低钯新型汽车尾气净化催化剂的研究

Study on low Content Palladium Catalysts for Automotive Emission Control

应用流动体系微型反应器、TPR、TPD技术研究了La＿Ce＿Zr＿Ti＿O,Pd＿La＿Ce＿Zr＿Ti＿O,Pd＿Rh＿La＿Ce＿Zr＿Ti＿O3种体系的催化剂在低钯负载量(<1.0‰)时的性能。研究结果表明:对低钯型汽车尾气净化催化剂,0.8‰的钯含量是比较合适的;铑在催化剂中对NO的转化具有独特作用,但并非不可替代;在Pd＿La＿Ce＿Zr＿Ti＿O催化剂中,TPR谱图上550℃左右的还原峰对应的氧物种应该是催化剂主要的活性物种。

The catalytic activity of La_Ce_Zr_Ti_O\,Pd_La_Ce_Zr_Ti_O\,Pd_Rh_La_Ce_Zr_Ti_O catalysts has been studied with flow_system microreactor temperature_programmed reduction(TPR) and temperature_programmed desorption(TPD) technique when the Pd content is not more than 1.0‰.It was shown that the appropriate Pd loading in low content palladium catalyst is 0.8‰;Rh has particular function to NO conversion,but it is able to be replaced by other components;the oxidation species whose reduciton temperature is about 550 ℃ in the TPR curve of Pd_La_Ce_Zr_Ti_O catalyst should be the main activity species.