本論文主要以理論計算研究鉑合金及鈷合金的氧氣還原反應機制，透過第一原理計算氧氣還原反應(Oxygen Reduction Reaction)之所有中間吸附物，O*、O2*、OH*、 OOH*、H2O2*、 H2O*和H*的吸附能以及七種反應路徑，包含三個O-O斷鍵步驟和四個O-H生成反應步驟的反應能量以及活化能，並藉由計算乾淨表面以及表面吸附含氧中間產物(ORR的關鍵中間產物)的分離能量(segregation energy)，比較所設計的表面合金和其ORR反應上的穩定性。
在研究鉑合金的部分，PtSn擁有比Pt更良好的活性，相較於其他PtM合金(M= Ag, Au, Co, Cu, Pd)擁有較好的穩定性，PtSn在ORR反應上，由於其較易使吸附含氧中間產物(oxygen-containing species, OCS)吸附於表面上生成穩定產物，故可以有效率提升其ORR活性以及穩定性。
對於鈷合金表面氧氣還原反應研究，加入少量白金在鈷金屬中，可以有效改善ORR活性，此外，如果加入第三種元素金做為取代，則可以更進一步改善CoPt合金的穩定性。

In this thesis, we computationally study oxygen reduction reaction (ORR) on Pt-based and Co-based alloys. The adsorption energies for all the possible adspecies, O*, O2*, OH*, OOH*, H2O2*, H2O* and H* and reaction energy/activation barriers for all the elementary steps, including 3 O-O cleavage and 4 O-H association steps were thoroughly examined by first-principles calculation. The segregation energy for clean and oxygen-containing species (OCS), key intermediates in ORR, adsorbed alloys were computed to model the as-prepared alloys and investigate their stability during ORR operation. In the study of Pt-based alloys, PtSn shows better activity than clean Pt catalysts and its stability is better than other PtM alloys (M = Ag, Au, Co, Cu, Pd). Its better ORR activity and stability are attributable to the abundant OCS formation on PtSn. In the study of Co-based alloys, adding small amount of Pt in Co can show improved ORR activity. Also, introducing the third element of Au in the subsurface of CoPt alloy can further enhance the stability.

1. Johansson, T.B., Renewable energy: sources for fuels and electricity. 1993: Island press.
2. Basu, S., Fuel Cell Science and Technology. 2007: Springer.
3. Grove, W.R., XXIV. On voltaic series and the combination of gases by platinum. The London and Edinburgh philosophical magazine and journal of science, 1839. 14(86): p. 127-130.
4. Nernst, W., On the electrolytic conduction of solid bodies at high temperatures. Z. Electrochem, 1899. 6(2): p. 41-43.
5. Baur, E. and H. Preis, Über Brennstoff‐Ketten mit Festleitern. Zeitschrift für Elektrochemie und angewandte physikalische Chemie, 1937. 43(9): p. 727-732.
6. Larminie, J., A. Dicks, and M.S. McDonald, Fuel cell systems explained. Vol. 2. 2003: J. Wiley Chichester, UK.
7. Cambridge, U.o. Types of Fuel Cells. 2015; Summary of the Electrochemical Reactions of Various Types of Fuel Cells]. Available from: http://www.ceb.cam.ac.uk/research/groups/rg-eme/teaching-notes/fuelcells/types-of-fuel-cells.
8. O'hayre, R., et al., Fuel cell fundamentals. 2016: John Wiley & Sons.
9. Jain, N., et al., Polymer Electrolyte Membrane Fuel Cells: Alternative to fossil fuels for power supply to Heavy Earth Moving and Allied Machinery in Mining and Civil Engineering Industry.
10. Wroblowa, H.S. and G. Razumney, Electroreduction of oxygen: A new mechanistic criterion. Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 1976. 69(2): p. 195-201.
11. Nørskov, J.K., et al., Origin of the overpotential for oxygen reduction at a fuel-cell cathode. The Journal of Physical Chemistry B, 2004. 108(46): p. 17886-17892.
12. Guo, S., et al., FePt and CoPt Nanowires as Efficient Catalysts for the Oxygen Reduction Reaction. Angewandte Chemie International Edition, 2013. 52(12): p. 3465-3468.
13. Toda, T., H. Igarashi, and M. Watanabe, Enhancement of the electrocatalytic O2 reduction on Pt–Fe alloys. Journal of Electroanalytical Chemistry, 1999. 460(1–2): p. 258-262.
14. Mani, P., R. Srivastava, and P. Strasser, Dealloyed binary PtM3 (M = Cu, Co, Ni) and ternary PtNi3M (M = Cu, Co, Fe, Cr) electrocatalysts for the oxygen reduction reaction: Performance in polymer electrolyte membrane fuel cells. Journal of Power Sources, 2011. 196(2): p. 666-673.
