管状传感器,进行NO_2敏感性能测试,探讨了相同NO_2浓度下,传感器敏感信号与温度的关系。结果表明:纳米La_(0.8)Sr_(0.2)CoO_3粉体在450℃时对NO_2的敏感信号最大,输出的电动势信号与NO_2浓度之间呈线性关系。

Using La（NO3）3-6H2O, Sr（YO3）2, and Co（NO3）2·6H2O as raw materials, the nanometer La0.8Sr0.2CoO3 powders was prepared by EDTA sol-gel method. Gel was calcined at 700 ℃, 800 ℃and 900 ℃ respectively. The samples were characterized by DTA, FT-IR, XRD and SEM techniques. The preparation process, thermal decomposition mechanism and performances of the powders have been studied. The results show that the spheric nanocrystalline La0.8Sr0.2CoO3 could be obtained after calcined at 700 ℃ for 2 h. The tube-type NO2 sensor was prepared with La0.8Sr0.2CoO3 powder calcined at 700 ℃ for 2 h as sensing material and its performance was tested. The results show that at 450℃ the sensor is the most sensitive to NO2. At a fixed temperature, EMF responses and NO2 concentrations are of linear relationship.