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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。
La 0.8 Sr 0.2 CoO 3 gel was prepared by EDTA complex sol-gel method using La (NO 3) 3 6H 2 O, Sr (NO 3) 2 and Co (NO 3) 2 · 6H 2 O as raw materials, , Calcined at 800 ℃ and 900 ℃ to obtain La_ (0.8) Sr_ (0.2) CoO_3 powder. The preparation process, thermal decomposition mechanism and powder properties were studied by DTA, FT-IR, XRD and SEM. After calcined at 700 ℃ for 2 h, La_ (0.8) Sr_ (0.2) CoO_3 pure phase nano-powder was obtained. The particles were spherical. The tube-shaped sensor was made by La 0.8 Sr 0.2 CoO 3 powder calcined at 700 ℃ for 2 h, and the NO 2 sensitivity was tested. The relationship between sensor sensitivity and temperature was also discussed under the same NO 2 concentration. The results show that the sensitive signal of nano - sized La 0.8 Sr 0.2 CoO 3 powder is the most sensitive to NO 2 at 450 ℃, and the output electromotive force signal has a linear relationship with NO 2 concentration.