近年來，因為發電效率高以及對環境的衝擊小，質子交換膜燃料電池(PEMFC)的應用引起很大的關注。然而，持久度差和高成本一直都是質子交換膜燃料電池的主要問題，因傳統的碳載體在燃料電池操作環境下會受到嚴重的腐蝕，而使用白金(Pt)當作觸媒也使成本居高不下。本論文選用碳化鉭(TaC)及氮化釩(VN)取代傳統的碳材當作觸媒載體，因其擁有良好的導電性與抗腐蝕性，這兩個特點是作為觸媒載體不可或缺的條件。除此之外，氮化釩也被作為共觸媒鍍覆在碳化鉭上，以期能夠減少白金的使用量，進而降低質子交換膜燃料電池的成本。
碳化鉭以熔鹽法(salt flux method)製備，並以溶膠凝膠法(sol-gel method)製備氧化釩(VOx)及氧化釩/碳化鉭複合物(VOx/TaC)，再經氮化後生成氮化釩(VN)及氮化釩/碳化鉭複合物(VN/TaC)。白金(鉑)奈米顆粒以化學還原法鍍覆於碳化鉭，也以原子層沉積法(ALD)鍍覆於氮化釩及氮化釩/碳化鉭複合物。碳化鉭上的白金重量百分比為2.08 %，且顆粒大小介於2-4奈米，氮化釩上的白金重量百分比隨著原子層沉積之循環數增加，從1.69%增加至5.75%，白金顆粒也從2-4奈米增大至6-9奈米。至於氮化釩/碳化鉭複合物，因氮化釩幾乎完全覆蓋碳化鉭，所以白金奈米顆粒幾乎鍍覆在氮化釩之薄膜上，白金重量百分比約為2.5%，且顆粒大小介於3-5奈米。
藉由循環伏安法(cyclic voltammetry, CV)及氧化還原反應(oxygen reduction reaction, ORR)探討自製電極之電化學表現。從CV曲線中可計算出電化學活性表面積(electrochemical surface area, ECSA)，Pt@TaC電極之ECSA值(66.2 m2/g)小於商用電極(Johnson Matthey, JM)之ECSA值(100.8 m2/g )；從ORR分析中計算出之質量活性(mass activity, MA)來看，Pt@TaC之MA值(3.9 A/g)遠小於商用電極之MA值(83.8 A/g)。
以Pt@TaC作為陽極或陰極(JM作為相對電極)之質子交換膜燃料電池之效率，隨白金承載量增加而增加。當Pt@TaC置於陽極時，其最大比功率密度為商用電極(863.2 mW/mg)之四倍；當Pt@TaC置於陰極時，其最大比功率密度(727.5 mW/mg)可與商用電極匹敵。以Pt@VN作為陽極或陰極(JM作為相對電極)時，以白金原子層沉積150循環圈數製備之Pt@VN-150表現最佳，因其白金顆粒分布密集且尺寸理想。當Pt@VN-150置於陽極時，其最大比功率密度(999.5 mW/mg)略高於商用電極；當Pt@VN-150置於陰極時，其最大比功率密度(300.5 mW/mg)低於商用電極。至於Pt@VN/TaC之效率，不論作為陽極或陰極(JM作為相對電極)時，其表現皆優於Pt@TaC；除此之外，當Pt@VN/TaC置於陰極時，其最大比功率密度(1357.5 mW/mg)甚至高於商用電極，此現象說明氮化釩亦為具有潛力之質子交換膜燃料電池共觸媒。

Proton exchange membrane fuel cell (PEMFC) has attracted much attention recently because of its high efficiency of generating electricity and low environmental impact. However, poor durability and high cost are two major problems of PEMFC because the traditional carbon support suffers from severe corrosion and the use of Pt as catalyst raises the cost. In this work, tantalum carbide (TaC) and vanadium nitride (VN) were chosen as the catalyst support to replace traditional carbon support because they possess high electrical conductivity and good corrosion resistance, which are important requirements for the catalyst support. Because VN can also act as the co-catalyst in PEMFC, VN/TaC composite was also fabricated in attempt to reduce the cost of PEMFC.
