摘要
氧化铝纳米管作为一种新型材料,由于其表面的电子结构和晶体结构发生了较大的变化,表现出纳米材料所特有的小尺寸效应、表面效应、量子效应以及宏观量子隧道效应等特殊性能,被广泛应用于电子、化工、医药、机械、航天航空、冶金等领域,特别有望在催化领域作为催化剂或载体得以应用并在催化领域带来新的活力与生机。
本文以AlCl3·6H2O为铝源,十六烷基三甲基溴化铵(CTAB)为模板剂,在水热体系中通过控制反应温度与时间合成了γ-Al2O3纳米管,并采用X-射线衍射、氮吸附、透射电子显微镜对合成的纳米管进行表征。结果表明,经煅烧并用盐酸处理后,即可得具有高比表面积的γ-Al2O3纳米管。其后,以此为载体,通过等体积浸渍法制备出不同Cu含量的催化剂,考察了载体、氧气浓度、二氧化硫、反应条件等在NO催化分解中对催化性能的影响并对机理进行简要的分析。结果表明,当氧化铝纳米管表面负载Cu的量为7 %时为最佳,其催化性能随温度的升高而增强,并且在600℃达到最大;在低温时,纳米Cu-γ-Al2O3催化剂显示出比Al2O3催化剂更高的催化活性;少量的O2(0.25﹪)对纳米Cu-γ-Al2O3催化活性没有太大的影响,而当O2含量高于0.25﹪时催化剂的活性随着O2浓度的增加而迅速降低;当反应体系中通入SO2时,纳米Cu-γ-Al2O3显示出了一定的抗硫性能。
总之,本文主要利用软模板法合成了具有高比表面积且半径较均一的氧化铝纳米管,并研究了负载Cu的催化剂在NO分解中的催化性能。研究结果在环境治理方面具有较大的现实意义,特别有望在脱硝反应中得以广泛的应用并带来新的希望。
As a new kind of materials, owing to its large variations in surface-electronic structure and crystal texture, alumina nanotube shows special characteristics of nanophase materials,such as small-size effects,surface effects,quantum effects and macro quanta tunneling effects. Now, for its spectial characteristics,alumina nanotubes have been used in electron,chemical industry,medication,machine,space flight aviation, metallurgy . In the future, alumina nanotubes are expected to bring in new applications and hopes in many areas,especially as a catalyst or catalytica carrier.
In this paper,γ-Al2O3 alumina nanotube was synthesized in hydrothermal system by using the AlCl3?6H2O as aluminous sources and the CTAB as templates. The controlling of reactive temperature and time is most important in the reactive process and it would directly effect the final structure of alumina nanotubes. Alumina nanotubes were characterized by the X-ray diffraction,the nitrogenadsorption and the transmission electron microscope and the results showed the preparedγ-Al2O3 alumina nanotube had large specific surface. Cu loaded catalyst was prepared by incipient wetness impregation of theγ-Al2O3 alumina nanotube with an aqueous solution of Cu(NO3)2. Then, we studied the influence of carrier and O2 concertration together with SO2 on the catalytic reduction of NO. The results are as following: catalyst, 7% Cu loaded on theγ-Al2O3 alumina nanotube, shows the highest activity among the different Cu content, and the activity increases with the temperature, reaches the light-off temperature at 600℃, and remains even at 650℃; small amount of oxygen (0.25%) causes little change on the activity, while dramastic decrease of activty is observed as arising oxygen concertration; in the presence of SO2, the catalyst still presents an activity to some extend.
In the final process, copper loaded in the surface ofγ-Al2O3 alumina nanotube show high catalytic activity in catalytic decomposition of NO,especially in low-temperature conditions,and they are hoped to be used widely in denitration reaction and bring in great ecomomic benefits.
引文
[1] Breslow, R, Acc. Chem. Res. 1995, 28: 146.
[2] Wulff, G. Chem.Rev.2002, 102: 1-27.
[3] Zen, J. M.; Kumar, A. S. Acc.Chem.Res.2001, 34: 772.
