在本篇論文中，藉由密度泛函理論(DFT)研究Pt(100)、Pd(100)以及其合金上的甲醇氧化反應(MOR)的機理。我們研究了甲醇氧化化反應在Pt、Pd與以3:1、1:1、1:3比例混成的合金上的催化活性和穩定性。首先我們計算甲醇與其裂解產物和氧化反應在(100)催化表面上吸附能，然後在計算反應能與反應的活化能障以及能勢面(PES)。Pt(100)上的可行路徑遵循CH₃OH￫CH₃O￫CH₂O￫CHO￫CO。分解反應有較低的能量，意謂著更好的活性，但也導致CO毒化Pt催化劑。另一方面，甲醇在Pd(100)最初優先斷裂C-H鍵並遵循CH₃OH￫CH₂OH￫CHOH￫CHO，CHO的中間體利於氧化反應形成CHOOH，而非利於解離反應在Pd(100)上形成毒化的CO，因此有效提升CO耐受性。在合金的計算中，相對於單金屬，Pt加入Pd能夠改善MOR的活性使反應有更低的能障。此外，加入Pd能夠改變催化路徑從甲醇分解變成氧化。而Pt/Pd為1比1的合金顯示出最佳的催化活性及穩定性。

In this thesis, the mechanism of methanol oxidation reaction (MOR) on Pt(100), Pd(100) and their alloys were investigated by density functional theory (DFT). We examined the catalytic activity and stability of MOR on Pt, Pd and the alloys with the ratio of 3:1, 1:1, 1:3. Our work started with the calculation of the adsorption energy of methanol and its fragments in the decomposition and oxidation reactions on the (100) surface of catalysts; then the reaction energy and activity barrier of the reactions and potential energy surface (PES). The energetically feasible pathway on Pt(100) follows CH₃OH￫CH₃O￫CH₂O￫CHO￫CO. The decomposition reaction has lower energetics, implying the better activity, but results the detrimental CO poisoning Pt catalyst. Methanol on Pd(100), on the other hand, preferentially breaks C-H bond initially and follows CH₃OH￫CH₂OH￫CHOH￫CHO. The intermediate of CHO favors the oxidation reaction forming CHOOH than the dissociation reaction forming the poisoning CO on Pd(100); thus efficiently enhance the CO tolerance. In the calculations of alloys, the reactions have lower barriers than those on Pt with Pd to improve MOR activity. Also, the addition of Pd can change the catalytic pathway from methanol decomposition to oxidation As a result, the alloy with Pt/Pd = 1/1 shows the best catalytic activity and stability.

參考資料
1. Armaroli, N. and V. Balzani, The Future of Energy Supply: Challenges and Opportunities. Angewandte Chemie International Edition, 2007. 46(1-2): p. 52-66.
2. Halim, F.A., et al., Overview on Vapor Feed Direct Methanol Fuel Cell. APCBEE Procedia, 2012. 3: p. 40-45.
3. Sakong, S. and A. Groß, The Importance of the Electrochemical Environment in the Electro-Oxidation of Methanol on Pt(111). ACS Catalysis, 2016. 6(8): p. 5575-5586.
4. Anderson, A.B. and H.A. Asiri, Reversible potentials for steps in methanol and formic acid oxidation to CO2; adsorption energies of intermediates on the ideal electrocatalyst for methanol oxidation and CO2 reduction. Physical Chemistry Chemical Physics, 2014. 16(22): p. 10587-10599.
5. Lin, Y.-C., et al., Combined Experimental and Theoretical Investigation of Nanosized Effects of Pt Catalyst on Their Underlying Methanol Electro-Oxidation Activity. The Journal of Physical Chemistry C, 2009. 113(21): p. 9197-9205.
6. Zhong, W. and D. Zhang, New insight into the CO formation mechanism during formic acid oxidation on Pt(111). Catalysis Communications, 2012. 29: p. 82-86.
7. Brummel, O., et al., Stabilization of Small Platinum Nanoparticles on Pt–CeO2 Thin Film Electrocatalysts During Methanol Oxidation. The Journal of Physical Chemistry C, 2016. 120(35): p. 19723-19736.
8. Greeley, J. and M. Mavrikakis, A First-Principles Study of Methanol Decomposition on Pt(111). Journal of the American Chemical Society, 2002. 124(24): p. 7193-7201.
9. Qi, X.Q., et al., DFT studies of the pH dependence of the reactivity of methanol on a Pd(1 1 1) surface. Journal of Molecular Structure, 2010. 980(1–3): p. 208-213.
10. Scaranto, J. and M. Mavrikakis, Density functional theory studies of HCOOH decomposition on Pd(111). Surface Science, 2016. 650: p. 111-120.
