纳米TiO_2的SAXS研究及掺杂效应
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摘要
小角X射线散射(SAXS)是一种用来探测从几到几百纳米尺度范围内物质结构的实验手段。物质内部该尺度范围内电子密度不均匀性是产生小角散射现象的根本原因。近年来，纳米氧化物材料及多孔材料方面的SAXS研究已引起科研工作者的极大兴趣。
采用溶胶一凝胶法制备了纳米TiO_2及掺杂纳米TiO_2，然后利用SAXS方法以及DTA和XRD方法对体系进行了研究，对其尺寸、微观结构进行了表征，研究了这些性质之间的关系。将分形概念和SAXS中其他表征物质结构的参数有机结合，研究了散射体的相变行为；将Porod定律和与传感性能有关的比表面有机的联系了起来。类似工作所查文献中未见报道。
分析表明热处理温度是导致纳米TiO_2长大的主要原因，在相变温度附近，晶体迅速地长大，相变后增长速度下降，而无论是否掺杂。加入少量的NB_2O_5或一定量的稀土元素Ce，可以改变纳米TiO_2的相变温度，并能影响晶粒的增长。
SAXS研究表明所有锐钛矿相纳米TiO_2体系满足Porod定律；锐钛矿相纳米TiO_2体系没有分形结构的现象；无定形的TiO_2纳米颗粒及相变温度以上热处理的体系均对Porod定律呈正偏离。
Small-angle X-ray scattering (SAXS) is the technique of choice for probing structure features that occur on length scales between approximately Inm and 100nm. The only requirement for SAXS is the presence of inhomogeneities in electron density. There is an increasing interest on the SAXS study of the oxide nanoparticles and porous materials in recent years.
The pure nano-TiO2 and doped-TiO2 are prepared by sol-gel process. The samples were investigated by synchrotron Small-Angle X-Ray Scattering, DTA and XRD. The size and microstructure were characterized. The phase transition behavior of sample was analyzed by using SAXS fractal theory. The relationship between Porod's law and specific surface was found first time. The average particle size increased with the annealing temperature increasing. When the temperature increased high enough, the anatase changed into rutile. A little Nb2O5or cerium doped into sample can change phase-transition temperature and influence the growth of particle. SAXS indicates that all anatase follow Porod's law but not show any fractal structure. Other samples gave a positive deviation from Porod's law.
采用溶胶一凝胶法制备了纳米TiO_2及掺杂纳米TiO_2，然后利用SAXS方法以及DTA和XRD方法对体系进行了研究，对其尺寸、微观结构进行了表征，研究了这些性质之间的关系。将分形概念和SAXS中其他表征物质结构的参数有机结合，研究了散射体的相变行为；将Porod定律和与传感性能有关的比表面有机的联系了起来。类似工作所查文献中未见报道。
分析表明热处理温度是导致纳米TiO_2长大的主要原因，在相变温度附近，晶体迅速地长大，相变后增长速度下降，而无论是否掺杂。加入少量的NB_2O_5或一定量的稀土元素Ce，可以改变纳米TiO_2的相变温度，并能影响晶粒的增长。
SAXS研究表明所有锐钛矿相纳米TiO_2体系满足Porod定律；锐钛矿相纳米TiO_2体系没有分形结构的现象；无定形的TiO_2纳米颗粒及相变温度以上热处理的体系均对Porod定律呈正偏离。
Small-angle X-ray scattering (SAXS) is the technique of choice for probing structure features that occur on length scales between approximately Inm and 100nm. The only requirement for SAXS is the presence of inhomogeneities in electron density. There is an increasing interest on the SAXS study of the oxide nanoparticles and porous materials in recent years.
