目前燃料電池之商業觸媒皆使用碳黑為載體，於鉑金屬的高使用量下，即使觸媒效率高，成本居高不下卻是燃料電池難以商業化之主要原因。本研究以高導電性氣相生長奈米碳纖(Vapor-grown carbon nano-fiber)取代目前商業碳黑為載體，製備甲醇燃料電池中的陰極觸媒。目的為藉氣相生長奈米碳纖高導電性的優點，可以提升鉑金屬之電子傳遞能力及鉑金屬的使用率，進而降低鉑金屬使用量以降低成本，達到商業化之目標。
本研究中首先以煅燒法去除碳纖內有機雜質，並以不同改質劑建立碳纖之改質技術，有效增加碳纖之親水性，並以含浸法及膠體化法合成觸媒，篩選出觸媒合成關鍵要素。兩種合成方法中尤以膠體化法為主要合成方法，其容易掌握觸媒合成關鍵之優點，有別於傳統含浸法鉑顆粒聚集及顆粒不均之缺點，有利於工業上大量生產。成功地以高導電度碳纖取代傳統碳黑，降低鉑金屬的使用量，合成出高於商業觸媒效率3倍之甲醇燃料電池。

One of the critical issues in the commercialization of Proton exchange membrane fuel cell (PEMFC) is the performance of the electrode catalyst, both for the anodic conversion of fuel and the cathodic conversion of oxygen. Even though the use of Pt-based catalyst resulted in superior fuel cell performance, the very expensive nature of Pt catalyst hindered the commercialization of PEMFC. New substrates for Pt catalyst are being sought to replace the widely used carbon black substrate, in order to enhance the efficiency of Pt and, accordingly, reduce the cost of catalyst. The properties of substrates become the vital parameters in determining the performances of the catalyst of interest. The present study focuses on the utilization of vapor-grown carbon nano-fiber (VGCNF) as the substrate for the preparation of Pt-based cathode catalyst (Pt/VGCNF), intended to be used in direct methanol fuel cell (DMFC). VGNCF with a high electrical conductivity and a high aspect ratio posseses the potential to enhance the performances of the Pt-based cathode catalyst. In this study, the effects of diameter of VGCNF, VGCNF modification method, Pt deposition method, and VGNCF activation method were investigated in order to enhance the performance of Pt/VGCNF catalysts. The optimized Pt/VGCNF catalyst prepared in this study had a much higher activity than the commercial Johnson Matthey catalyst.

參考文獻
1. Carrette, L., Friedrich, K. A., Stimming, U., “Fuel Cells - Fundamentals and Applications” , Fuel Cells , Vol.1, pp.5(2001).
2. Sopian, K., Daud, W. R. W., ”Challenges and future developments in proton exchange membrane fuel cells” , Renewable Energy , Vol.31, pp.719-727(2006).
3. Thomas, S., Zalbowitz, M., Fuel Cells - Green power , Los Alamos National Laboratory, New Mexico, (1999).
4. Vishnyakov, V. M., “Proton exchange membrane fuel cells” , Vacuum , Vol.80, pp.1053-1065(2006).
5. http://www.fuelcelltoday.com/index/0,1571,,00.html.
6. Bruijn, F. D., “The current status of fuel cell technology for mobile and stationary applications” , Green Chemisty , Vol.7, pp.132-150(2005).
7. http://www.matthey.com/index.htm.
8. Carlson, E., Maloney, R., Kopf, P., Rancatore, R., Lasher, S., Yang, Y., “2004 Hydrogen and Fuel Cells Merit Meeting” , Philadelphia, PA, May pp.24-27, (2004).
9. Kunchan, L., Zhang, J., Wang, H., Wilkinson, D. P., “ Progress in the synthesis of carbon nanotube- and nanofiber-supported Pt electrocatalysts for PEM fuel cell catalysis” , Journal of Applied Electrochemistry , Vol.36, pp.507-522(2006).
10. Antolini, E., “Review formation, microstructural characteristics and stability of carbon supported platinum catalysts for low temperature fuel cells” , Journal of Materials Science , Vol.38, pp.2995-3005(2003).
11. Wasmus, S., Kuver, A., “Methanol oxidation and direct methanol fuel cells: a selective review” , Journal of Electroanalytical Chemistry , Vol.461, pp.14-31(1999).
12. Hogarth, M. P., Ralph, T. R., “Catalyst for low temperature fuel cells” , Platinum Metals Review , Vol.46, pp.146-164(2002).
13. Li , W., Liang, C., Qiu, J., Zhou, W., Han, H., Weia, Z., Suna, G., Xina, Q., ” Carbon nanotubes as support for cathode catalyst of a direct methanol fuel cell” , Carbon , Vol.40, pp.787-803(2002).