11. Yang, J., et al., Theoretical study on the effective methanol decomposition on Pd(1 1 1) surface facilitated in alkaline medium. Journal of Electroanalytical Chemistry, 2011. 662(1): p. 251-256.
12. Jiang, R., et al., Density Functional Investigation of Methanol Dehydrogenation on Pd(111). The Journal of Physical Chemistry C, 2009. 113(10): p. 4188-4197.
13. Jiang, Z., B. Wang, and T. Fang, A theoretical study on the complete dehydrogenation of methanol on Pd (100) surface. Applied Surface Science, 2016. 364: p. 613-619.
14. Lu, X., et al., Methanol oxidation on Ru(0001) for direct methanol fuel cells: analysis of the competitive reaction mechanism. RSC Advances, 2016. 6(3): p. 1729-1737.
15. Jiang, R., et al., Methanol dehydrogenation on Rh(1 1 1): A density functional and microkinetic modeling study. Journal of Molecular Catalysis A: Chemical, 2011. 344(1–2): p. 99-110.
16. Hernández, J., et al., Methanol oxidation on gold nanoparticles in alkaline media: Unusual electrocatalytic activity. Electrochimica Acta, 2006. 52(4): p. 1662-1669.
17. Jiang, R., et al., Dehydrogenation of methanol on Pd(100): comparison with the results of Pd(111). Physical Chemistry Chemical Physics, 2010. 12(28): p. 7794-7803.
18. Wu, Y.-N., et al., High-performance core–shell PdPt@Pt/C catalysts via decorating PdPt alloy cores with Pt. Journal of Power Sources, 2009. 194(2): p. 805-810.
19. Wang, X., L. Chen, and B. Li, A density functional theory study of methanol dehydrogenation on the PtPd3(111) surface. International Journal of Hydrogen Energy, 2015. 40(31): p. 9656-9669.
20. Wang, J., et al., Comparative study to understand the intrinsic properties of Pt and Pd catalysts for methanol and ethanol oxidation in alkaline media. Electrochimica Acta, 2015. 185: p. 267-275.
21. Chen, D.-J. and Y.J. Tong, Irrelevance of Carbon Monoxide Poisoning in the Methanol Oxidation Reaction on a PtRu Electrocatalyst. Angewandte Chemie International Edition, 2015. 54(32): p. 9394-9398.
22. Ding, Q., et al., Insight into the Reaction Mechanisms of Methanol on PtRu/Pt(111): A Density Functional Study. Applied Surface Science, 2016. 369: p. 257-266.
23. Lu, X., et al., Methanol Oxidation on Pt3Sn(111) for Direct Methanol Fuel Cells: Methanol Decomposition. ACS Applied Materials & Interfaces, 2016. 8(19): p. 12194-12204.
24. Sheng, T. and S.-G. Sun, Insight into the promoting role of Rh doped on Pt(111) in methanol electro-oxidation. Journal of Electroanalytical Chemistry, 2016. 781: p. 24-29.
25. Ren, H., et al., Inhibition of coking and CO poisoning of Pt catalysts by the formation of Au/Pt bimetallic surfaces. Applied Catalysis A: General, 2010. 375(2): p. 303-309.
26. Roy Chowdhury, S., S. Ghosh, and S.K. Bhattachrya, Improved Catalysis of Green-Synthesized Pd-Ag Alloy-Nanoparticles for Anodic Oxidation of Methanol in Alkali. Electrochimica Acta, 2017. 225: p. 310-321.
27. Jurzinsky, T., et al., On the Influence of Ag on Pd-based Electrocatalyst for Methanol Oxidation in Alkaline Media: A Comparative Differential Electrochemical Mass Spectrometry Study. Electrochimica Acta, 2016. 199: p. 270-279.
28. Yang, Y., et al., Free-standing ternary PtPdRu nanocatalysts with enhanced activity and durability for methanol electrooxidation. Electrochimica Acta, 2016. 222: p. 1094-1102.
29. Fan, Y., et al., A porous ternary PtPdCu alloy with a spherical network structure for electrocatalytic methanol oxidation. RSC Advances, 2016. 6(86): p. 83373-83379.
30. Ferrin, P. and M. Mavrikakis, Structure Sensitivity of Methanol Electrooxidation on Transition Metals. Journal of the American Chemical Society, 2009. 131(40): p. 14381-14389.
31. Hoshi, N., et al., Structural Effects of Electrochemical Oxidation of Formic Acid on Single Crystal Electrodes of Palladium. The Journal of Physical Chemistry B, 2006. 110(25): p. 12480-12484.
32. wiki, https://zh.wikipedia.org/wiki/%E8%B5%9D%E5%8A%BF.