本研究以改良直接甲醇燃料電池(DMFC)電極觸媒為主要的課題，而以降低貴重金屬的用量並提高電化學活性為目的。在相同鉑含量(10 wt %)的條件下，嘗試在Pt-Ru/XC觸媒(XC代表碳黑)中，以錫(Sn)取代釕(Ru)或添加錫或鎢(W)，觀察對觸媒電催化性能的效應；也將少量碳奈米管(CNT)添加於擔體或直接添加於觸媒中，觀察是否可提昇其效能。此外也採用多次含浸法製備觸媒，藉以進一步提昇其效能。
結果顯示：以錫取代釕製成Pt-Sn/XC觸媒之電催化性能比Pt-Ru/XC差；但在Pt-Ru/XC中添加錫或鎢，製成Pt-Ru-Sn/XC和Pt-Ru-W/XC兩種觸媒，都比原先的Pt-Ru/XC有較高的電催化活性，但兩種觸媒的活性大致相同。此外也發現：當Pt的含量相同時，Sn對Ru之原子比有一最佳值；以乙二醇取代甲醇作為還原劑製備時可使觸媒的效能提昇。
我們發現若在含10 wt % Pt之Pt-Ru-Sn/XC觸媒碳材中混予5 wt % CNT，製成Pt-Ru-Sn/(95%+5%XC)觸媒，電催化活性會有大幅度的增加。此一觸媒(僅含鉑10 wt %)之電催化活性與含20 wt % Pt之E-TEK Pt-Ru/C商用觸媒大致相同，且已相當接近Johnson-Matthey含20 wt % Pt之Pt-Ru/C商用觸媒。此一效果，應歸因於碳奈米管有較高的導電度。

The main objective of this study is to improve the performance of the anode catalyst in direct methanol fuel cell and to cut down the using amounts of valuable metals. With the same Pt loading on carbon supports, we tried to replace Ru with Sn, or added Sn or W in the Pt-Ru/XC catalysts (XC represents carbon black), and investigated the effects on the electrocatalytic performance. We also investigated the effects of adding a small amount of CNT to the support or directly adding to the catalyst and preparing the catalysts by multiple impregnation.

Experimental results reveal that the electrocatalytic performance of Pt-Sn/XC catalysts is worse than that of Pt-Ru/XC catalyst; Pt-Ru-Sn/XC and Pt-Ru-W/XC catalysts have higher electrocatalytic activities than the original Pt-Ru/XC catalyst. Additionally, with the same Pt loading, there is an optimal atomic ratio of Sn to Ru, and using ethylene glycol as the reducting agent could improve the performance of catalysts.

When preparing Pt-Ru-Sn/C catalyst of 10wt% Pt with the addition of 5 wt % CNT to the support, the electrocatalytic activity would largely increase. The electrochemical performance of this catalyst (containing Pt 10 wt %) is almost the same as that of E-TEK Pt-Ru/C catalyst, and is approaching to that of Johnson-Matthey Pt-Ru/C catalyst (both containing Pt 20 wt %). The result is attributed to the higher electronic conductivity of CNT.

[1] 鄭耀宗, 徐耀昇, “燃料電池技術進展的現況分析”, 節約能源論文發表會論文專輯, 409 (1999).
[2] 許寧逸, 顏溪成, ”由碳能朝向氫能的燃料電池”, 科學發展, 367
期, 6 (2003).
[3] 林昇佃, 余子隆, 張幼珍, 翁芳柏, 李碩仁, 林育才, 吳和生, 魏榮宗, 林修正, 賴子珍, 曾盛恕, 詹世弘, “燃料電池－新世紀能源”, 滄海書局 (2004初版).
[4] T. Frelink, W. Visscher, J.A.R. van Veen, “Particles size effect of carbon-supported platinum catalysts for the electrooxidation of
methanol”, J. Electroanal. Chem., 382, 65 (1995).
[5] L. Jiang, G. Sun, S. Sun, J. Liu, S. Tang, H. Li, B. Zhou, Q. Xin, “Structure and chemical composition of supported Pt-Sn electrocatalysts for ethanol oxidation”, J. Electrochem. Soc., 132, 2601 (1985).
