Nanocrystalline SnO2 was prepared by precipitation using tin chloride pentahydrate as raw materials and polyethylene glycol as the surfactant. The traditional indirectly heated sintered-type tin oxide gas sensors were prepared by grinding, coating, sintering, soldering, aging the obtained nanocrystalline SnO2. The structure, specific surface area and morphology of the samples of obtained nanocrystalline SnO2 were characterized by X-ray diffraction (XRD), nitrogen adsorption isotherms (BET), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Gas sensing property of the sensors to ethanol, formaldehyde, acetone, methanol gases was measured by the static volumetric method. The results show that the particle size of nanocrystalline SnO2 is very small with good homogeneity, the particle size is range from 5 to 8 nm; the maximum specific surface area is up to 73. 29 m2/g with porous structure, the size of the most probable pore diameter is between 4. 7 and 6. 1nm; the porous structure may be formed in the gas passage, which is conducive to the diffusion of gas molecules to improve the gas sensing performance. The gas sensitivity test shows that all sensors have higher response to ethanol, formaldehyde, acetone, methanol gases. The application of polyethylene glycol modified nanocrystalline SnO2 material has good prospects for gas sensor development.%以五水四氯化锡为原材料,聚乙二醇为表面包覆剂,用沉淀法制备出二氧化锡纳米粉体.将制得的二氧化锡纳米粉体经过研磨、涂覆、烧结、焊接、老化等步骤即制得旁热式烧结型二氧化锡气敏元件.取少量二氧化锡纳米粉体采用X射线衍射、比表面测试、扫描电镜和透射电镜等测试手段对材料的结构、比表面积和形貌进行了表征；采用静态配气法测试了气敏元件对乙醇、甲醛、丙酮、甲醇等气体的气敏性能.结果表明:制备的二气化锡粉体粒径非常小且均一性比较好,颗粒大小约为5～8 nm;比表面积极大,最高达到每克73.29平方米,具有多孔结构,最可几孔径为4.7～6.1 nm,多孔结构可形成气体通道有利于气体分子扩散,从而提高气敏性能.通过添加聚乙二醇作为表面包覆剂对二氧化锡进行修饰,提高了二氧化锡材料的气敏性能,研究表明各元件对乙醇、甲醛、丙酮、甲醇等气体都具有很高的灵敏度,具有较大的应用前景.
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