TaC was fabricated by a salt flux method, while VOx and VOx/TaC were fabricated by a sol-gel method followed by nitridation to form VN and VN/TaC, respectively. Pt nanoparticles were deposited on TaC by chemical reduction method using sodium borohydride as reducing agent and on VN and VN/TaC by atomic layer deposition (ALD). The Pt particle size on TaC ranged from 2 to 4 nm. Due to low surface area or surface chemistry condition of TaC, the Pt loading on TaC was 2.08 wt%, which is lower than the expected value (10 or 20 wt%). The Pt particle sizes on VN were 2-4 nm, 3-5 nm, and 6-9 nm when the ALD cycle numbers were 100, 150, and 200, respectively. The Pt loading on VN increased linearly from 1.69 wt% to 5.75 wt% as the ALD cycle number increased. As for Pt@VN/TaC, because TaC was almost fully covered by VN thin film, most Pt nanoparticles were deposited on VN thin film with the particle size ranging from 3 to 5 nm, and Pt loading was about 2.5 wt%.
The electrochemical behaviors of Pt@TaC, homemade Pt@XC-72, and commercial Pt@XC-72 (Johnson Matthey, JM) were examined by cyclic voltammetry (CV) and oxygen reduction reaction (ORR) analyses. From the CV curves, the electrochemical surface area (ECSA) value of Pt@TaC (66.2 m2/g) was lower than those of homemade Pt@XC-72 (80.6 m2/g) and JM (100.8 m2/g). From the ORR curves, the mass activity of Pt@TaC (3.9 A/g) was much lower than those of homemade Pt@XC-72 (107.2 A/g) and JM (83.8 A/g).
The performance of PEMFC using Pt@TaC electrode as the anode or the cathode (JM acting as the opposite electrode) increased with increasing the Pt loading. As the anode, it showed 4 times higher specific maximum power density than that of commercial JM (863.2 mW/mg), and it showed comparable specific maximum power density (727.5 mW/mg) to commercial JM as the cathode. For Pt@VN, VN deposited by 150 ALD cycles showed the best performance among three different cycle numbers (100, 150, and 200) as the anode or cathode (JM acting as the opposite electrode) due to the dense distribution and small particle size of Pt. It showed a little higher specific maximum power density (999.5 mW/mg) than that of commercial JM as the anode, while it showed lower specific maximum power density (300.5 mW/mg) than that of commercial JM as the cathode. When Pt@VN/TaC was employed as the anode or cathode (JM acting as the opposite electrode), it showed improved performance than that of Pt@TaC when the Pt loading was the same. Furthermore, Pt@VN/TaC even showed higher specific maximum power density (1357.5 mW/mg) than that of commercial JM as the cathode. This indicates that VN might be a promising co-catalyst for PEMFC.

Table of Contents
摘要 I
Abstract III
誌謝 V
Chapter I Introduction 1
1-1 Background of Research 1
1-2 The Development of Fuel Cells 1
1-3 Types of Full Cells 2
1-4 Advantages and Applications of Fuel Cells 7
1-5 Motivation of Research 8
1-6 Overview of Tantalum Carbide and Vanadium Nitride 10
1-6-1 Characteristics of tantalum carbide 10
1-6-2 Characteristics of vanadium nitride 11
Chapter II Literature Review 14
2-1 Principle of PEMFC 14
2-2 Components of PEMFC 14
2-2-1 Bipolar plates 14
2-2-2 Gas diffusion layer 18
2-2-3 Catalyst layer 21
2-2-3-1 Catalyst support 21
A. Carbon based catalyst support 21
B. Non-carbon based catalyst support 23
2-2-3-2 Catalyst 26
A. Materials 26
B. Particle size effect 26
C. Methods of depositing catalysts 30
2-2-4 Proton exchange membrane 30
Chapter III Experimental Procedures 35
3-1 Fabrication of TaC, VN, and VN/TaC 35
3-1-1 Fabrication of TaC 35
3-1-2 Fabrication of VN and VN/TaC 35
3-2 Deposition of Pt Nanoparticles by Chemical Reduction or ALD 35
3-3 Characterization 38
3-4 Electrochemical Characterization 39
3-5 Preparation of Membrane Electrode Assembly 40
3-6 Single Cell Performance of PEMFC 42
Chapter IV Results and Discussion 44
4-1 Characteristics of TaC, VN, and VN/TaC 44
4-1-1 Crystallinity 44
4-1-2 TGA analysis 44
4-1-3 Morphology, surface area, and porosity 49
4-2 Characterization of Pt Nanoparticles 54
4-2-1 Particle size and dispersion of Pt nanoparticles 54
4-2-2 Pt loading 59
4-3 Electrochemical Characterization of Pt@TaC and Pt@XC-72 66
4-4 Performance of MEA 71
4-4-1 Performance of Pt@TaC 71
4-4-2 Performance of Pt@VN 76
4-4-3 Performance of Pt@VN/TaC 82
Chapter V Conclusions 87
Chapter VI Suggested Future work 89
References 90

1. D. G. Löffler, K. Taylor, and D. Mason, “A light hydrocarbon fuel processor producing high-purity hydrogen,” J. Power Sources, 117 (2003) 84-91.