15. Toda, T., et al., Enhancement of the electroreduction of oxygen on Pt alloys with Fe, Ni, and Co. Journal of The Electrochemical Society, 1999. 146(10): p. 3750-3756.
16. Stamenkovic, V.R., et al., Trends in electrocatalysis on extended and nanoscale Pt-bimetallic alloy surfaces. Nat Mater, 2007. 6(3): p. 241-247.
17. Stamenkovic, V.R., et al., Effect of Surface Composition on Electronic Structure, Stability, and Electrocatalytic Properties of Pt-Transition Metal Alloys:  Pt-Skin versus Pt-Skeleton Surfaces. Journal of the American Chemical Society, 2006. 128(27): p. 8813-8819.
18. Gasteiger, H.A., et al., Activity benchmarks and requirements for Pt, Pt-alloy, and non-Pt oxygen reduction catalysts for PEMFCs. Applied Catalysis B: Environmental, 2005. 56(1–2): p. 9-35.
19. Stamenković, V., et al., Surface Composition Effects in Electrocatalysis:  Kinetics of Oxygen Reduction on Well-Defined Pt3Ni and Pt3Co Alloy Surfaces. The Journal of Physical Chemistry B, 2002. 106(46): p. 11970-11979.
20. Stamenković, V., et al., Surface segregation effects in electrocatalysis: kinetics of oxygen reduction reaction on polycrystalline Pt3Ni alloy surfaces. Journal of Electroanalytical Chemistry, 2003. 554–555: p. 191-199.
21. Zhang, J., PEM fuel cell electrocatalysts and catalyst layers: fundamentals and applications. 2008: Springer Science & Business Media.
22. Wang, G., et al., Ni@Pt core–shell nanoparticles with enhanced catalytic activity for oxygen reduction reaction. Journal of Alloys and Compounds, 2010. 503(1): p. L1-L4.
23. Neyerlin, K.C., et al., Electrochemical activity and stability of dealloyed Pt–Cu and Pt–Cu–Co electrocatalysts for the oxygen reduction reaction (ORR). Journal of Power Sources, 2009. 186(2): p. 261-267.
24. Oezaslan, M. and P. Strasser, Activity of dealloyed PtCo3 and PtCu3 nanoparticle electrocatalyst for oxygen reduction reaction in polymer electrolyte membrane fuel cell. Journal of Power Sources, 2011. 196(12): p. 5240-5249.
25. Srivastava, R., et al., Efficient Oxygen Reduction Fuel Cell Electrocatalysis on Voltammetrically Dealloyed Pt–Cu–Co Nanoparticles. Angewandte Chemie International Edition, 2007. 46(47): p. 8988-8991.
26. Gupta, G., et al., Highly Stable and Active Pt−Cu Oxygen Reduction Electrocatalysts Based on Mesoporous Graphitic Carbon Supports. Chemistry of Materials, 2009. 21(19): p. 4515-4526.
27. Su, B.-J., et al., Preparation of PtSn/C electrocatalysts with improved activity and durability toward oxygen reduction reaction by alcohol-reduction process. Materials Chemistry and Physics, 2012. 135(2–3): p. 395-400.
28. D'Villa-Silva, M., et al., Comparative Studies of Oxygen Reduction Reaction and Ethanol Oxidation Reaction on PtSn/C and PtNi/C Catalysts. ECS Transactions, 2011. 41(1): p. 1299-1306.
29. Li, B., et al., PtSnP/C and PtSn/C as efficient cathode catalysts for oxygen reduction reaction in microbial fuel cells. International Journal of Hydrogen Energy, 2017. 42(8): p. 5261-5271.
30. Zhang, N., et al., Pt/Tin Oxide/Carbon Nanocomposites as Promising Oxygen Reduction Electrocatalyst with Improved Stability and Activity. Electrochimica Acta, 2014. 117: p. 413-419.
31. Dupont, C., et al., Restructuring of the Pt 3 Sn (111) surfaces induced by atomic and molecular oxygen from first principles. The Journal of chemical physics, 2009. 130(12): p. 124716.
32. Wu, G., et al., A Strategy to Promote the Electrocatalytic Activity of Spinels for Oxygen Reduction by Structure Reversal. Angewandte Chemie International Edition, 2016. 55(4): p. 1340-1344.
33. Aijaz, A., et al., Co@Co3O4 Encapsulated in Carbon Nanotube-Grafted Nitrogen-Doped Carbon Polyhedra as an Advanced Bifunctional Oxygen Electrode. Angewandte Chemie International Edition, 2016. 55(12): p. 4087-4091.
