溶胶-凝胶法制备H_2S气敏材料LaFeO_3

Preparation of H_2S sensing material LaFeO_3 by sol-gel method

以La(NO3)3.6H2O、Fe(NO3)3.9H2O和柠檬酸为原料,采用溶胶–凝胶法制备了纳米LaFeO3。利用XRD和SEM对所合成材料的结构和形貌进行了表征,利用静态配气法测试了材料的气敏性能。研究了不同煅烧温度对LaFeO3气敏性能的影响。结果表明,600和800℃煅烧2 h均可得到不规则的块状纯钙钛矿相的LaFeO3,其中600℃煅烧得到的LaFeO3对H2S气体具有良好的灵敏度和选择性。在295℃的工作温度下,LaFeO3(600℃)对体积分数为100×10–6的H2S气体的灵敏度达到141.6,对体积分数为10×10–6的H2S气体的灵敏度也可达13.0。

The nano-LaFeO3 was prepared by sol-gel method using La（NO3）3 ·6H2O, Fe（NO3）3·9H2O and citric acid as raw materials. The structure and morphology of the prepared LaFeO3 were characterized with XRD and SEM. The gas-sensing properties of the prepared LaFeO3 were tested by static distribution. The influence of the calcination temperature on gas-sensing properties of the prepared LaFeO3 was investigated. The results show that pure perovskite LaFeO3 which is a kind of irregular and massive particle, can be obtained by calcining both at 600 and 800℃ for 2 h, and the LaFeO3 calcined at 600℃ possesses remarkable sensitivity and good selectivity to H2S gas. The gas sensitivity can reach 141.6 to H2S of 100×10-6 （volume fraction） and 13.0 to H2S of 10× 10-6 （volume fraction） at the working temperature of 295℃, respectively.