热处理温度对氧化锡气敏特性的影响

INFLUENCE OF HEAT TREATMENT TEMPERATURE ONGAS SENSING PROPERTIES OF SnO2SENSORS

利用硝酸氧化法、化学沉淀法合成了纳米ＳｎＯ２及贵金属掺杂ＳｎＯ２材料，并对合成材料进行了物相表征和气体灵敏度测量．结果表明：在４００℃～９００℃热处理温度范围内，ＳｎＯ２的平均晶粒度随处理温度升高而增大，但均＜４０ｎｍ；纯ＳｎＯ２材料的气体灵敏度随平均晶粒度的增大而减小，主要受尺寸效应控制，而贵金属掺杂ＳｎＯ２的气体灵敏度受尺寸效应和催化效应共同控制；通过控制掺杂和热处理温度可改善ＳｎＯ２的气敏性能。

anosized powders of pure and noble metal doped SnO2 were prepared by chemical precipitation and oxidation of Sn with HNO3,respectively.Phase structure and gas sensitivity of these materials were also measured.It can be shown that the mean grain size of pure SnO2 powder increase with the increase of heat treatment temperature in temperature range of 400 to 900 ,and that of all powders is smaller than 40 nm;their gas sensitivity decrease as their grain size rise.The gas sensitivity of pure SnO2 sensor is mainly controlled by grain size,but that of noble metal doped SnO2 sensors are dominated by both grain size and catalysis.Thus,we are able to detect inflammable gases selectively or generally through controlling dopant and heat treatment temperature.