钯前驱体对纳米棒CeO_2载钯催化剂催化甲苯燃烧性能的影响

Effect of palladium precursor on the performance of nanorods CeO_2-supported palladium catalyst for toluene catalytic combustion

针对挥发性有机物污染日益严重问题,本文采用水热法制备了纳米棒二氧化铈,并以其为载体,通过浸渍法制备了不同前驱体的Pd/CeO2催化剂。采用透射电子显微镜、X射线衍射、X射线光电子能谱和氢气程序升温还原等手段对催化剂进行了表征,并在微型固定床反应器上评价了催化剂催化甲苯的燃烧性能。结果表明:在采用不同前驱体制备的Pd/CeO2催化剂中,Pd均以Pd2+的形式存在于纳米棒状CeO2表面;在以硝酸钯和氯化钯为前驱体的Pd/CeO2催化剂中,前者具有更低的氢气还原温度,同时在甲苯催化燃烧反应中显示出更低的t50和t90,分别为219和236℃。结果表明,以硝酸钯为前驱体的催化剂具有更高的催化活性。

For the problem of volatile organic compounds pollution increasing seriously,palladium catalysts with various precursors supported on CeO2 nanorods were prepared by impregnation method.These catalysts were characterized using transmission electron microscopy（TEM）,X-ray diffraction（XRD）,X-ray photoelectron spectroscopy（XPS）and H2 temperature programmed reduction.The catalytic performance of these catalysts for toluene combustion was evaluated in a fixed-bed microreactor.The results show that palladium highly dispersed on the CeO2 nanorods surface as Pd2＋states in all the Pd/CeO2 catalysts with various precursors.Pd-N/CeO2（palladium nitrate as precursor）shows a lower reduction temperature than that of Pd-C/CeO2（palladium chloride as precursor）,and show a lower t50 and t90at 219 and 236℃,respectively,in toluene catalytic combustion,indicating that Pd-N/CeO2 possesses higher catalytic activity than that over Pd-C/CeO2.