钯前驱体对纳米棒 CeO2载钯催化剂催化甲苯燃烧性能的影响

摘要

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 precur-sors 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 pro-grammed reduction.The catalytic performance of these catalysts for toluene combustion was evaluated in a fixed-bed microreac-tor.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 t90 at 219 and 236 ℃,respectively,in toluene catalytic combus-tion,indicating that Pd-N/CeO2 possesses higher catalytic activity than that over Pd-C/CeO2 .