[4] Iijima S. Helical microtubules of graphiteic carbon, Nature, 1991, 345:56.
[5] Seifert G,K0hler T,Tenne R,J.Phys.Chem.B,2002,106:2497.
[6] TenneRM,GenutLM,HodesG.Polyhedral and cylindrical slnletares of tungsten disulfide.Namre,1992,360 (6403):444-446.
[7] Feldman E W。Srolovitz D J,TenneR.High-Rate,Gas-Phase Growth ofMoS,Nested Inorganic Fullerenes andNanotubes.Science,1995,26(7):222-225.
[8] NasreenG,ChopraR J.CherreyLK,et a1.BoronNi, deNanotubes.Seience1995,26(9): 966-967.
[9] HoyerP.Formationofat,anium Dioxide Nanotube Array.Langmuir,1996,12(6):1411- 1413.
[10] Kuang D B.Fang Y P,Liu H Q,et al.Fabrication of boehmite AlOOH and gamma- A12O3 nanotubes via a soft solution route.Journal of Matcrials Chemistry,2003,13(4):236-285.
[11] Spahr M E,Bitterli P,Nesper R。ct a1.Redox.active nanotubes ofvanadium oxide.Angewandte Chemie-Intemational Edition,1998,37(9):1263-1265
[12] Pu L.BaoXM,Zou JP,gt a.Individual alumina nanotubes.Angewandte Chemie–International Edition。2001,40 (1):1490-1493.
[13] Nath M , Rao CN R . Nanotubes ofgroup 4 mctal disulfides , Angewandte Chemie-Intemational Edition,2002,4l(18):345l-3454.
[14] Wu J J,Liu S C,Wu CT,ec a1.Heterostructures ofZnO-Zn enaxial nanocables end ZnOnanombes.Applied Physics Letters,2002,81(7):1312一1314.
[15] Hernandcz BAt Chang K S,E R Fisher,et a1.Sol—gel template synthesis and characterization of TiO2 and nanotabes.Chemistry of Materlals,2002,14(2).80-482.
[16] Nath M,Rao C N R.New metal disulfide nanotubes.Journal of the American ChemicalSociety,2001,123(20):484l-4842.
[17] Chen J, The Z L,Li S L.Lithium intercalation in open-ended TiS,anotubcs Chemie- Intemational Edition,2003,42(19):2147-2151.
[18] Dleezik L,Engeihardt R,Ernst K.眈a1.Hexagonal nanotubes of ZnS bychemica Lannve Ysion of monoety stalline ZnO columns.Applied Physics Letters,2001,78(23): 3687-3689.
[19] JiangX C,Xie Y,Lu J,ct a1.Synthesis of novel nickel sulfide layer-rolled structures.Advanced Materials,200l,13(10):1278-1281.
[20] Jiangx C·Mayers B,HerriekT S,et a1.Direct synthesis of CdSe nanocables and CdSe nanotabus by reacting cadmium saltswith Sellanowires Advanced Materials,2003,15(10):1740-1743.
[21] Hultaen J C,Jirage K B t Martin C R,Introducing chemical transport selectivity into gold nanotubule membranes.Journal of the American Chemical Society,1998,120:6603-6604.
[22] Tourillon G. Ponter L,Levy J P,et a1.Electroe hemicany synthesized Co and Fe nenowires and nanotubes.Electrochemicatend,2000,3(1):20-23.
[23] Mayers B,Xia Y N.Formation of tellurium nanombes throae Concentration-dcplction at the surfaces of seeds.Advanced Materials,2002,14(4):279-282.
[24] Fang X S,YeC H,XuX X,et aI.Synthesis and photolumine scanee of alpha-A12O3 nanowires.Journal of Physics—Condensed Matter,2004,16(23):4157-4163.
[25] Xian Z L. Han C Y,Welp U,et al. Fabrication of alumina nanotubes and nanowircs by etching porous aIumina membranes.Nano Letter,2002,2(11);1293-1297.
