纳米LaFeO_3的制备及H_2S气敏性能研究

Preparation and H_2S Gas Sensing Properties of LaFeO_3 Nanocrystal

以无机物K3[Fe(CN)6]和La(NO3)3.nH2O为原料,用热分解配合物前驱体法制备了LaFeO3纳米粉体.用X-射线粉末衍射仪(XRD)和透射电镜(TEM)对产物的物相、形貌进行了表征.本工作还以沉淀法相同温度条件下煅烧出的LaFeO3作了对比.结果显示:热分解法在煅烧温度为700℃即可生成纳米晶LaFeO3,TEM显示产物为均匀的椭球形颗粒,充分表明该方法制备的材料具有良好分散性,且纯度较高.将合成材料制备成旁热式气敏元件,气敏性能测试结果表明:合成材料对H2S具有高的灵敏度和选择性,在192℃工作时,对35μL/LH2S气体的灵敏度可达72倍.

Nanomaterial of rare-earth composite oxide LaFeO3 with the structure of pervoskite type was synthesized by a coordination complex thermal decomposition method, the precursor was prepared by a chemical precipitation method of K3 [Fe（CN）6] and La（NO3）3 ·nH2O. The structure and crystal state of the powder were determined using X-ray diffractometer （XRD）. The particle shape and size were analyzed with the help of transmission electron microscopy （TEM）, the results show that the powders synthesized by thermal decomposition method take on better dispersion and purity than that of co-precipitation. Furthermore, the gas sensing properties were tested at static state. It can be seen that the gas sensors based on LaFeO3 nanopowder show remarkable sensitivity and good selectivity to H2S, the gas sensitivity can reach 72 times to 35μL/L H2S at 192℃ in air, and the detecting range of H2S was also decided in this experiment,