2. http://www.juliantrubin.com/bigten/fuel_cell_experiments.html
3. http://ethw.org/Bacon%27s_Fuel_Cell
4. N.H. Behling, Fuel cells: current technology challenges and future research needs, Elsevier, (2013).
5. https://www.britannica.com/biography/Francis-Thomas-Bacon
6. https://www.rogerebillings.com/1991-the-first-hydrogen-fuel-cell-car/
7. http://www.fuelcelltoday.com/history
8. L. Carrette, K. A. Friedrich, and U. Stimming, “Fuel cells: principles, types, fuels, and applications,” ChemPhysChem, 1 (2000) 162-193.
9. B. H. Steele and A. Heinzel, “Materials for fuel-cell technologies,” Nature, 414 (2001) 345-352.
10. H. Liu, C. Song, L. Zhang, J. Zhang, H. Wang, and D. P. Wilkinson, “A review of anode catalysis in the direct methanol fuel cell,” J. Power Sources, 155 (2006) 95-110.
11. J. Larminie and A. Dicks, Fuel cell systems explained, John Wiley & Sons, Chichester, (2003).
12. T. Wilberforce, A. Alaswad, A. Palumbo, M. Dassisti, and A. G. Olabi, “Advances in stationary and portable fuel cell applications,” Int. J. Hydrogen Energy, 41 (2016) 16509-16522.
13. S. Sharma and B. G. Pollet, “Support materials for PEMFC and DMFC electrocatalysts—A review,” J. Power Sources, 208 (2012) 96-119.
14. R. Borup, J. Meyers, B. Pivovar, Y. S. Kim, R. Mukundan, N. Garland, D. Myers, M. Wilson, F. Garzon, D. Wood, P. Zelenay, K. More, K. Stroh, T. Zawodzinski, J. Boncella, J. E. McGrath, M. Inaba, K. Miyatake, M. Hori, K. Ota, Z. Ogumi, S. Miyata, A. Nishikata, Z. Siroma, Y. Uchimoto, K. Yasuda, K. I. Kimijima, and N. Iwashita, “Scientific aspects of polymer electrolyte fuel cell durability and degradation,” Chem. Rev., 107 (2007) 3904–3951.
15. Y. Y. Shao, G. P. Yin, Z. B. Wang, and Y. Z. Gao, “Proton exchange membrane fuel cell from low temperature to high temperature: material challenges,” J. Power Sources, 167 (2007) 235-242.
16. Y. Y. Shao, G. P. Yin, and Y. Z. Gao, “Understanding and approaches for the durability issues of Pt-based catalysts for PEM fuel cell,” J. Power Sources, 171 (2007) 558-566.
17. X. Cheng, Z. Shi, N. Glass, L. Zhang, J. Zhang, D. Song, Z. S. Liu, H. Wang, and J. Shen, “A review of PEM hydrogen fuel cell contamination: impacts, mechanisms, and mitigation,” J. Power Sources, 165 (2007) 739-756.
18. D. J. Ham, and J. S. Lee, “Transition metal carbides and nitrides as electrode materials for low temperature fuel cells,” Energies, 2 (2009) 873-899.
19. Z. Hu, C. Chen, H. Meng, R. Wang, P. K. Shen, and H. Fu, “Oxygen reduction electrocatalysis enhanced by nanosized cubic vanadium carbide,” Electrochem. Commun., 13 (2011) 763-765.
