開採石油時一併被釋出之天然氣雖同為能源燃料，但由於運輸與儲存困難， 以及其中含量最多的甲烷造成之溫室效應十分強烈，因此通常會直接被焚燒。尋找 更有效且不浪廢資源的方法即成為一重要的研究趨勢。將其部分氧化形成更有經濟 價值之液態醇類或醛類即為一種解決方式，因此許多科學家都嘗試欲使用綠色化學 的方法來進行天然氣中烷類的轉換。
本實驗室先前所發表的論文中探討利用四氮錯合金屬石墨烯進行電化學析氧 反應可提升催化效率，故本研究將透過於中心金屬上添加軸位配位基的方式進行提 升此催化劑效能的探討。研究中以恆定電極電位密度泛函理論計算控制系統電壓在 0.00VSHE 至 1.00VSHE，探討添加軸位配位基是否影響烷類的羥基化反應。
結果顯示，添加軸位配位基確實能使低電壓下的反應活化能降低，但其對於 電壓的敏感度一併被降低，而對電壓的敏感度也會隨著受質大小而改變。天然氣的 轉化利用將會是能源需求下的一盞明燈，在未來，將可利用本研究之結果，進一步 尋找出合適之烷類羥基化反應催化劑。

Although the natural gas that released during oil exploitation also an energy, whereas there is a challenge for its storage and transport. One of the main reasons is due to the greenhouse effect that caused by the huge number of methane in natural gas and it makes burning occur in general. As a consequence, there will be a significant trend of study in order to demonstrate a more effective and energy-saving way to deal with natural gas. To oxidate and form a liquid state alcohols or aldehydes will be a problem-solving technique for this issue as it brings an economic value. Thus, lots of scientists are inspirated in figure out the study of transforming alkanes in natural gas with green chemistry.
According to the previous study that examinate the electrochemical oxygen evolution reaction on metal N-doped graphene will increase the C-H activation ability. Therefore, this study is focused on increase C-H activation ability through adding axial ligands on the central metal. In this study, constant potential density functional theory has been discussed to calculate the potential in between 0.00VSHE to 1.00VSHE, in order to study whether or not adding axial ligands will affect hydroxylation reactions affinity on alkanes.
The result indicated that adding axial ligands will lower down the activation energy of C- H activation under low potential, however, it reduces the sensitivity of potential at the same time. Furthermore, the sensitivity to potential of catalyst will be affected by the size of substrates in the reaction investigated as well.

1. Shaik, S.; Kumar, D.; de Visser, S. P., A Valence Bond Modeling of Trends in Hydrogen Abstraction Barriers and Transition States of Hydroxylation Reactions Catalyzed by Cytochrome P450 Enzymes. J. Am. Chem. Soc. 2008, 130 (31), 10128-10140.
2. Luo, J.-H.; Hong, Z.-S.; Chao, T.-H.; Cheng, M.-J., Quantum Mechanical Screening of Metal-N4-Functionalized Graphenes for Electrochemical Anodic Oxidation of Light Alkanes to Oxygenates. J. Phys. Chem. C 2019, 123 (31), 19033-19044.
3. Ravi, M.; Ranocchiari, M.; van Bokhoven, J. A., The Direct Catalytic Oxidation of Methane to Methanol—A Critical Assessment. Angew. Chem. Int. Ed. 2017, 56 (52), 16464- 16483.
4. Sun, M.; Zhang, J.; Putaj, P.; Caps, V.; Lefebvre, F. d. r.; Pelletier, J.; Basset, J.- M., Catalytic oxidation of light alkanes (C1–C4) by heteropoly compounds. Chem. Rev. 2014, 114 (2), 981-1019.
5. Gleaves, J. T.; Ebner, J.; Kuechler, T., Temporal analysis of products (TAP)—a unique catalyst evaluation system with submillisecond time resolution. Caral. Rev. 1988, 30 (1), 49-116.
6. Grant, J. T.; Venegas, J. M.; McDermott, W. P.; Hermans, I., Aerobic Oxidations of Light Alkanes over Solid Metal Oxide Catalysts. Chemical Reviews 2018, 118 (5), 2769- 2815.
7. Gunay, A.; Theopold, K. H., C−H Bond Activations by Metal Oxo Compounds. Chem. Rev. 2010, 110 (2), 1060-1081.
8. Groves, J. T.; Gilbert, J. A., Electrochemical generation of an iron (IV) porphyrin. Inorg. Chem. 1986, 25 (2), 123-125.
9. Bockris, J. O. M.; Otagawa, T., The electrocatalysis of oxygen evolution on perovskites. J. Electrochem. Soc. 1984, 131 (2), 290.
10. Man, I. C.; Su, H.-Y.; Calle-Vallejo, F.; Hansen, H. A.; Martínez, J. I.; Inoglu, N. G.; Kitchin, J.; Jaramillo, T. F.; Nørskov, J. K.; Rossmeisl, J., Universality in Oxygen Evolution Electrocatalysis on Oxide Surfaces. ChemCatChem 2011, 3 (7), 1159-1165.
11. Sono, M.; Roach, M. P.; Coulter, E. D.; Dawson, J. H., Heme-Containing Oxygenases. Chem. Rev. 1996, 96 (7), 2841-2888.
12. Xie, M.-H.; Yang, X.-L.; He, Y.; Zhang, J.; Chen, B.; Wu, C.-D., Highly Efficient C�H Oxidative Activation by a Porous MnIII–Porphyrin Metal–Organic Framework under Mild Conditions. Chem. Eur. J. 2013, 19 (42), 14316-14321.
