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以锡粉和硝酸为主要原料,采用水热法合成了纳米晶SnO2粉体,研究了其厚膜元件对空气中低体积分数H2S气体(2~100μL/L)的敏感特性.结果表明:170℃水热处理3~13 h获得的SnO2粉体结晶良好,呈四方相金红石结构,其X射线射峰宽化明显,颗粒尺寸为数纳米且分布窄.随着水热处理时间的延长,颗粒尺寸及结晶程度有所提高.170℃水热处理9 h得到的SnO2粉体颗粒尺寸约为4.4 nm.利用该粉体制作的厚膜元件晶粒细小均匀,晶粒尺寸约为10.0 nm.在最佳工作温度150℃下该元件对低浓度H2S气体具有良好的响应-恢复特性,对50μL/L H2S的灵敏度为20.5,敏感体积分数下限低至2μL/L,而对体积分数高至1000μL/L的CO及CH4两种气体均不敏感.
The tin oxide and nitric acid were used as raw materials to synthesize nanocrystalline SnO2 powders by hydrothermal method, and the sensitive properties of the thick-film components to low volume fraction H2S gas (2 ~ 100 μL / L) in air were studied. The results showed that: 170 The hydrothermal treatment of SnO2 powder for 3 ~ 13 h showed good crystallization and tetragonal rutile structure, the X-ray peak broadened obviously, the particle size was several nanometers and the distribution was narrow.With the extension of hydrothermal treatment time, the particle size and crystallization The particle size of SnO2 powder obtained by hydrothermal treatment at 170 ℃ for 9 h is about 4.4 nm.The thick film elements fabricated by this powder have fine and uniform grains with a grain size of about 10.0 nm.At the optimum working temperature At 150 ℃, the device has good response-recovery characteristics to low concentration of H2S gas with a sensitivity of 20.5 for 50μL / L H2S and a low limit of 2μL / L for volume fraction of CO and up to 1000μL / L for CO and CH4 two gases are not sensitive.