[6] W. J. Zhou, W. Z. Li, S.Q. Song, Z. H. Zhou, L. H. Jiang, G. Q. Sun, Q. Xin, K. Poulianitis, S. Kontou, P. Tsiakaras, “Bi- and tri-metallic Pt-based anode catalysts for direct ethanol fuel cells”, Journal of Power Sources, 131, 217 (2004).
[7] Z. Liu, L. M. Gan, L. Hong, W. Chen, J. Y. Lee, “Carbon-supported Pt nanoparticles as catalysts for proton exchange membrane fuel cells”, Journal of Power Sources, 139, 73 (2005).
[8] W. J. Zhou, S. Q. Song, W. Z. Li, Z. H. Zhou, G. Q. Sun, Q. Xin, S. Douvartzides, P. Tsiakaras, “Direct ethanol fuel cells based on PtSn anodes：the effect of Sn content on the fuel cell performances”, Journal of Power Sources, 140, 50 (2005).
[9] W. Li, C. Liang, W. Zhou, J. Qiu, Z. Zhou, G. Sun, Q. Xin, “Preparation and characterization of multiwalled carbon nanotube-supported platinum for cathode catalysts of methanol fuel cells”, J. Phys. Chem. B, 107, 6292 (2003)
[10] N. Nakagawa, Y. Xiu, “Performance of a direct methanol fuel cell operated at atmospheric pressure”, J. Power Sources, 118, 248
(2003).
[11] Z. Ogumi, T. Kuroe, Z. I. Takehara, J. Electrochem. Soc., 132, 2601
(1985).
[12] Z. Zhou, W. Zhou, S. Wang, G. Wang, L. Jiang, H. Li, G. Sun, Q. Xin, “Preparation of highly active 40 wt. % Pt/C cathode electrocatalysts for DMFC via different routes”, Catalysis Today,93-95, 523-528 (2004).
[13] A. J. Dickinson, L. P. L. Carrette, J. A. Collins, K. A. Friedrich, U. Stimming, “Performance of methanol oxidation catalysts with varying Pt：Ru ratio as a function of temperature”, J. Appl. Electrochemistry, 34 , 975 (2004).
[14] J. H. Choi, K. W. Park, B. K. Kwon, Y. E. Sung, “Methanol Oxidation on Pt/Ru, Pt/Ni, and Pt/Ru/Ni Anode Electrocatalysts at Different Temperatures for DMFCs”, J. Electrochem. Soc., 150, A973 (2003).
[15]葉長青, 王振熙, 第24屆台灣區觸媒與反應工程研討會 (2006).
[16] C. Roth, M. Goetz , H. Fuess , “Synthesis and characterization of carbon-supported Pt-Ru-WOx catalysts by spectroscopic and diffraction methods”, J. Appl. Electrochemistry., 31 , 793 (1998).
[17] M. P. Ralph, T. R. Hogarth, Platinum Met. Rev., 46, 146 (2002).
[18] Y. Takasu, T. Kawaguchi, W. Sugimoto, Y. Murakami, “Effects of the surface area of carbon support on the characteristics of highly-dispersed Pt-Ru particles as catalysts for methanol oxidation”, Electrochimica Acta, 48, 3861 (2003).
[19] L. X. Yang, R. G. Allen, K. Scott, P. Christenson, S. Roy, “A comparative study of PtRu and PtRuSn thermally formed on titanium mesh for methanol electro-oxidation”, J. Power Sources, 137,257 (2004).
[20] M. Gotz, H. Wendt, “Binary and ternary anode catalyst formulations including the elements W, Sn and Mo for PEMFCs operated on methanol or reformate gas”, Electrochimica Acta., 43, 3637 (1998).
[21] J. Larminie et al., Fuel Cell Systems Explained 2nd,Wiley (2003).
[22] X. Wang, I.M. Hsing, “Surfactant stabilized Pt and Pt alloy electrocatalyst for polymer electrolyte fuel cells”, Electrochimica
Acta., 47, 2981 (2002).
[23] C. S. Lin, M. R. Khan, S. D. Lin, “The preparation of Pt nanoparticles by methanol and citrate”, J. Colloid and Interface Science, 299, 678 (2006).
