铈锆储氧材料在浓差型汽车氧传感器中的应用研究

Research on the application of CeO_2-ZrO_2 oxygen storage compound to potentiometric automobile oxygen sensor

传统浓差型汽车氧传感器在结构上必须有连通大气的空气通道以提供恒定的氧分压,使得其制作工艺复杂、成本高、不便于微型化。文章提出利用铈基储氧材料的储氧特性,使其作为固态氧分压参考层,来制备一种新型的用于监测汽车尾气排放的氧浓差型氧传感器。研究利用添加锆形成铈锆复合固溶体氧化物(CZO)来改善氧化铈氧储能力(OSC),采用共沉淀法制备了CZO体系储氧材料,研究了老化温度对其相结构、比表面积及氧储能力的影响,并对制作的传感器进行测试,结果显示:在空燃比为1附近电势发生突变,突变电势范围为520～-200mV,贫燃时输出电势为负,富燃时输出电势为正。

Traditional potentiometric automobile oxygen sensor must be directly exposed to the air by an air duct so as to provide invariable oxygen partial pressure, and therefore, has many problems such as complex fabrication process, high cost, difficult to be miniaturized, and etc. A novel potentiometric oxygen sensor employing oxygen storage material CeO2 as the solid-state reference is proposed in this paper. The Oxygen Storage Capacity （OSC） of the solid-state reference is raised by doping Zr in CeO2. The CeO2-ZrO2 compound （CZO） is prepared using chemical co-precipitation method. The effects of high temperature on its phase structure, BET surface area and OSC are studied. Test experiments of the sensor were performed with various A/F value mixture gas at various operating temperatures. Experiment results show that the output voltage of the sensor is negative at lean-burn condition and positive at rich-burn condition, which is different from that of traditional oxygen sensor with a difference of 1 000~100 mV.