温湿度对SnO2基CO气体传感器敏感特性的影响

采用溶胶-凝胶法制备了纳米SnO2粉体及Pd掺杂浓度比分别为0.2 mol%、2 mol%1、0 mol%的三种掺杂粉体。以制得的粉体作为敏感材料,制成陶瓷微热板式CO气体传感器。在自行搭建的气体测试平台上,测试了各传感器在不同环境温湿度条件下对CO的响应,研究了Pd掺杂浓度对传感器湿度稳定性的影响,探讨了湿度影响传感器灵敏度的机理。实验结果表明:0.2 mol%Pd掺杂器件在不同湿度条件下灵敏度离散度由掺杂前的20.5%降低至8.63%,有效提高了传感器的湿度稳定性。10 mol%Pd掺杂器件在湿度大于50%相对湿度时,对20×10-6 CO出现反常响应,在还原气体CO出现时气敏膜电导减小。

The effect of the temperature and humidity on the sensitivity of SnO2-based CO gas sensors

Pure SnO2 nano-powder and Pd-doped powders with doping concentration of 0.2 mol%,2 mol% and 10 mol% were synthesized via sol-gel method,which powders were used as sensitive materials for the CO gas sensors prepared on the ceramic hotplate.The sensitivity of the sensors on the different temperature and humidity conditions was tested on the self-made testing platform.The effect of doping concentration on the humidity stability of the sensors was studied and the mechanism of the sensitivity on humidity was discussed.The results show that the 0.2 mol% Pd-doping sensor decreases the discrete of sensitivity on different humidity conditions from 20.5% of the undoped sensor to 8.63%,which increases the humidity stability of the sensor effectively.10 mol% Pd-doping sensor displays different response to 20×10-6 CO on above 50% relative humidity conditions and the conductance of sensing film deceases on the presence of reduced gas of CO.