20. M. Chiwata, K. Kakinuma, M. Wakisaka, M. Uchida, S. Deki, M. Watanabe, and H. Uchida, “Oxygen reduction reaction activity and durability of Pt catalysts supported on titanium carbide,” Catalysts, 5 (2015) 966-980.
21. Y. N. Regmi, G. R. Waetzig, K. D. Duffee, S. M. Schmuecker, J. M. Thode, and B. M. Leonard, “Carbides of group IVA, VA and VIA transition metals as alternative HER and ORR catalysts and support materials,” J. Mater. Chem. A, 3 (2015) 10085-10091.
22. Y. Liu, T. G. Kelly, J. G. Chen, and W. E. Mustain, “Metal carbides as alternative electrocatalyst supports,” ACS Catal., 3 (2013) 1184-1194.
23. M. Yang, Z. Cui, and F. J. DiSalvo, “Mesoporous chromium nitride as a high performance non-carbon support for the oxygen reduction reaction,” Phys. Chem. Chem. Phys., 15 (2013) 7041-7044.
24. Y. R. Liu, Y. C. Hsueh, and T. P. Perng, “Fabrication of TiN inverse opal structure and Pt nanoparticles by atomic layer deposition for proton exchange membrane fuel cell,” Int. J. Hydrogen Energy, 42 (2017) 10175-10183.
25. N. Y. Kim, J. H. Lee, J. A. Kwon, S. J. Yoo, J. H. Jang, H. J. Kim, D. H. Lim, and J. Y. Kim, “Vanadium nitride nanofiber membrane as a highly stable support for Pt-catalyzed oxygen reduction reaction,” J. Ind. Eng. Chem., 46 (2017) 298–303.
26. T. Huang, S. Mao, G. Zhou, Z. Wen, X. Huang, S. Ci, and J. Chen, “Hydrothermal synthesis of vanadium nitride and modulation of its catalytic performance for oxygen reduction reaction,” Nanoscale, 6 (2014) 9608-9613.
27. J. Yin, L. Wang, P. Yu, L. Zhao, C. Tian, B. Jiang, D. Zhao, W. Zhou, and H. Fu, “A platinum–vanadium nitride/porous graphitic nanocarbon composite as an excellent catalyst for the oxygen reduction reaction,” ChemElectroChem, 2 (2015) 1813-1820.
28. I. J. Hsu, Y. C. Kimmel, Y. Dai, S. Chen, and J. G. Chen, “Rotating disk electrode measurements of activity and stability of monolayer Pt on tungsten carbide disks for oxygen reduction reaction,” J. Power Sources, 199 (2012) 46-52.
29. Y. Liu and W. E. Mustain, “Structural and electrochemical studies of Pt clusters supported on high-surface-area tungsten carbide for oxygen reduction,” ACS Catal., 1 (2011) 212-220.
30. M. Pang, C. Li, L. Ding, J. Zhang, D. Su, W. Li, and C. Liang, “Microwave-assisted preparation of Mo2C/CNTs nanocomposites as efficient electrocatalyst supports for oxygen reduction reaction,” Ind. Eng. Chem. Res., 49 (2010) 4169-4174.
31. Y. C. Kimmel, X. Xu, W. Yu, X. Yang, and J. G. Chen, “Trends in electrochemical stability of transition metal carbides and their potential use as supports for low-cost electrocatalysts,” ACS Catal., 4 (2014) 1558-1562.
32. Y. Zhong, X. Xia, F. Shi, J. Zhan, J. Tu, and H. J. Fan, “Transition metal carbides and nitrides in energy storage and conversion,” Adv. Sci., 3 (2016) 1500286.
33. Z. Pan, Y. Xiao, Z. Fu, G. Zhan, S. Wu, C. Xiao, G. Hu, and Z. Wei, “Hollow and porous titanium nitride nanotubes as high-performance catalyst supports for oxygen reduction reaction,” J. Mater. Chem. A, 2 (2014) 13966-13975.
34. N.S. Gajbhiye and R.S. Ningthoujam, “Low temperature synthesis, crystal structure and thermal stability studies of nanocrystalline VN particles,” Mater. Res. Bull., 41 (2006) 1612-1621.