The pure nano-TiO2 and doped-TiO2 are prepared by sol-gel process. The samples were investigated by synchrotron Small-Angle X-Ray Scattering, DTA and XRD. The size and microstructure were characterized. The phase transition behavior of sample was analyzed by using SAXS fractal theory. The relationship between Porod's law and specific surface was found first time. The average particle size increased with the annealing temperature increasing. When the temperature increased high enough, the anatase changed into rutile. A little Nb2O5or cerium doped into sample can change phase-transition temperature and influence the growth of particle. SAXS indicates that all anatase follow Porod's law but not show any fractal structure. Other samples gave a positive deviation from Porod's law.
引文
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[13]Maria Christina Carotta, Giuliano Martinelli, Luigi Crema, et al. Array of think film sensors for atmospheric pollutant monitoring[J].Sensors and Actuators,2000,B68:1-8
[14]Maria Christina Carotta, Giuliano Martinelli, Luigi Crema, et al. Nanostructured thick-film gas sensors for atmospheric pollutant monitoring: quantitative analysis on field tests[J].Sensors and Actuators,2001,B76:336-342
[15]M.Ferroni, M.C.Carotta, V.Guidi, et al. Structural characterization of Nb-TiO_2 nanosized thick-films for gas sensing application[J].Sensors and Actuators, 2000,B68:140-145.
[16]M.Ferroni, M.C.Carotta, V.Guidi, et al. Preparation and characterization of nanosized titania sensing film[J].Sensors and Actuators, 2001,B77:163-166.
[17]C.Garzella, E.Comini, E.Tempesti, et al.TiO_2 thin films by a novel sol-gel processing for gas sensor applications[J].Sensors and Actuators, 2000,B68:189-196.
[18]Mohammed Mabrook, Peter Hawkins. A rapidly-responding sensor for benzene, methanol and ethanol vapours based on films of titanium dioxide dispersed in a polymer operating at room temperature[J].Sensors and Actuators, 2001,B75:197-202
[19]E.Comini, V.Guidi, C.Frigeri, et al. CO sensing properties of titanium and iron oxide nanosized thin films[J].Sensors and Actuators, 2001,B77:16-21.
[20]Y.X.Li, K.Galatsis, W.Wlodarski, et al. Microstructural characterization of MoO_3-TiO_2 nanocomposite thin films for gas sensing[J].Sensors and Actuators, 2001,B77:27-34.
[21]K.Galatsis, Y.X.Li, W.Wlodarski, et al. Semiconductor MoO_3-TiO_2 thin film gas sensors[J].Sensors and Actuators, 2001,B77:472-477.
[22]Serge Zhuiykov, Wojtek Wlodarski, Yongxiang Li. Nanocrystalline V_2O_5-TiO_2 thin-films for oxygen sensing prepared by sol-gel process[J].Sensors and Actuators, 2001, B77:484-490.
[23]Takeo Hyodo, Tomonori Mori, Akihiko Kawahara, et al. Gas sensing properties of semiconductor heterolayer sensors fabricated by slide-off transfer printing[J]. Sensors and Actuators, 2001,B77:41-47.
[24]Akihiko Kawahara, Hiroaki Katsuki, Makoto Egashira. Fabrication of semiconductor oxide thick films by slide-off transfer printing and their NO_2-sensing properties[J]. Sensors and Actuators, 1998,B49:273-278.
[25]N.Bonini, M.C.Carotta, A.Chiorino, et al. Doping of a nanostructured titania thick film: structural and electrical investigations[J]. Sensors and Actuators, 2000,B68: 274-280.
[26]Masataka Kudo, Tomomi Kosaka, Yoshiaki Yakahashi, et al. Sensing functions to NO and O_2 of Nb_2O_5-or Ta_2O_5- loaded TiO_2 and ZnO[J]. Sensors and Actuators, 2000,B69:10-15.
[27]L.L.W.Chow, M.M.F.Yuen, P.C.H.Chan, et al. Reactive sputtered TiO_2 thin film humidity
sensor with negative bias[J]. Sensors and Actuators, 2001,B76:310-315.