14. Li, W., Liang, C., Zhou, W., Qiu, J., Zhou, Z., Sun, G., Xina, Q., “Preparation and characterization of multiwalled Carbon nanotube-supported platinum for cathode catalysts of direct methanol Fuel cells” , The Journal of Physical Chemistry B , Vol.107, pp.6292-6299(2003).
15. Wang, X., Li, W., Chen, Z., Waje, M., Yan, Y., “Durability investigation of carbon nanotube as catalyst support for proton exchange membrane fuel cell” , Journal of Power Sources , Vol.158, pp.154-159(2006).
16. 范月英、成會明、蘇革、魏永良、沈祖洪，「氣相生長奈米碳纖維的研究進展」，新型碳材料，第14卷，第2期，1999.
17. McKenzie, S., “Columbian Chemicals: Status of Carbon
Nanotechnology and Fuel Cell Electrocatalysts” , Dayton(2006).
18. Tibbetts, G. G., Lake, M. L., Strong, K. L., Rice, B. P., ”A review of the fabrication and properties of vapor-grown carbon nanofiber/polymer composites” , Composites Science and Technology , Vol.67, 1709-1718(2007).
19. Chan, L. H., Hong, K. H., Xiao, D. Q., Lin, T. C., Lai S. H., Hsieh, W. J., Shih, H. C., ”Resolution of the binding configuration in nitrogen-doped carbon nanotubes” , Physical Review B , Vol.70, pp. 125408(2004).
20. Cui, H., Zhou, O., Stoner, B. R., “Deposition of aligned bamboo- like carbon nanotubes via microwave plasma enhanced chemical vapor deposition” , Journal of Applied Physics , Vol.88, No.10, pp.6072-6074(2000).
21. Yoo, J. B., Hana, J. H., Choia, S. H., Lee, T. Y., Parka, C. Y., Jeongb, T. W., Lee, J. H., Yu, S., Parkc, G., Yi, W. K., Kimd, H. S., Baikd, Y. J., Kim, J. M., ”Emission characteristics of boron nitride coated carbon nanotubes” , Physica B , Vol.323, pp.180-181(2002).
22. Wang, C. H., Shih, H. C., Tsai, Y. T., Dub, H. Y., Chenc, L. C., Chenc, K. H., “High methanol oxidation activity of electrocatalysts supported by directly grown nitrogen- containing carbon nanotubes on carbon cloth” , Electrochimica Acta , Vol.52, pp.1612-1617(2006).
23. Hara, M., Yoshida, T., Takagaki, A., Takata, T., Kondo, J. N., Hayashi, S., Domen, K., “A Carbon Material as a Strong Protonic Acid“ , Angewandte Chemie International Edition , Vol.43, pp.2955-2958(2004).
24. Li , X., Hsing, I. M., “The effect of the Pt deposition method and the support on Pt dispersion on carbon nanotubes” , Electrochimica Acta , pp.9(2006).
25. Lordi, V., Yao, N., Wei, J., Yu, R., Chen, L., “Method for supporting platinum on single walled carbon nanotube for a selective hydrogenation catalyst” , Chemistry Materials , Vol.13, pp.733-737(2001).
26. Figueiredo, J. L., Pereira, M. F. R., Freias, M. M. A., Orfao, J. J. M, “Modification of the surface chemistry of activated carbons” , Carbon , Vol.37, pp.1379-1389(1999).
27. Kongkannand, A., Vinodgopal, K., Kuwabata, S., Kamat, P. V., “Highly dispersed Pt catalysts on Single-walled carbon nanotubes and their role in methanol oxidation” , The Journal of Physical Chemistry B , Vol.110, pp.16185(2006).
28. O’Connell, M. J., Boul, P., Ericson, L. M., Huffman, Y. W., Haroz, E., Kuper, C., Tour J., “Reversible water-solubilization of single-walled carbon nanotubes by polymer wrapping” , Chemical Physics Letters , Vol.342, pp.265-271(2001).
29. Olek, M., Hilgendorff , M., Giersig, M., “A simple route for the attachment of colloidal nanocrystals to noncovalently modified multiwalled carbon nanotubes” , Colloids and Surfaces A , Vol.292, pp.83-85(2007).
30. Zhao, X., Lin, W., Song, N., Chen, X., Fan, X., Zhou, Q., “Water soluble multi-walled carbon nanotubes prepared via nitroxide-mediated radical polymerization” , Journal of Materials Chemistry , Vol.16, pp.4619-4625(2006).
31. Liu, J., Casavant, M. J., Cox, M., Walters, D. A., Boul, P., Lu, W., Rimberg, A. J., Smith, K. A., Colbert, D. T., Smalley, R. E., “Controlled deposition of individual single-walled carbon nanotubes on chemically functionalized templates” , Chemical Physics Letters , Vol.303, pp.125-129(1999).