[24] Z. Liu, L. M. Gan, L. Hong, W. Chen, J. Y. Lee, “Carbon-supported Pt nanoparticles as catalysts for proton exchange membrane fuel cells”, J. Power Sources, 139, 73 (2005).
[25] J. Prabhuram, X. Wang, C. L. Hui, I. M. Hsing, “Synthesis and characterization of surfactant-stabilized Pt/C nanocatalysts for fuel cell applications”, J. Phys. Chem. B, 107, 11057 (2003).
[26] E. S. Steigerwalt, G. A. Deluga, C. M. Lukehart, “Pt-Ru/Carbon fiber nanocomposites：synthesis, characterization, and performance as anode catalysts of direct methanol fuel cells. A search for exceptional performance.”, J. Phys. Chem. B, 106, 760 (2002).
[27] P. V. Samant, C. M. Rangel, M. H. Romero, J. B. Fernandes, J. L. Figueiredo, “Carbon supports for methanol oxidation catalyst”, J. Power Sources, 151, 79 (2005).
[28] H. Tang, J. Chen, S. Yao, L. Nie, Y. Kuang, Z. Huang, D. Wang, Z. Ren, “Deposition and electrocatalytic properties of platinum on well-aligned carbon nanotube(CNT) arrays for methanol oxidation”, Materials Chemistry and Physics, 92, 548 (2005).
[29] T. Matsumoto, T. Komatsu, H. Nakano, K. Arai, Y. Nagashima, E. Yoo, T. Yamazaki, M. Kijima, H. Shimizu, Y. Takasawa, J. Nakamura, “Effcient usage of highly dispersed Pt on carbon nanotubes for electrode catalysts of polymer electrode fuel cells”,
Catalysis Today, 90, 277 (2004).
[30] C. Liu, H. T. Cong, F. Li, “Semi-continuous synthesis of single-walled Carbon nanotubes by a hydrogen arc discharge method”, Carbon, 37, 1865 (1999).
[31] C. Liu, H. M. Cheng, H. T. Cong, F. Li, G. Su, B. L. Zhou, and M. S., “Dresselhaus Synthesis of Macroscopically Long Ropes of
Well-Aligned Single-Walled Carbon Nanotubes”, Adv. Mater., 12,
1190 (2000).
[32] W. H. Lizcano-Valbuena, D. C. de Azevedo, E. R. Gonzalez, “Supported metal nanoparticles as electrocatalysts for low-temperature fuel cells”, Electrochimica
Acta., 49, 1289 (2004).
[33] T.C. Deivaraj and Jim Yang Lee, “Preparation of carbon-supported PtRu nanoparticles for direct methanol fuel cell applications – a comparative study”, J. Power Sources., 142, 43 (2005).
[34] X. Zhang, K.Y. Chan , “Water-in-Oil Microemulsion Synthesis of Platinum-Ruthenium Nanoparticles, Their Characterization and Electrocatalytic Properties”,Chem. Mater., 15, 451 (2003).
[35] Z.He, J. Chen, D. Liu, H. Zhou, Y. Kuang, “Electrodeposition of Pt-Ru nanoparticles on catrbon nanotubes and their electrocatalytic properties for methanol electrooxidation”, Diamond and Related Materials, 13, 1764 (2004).
[36] Y. T. Kho, S. Srinivasan, “Mass Transport Phenomens in Proton Exchange Membrane Fuel Cells Using O2/He,O2/Ar and O2/N2 Mixture Ⅱ Theoretical Analysis”, J. Electrochem.Soc., 141, 2089
(1994).
[37] T. E. Springer, D. Raistrick, “Electrical Impedance of a Pore Wall for the Flooded-Agglomerate Model of Porous Gas-Diffusion
Electrodes”, J. Electrohem. Soc., 136, 1594 (1989).
[38] K. W. Park, B. K. Kwon, J. H. Choi, Y. M. Kim, Y. E. Sung, “New RuO2 and carbon-RuO2 composite diffusion layer for use in direct methanol fuel cells”, J. Power Sources., 439, 109 (2002).
[39] T. Bewer, T. Beckmann, H. Dohle, J. Mergel, D. Stolten, “Novel method for investigation of two-phase flow in liquid feed direct methanol fuel cells using an aqueous H2O2 solution” , J. Power Sources, 125, 1 (2004).
