本實驗以溶膠凝膠法使奈米碳管(以下簡稱碳管。)表面均勻包覆一層銳鈦礦相(Anatase)二氧化鈦。藉電子顯微鏡、X光繞射分析等方式確認其成分與結構，光譜分析(紫外光-可見光光譜、螢光光譜)驗證其光反應性。藉光降解(Photodegradation)實驗，我們找出最佳的碳管與二氧化鈦比例，並發現無論在紫外光或可見光下，降解能力均優於Degussa Aeroxide® P25。
碳管擁有卓越的導電性，因此二氧化鈦上被激發的光電子易傳導到碳管上，延長了再結合的時間，使二氧化鈦活性增加；此外，碳管的高比表面積，使複合材展現良好的吸附性，在光降解亞甲基藍反應上有優異的表現。

Carbon nanotubes are uniformly coated with titanium dioxide by sol-gel technique. Morphology, composition, and photoreactivity of the as-made composite are investigated by electron microscopy, X-ray diffraction, UV-Visible spectrum, and Photoluminescence spectroscope data, respectively. The composites show a superior efficiency of photocatalysis than Degussa Aeroxide® P25 in photo-degradation experiment.
Due to the excellent conductivity of carbon nanotubes, the photoelectron excited in titanium dioxide can be easily transferred to carbon nanotubes. As a result, the recombination kinetic of exciton is prolonged, and the photocatalysis of titanium dioxide is improved. Moreover, the high specific surface area of carbon nanotubes provides substantial amount of adsorption sites and therefore improve performance of photo-degradation experiment.

1 M. Dresselhaus, G. D., Ph. Avouris. Carbon Nanotubes. (Springer-Verlag, 2001).
2 Hamada, N., Sawada, S. & Oshiyama, A. New One-Dimensional Conductors - Graphitic Microtubules. Physical Review Letters 68, 1579-1581 (1992).
3 Thostenson, E. T., Ren, Z. F. & Chou, T. W. Advances In The Science And Technology Of Carbon Nanotubes And Their Composites: A Review. Composites Science And Technology 61, 1899-1912 (2001).
4 Diebold, U. The Surface Science Of Titanium Dioxide. Surface Science Reports 48, 53-229 (2003).
5 Fujishima, A. & Honda, K. Electrochemical Photolysis Of Water at a Semiconductor Electrode. Nature 238, 37-+ (1972).
6 Linsebigler, A. L., Lu, G. Q. & Yates, J. T. Photocatalysis On TiO2 Surfaces - Principles, Mechanisms, And Selected Results. Chemical Reviews 95, 735-758 (1995).
7 Marshall, J. M. & Dimova-Malinovska, D. Photovoltaic And Photoactive Materials : Properties, Technology, And Applications. (Kluwer Academic, 2002).
8 Tang, H., Prasad, K., Sanjines, R., Schmid, P. E. & Levy, F. Electrical And Optical-Properties Of TiO2 Anatase Thin-Films. J Appl Phys 75, 2042-2047 (1994).
9 Bickley, R. I., Gonzalezcarreno, T., Lees, J. S., Palmisano, L. & Tilley, R. J. D. A Structural Investigation Of Titanium-Dioxide Photocatalysts. Journal Of Solid State Chemistry 92, 178-190 (1991).
10 Kawahara, T. Et Al. A Patterned TiO2(Anatase)/TiO2(Rutile) Bilayer-Type Photocatalyst: Effect Of The Anatase/Rutile Junction On The Photocatalytic Activity. Angewandte Chemie-International Edition 41, 2811-+ (2002).
11 Hurum, D. C., Agrios, A. G., Gray, K. A., Rajh, T. & Thurnauer, M. C. Explaining The Enhanced Photocatalytic Activity Of Degussa P25 Mixed-Phase TiO2 Using Epr. Journal Of Physical Chemistry B 107, 4545-4549, Doi:10.1021/Jp0273934 (2003).
12 Dechakiatkrai, C., Chen, J., Lynam, C., Phanichphant, S. & Wallace, G. G. Photocatalytic Oxidation Of Methanol Using Titanium Dioxide/Single-Walled Carbon Nanotube Composite. Journal Of The Electrochemical Society 154, A407-A411, Doi:10.1149/1.2709498 (2007).
13 Kang, S. Z., Cui, Z. Y. & Min, J. Composite Of Carboxyl-Modified Multi-Walled Carbon Nanotubes And TiO2 Nanoparticles: Preparation And Photocatalytic Activity. Fullerenes Nanotubes And Carbon Nanostructures 15, 81-88, Doi:10.1080/15363830601177719 (2007).
14 Orlanducci, S. et al. Nanocrystalline TiO2 On Single Walled Carbon Nanotube Arrays: Towards The Assembly Of Organized C/TiO2 Nanosystems. Carbon 44, 2839-2843, Doi:10.1016/J.Carbon.2006.03.018 (2006).
15 Wang, H., Quan, X., Yu, H. T. & Chen, S. Fabrication Of A TiO2/Carbon Nanowall Heterojunction And Its Photocatalytic Ability. Carbon 46, 1126-1132, Doi:10.1016/J.Carbon.2008.04.016 (2008).
