纳米LaFeO_3的微波辅助液相合成及其甲醛敏感性研究

Microwave-assisted liquid phase synthesis and formaldehyde gas-sensing properties of LaFeO_3 nanocrystal

以分析纯La(NO_3)_3、K_3[Fe(CN)_6]为原料,利用微波辅助液相法合成纳米LaFeO_3,并与配合物热分解法进行对比。X射线粉末衍射仪(XRD)、透射电子显微镜(TEM)分析结果表明,两种方法合成的产物均为正交钙钛矿结构纳米LaFeO_3,但微波辅助有利于减小纳米LaFeO_3的粒径。气敏测试结果表明,微波合成纳米LaFeO_3对所测试气体的响应均显著高于配合物热分解法,在最佳工作温度225℃时对甲醛具有高灵敏度和良好选择性,对100μL/L甲醛的灵敏度高达346.7,即使对10μL/L甲醛也有一定响应。

With analytical La（NO3）3 and K3[Fe（CN）6] as feedstocks, nanocrystalline of LaFeO3 was respectively synthesized by microwave-assisted liquid process and coordination complex thermal decomposition. Crystal structure and morphology of the as-prepared samples were characterized using X-ray diffractometer（XRD） and transmission electron microscopy（TEM）. The characterization results show that the as-prepared LaFeO3 by two methods are both pure orthorhombic perovskite structure, however, the particle size of LaFeO3 synthesized by the microwave-assisted process is smaller. The gas sensing results reveal that the response of LaFeO3 prepared by microwave-assisted process is obviously higher to these tested gases. At the optimal working temperature of 225 ℃, the LaFeO3-based sensor possesses remarkable sensitivity and good selectivity to HCHO gas, its gas sensitivity reaches 346.7 to 100 μL/L HCHO in air, and there is some response even to 10 μL/L HCHO.