35. Mechanical Engineering Community, October 2015, PEMFC, (Online),
https://mechanical-engg.com/blogs/entry/873-pemfc-proton-exchange-membrane-fuel-cell/
36. S. S. Dihrab, K. Sopian, M. A. Alghoul, and M. Y. Sulaiman, “Review of the membrane and bipolar plates materials for conventional and unitized regenerative fuel cells,” Renewable Sustainable Energy Rev., 13 (2009) 1663-1668.
37. A. Hermann, T. Chaudhuri, and P. Spagnol, “Bipolar plates for PEM fuel cells: a review,” Int. J. Hydrogen Energy, 30 (2005) 1297-1302.
38. V. Mehta and J. S. Cooper, “Review and analysis of PEM fuel cell design and manufacturing,” J. Power Sources, 114 (2003) 32-53.
39. L. Cindrella, A. M. Kannan, J. F. Lin, K. Saminathan, Y. Ho, C. W. Lin, and J. Wertz, “Gas diffusion layer for proton exchange membrane fuel cells: a review,” J. Power Sources, 194 (2009) 146-160.
40. S. Park, J. W. Lee, and B. N. Popov, “A review of gas diffusion layer in PEM fuel cells: Materials and designs,” Int. J. Hydrogen Energy, 37 (2012) 5850-5865.
41. Y. Shao, J. Liu, Y. Wang, and Y. Lin, “Novel catalyst support materials for PEM fuel cells: current status and future prospects,” J. Mater. Chem., 19 (2009) 46-59.
42. E. Antolini, “Carbon supports for low-temperature fuel cell catalysts,” Appl. Catal., B, 88 (2009) 1-24.
43. X. Wang, W. Li, Z. Chen, M. Waje, and Y. Yan, “Durability investigation of carbon nanotube as catalyst support for proton exchange membrane fuel cell,” J. Power Sources, 158 (2006) 154-159.
44. C. Liu, C. C. Wang, C. C. Kei, Y. C. Hsueh, and T. P. Perng, “Atomic layer deposition of platinum nanoparticles on carbon nanotubes for application in proton-exchange membrane fuel cells,” Small, 5 (2009) 1535-1538.
45. Y.C. Hsueh, C. C. Wang, C. Liu, C. C. Kei, and T. P. Perng, “Deposition of platinum on oxygen plasma treated carbon nanotubes by atomic layer deposition,” Nanotechnology, 23 (2012) 405603.
46. Y. C. Hsueh, C. C. Wang, C. C. Kei, Y. H. Lin, C. Liu, and T. P. Perng, “Fabrication of catalyst by atomic layer deposition for high specific power density proton exchange membrane fuel cells,” J. Catal., 294 (2012) 63-68.
47. K. Lee, J. Zhang, H. Wang, and D. P. Wilkinson, “Progress in the synthesis of carbon nanotube- and nanofiber-supported Pt electrocatalysts for PEM fuel cell catalysis,” J. Appl. Electrochem., 36 (2006) 507-522.
48. F. Z. Martin, D. S. Escario, E. Morallon, and C. S. M. Lecea, “Pt/carbon nanofibers electrocatalysts for fuel cells Effect of the support oxidizing treatment,” J. Power Sources, 171 (2007) 302-309.
49. W. Li, M. Waje, Z. Chen, P. Larsen, and Y. Yan, “Platinum nanopaticles supported on stacked-cup carbon nanofibers as electrocatalysts for proton exchange membrane fuel cell,” Carbon, 48 (2010) 995-1003.
50. D. Sebastián, J. Calderón, J. G. Expósito, E. Pastor, M. V. M. Huerta, I. Suelves, R. Moliner, and M. J. Lázaro, “Influence of carbon nanofiber properties as electrocatalyst support on the electrochemical performance for PEM fuel cells,” Int. J. Hydrogen Energy, 35 (2010) 9934-9942.
51. B. Liu and S. Creager, “Silica–sol-templated mesoporous carbon as catalyst support for polymer electrolyte membrane fuel cell applications,” Electrochim. Acta, 55 (2010) 2721-2726.
52. S. Song, Y. Liang, Z. Li, Y. Wang, R. Fu, and D. Wu, “Effect of pore morphology of mesoporous carbons on the electrocatalytic activity of Pt nanoparticles for fuel cell reactions,” Appl. Catal., B, 98 (2010) 132-137.
