Using cerium carbonate, lanthanum oxide and manganese nitrate as raw materials, Ce-La-Mn aerogel was prepared by sol-gel method combined with supercritical drying technology, and ultrafine particles of Ce-La-Mn mixed oxides were got after heat treatment at 850℃. The prepared materials were characterized by TG-DTA, XRD, FT-IR and TEM. The catalytic properties of ultrafine Ce-La-Mn mixed oxides were tested by reaction "2CO+2NO= 2CO2 +N2". The key aim was to examine the effect of supercritical fluid drying technology and Ce-doping on ultrafine Ce-La-Mn mixed oxides' crystal structure, morphology and catalytic activity. The results show; at 260℃, Ce-La-Mn mixed oxides was brown loose flocculent powder with good dispersibility. The particles were spherical about 10nm in size. The main crystal components were CeO2, MnO, La5O7NO3 and La(OH)2NO3, After thermal treating at 850℃, Ce-La-Mn mixed oxides were made up of lots of quasi-global grains smaller than 20nm;the main crystal components of the Ce-La-Mn mixed oxides were LaMnO3+λ La2 O3 and CeO2 heat treatment could enhance the crystallinity of the materials. Ce-doping increased the oxygen vacancies of LaMnOs+λ lattice, improved the condition of redox catalysis, effected the migration of the perovskite lattice oxygen and advanced the catalysis activity of Ce-La-Mn mixed oxides.%以碳酸铈、氧化镧和硝酸锰为主要原料,采用“溶胶-凝胶”法结合“超临界流体干燥”技术获取Ce-La-Mn气凝胶,在850℃热处理制备Ce-La-Mn混合氧化物,并采用TG-DTA、XRD、FT-IR和TEM进行表征,用“2CO+2 NO=2CO2+ N2”特征反应测试超细粒子的催化活性,考察超临界流体干燥技术与铈掺杂对超细Ce-La-Mn 混合氧化物的结构、形貌和催化活性的影响.结果显示:经260℃超临界流体干燥得到的Ce-La-Mn气凝胶为分散性好的棕色絮状粉末,由大量直径小于10nm的球型颗粒组成,晶相为CeO2、MnO、La5O7NO3和La(OH)2NO3;经850℃热处理得到的Ce-La-Mn混合氧化物的粒径约为20nm,晶相为LaMnO3+λ、La2O3和CeO2;铈掺杂增加了LaMnO3+λ晶格中氧空缺数量,改善了催化的气氛条件,提高了Ce-La-Mn混合氧化物的催化活性.
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