32. F. Pinna, “Supported Metal Catalysts Preparation” , Catalysis Today , Vol.41, NO.1, pp.129-137(1998).
33. Jackson, S. D., Willis, J., Mclellan, G. D., Webb, G., Keegan, M. B. T., Moyes, R.B., Simpson, S., Wells, P. B., Whyman, R., “Supported
metal catalysts: Preparation, characterization, and function” , Journal of catalysis , Vol.139, pp.191(1993).
34. Perego, C., Villa, P., “Catalyst preparation methods” , Cataysis Today , Vol.34, pp.281(1997).
35. Chien, C. C., Jeng, K. T., “Effective preparation of carbon nanotube-supported Pt-Ru electrocatalysts” , Materials Chemistry and Physics , Vol.99, pp.80-87(2006).
36. Li, W., Liang, C., Zhou, W., Qiu, J., Li, H., Sun, G., Xin, Q., “Homogeneous and controllable Pt particles deposited on multi-wall carbon nanotubes as cathode catalyst for direct methanol fuel cells” , Carbon , Vol.42, pp.423-460(2004).
37. Rajalakshmib, N., Ryub, H., Shaijumona, M. M., Ramaprabhua, S., ” Performance of polymer electrolyte membrane fuel cells with carbon nanotubes as oxygen reduction catalyst support material” , Journal of Power Sources , Vol.140, pp.250-257(2005).
38. Starz, K. A., Auer, A., Lehmann, T., Zuber, R., “Characterization of platinum-based electrocatalysts for mobile PEMFC applications” , Journal Power Sources , Vol.84, pp.167(1999).
39. Wang, Y., Ren, J., Deng, K., Gui, L., Tang, T., “Preparation of Tractable Platinum, Rhodium, and Ruthenium Nanoclusters with Small Particle Size in Organic Media” , Chemistry Materials , Vol.12, pp.1622-1627( 2000).
40. Bai, Y., Wu, C., Wu, F., Yi, B., “Carbon-supported platinum catalysts for on-site hydrogen generation from NaBH4 solution” , Materials Letters , Vol.60, pp.2236-2239(2006).
41. Zhou, Z., Zhou, Wang, W., S., Wang, G., Jiang, L., Li, H., Sun, G., ”Preparation of highly active 40 wt%Pt/C cathode electrocatalysts for DMFC via different routes” , Catalyst Today , Vol.93, pp.523-528(2004).
42. Peuckert, M., Yoneda, T., Dalla Betta, R. A., Boudart M., “Oxygen reduction on small supported platinum particle” , The Electrochemical Society , Vol.133, No.5, pp.944-947(1986).
43. Finegan, I. C., Tibbetts, G. G., “Electrical conductivity of vapor-grown carbon fiber/thermoplastic composites” , Journal Materials Research , Vol.16, No.6, pp.1668-1674(2001).
44. Ci, L., Wei, J., Wei, B., Liang, J., Xu, C., Wu, D., “Carbon nanofibers and single-walled carbon nanotubes prepared by the floating catalyst method” , Carbon , Vol.39, pp.329-335(2001).
45. Banks, C. E., Crossley, A., Salter, C., Wilkins, S. J., Conpton, R. G., “Carbon nanotubes contain metal impurities which are responsible for the “ electrocatalysis” seen at some nanotube-modified electrodes” , Angewandte Chemie International Edition , Vol.45, pp.2533-2537(2006).
46. Liu, Z., Lin, X., Lee, J. Y., Zhang, W., Han, M., Gan, L. M., “Preparation and Characterization of Platinum-Based Electrocatalysts on Multiwalled Carbon Nanotubes for Proton Exchange Membrane Fuel Cells” , Electrochimica Acta , Vol.52, pp.1612-1617(2006).
47. Wang, M., Woo, K.D., Kim, D. K., “Preparation of Pt nanoparticles on carbon nanotubes by hydrothermal method” , Energy coversion and management , Vol.47, pp.3235-3240(2006).
48. Boehm, H. P., “Surface oxides on carbon and analysis: a critical assessment” , Carbon , Vol.40, pp.145(2002).
49. Castilla, C. M., Marin, F. C., Maldonado-hodar, F. J., Utrilla, J. R., “Effects of non-oxidant acid treatment carbon with very low ash content” , Carbon , Vol.36, pp.145(1998).
50. U. A. Paulus, T. J. Schmidt, H. A. Gasteiger, R. J. Behem, “Oxygen reduction on a thin-film rotating ring-disk electrode study”, Journal of Electroanalytical Chemistry , Vol.495, pp.134(2001).
51. W. Li, X. Wang, Z. Chen, M. Waje, Y. Yan, “Carbon nanotube film by filtration as cathode catalyst support for proton-exchange membrane fuel cell”, Langmuir , Vol.21, pp.9386(2005).
52. http://en.wikipedia.org/wiki/Dimethylformamide
53. http://www.sigmaaldrich.com/catalog/search/ProductDetail/Aldrich