[40] J. Kim, S. M. Lee, S. Srinivasan, “Modeling of Proton Exchange Membrane Fuel Cell Performance with an Empirical Equation”, J.
Electrochem. Soc., 142, 2670 (1995).
[41] M. D. Bernardi, M. W. Verbrugge, “A Mathematical Model of the Solid-Polymer-Electrolyte Fuel Cell”, J. Electrochem. Soc., 139,
2477 (1992).
[42] 李振彬, 直接甲醇燃料電池中陽極觸媒層效能之改良, 國立成功大學化學工程學系碩士論文 (2005).
[43] W. R. Runyan et al., Semiconductor Measurements & Instrumentation, 2nded., McGRAW-HALL (1997).
[44] L. Dubau, F. Hahn, C. Coutanceau, J.-M. Le´ger, C. Lamy, “On the structure effects of bimetallic PtRu electrocatalysts towards methanol oxidation”, J. Electroanal. Chem., 554-555, 407 (2003).
[45] W. Zhou, Z. Zhou, S. Song, W. Li, G. Sun, P. Tsiakaras, Q. Xin, “Pt Based anode catalysts for direct ethanol fuel cells”, Applied Catalysis, 46, 273 (2003).
[46] Iijima S., Nature., 221, 56 (1991).
[47] T. Frelink, W. Visscher, J. A. R. van Veen, “On the role of Ru and Sn as promotors of methanol electro-oxidation over Pt”, Surface Science, 335, 353 (1995).
[48] D. J. Suh, C. Kwak, J.-H. Kim, S. M. Kwon, T.-J. Park,“Removal of carbon monoxide from hydrogen-rich fuels by selective low-temperature oxidation over base metal added platinum catalysts”, J. Power Sources, 142, 70 (2005).
[49] W. J. Zhou, B. Zhou, W. Z. Li, Z. H. Zhou, S. Q. Song, G. Q. Sun, Q. Xin, S. Douvartzides, M. Goula, P. Tsiakaras, “Performance comparison of low-temperature direct alcohol fuel cells with different anode catalysts”, J. Power Sources, 126, 16 (2004).
[50] 成會明, 張勁燕, ”奈米碳管”, 五南圖書出版公司 (2004).
[51] R. K Gupta, I. Dwivedy, “International patenting activity in the field of carbon nanotubes”, Current Applied Physics, 5, 163 (2005).
[52] P. Kim, J. B. Joo, W. Kim, J. Kim, I. K. Song, J. Yi, “NaBH4-assisted ethylene glycol reduction for preparation of carbon-supported Pt catalyst for methanol electro-oxidation”, J. Power Sources, 160, 987 (2006).
[53] P. Serp, M. Corrias, P. Kalck, “Carbon nanotubes and nanofibers in catalysis”, Applied Catalysis, 253, 337 (2003).
[54] K. I. Han, J. S. Lee, S. O. Park, S. W. Lee, Y. W. Park, H. Kim, “Studies on the anode catalysts of carbon nanotube for DMFC”, Electrochimica Acta, 50, 791 (2004).
[55] Z. Liu, X. Lin, J. Y. Lee, W. Zhang, M. Han, L. M. Gan, “Preparation and characterization of platinum-based electrocatalysts on multiwalled carbon nanotubes for proton exchange membrane fuel cells”, Langmuir, 18, 4054 (2002).
[56] L. S. Sarma, T. D. Lin, Y. W. Tsai, J. M. Chen, B. J. Hwang, “Carbon-supported Pt-Ru catalysts prepared by the Nafion stabilized alcohol-reduction method for application in direct methanol fuel cells”, J. Power Sources, 139, 44 (2005).
[57] E. Passalacqua, F. Lufrano, G. Squadrito, A. Patti, L. Giorgi, “Nafion content in the catalyst layer of polymer electrolyte fuel cells：effects on structure and performance”, Electrochimica Acta, 46, 799 (2001).
[58] G. Q. Lu, C. Y. Wang, T. J. Yen, X. Zhang, “Development and characterization of a silicon-based micro direct methanol fuel cell”, Electrochimica Acta, 49, 821 (2004).