[26] Shan XF, Wu X L,G S Huang,et a1.AIumina nanotubes and nanowires from A12O3 based poroas alumina membranes.Applied Physics a-Materials Scienca&Processing,2005,81(3):621-625.
[27] MeiYF,SiuGG,FuRKY,ctal,Formation mechanism of alumina nanotubes and nanowires from highly ordered porous anodic alumina template.Journal of Applied Physics,2005,9(7):3- 4
[28] ZhangY J,Liu J,HeRR,etal.Synthesis of alumina nanotubes using carbon nanotubes as templ-ates. Chemical Physics Letters,2002,360 (5-6):579-584.
[29] Lee J S,MinB,ChoK,etal.A12O3 nanotubes and nanorods fabricatedby coating and filling of carbon nanombes atomic-layerdeposition.Journal of Crystal Growth,2003,254(3-4):443-448.
[30] Zou J P, Pu L,Bao X Mr et al.Branchy alumina nanotubcs,Applied Physics letters,2002,80(6):1079-1081.
[31] Lj YB,Bando Y,Golberg D,et al.Single-crystalline alpha- A12O3 nanotabes converted from A12O3 Coallowires.Advanced Materials,2005,17(11):1401-1405.
[32] Lee H C Kim HJ,Chung S H,et al.Synthesis of undirectional alumina nanostractures without added organic solvents.Journal of the American Chemical Society,2003,125(10):2882-2883.
[33] Qu LH,Hec Q,Yang Y,et al.Hydrothcrmal synthesis of alumina nanombes templated by anionic surfactant.Materials Letters,2005,59(29-30):4034-4037.
[34] Kuang D B.Fang Y P,Liu H Q,et al.Fabrication of boehmite AlOOH and gamma- A12O3 nanotubes via a soft solution route.Journal of Matcrials Chemistry,2003,13(4):660-662.
[35] Tan B,Ge J C, Zhou LH,etal.Afacileand controllable synthesis of gamma- A12O3 narto Flttuetnres without a surfaetant,European Journal alofinorganic Chemisn'y,2005,(21):4366-4369.
[36] HOU HW,Xie Y,Yang Q,eta1.Preparation and characterization of gamma.A1OOH nanotubes and anorods.Nanotechnology,2005,16(6):74l-745.
[37] Linnolahti M.T.Pakkanan A.Moleeular su-nctures of alumina nanoballs and nanotubes:Atheoretical study.Inorganic Chemistry,2004,43(3):1184-1189.
[38] Cheng B C,Ou S C. Zhou H Y,et a1.A12O3 nanotubes synthesized via homogenization precipitation followed by heat treatment.Journal of Physical Chernistry B,2006,110(23):15749-15754.
[39] H wang,Min B D,Lee J S,etal. A12O3 nanotubes fabricated by wet etching of ZnO/ A12O3 core/shell nanofibers.Advanced Materials,2004,16(5):422-425.
[40] Hultaen J.C, Jirage K.B, Martin C.R, Introducing chemical transport selectivity into gold nanotubule membranes. Journal of the American Chemical Society, 1998, 120: 6603-6604.
[41] Sui Y C, Aeosta D R,Gonzalez-Leon JA,et a1.Structure and deformation ofmultibranched carbon nanotubes synthesized by CVD in the AAO template. Journal of Physical Chemistry B,2001,105(8):1523-1527.
[42] Li X H, Liu W M,Li H L.Template synthesis of well.aligned titanium dinxide nanotubes.Applied Physicsa-Materlals Science&Processing,2005,80(2):317-320.
[43] Ji G B,Su HL,Tang S L,ct a1.Simplified synthesis ofcobalt ferrite nanotubes using sol—gel method.Chemistry Letters,2005,34(I):86-87.
[44] Hua Z H,Yang S G,Huang H Bt et al. Metal nanotubes prepared by a sol—gel method followed by a hydrogen reduction procedure.Nanote chnology,2006,17(20):5106-5110.