34. Pan, F., et al., A facile synthesis of nitrogen/sulfur co‐doped graphene for the oxygen reduction reaction. ChemCatChem, 2016. 8(1): p. 163-170.
35. Wei, J., et al., A graphene-directed assembly route to hierarchically porous Co–N x/C catalysts for high-performance oxygen reduction. Journal of Materials Chemistry A, 2015. 3(32): p. 16867-16873.
36. Liu, Y., et al., Transition metals (Fe, Co, and Ni) encapsulated in nitrogen-doped carbon nanotubes as bi-functional catalysts for oxygen electrode reactions. Journal of Materials Chemistry A, 2016. 4(5): p. 1694-1701.
37. Shao, M., et al., Recent Advances in Electrocatalysts for Oxygen Reduction Reaction. Chemical Reviews, 2016. 116(6): p. 3594-3657.
38. Strasser, P., et al., Lattice-strain control of the activity in dealloyed core–shell fuel cell catalysts. Nat Chem, 2010. 2(6): p. 454-460.
39. Liang, Y.-T., et al., The performance and stability of the oxygen reduction reaction on Pt-M (M = Pd, Ag and Au) nanorods: an experimental and computational study. Chemical Communications, 2015. 51(30): p. 6605-6608.
40. Zhang, J., et al., Stabilization of Platinum Oxygen-Reduction Electrocatalysts Using Gold Clusters. Science, 2007. 315(5809): p. 220.
41. Lin, S.-P., et al., Trends of Oxygen Reduction Reaction on Platinum Alloys: A Computational and Experimental Study. The Journal of Physical Chemistry C, 2015. 119(27): p. 15224-15231.
42. Parr, R.G., Density functional theory of atoms and molecules, in Horizons of Quantum Chemistry. 1980, Springer. p. 5-15.
43. Kohn, W. and L.J. Sham, Self-consistent equations including exchange and correlation effects. Physical review, 1965. 140(4A): p. A1133.
44. Perdew, J.P. and Y. Wang, Accurate and simple analytic representation of the electron-gas correlation energy. Physical Review B, 1992. 45(23): p. 13244.
45. Perdew, J.P., et al., Atoms, molecules, solids, and surfaces: Applications of the generalized gradient approximation for exchange and correlation. Physical Review B, 1992. 46(11): p. 6671.
46. Hamann, D.R., M. Schlüter, and C. Chiang, Norm-Conserving Pseudopotentials. Physical Review Letters, 1979. 43(20): p. 1494-1497.
47. Kresse, G. and J. Furthmüller, Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Physical review B, 1996. 54(16): p. 11169.
48. Kresse, G. and J. Furthmüller, Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set. Computational Materials Science, 1996. 6(1): p. 15-50.
49. Kresse, G. and J. Hafner, Ab initio molecular dynamics for liquid metals. Physical Review B, 1993. 47(1): p. 558.
50. Kresse, G. and J. Hafner, Ab initio molecular-dynamics simulation of the liquid-metal–amorphous-semiconductor transition in germanium. Physical Review B, 1994. 49(20): p. 14251.
51. Perdew, J.P., K. Burke, and M. Ernzerhof, Generalized gradient approximation made simple. Physical review letters, 1996. 77(18): p. 3865.
52. Blöchl, P.E., Projector augmented-wave method. Physical review B, 1994. 50(24): p. 17953.
53. Kresse, G. and D. Joubert, From ultrasoft pseudopotentials to the projector augmented-wave method. Physical Review B, 1999. 59(3): p. 1758.
54. Monkhorst, H.J. and J.D. Pack, Special points for Brillouin-zone integrations. Physical review B, 1976. 13(12): p. 5188.
55. Henkelman, G., B.P. Uberuaga, and H. Jónsson, A climbing image nudged elastic band method for finding saddle points and minimum energy paths. The Journal of chemical physics, 2000. 113(22): p. 9901-9904.
56. Tripković, V., et al., The oxygen reduction reaction mechanism on Pt(1 1 1) from density functional theory calculations. Electrochimica Acta, 2010. 55(27): p. 7975-7981.
57. Keith, J.A., G. Jerkiewicz, and T. Jacob, Theoretical investigations of the oxygen reduction reaction on Pt (111). ChemPhysChem, 2010. 11(13): p. 2779-2794.
58. 楊詔宇, 藉由錫與銀的合金化增益酸性環境下鉑奈米棒之乙醇氧化反應, in 材料科學與工程研究所. 2016, 國立中央大學.