[28]张晋远．X光小角散射，黄胜涛主编，固体X射线学(二)：第六章，北京，高等教育出版社，1990
[29]荣丽霞．中国科学院博士论文，2003
[30]Krishnamurti P.. Indian J. Phys., 1930, 5:473
[31]Glatter O., Kraty O.. Small Angle X-ray Scattering, New York, Academic Press, 1982
[32]. Guinier A., Fournet G.. Small-Angle Scattering of X-rays (translated by C.B. Walker), New York,John Wiley & Sons,1955
[33]．许顺生．X射线学及电子显微术的进展，上海，上海科学技术出版社，1966：76-169
[34]. Debye A., Bueche A.N.. Scattering by an inhomogeneous solid, J. Appl. Phys., 1949,20:518-526
[35]. Debye A.,Anderson H.R., Brumberger H.. Scattering by an inhomogenous solid. Ⅱ. The correlation function and its application, J. Appl. Phys., 1957, 28:679-683
[36]Chu B., Hsiao B. S..Small-Angle X-ray scattering of polymers, Chem. Rev. 2001,101:1727-1761
[37]. Chu B..Structure and dynamics of block copolymer colloids,Langmuir, 1995,11(2):414-421
[38]. Pedersen J. S., Svaneborg C.. Scattering from block copolymer micelles, Current Opinion in Colloid & Interface Science, 2002, 7:158-166
[39]Hackly V.A., Anderson M.A., Spooner S.. A small-angle x-ray scattering study of microstructure evolution during sintering of Sol-gel-derived porous nanophase titania, J. Mater. Res. 1992, 7(9):2555-2570
[40]Mcmahon R, Snook L., Small angle X-ray scattering from porous mass fractal solids, J.Chem.Phys., 1996,105(6):2223-2227
[41]施士元．X射线晶体学，北京，科学出版社，1959
[42]孟昭富．小角X射线散射理论及应用，长春，吉林科学出版社，1996
[43]王华馥，吴自勤．固体物理实验方法，北京，高等教育出版社，1990
[44]M．B．亚沃尔斯基．X射线学基础，北京，地质出版社，1959
[45]王元熙．X射线及X射线衍射，北京，高等教育出版社，1986
[46]M.M.Woolfson, An introduction to X-ray crystallography, Cambridge University Press,1978
[47]周公度．晶体结构测定，北京，科学出版社，1981
[48]王煜明．非晶体及晶体缺陷的X射线衍射，北京，科学出版社，1988
[49]黄胜涛．固体X射线学(二)，北京，高等教育出版社出版，1990
[50]敖力布，林鸿溢．分形学导论，呼和浩特，内蒙古人民出版社，1996
[51]B．H．Kaye．分形漫步，沈阳，东北大学出版社，1994．9
[52]谢和平，薛秀谦．分形应用中的数学基础方法，北京，科学出版社，1997
[53]杨展如．分形物理学，上海，上海科技教育出版社，1996
[54]Mandelbrot B.B..Fractal:chance and dimension, New York, Freeman, 1977
[55]Mandelbrot B.B.. The fractal geometry of nature, New York, Freeman, 1977
[56]Schmidt RW.. Modern aspects of small-angle scattering, edited by Brumberger H., Kluwer Academic Publishers, Dordrecht, Netherlands, 1993
[57]黄惠忠．纳米材料分析，北京，化学工业出版社，2003
[58]Ding XZ, Liu X H, He Y Z et al. J.Amer.Cera.soc. 1997,80:3157
[2]Hoffmann M.,R.Choiw.[J].Chem Rev, 1993, 95:69
[3]Oregan B., Greatzel M.. A low-cost high-efficiency solar cell based on dye-sensitized colloidal TiO_2 films[J]. Nature, 1991, 353:737
[4]Sopyan I, Watanabe M., Murasawa S., et al. Efficent TiO_2 Power and film photocatalysts with rutile crystal structure[J]. Chem Lett, 1996,289(1):69-74
[5]Kobayashi A.. Measurement and sensors[J].Sensors and actuators, 1988,13:29-41
[6]Takahashik, Sensor Materials for the future: Intelligent Materials[J].Sensors and Actuators 1988,13:3-10
[7]蒲敏，吴东，孙予罕．TiO_2光电池的制备与应用研究进展[J]．材料科学与工程，2001，19(3)：113-116
[8]K.Bange,CR. Ottermann, O. Anderson, U. Jeschkowshy, M.Laube, R.Feile.[J].Thin Solid Films 1991,197:279
[9]颜秀茹，郭伟巍，宋宽秀等．载体SiO_2上纳米TiO_2膜的制备及光催化性能[J]．太阳能学报，2001,22(2)：196-199
[10]T. Gerfin, M.Gratzel, L.Walder. Progress Inorganic Chemistry,1997,44:345.