[45] Liu X H,Wang J Q,Zhang J Y, et a1.Sol—gel template synthesis of ZnO nanotube sandits coaxial nanocornposites of LiMn2O4/ZnO.Materials Science and Engineering a-Structural Materials Properties Microstracture and Processing,2006,430(1-2):248-253.
[46] Liu Z Q,Zhang D H,Hart S,et a1. Single crystalline magnetite nanotubes.Journal of the American Chemical Society,2005,127(1): 6-7.
[47] Yada M,Mihara M,Monri S,et a1.Rare earth (Er, Tm,Yb,Lu)oxide nanotubes templated by dodecylanlfate assemblies.Advanced Materials,2002,14 (4):309-313.
[48] Ran C N R,Nath M.Inorganic nanotubes.Dalton Transactions,2003 (1):1-24.
[49]Jia C J, Sun L D, Yan Z G, et al. Ironoxide nanotubes-Single-crystall in eiron oxide nanotube. Angewandte Chemie International Edition,2005,44(28):4328-4333.
[50] Chen Y F,Lee C Y, Yeng M Y, et al. Preparing titanium oxide with various morphologies. Materials Chemistry and Physics, 2003,81:39~44.
[51] Wang Y Q ,Hu G Q, Duan X F, etal ,microstructure and formation mechanism of titanium dioxide nanotubes. Chemical Physics Letters, 2002,365:427~431.
[52] Ma Dongling,Schadler LS,Siegel RW,etal.Preparation and structure investigation of nanoparticle-assembled titanium dioxide microtubes. Applied Letters,2003 Physics, 83(9);1839~1841.
[53] Tang Qun,Liu Zhaoping, Li shu,etal. Synthesis of yttrium hydroxide and oxide nanotubes.Journal of Crystal Growth,2003,259:208~214.
[54]韩才元,徐明厚.煤粉燃烧[M].北京:科学出版社,2001.
[55]贾毅峰,兰雯.浅谈氮氧化物的污染与治理技术广.西轻工业,2007(9):10-11
[56]杨宗鑫,王兵,林孟雄等.大气污染过程中氮氧化合物对大气的危害及防治.内蒙古石油化工,2008(21):26-28.
[57]王海强,吴忠标.烟气氮氧化物脱除技术的特点分析[ J ].能与环境,2004, (3): 27-301.
[58] Bosch H. Janssen F. J. Formation and control of nitrogen oxides. Catal. Today, 1988, 2 (4): 369-379.
[59] Busca G. Lietti L. Ramis G. and Berti F. Chemical and mechanistic aspects of the selective catalytic reduction of NOx by ammonia over oxide catalysts: A review. Appl. Catal., 1998, B18:1-36.
[60] Armor J. N. Selective catalytic reduction of NOx with methane over metal exchange zeolites. Appl. Catal., 1992, B1(2-3):239- 256.
[61] Ertl G. Knzinger and Weitkamp J. Environmental Catalysis Wyley-VCH, Weihei FRG, 1999.
[62] Meyers R. A. Dittrick D. K. in The Wiley Encyclopedia of Environmental Pollution and Cleanup. Vol 1, 50, Wiley, New York. 1999.
[63] Armor J. N. Catalytic removal of nitrogen oxides: where are the opportunities Catal. Today, 1995, 26(2):99-105.
[64] ZHANG Jin-qiao, FAN Wei-bin, LIU Yu-ying, et al. Synthesis and catalytic property of a Co-exchanged Beta/Y composite for the selective catalytic reduction of NO by CH4 in the presence of excessive oxygen. Applied Catalysis B: Environmental, 2007, 76 (1-2): 174-184.
[65] ZHANG Jin-qiao, LIU Yu-ying, FAN Wei-bin, et al. Effect of SO2 on catalytic performance of CoH-FBZ for selective catalytic reduction of NO by CH4 in the presence of O2. Environmental Engineering Science, 2007, 24 (3): 292-300.
