TiO_2-WO_3复合氧化物电极材料对NO_2气敏性能的研究

采用共沉淀法制备了TiO2添加量为0%~20%(质量分数)的TiO2-WO3复合氧化物材料,并利用XRD、SEM等测试手段对材料的成分结构进行了分析。通过丝网印刷,将此复合氧化物材料制备为混合电势型NO2气敏传感器的敏感电极,并对其在500~700℃温度范围内的NO2气敏性能进行研究,分析TiO2添加量、工作温度等因素对气敏性能的影响,并探讨其机理。结果表明:TiO2和WO3没有形成中间相,添加的TiO2一方面由于粒径细小,增大了敏感电极的比表面积,提高了材料的低温敏感性能;另一方面由于促进了NO2的气相分解反应,降低了材料的高温敏感性能。当TiO2添加量为10%时,复合氧化物电极材料在550℃表现出对NO2较高的敏感性能,且响应-恢复特性较好。

Study on NO2 Gas Sensitive Properties of TiO2-WO3 Mixed Oxides Electrode

TiO2-WO3 Mixed oxides were prepared by coprecipitation. The composition and microstructure of the mixed oxides were analyzed by XRD and SEM. The mixed oxides were made as sensing electrodes of mixed potential gas sensors by screen-printing. NO2 Gas sensitive properties at 500~700℃ were investigated,and the effects of adding amount of TiO2 and working temperature were discussed. The results showed intermediate phase was not formed between TiO2 and WO2. The specific surface area of the sensing electrode was enlarged and the gas sensitive properties were improved at low temperature because of the small grain size of TiO2. On the other hand, the sensitive properties were deteriorated at high temperature because of the promoting of NOz decomposition by TiO2. The sensor with 10%TiO2-WO3 sensing electrode showed the highest response to NO2 at 550 ℃ and better response-recovery properties than pure WO3.