氧化铋掺杂制备SnO2棒状晶粒气敏材料的研究

The Preparation of Bismuth-Oxide-Doped Tin-Oxide Nanorods and Their Gas-Sensing Property

探讨了氧化铋掺杂的SnO2纳米棒状晶粒气敏材料的制备,并测试了材料的气敏特性。氧化铋在高温形成液相,促进SnO2棒状晶粒的形成,同时氧化铋作为气敏材料的添加剂提高了对乙醇等气体的灵敏度。结果表明,采用液相沉淀法制备纳米粉体,在Bi添加量为10mol%,850℃保温2h的烧结条件下,得到的SnO2棒状晶粒直径约50nm,线径比为5,且较为均一。粉体经过稀硝酸溶液浸泡,其晶粒形貌及相结构不变,酸洗处理后的棒晶粉体制备的气敏元件,电阻值适中,对气体灵敏度提高。对乙醇、丙酮、汽油、苯和氨气的测试说明,氧化铋掺杂的SnO2棒状晶粒作为气敏材料,在不同温区对乙醇和丙酮的灵敏度较高,而且工作温度较低,对汽油、苯和氨气等气体有较好的选择性。

SnO2 nanorods doped with bismuth were prepared by Liquid-Phase Precipitation method and their gas-sensing properties studied. Samples with optimal qualities can be obtained by sintering the precipitation of Sn（OH）4 with 10 mol% bismuth oxide added. The nanorods are found to be of good uniformity and large aspect ratio （5：1）. Subsequent nitrification treatment by dilute nitric acid does not alter the structure and morphology of the nanorods. The effect of bismuth on SnO2 gas sensors is twofold： the liquid phase of bismuth oxide assists the formation of rod-like particles at calcination temperatures （〉820℃）, and as an additive it enhances the sensitivity of SnO2 to ethanol etc.. Experiments on various VOCs indicated that the nanorods have better sensitivity to ethanol and acetone in a wide temperature range than spherical SnO2 particles, hence lower working temperatures and better long-term stability.