旁热式TiO_2/MoO_3复合厚膜邻二甲苯气敏陶瓷元件的制备及特性表征

Preparation and characterization of heater -type o - dimethylbenzene Sensitive ceramic element with TiO2/MoO3 complex thick film

采用溶胶-凝胶方法,在TiO_2中以不同配比掺杂MoO_3,制得TiO_2/MoO_3复合粉体。经过调浆、涂覆、烧结、陈化和封装等工艺,进而制得旁热式厚膜陶瓷元件。以电阻为感量,以氮气为稀释气体,分别在不同浓度的邻二甲苯,甲醇,乙醇,H_2,CO或O_2气气氛中,测试元件的气敏特性,获得了仅对邻二甲苯具有良好灵敏度、选择性和响应时间的气敏元件,为检测和治理工业废气和废水中的邻二甲苯有机污染,提供了可供开发应用的传感元件。

Sol precursors are prepared with a series of wt% by sol-gel process using titanium butoxide Ti(On-Bu)4(AR) and ammonium molybdate(NH4)2MoO4(AR) as starting materials, and using HOAc as medium with pH = 3.8. The TiO2/MoO3 complex powders are obtained by drying the sol and then calcining. The TiO2/MoO3 elements are prepared by mixing above-mentioned powders with water and binder, coating on a ceramic tube as substrate, sintering at 500C/2h, ageing and capsulating. The measurements of gas - sensitivity of these elements are obtained respectively in the six atmosphere, namely o - dimethylbenzene, methyl alcohol, ethanol, H2, CO and O2. The results show these TiO2/MoO3 elements are only senstive to o - dimethyl - benzene, display high selectivity, its response time 1min, the best TiO2/MoO3 furmula is 3.0wt% MoO3, the best VH is 6v(analogous to the element temperature t= 400C.