16 Wang, S., Gong, Q. M. & Liang, J. Sonophotocatalytic Degradation Of Methyl Orange By Carbon Nanotube/TiO2 In Aqueous Solutions. Ultrasonics Sonochemistry 16, 205-208, Doi:10.1016/J.Ultsonch.2008.08.002 (2009).
17 Xia, X. H. et al. Preparation Of Multi-Walled Carbon Nanotube Supported TiO2 And Its Photocatalytic Activity In The Reduction Of CO2 With H2O. Carbon 45, 717-721, Doi:10.1016/J.Carbon.2006.11.028 (2007).
18 Yao, Y., Li, G., Ciston, S., Lueptow, R. M. & Gray, K. A. Photoreactive TiO2/Carbon Nanotube Composites: Synthesis And Reactivity. Environmental Science & Technology 42, 4952-4957, Doi:10.1021/Es800191n (2008).
19 Eder, D. & Windle, A. H. Carbon-Inorganic Hybrid Materials: The Carbon-Nanotube/TiO2 Interface. Advanced Materials 20, 1787-+ (2008).
20 Woan, K., Pyrgiotakis, G. & Sigmund, W. Photocatalytic Carbon-Nanotube-TiO2 Composites. Advanced Materials 21, 2233-2239, Doi:10.1002/Adma.200802738 (2009).
21 Hoffmann, M. R., Martin, S. T., Choi, W. Y. & Bahnemann, D. W. Environmental Applications Of Semiconductor Photocatalysis. Chemical Reviews 95, 69-96 (1995).
22 Wang, W. D., Serp, P., Kalck, P. & Faria, J. L. Visible Light Photodegradation Of Phenol On MWNT-TiO2 Composite Catalysts Prepared By A Modified Sol-Gel Method. Journal Of Molecular Catalysis A-Chemical 235, 194-199, Doi:10.1016/J.Molcata.2005.02.027 (2005).
23 Yen, C. Y. et al. The Effects Of Synthesis Procedures On The Morphology And Photocatalytic Activity Of Multi-Walled Carbon Nanotubes/TiO2 Nanocomposites. Nanotechnology 19, 11, Doi:04560410.1088/0957-4484/19/04/045604 (2008).
24 Jitianu, A. et al. Synthesis And Characterization Of Carbon Nanotubes - TiO2 Nanocomposites. Carbon 42, 1147-1151, Doi:Doi 10.1016/J.Carbon.2003.12.041 (2004).
25 Wang, W. D., Serp, P., Kalck, P. & Faria, J. L. Photocatalytic Degradation Of Phenol On Mwnt And Titania Composite Catalysts Prepared By A Modified Sol-Gel Method. Appl. Catal. B-Environ. 56, 305-312, Doi:10.1016/J.Apcatb.2004.09.018 (2005).
26 Banerjee, S., Hemraj-Benny, T. & Wong, S. S. Covalent Surface Chemistry Of Single-Walled Carbon Nanotubes. Advanced Materials 17, 17-29, Doi:10.1002/Adma.200401340 (2005).
27 Anpo, M., Shima, T., Kodama, S. & Kubokawa, Y. Photocatalytic Hydrogenation Of CH3CCH With H2O On Small-Particle TiO2 - Size Quantization Effects And Reaction Intermediates. J Phys Chem-Us 91, 4305-4310 (1987).
28 Cahay, M. & Electrochemical Society. Quantum Confinement Vi : Nanostructured Materials And Devices : Proceedings Of The International Symposium. (Electrochemical Society, 2001).
29 Sakthivel, S. & Kisch, H. Daylight Photocatalysis By Carbon-Modified Titanium Dioxide. Angewandte Chemie-International Edition 42, 4908-4911, Doi:10.1002/Anie.200351577 (2003).
30 Asahi, R., Morikawa, T., Ohwaki, T., Aoki, K. & Taga, Y. Visible-Light Photocatalysis In Nitrogen-Doped Titanium Oxides. Science 293, 269-271 (2001).
31 Yu, J. C., Yu, J. G., Ho, W. K., Jiang, Z. T. & Zhang, L. Z. Effects Of F- Doping On The Photocatalytic Activity And Microstructures Of Nanocrystalline TiO2 Powders. Chem Mater 14, 3808-3816, Doi:Doi 10.1021/Cm020027c (2002).
32 Sze, S. M. Semiconductor Devices, Physics And Technology. 2nd Edn, (Wiley, 2002).
33 Kong, J. et al. Nanotube Molecular Wires As Chemical Sensors. Science 287, 622-625 (2000).
34 Levitsky, I. A. & Euler, W. B. Photoconductivity Of Single-Wall Carbon Nanotubes Under Continuous-Wave Near-Infrared Illumination. Applied Physics Letters 83, 1857-1859, Doi:10.1063/1.1606099 (2003).
35 Yu, Y. et al. Enhancement Of Adsorption And Photocatalytic Activity Of TiO2 By Using Carbon Nanotubes For The Treatment Of Azo Dye. Appl. Catal. B-Environ. 61, 1-11, Doi:Doi 10.1016/J.Apcatb.2005.03.008 (2005).