Ce-La-Mn超细粒子的制备、表征及催化性能研究  

Preparation,Characterization and Catalytic Property of Ce-La-Mn Ultrafine Particles

作　　者：陈阳[1] 黄艳[1] 余高奇[2] 汪厚植[2] 赵慧忠[2] 张侃[1] 

机构地区：[1]武汉科技大学化学工程与技术学院,武汉430081 [2]武汉科技大学耐火材料与高温陶瓷国家重点实验室培育基地,武汉430081

出　　处：《材料导报》2012年第14期43-46,50,共5页Materials Reports

基　　金：湖北省教育厅重点科技研究项目(2002A01018);湖北省优秀青年人才科研计划项目(2002B011004);武汉科技大学校基金(2008XY12)

摘　　要：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+2NO=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。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,La2O3 and CeO2;heat treatment could enhance the crystallinity of the materials.Ce-doping increased the oxygen vacancies of LaMnO3+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.

关 键 词：超细粒子 LaMnO3+λ 超临界流体干燥 稀土 催化活性 

分 类 号：TQ133.3[化学工程—无机化工]