[11]K.Sunada, Y.Kikuchi, K.Hashimoto, A.Fujishima. Environmental Science and Technology, 1998,32:726
[12]吕笑梅，方靖淮，陆祖宏．敏化TiO_2纳米晶太阳能电池[J]．功能材料，1998,29(6)：574-577
[13]Maria Christina Carotta, Giuliano Martinelli, Luigi Crema, et al. Array of think film sensors for atmospheric pollutant monitoring[J].Sensors and Actuators,2000,B68:1-8
[14]Maria Christina Carotta, Giuliano Martinelli, Luigi Crema, et al. Nanostructured thick-film gas sensors for atmospheric pollutant monitoring: quantitative analysis on field tests[J].Sensors and Actuators,2001,B76:336-342
[15]M.Ferroni, M.C.Carotta, V.Guidi, et al. Structural characterization of Nb-TiO_2 nanosized thick-films for gas sensing application[J].Sensors and Actuators, 2000,B68:140-145.
[16]M.Ferroni, M.C.Carotta, V.Guidi, et al. Preparation and characterization of nanosized titania sensing film[J].Sensors and Actuators, 2001,B77:163-166.
[17]C.Garzella, E.Comini, E.Tempesti, et al.TiO_2 thin films by a novel sol-gel processing for gas sensor applications[J].Sensors and Actuators, 2000,B68:189-196.
[18]Mohammed Mabrook, Peter Hawkins. A rapidly-responding sensor for benzene, methanol and ethanol vapours based on films of titanium dioxide dispersed in a polymer operating at room temperature[J].Sensors and Actuators, 2001,B75:197-202
[19]E.Comini, V.Guidi, C.Frigeri, et al. CO sensing properties of titanium and iron oxide nanosized thin films[J].Sensors and Actuators, 2001,B77:16-21.
[20]Y.X.Li, K.Galatsis, W.Wlodarski, et al. Microstructural characterization of MoO_3-TiO_2 nanocomposite thin films for gas sensing[J].Sensors and Actuators, 2001,B77:27-34.
[21]K.Galatsis, Y.X.Li, W.Wlodarski, et al. Semiconductor MoO_3-TiO_2 thin film gas sensors[J].Sensors and Actuators, 2001,B77:472-477.
[22]Serge Zhuiykov, Wojtek Wlodarski, Yongxiang Li. Nanocrystalline V_2O_5-TiO_2 thin-films for oxygen sensing prepared by sol-gel process[J].Sensors and Actuators, 2001, B77:484-490.
[23]Takeo Hyodo, Tomonori Mori, Akihiko Kawahara, et al. Gas sensing properties of semiconductor heterolayer sensors fabricated by slide-off transfer printing[J]. Sensors and Actuators, 2001,B77:41-47.
[24]Akihiko Kawahara, Hiroaki Katsuki, Makoto Egashira. Fabrication of semiconductor oxide thick films by slide-off transfer printing and their NO_2-sensing properties[J]. Sensors and Actuators, 1998,B49:273-278.
[25]N.Bonini, M.C.Carotta, A.Chiorino, et al. Doping of a nanostructured titania thick film: structural and electrical investigations[J]. Sensors and Actuators, 2000,B68: 274-280.