[66]张金桥,贺勇,刘于英等.程序升温脱附研究CoH-FBZ上NOx的吸附.燃料化学学报, 2007, 35 (4): 452-457.
[67]张金桥,刘于英,樊卫斌,等.富氧条件下CoH-FBZ选择催化CH4还原NO催化性能及表征,化工学报,2006, 57(9): 2105-2110.
[68] Traa Y. Burger B. and Weitkamp J. Zeolite-based materials for the selective catalytic reduction of NOx with hydrocarbons. Micropor. Mesopor. Mater., 1999, 30:3-41.
[69] Economic evaluation of air quality targets for sulfur dioxide, nitrogen oxide, fine and suspended particlulate matter and lead, final report, XIII, 80, Office for official publications of European Communities Luxembourg. 1998.
[70] Iwamoto M. Furukawa H. Mine Y. Uemura F. Mikuriya and Kagawa S. J. Chem. Soc. Chem. Commun. 1986,12:72.
[71]“The Nitric Oxide Hompage”in www.apnet.com/www.jussayno.htlm.
[72] Farrauto R. J. and Heck R. M. Catalytic converters: state of the art and perspectives. Catal. Today, 1999, 51(3-4):351-360.
[73] Li Y. Hall W. K. Stoichiometric catalytic decomposition of nitric oxide over copper- exchanged zeolite (CuZSM-5) catalysts. J. Phys. Chem. 1990, 94(16): 6145-6148.
[74]伍斌,童志权.NO分解催化剂的研究进展.工业催化,2005,13 (7): 52-55.
[75]朱洪法.催化剂载体,北京:化学工业出版社,1980.
[76]朱屯,王福明,王习东等.国外纳米材料技术进展与应用.北京:化学工业出版社,2002:133
[1]杜淼.李斌.任海萍.孙中溪.纳米介孔氧化铝制备及表征.无机盐工业.2008(40):30- 33.
[2]徐平坤,董应榜.刚玉耐火材料.冶金工业出版社.北京1999.
[3]于岩.阮玉忠.黄清明.周敏.杜育红.吴任平.铝厂污泥在不同煅烧温度的晶相结构研究.结构化学.2003(22):23-26.
[4] Kaluza L,ZdrazilM,Zilkova N,etal.Cata.Commun.[J],2002,3:151-15.
[5]李志平,赵瑞红,郭奋,陈建峰,王刚.高比表面积有序介孔氧化铝的制备与表征2008(29):2-4.
[6]霍彩霞,何丽君.以尿素为沉淀剂制备纳米γ2Al2O3粉体.期甘肃联合大学学报(自然科学版).2004(18):8-11.
[1] Burch R, Millington P.J. Walker A.P. Mechanism of selective selection reduction of nitrogen monoxide on platinum-based catalysts in the present of excess oxygen. Appl. Catal., 1994, B4(1):65-94.
[2] Bamwenda G.R. Ogata A. Obuchi A. Oi J. Mizuno K. Skrzypek J. Selective reduction of nitric oxide with propene over platinum-group based catalysts: Studies of surface species and catalytic activity. Appl. Catal., 1995, B6(4): 311-323
[3] Rottlander C. Andorf R. Plog C. Krutzsch and Baerns M. Selective NO reduction by propane and propene over a Pt/ZSM-5 catalyst: a transient study of the reaction mechanism. Appl. Catal., 1996, B11(1): 49-63.
[4] Burchi R. and Ramli A. A kinetic investigation of the reduction of NO by CH4 on silica and alumina-supported Pt catalysts. Appl. Catal., 1998, B15(1) :63-73.
[5] Kikuchi E, Yogo K. Selective catalytic reduction of nitrogen monoxide by methane on zeolite catalysts in an oxygen-rich atmosphere. Catal Today, 1994, 22:73-86.
[6] Resaco C. J. D. E. Bifunctionality of palladium-based catalysts used in the reduction of nitric oxide by methane in the presence of oxygen. Appl. Catal., 1996, B7(1-2) :113-126.