53. L. Calvillo, M. Gangeri, S. Perathoner, G. Centi, R. Moliner, and M. J. Lázaro, “Synthesis and performance of platinum supported on ordered mesoporous carbons as catalyst for PEM fuel cells: Effect of the surface chemistry of the support,” Int. J. Hydrogen Energy, 36 (2011) 9805-9814.
54. G. R. S. Banda, K. I. B. Eguiluz, and L. A. Avaca, “Boron-doped diamond powder as catalyst support for fuel cell applications,” Electrochem. Commun., 9 (2007) 59-64.
55. X. Lu, J. Hu, J. S. Foord, and Q. Wang, “Electrochemical deposition of Pt–Ru on diamond electrodes for the electrooxidation of methanol,” J. Electroanal. Chem., 654 (2011) 38-43.
56. S. Liu, J. Wang, J. Zeng, J. Ou, Z. Li, X. Liu, and S. Yang, “Green electrochemical synthesis of Pt/graphene sheet nanocomposite film and its electrocatalytic property,” J. Power Sources, 195 (2010) 4628-4633.
57. L. Qu, Y. Liu, J. B. Baek, and L. Dai, “Nitrogen-doped graphene as efficient metal-free electrocatalyst for oxygen reduction in fuel cells,” ACS Nano, 4 (2010) 1321-1326.
58. P. Zhang, S. Y. Huang, and B. N. Popov, “Mesoporous tin oxide as an oxidation-resistant Catalyst Support for proton exchange membrane fuel cells,” J. Electrochem. Soc., 157 (2010) B1163-B1172.
59. I. S. Park, E. Lee, and A. Manthiram, “Electrocatalytic properties of indium tin oxide-supported Pt nanoparticles for methanol electro-oxidation,” J. Electrochem. Soc., 157 (2010) B251-B255.
60. T. Ioroi, Z. Siroma, N. Fujiwara, S. Yamazaki, and K. Yasuda, “Sub-stoichiometric titanium oxide-supported platinum electrocatalyst for polymer electrolyte fuel cells,” Electrochem. Commun., 7 (2005) 183-188.
61. H. H. Hwu and J. G. G. Chen, “Potential application of tungsten carbides as electrocatalysts,” J. Vac. Sci. Technol., A, 21 (2003) 1488-1493.
62. N. Cheng, M. N. Banis, J. Liu, A. Riese, S. Mu, R. Li, T. K. Sham, and X. Sun, “Atomic scale enhancement of metal–support interactions between Pt and ZrC for highly stable electrocatalysts,” Energy Environ. Sci., 8 (2015) 1450-1455.
63. B. Avasarala, T. Murray, W. Li, and P. Haldar, “Titanium nitride nanoparticles based electrocatalysts for proton exchange membrane fuel cells,” J. Mater. Chem., 19 (2009) 1803-1805.
64. J. K. Nørskov, J. Rossmeisl, A. Logadottir, and L. Lindqvist, “Origin of the overpotential for oxygen reduction at a fuel-cell cathode,” J. Phys. Chem. B, 108 (2004) 17886-17892.
65. J. X. Wang, T. E. Springer, P. Liu, M. Shao, and R. R. Adzic, “Hydrogen oxidation reaction on Pt in acidic media: adsorption isotherm and activation free energies,” J. Phys. Chem. C, 111 (2007) 12452-12433.
66. J. Xie, D. L. Wood, K. L. More, P. Atanassov, and R. L. Borup, “Microstructural changes of membrane electrode assemblies during PEFC durability testing at high humidity conditions,” J. Electrochem. Soc., 152 (2005) A1011-A1020.
67. E. Guilminot, A. Corcella, F. Charlot, F. Maillard, and M. Chatenet, “Detection of PtZ+ ions and Pt nanoparticles inside the membrane of a used PEMFC,” J. Electrochem. Soc., 154 (2007) B96-B105.
68. J. Zhang and J. Fang, “A general strategy for preparation of Pt 3d-transition metal (Co, Fe, Ni) nanocubes,” J. Am. Chem. Soc., 131 (2009) 18543-18547.
69. Z. Peng and H. Yang, “Synthesis and oxygen reduction electrocatalytic property of Pt-on-Pd bimetallic heteronanostructures,” J. Am. Chem. Soc., 131 (2009) 7542-7543.
