掺Pd的SnO_2介孔薄膜的气敏特性研究

Investigation on Gas Sensing Properties of Mesoporous SnO_2 Thin Films Doped With Pd

采用蒸发诱导自组装工艺制备了Pd-SnO2介孔金属氧化物薄膜。采用静态配气法,研究了Pd掺杂量对SnO2元件气敏性的影响,并通过测定电化学阻抗谱,分析了介孔金属氧化物的气敏机理。结果表明:Pd掺杂降低了SnO2元件对氢气初始响应温度,并提高了元件对氢气灵敏度;Pd掺杂量为0.5%时,SnO2元件对氢气的气敏性最好;温度为175℃时,0.5%Pd-SnO2对体积分数为1 000×10-6氢气灵敏度为22.6;阻抗分析表明,通入还原性气体后,氧化物的晶界电阻明显减小。

Mesostructured Pd-SnO2 thin films were successfully prepared on slide glass by evaporation-induced self-assembly process.The gas sensing properties of Pd-SnO2 thin films fabricated on alumina ceramic tube were measured by a stationary state gas distribution method.With palladium doping,fabricated SnO2 sensor shows better sensitivity towards hydrogen than undoped SnO2 sensor and maximum sensitivity is observed for 0.5wt%Pd-doped SnO2.The film（0.5%） shows the highest sensitivity of 22.6 to 1 000×10-6 H2 gas at the operating temperature of 175 ℃.From impedance changes,it can be conclude that the polarization resistances reduce sharply when the sensor exposes to the reduceing gas.