13. Groves, J. T.; Nemo, T. E., Aliphatic hydroxylation catalyzed by iron porphyrin complexes. J. Am. Chem. Soc. 1983, 105 (20), 6243-6248.
14. Sacramento, J. J. D.; Goldberg, D. P., Factors Affecting Hydrogen Atom Transfer Reactivity of Metal–Oxo Porphyrinoid Complexes. Acc. Chem. Res. 2018, 51 (11), 2641- 2652.
15. Kadish, K. M.; Van Caemelbecke, E., Electrochemistry of porphyrins and related macrocycles. J. Solid State Electrochem. 2003, 7 (5), 254-258.
16. Liu, W.; Zhang, L.; Liu, X.; Liu, X.; Yang, X.; Miao, S.; Wang, W.; Wang, A.; Zhang, T., Discriminating Catalytically Active FeNx Species of Atomically Dispersed Fe– N–C Catalyst for Selective Oxidation of the C–H Bond. J. Am. Chem. Soc. 2017, 139 (31), 10790-10798.
17. Safo, M. K.; Gupta, G. P.; Walker, F. A.; Scheidt, W. R., Models of the cytochromes b. Control of axial ligand orientation with a hindered porphyrin system. J. Am. Chem. Soc. 1991, 113 (15), 5497-5510.
18. Li, J.-C.; Wei, Z.; Liu, D.; Du, D.; Lin, Y.; Shao, M., Dispersive Single-Atom Metals Anchored on Functionalized Nanocarbons for Electrochemical Reactions. Top. Curr. Chem. 2019, 377 (1), 4.
19. Russell, G. A.; Tashtoush, H., Free-radical chain-substitution reactions of alkylmercury halides. J. Am. Chem. Soc. 1983, 105 (5), 1398-1399.
20. Lam, T.-L.; Tong, K.-C.; Yang, C.; Kwong, W.-L.; Guan, X.; Li, M.-D.; Kar-Yan Lo, V.; Lai-Fung Chan, S.; Lee Phillips, D.; Lok, C.-N.; Che, C.-M., Luminescent ruffled iridium(iii) porphyrin complexes containing N-heterocyclic carbene ligands: structures, spectroscopies and potent antitumor activities under dark and light irradiation conditions. Chem. Sci. 2019, 10 (1), 293-309.
21. Takahashi, A.; Yamaki, D.; Ikemura, K.; Kurahashi, T.; Ogura, T.; Hada, M.; Fujii, H., Effect of the Axial Ligand on the Reactivity of the Oxoiron(IV) Porphyrin π-Cation Radical Complex: Higher Stabilization of the Product State Relative to the Reactant State. Inorg. Chem. 2012, 51 (13), 7296-7305.
22. Kohn, W.; Sham, L. J., Self-Consistent Equations Including Exchange and Correlation Effects. Phys. Rev. 1965, 140 (4A), A1133-A1138.
23. Perdew, J. P.; Burke, K.; Ernzerhof, M., Generalized Gradient Approximation Made Simple. Phys. Rev. Lett. 1996, 77 (18), 3865-3868.
24. Henkelman, G.; Jónsson, H., A dimer method for finding saddle points on high dimensional potential surfaces using only first derivatives. J. Chem. Phys. 1999, 111 (15), 7010-7022.
25. Kresse, G.; Joubert, D., From ultrasoft pseudopotentials to the projector augmented- wave method. Phys. Rev. B 1999, 59 (3), 1758-1775.
26. Blöchl, P. E., Projector augmented-wave method. Phys. Rev. B 1994, 50 (24), 17953- 17979.
27. Valdés, Á.; Qu, Z. W.; Kroes, G. J.; Rossmeisl, J.; Nørskov, J. K., Oxidation and Photo-Oxidation of Water on TiO2 Surface. J. Phys. Chem. C 2008, 112 (26), 9872-9879. 28. Jinnouchi, R.; Anderson, A. B., Aqueous and Surface Redox Potentials from Self- Consistently Determined Gibbs Energies. J. Phys. Chem. C 2008, 112 (24), 8747-8750.
29. Goodpaster, J. D.; Bell, A. T.; Head-Gordon, M., Identification of Possible Pathways for C–C Bond Formation during Electrochemical Reduction of CO2: New Theoretical Insights from an Improved Electrochemical Model. J. Phys. Chem. Lett. 2016, 7 (8), 1471- 1477.
30. Nørskov, J. K.; Rossmeisl, J.; Logadottir, A.; Lindqvist, L.; Kitchin, J. R.; Bligaard, T.; Jónsson, H., Origin of the Overpotential for Oxygen Reduction at a Fuel-Cell Cathode. J. Phys. Chem. B 2004, 108 (46), 17886-17892.
31. Shen, M. H.; Chao, T. H.; Tang, Y. T.; Cheng, M. J., First-Principles Evaluation of One-Dimensional Metal-Organic Frameworks for Electrocatalytic C-H Activation of Natural Gas. Chem Asian J 2021, 16 (4), 292-295.
32. Latimer, A. A.; Kulkarni, A. R.; Aljama, H.; Montoya, J. H.; Yoo, J. S.; Tsai, C.; Abild-Pedersen, F.; Studt, F.; Nørskov, J. K., Understanding trends in C-H bond activation in heterogeneous catalysis. Nat. Mater. 2017, 16 (2), 225-229.