[26]Masataka Kudo, Tomomi Kosaka, Yoshiaki Yakahashi, et al. Sensing functions to NO and O_2 of Nb_2O_5-or Ta_2O_5- loaded TiO_2 and ZnO[J]. Sensors and Actuators, 2000,B69:10-15.
[27]L.L.W.Chow, M.M.F.Yuen, P.C.H.Chan, et al. Reactive sputtered TiO_2 thin film humidity
sensor with negative bias[J]. Sensors and Actuators, 2001,B76:310-315.
[28]张晋远．X光小角散射，黄胜涛主编，固体X射线学(二)：第六章，北京，高等教育出版社，1990
[29]荣丽霞．中国科学院博士论文，2003
[30]Krishnamurti P.. Indian J. Phys., 1930, 5:473
[31]Glatter O., Kraty O.. Small Angle X-ray Scattering, New York, Academic Press, 1982
[32]. Guinier A., Fournet G.. Small-Angle Scattering of X-rays (translated by C.B. Walker), New York,John Wiley & Sons,1955
[33]．许顺生．X射线学及电子显微术的进展，上海，上海科学技术出版社，1966：76-169
[34]. Debye A., Bueche A.N.. Scattering by an inhomogeneous solid, J. Appl. Phys., 1949,20:518-526
[35]. Debye A.,Anderson H.R., Brumberger H.. Scattering by an inhomogenous solid. Ⅱ. The correlation function and its application, J. Appl. Phys., 1957, 28:679-683
[36]Chu B., Hsiao B. S..Small-Angle X-ray scattering of polymers, Chem. Rev. 2001,101:1727-1761
[37]. Chu B..Structure and dynamics of block copolymer colloids,Langmuir, 1995,11(2):414-421
[38]. Pedersen J. S., Svaneborg C.. Scattering from block copolymer micelles, Current Opinion in Colloid & Interface Science, 2002, 7:158-166
[39]Hackly V.A., Anderson M.A., Spooner S.. A small-angle x-ray scattering study of microstructure evolution during sintering of Sol-gel-derived porous nanophase titania, J. Mater. Res. 1992, 7(9):2555-2570
[40]Mcmahon R, Snook L., Small angle X-ray scattering from porous mass fractal solids, J.Chem.Phys., 1996,105(6):2223-2227
[41]施士元．X射线晶体学，北京，科学出版社，1959
[42]孟昭富．小角X射线散射理论及应用，长春，吉林科学出版社，1996
[43]王华馥，吴自勤．固体物理实验方法，北京，高等教育出版社，1990
[44]M．B．亚沃尔斯基．X射线学基础，北京，地质出版社，1959
[45]王元熙．X射线及X射线衍射，北京，高等教育出版社，1986
[46]M.M.Woolfson, An introduction to X-ray crystallography, Cambridge University Press,1978
[47]周公度．晶体结构测定，北京，科学出版社，1981
[48]王煜明．非晶体及晶体缺陷的X射线衍射，北京，科学出版社，1988
[49]黄胜涛．固体X射线学(二)，北京，高等教育出版社出版，1990
[50]敖力布，林鸿溢．分形学导论，呼和浩特，内蒙古人民出版社，1996
[51]B．H．Kaye．分形漫步，沈阳，东北大学出版社，1994．9
[52]谢和平，薛秀谦．分形应用中的数学基础方法，北京，科学出版社，1997
[53]杨展如．分形物理学，上海，上海科技教育出版社，1996
[54]Mandelbrot B.B..Fractal:chance and dimension, New York, Freeman, 1977
[55]Mandelbrot B.B.. The fractal geometry of nature, New York, Freeman, 1977
[56]Schmidt RW.. Modern aspects of small-angle scattering, edited by Brumberger H., Kluwer Academic Publishers, Dordrecht, Netherlands, 1993
[57]黄惠忠．纳米材料分析，北京，化学工业出版社，2003
[58]Ding XZ, Liu X H, He Y Z et al. J.Amer.Cera.soc. 1997,80:3157