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.
参考文献
| [1] | Guido Saracco;Giovanni Scibilia;Antonio Iannibello;Giancarlo Baldi .Methane combustion on Mg-doped LaCrO_3 perovskite catalysts[J].Applied Catalysis, B. Environmental: An International Journal Devoted to Catalytic Science and Its Applications,1996(2):229-244. |
| [2] | Davide F;Lucio F .Methane combustion on some perovskite-like mixed oxides[J].Applied Catalysis B:Environmental,1998,16(02):119. |
| [3] | Seiyama T .Toal oxidation of hydrocarbons on perovskite oxides[J].Catalysis Review:Science and Engineering,1992,34(02):281. |
| [4] | Yong F;Yu Y .The oxidation of hydrocarbons and CO over metal oxides Ⅳ perovskites-type oxides[J].Journal of Catalysis,1975,36(03):266. |
| [5] | Nolan M;Parker S C;Watson G W .The electronic structure of oxygen vacancy defects at the low index surfaces of ceria[J].Surface Science,2005,595(1-3):223. |
| [6] | 张昕,万惠霖,翁维正,杨乐夫,伊晓东.丙烷选择氧化制丙烯醛催化剂中Ce的作用[J].物理化学学报,2003(06):492-497. |
| [7] | 赵秀华,蒋晓原,陈宏桦,郑小明.CuO/Ce0.5Ti0.5O2的制备与表征及其对NO+CO反应的催化活性[J].物理化学学报,2008(06):1023-1029. |
| [8] | Alemi A A et al.Synthesis and studies of Zn-doped LaMnO3+d nanoperovskite by sol-gel processing[J].Radiat Effects Defects Solids,1998,163(11):893. |
| [9] | 张敬畅,曹维良,于定新,石锦华,窦正仓.超临界流体干燥法制备纳米级TiO2的研究[J].无机材料学报,1999(01):29-35. |
| [10] | Choi HJ;Moon J;Shim HB;Han KS;Lee EG;Jung KD .Preparation of nanocrystalline CeO2 by the precipitation method and its improved methane oxidation activity[J].Journal of the American Ceramic Society,2006(1):343-345. |
| [11] | Wang C X;Dou B S;Fan S R.Defects in perovskitetype catalysts CaxLa1-x MnO3+λ and their role in ammonia oxidation[J].Science in China(Series D),1984(08):12. |
| [12] | Ran R;Wu XD;Quan CZ;Weng D .Effect of strontium and cerium doping on the structural and catalytic properties of PrMnO3 oxides[J].Solid state ionics,2005(9/10):965-971. |
| [13] | Wang Y;Wang Y;Meng YL;Ding HM;Shan YK;Zhao X;Tang XZ .A highly efficient visible-light-activated photocatalyst based on bismuth- and sulfur-codoped TiO2[J].The journal of physical chemistry, C. Nanomaterials and interfaces,2008(17):6620-6626. |
| [14] | Goldschmidt V V M .Die gesetze der krystallochemie[J].Naturwissenschaften,1926,14(21):477. |
| [15] | Markovic D;Kusigerski V;Tadic M et al.The influence of the heat treatment on the structural and magnetic properties of nanoparticle La0.7 Ca0.3 MnO3 prepared by glycine-nitrate method[J].Journal of Alloys and Compounds,2010,494(1 2):52. |
| [16] | Vázquez-vázquez C et al.Characterization of La0.67 Cao.33-MnO3-δ particles prepared by the sol-gel route[J].Journal of Materials Chemistry,1998,8(04):993. |
| [17] | Lei Sun;Taicheng An;Shungang Wan .Effect of synthesis conditions on photocatalytic activities of nanoparticulate TiO2 thin films[J].Separation and Purification Technology,2009(1):83-89. |
| [18] | Pari G;Mathi J S et al.Density-functional description of the electronic structure of LaMOs (M=Sc,Ti,V,Cr,Mn,Fe,Co,Ni)[J].Physical Review B:Condensed Matter,1995,51(23):16575. |
| [19] | Ferri D et al.NO reduction by H2 over perovskite-like mixed oxides[J].Applied Catalysis B:Environmental,1998,16(04):339. |
| [20] | Zaki MI.;Al-Sagheer FA.;Pasupulety L.;Hasan MA. .In situ FTIR spectra of pyridine adsorbed on SiO2-Al2O3, TiO2, ZrO2 and CeO2: general considerations for the identification of acid sites on surfaces of finely divided metal oxides[J].Colloids and Surfaces, A. Physicochemical and Engineering Aspects,2001(3):261-274. |
| [21] | Xie YB;Yuan CW .Transparent TiO2 sol nanocrystallites mediated homogeneous-like photocatalytic reaction and hydrosol recycling process[J].Journal of Materials Science,2005(24):6375-6383. |
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