70. J. Kim, Y. Lee, and S. Sun, “Structurally ordered FePt nanoparticles and their enhanced catalysis for oxygen reduction reaction,” J. Am. Chem. Soc., 132 (2010) 4996-4997.
71. J. Wu, A. Gross, and H. Yang, “Shape and composition-controlled platinum alloy nanocrystals using carbon monoxide as reducing agent,” Nano Lett., 11 (2011) 798-802.
72. L. Wang, Y. Nemoto, and Y. Yamauchi, “Direct synthesis of spatially-controlled pt-on-pd bimetallic nanodendrites with superior electrocatalytic activity,” J. Am. Chem. Soc., 133 (2011) 9674-9677.
73. Y. Nie, L. Li, and Z. Wei, “Recent advancements in Pt and Pt-free catalysts for oxygen reduction reaction,” Chem. Soc. Rev., 44 (2015) 2168-2201.
74. F. Maillard, M. Martin, F. Gloaguen, and J. M. Léger, “Oxygen electroreduction on carbon-supported platinum catalysts. Particle-size effect on the tolerance to methanol competition,” Electrochim. Acta, 47 (2002) 3431-3440.
75. K. J. J. Mayrhofer, B. B. Blizanac, M. Arenz, V. R. Stamenkovic, P. N. Ross, and N. M. Markovic, “The impact of geometric and surface electronic properties of pt-catalysts on the particle size effect in electrocatalysis,” J. Phys. Chem. B, 109 (2005) 14433-14440.
76. M. Shao, A. Peles, and K. Shoemaker, “Electrocatalysis on platinum nanoparticles: particle size effect on oxygen reduction reaction activity,” Nano Lett., 11 (2011) 3714-3719.
77. L. Xiong and A. Manthiram, “High performance membrane-electrode assemblies with ultra-low Pt loading for proton exchange membrane fuel cells,” Electrochim. Acta, 50 (2005) 3200-3204.
78. R. O’Hayre, S. J. Lee, S. W. Cha, and F. B. Prinz, “A sharp peak in the performance of sputtered platinum fuel cells at ultra-low platinum loading,” J. Power Sources, 109 (2002) 483-493.
79. D. Gruber, N. Ponath, J. Müller, F. Lindstaedt, “Sputter-deposited ultra-low catalyst loadings for PEM fuel cells,” J. Power Sources, 150 (2005) 67-72.
80. M. S. Saha, A. F. Gullá, R. J. Allen, and S. Mukerjee, “High performance polymer electrolyte fuel cells with ultra-low Pt loading electrodes prepared by dual ion-beam assisted deposition,” Electrochim. Acta, 51 (2006) 4680-4692.
81. C. R. K. Rao and D. C. Trivedi, “Chemical and electrochemical depositions of platinum group metals and their applications,” Coord. Chem. Rev., 249 (2005) 613-631.
82. J. D. Qiu, G. C. Wang, R. P. Liang, X. H. Xia, and H. W. Yu, “Controllable deposition of platinum nanoparticles on graphene as an electrocatalyst for direct methanol fuel cells,” J. Phys. Chem. C, 115 (2011) 15639-15645.
83. J. H. Wee, K. Y. Lee, and S. H. Kim, “Fabrication methods for low-Pt-loading electrocatalysts in proton exchange membrane fuel cell systems,” J. Power Sources, 165 (2007) 667-677.
84. S.J. Peighambardoust, S. Rowshanzamir, and M. Amjadi, “Review of the proton exchange membranes for fuel cell applications,” Int. J. Hydrogen Energy, 35 (2010) 9349-9384.
85. B. Smitha, S. Sridhar, and A.A. Khan, “Solid polymer electrolyte membranes for fuel cell applications—a review,” J. Membr. Sci., 259 (2005) 10-26.
86. M. Rikukawa and K. Sanui, “Proton-conducting polymer electrolyte membranes based on hydrocarbon polymers,” Prog. Polym. Sci., 25 (2000) 1463-1502.
87. N. W. Deluca and Y. A. Elabd, “Polymer electrolyte membranes for the direct methanol fuel cell: a review,” J. Polym. Sci., Part B: Polym. Phys., 44 (2006) 2201-2225.
88. Y. M. Chi, M.S. thesis, National Tsing Hua University (2015) 83.