本論文包含兩項研究主題。第一部分探討氫化鈀於高壓環境下的結構與光譜特性。研究利用鑽石高壓砧建立高壓條件，以煤油作為壓力傳遞介質與氫源，並結合雷射加熱、拉曼光譜與 X 光繞射分析鈀和含氫介質的反應。雷射加熱後，樣品腔內出現黑色沉積物；其拉曼光譜呈現 D band、G band 與 2D band 訊號，顯示煤油在局部高溫下裂解並生成碳質產物。X 光繞射結果顯示，在 4.13 GPa 下觀察到一組晶格常數約為 4.11 Å 的面心立方結構繞射峰，明顯大於純鈀的晶格常數 3.894 Å ，顯示可能有氫原子進入鈀晶格並形成氫化鈀相關相。由於樣品中可能同時存在氫化鈀、富鈀相、碳相，以及鈀–碳或鈀–碳–氫相關相，因此本研究將其保守歸類為鈀基面心立方結構相。
第二部分探討甲烷裂解的氣體與固態碳產物特性，並比較高溫熱裂解與大氣雙極性電漿裂解對碳產物的影響。高溫裂解實驗於直立式高溫爐中進行，反應溫度為925–1150 °C，甲烷流量為 8–50 LPM。結果顯示，提高反應溫度並降低流量可有效提升甲烷轉化率；在 1142–1150 °C 且流量為 8 LPM 的條件下，轉化率可達 67–69.3%。氣相層析分析結果顯示，高溫、低流量條件下的甲烷訊號明顯降低，氫氣相對訊號則提升至約 82–85%，顯示較高反應溫度與較長停留時間有利於甲烷裂解及氫氣生成。固態碳主要沉積於高溫反應區、集塵桶及管線區域。掃描式電子顯微鏡分析顯示，碳粉主要由數百奈米尺度的近球狀顆粒組成；濾袋集塵桶與旋風集塵桶所收集碳粉的平均粒徑分別為 482.3 ± 80.2 nm 與 566.7 ± 127.2 nm，顯示集塵系統具有一定程度的粒徑分離效果。X 光繞射與拉曼光譜分析結果顯示，碳產物具有低結晶度類石墨碳或亂層石墨碳特徵，並含有明顯的缺陷與亂層堆疊結構。綜合而言，本研究利用 X 光繞射與拉曼光譜技術追蹤高壓鈀–氫系統中的氫化與碳化現象；同時顯示高溫甲烷裂解可產生氫氣與固態碳，而碳產物的結構與粒徑分布則受到反應條件及集塵方式影響。

This thesis comprises two studies. The first investigates the structural and spectroscopic properties of palladium hydride under high pressure. A diamond anvil cell was used to generate high pressure, with kerosene serving as both the pressure-transmitting medium and the hydrogen source. Laser heating, Raman spectroscopy, and X-ray diffraction were used to characterize the reaction products. The Raman spectra exhibited D, G, and 2D bands, indicating kerosene decomposition and carbon formation. At 4.13 GPa, X-ray diffraction revealed a face-centered cubic phase with a lattice constant of approximately 4.11 Å, larger than that of pure palladium (3.894 Å), suggesting hydrogen incorporation into the Pd lattice. Because palladium hydride, Pd-rich phases, carbon phases, and Pd–C(H)-related phases may coexist, this phase is conservatively identified as a palladium-based face-centered cubic phase.
The second study examines the gaseous and solid products of methane pyrolysis and compares the carbon products obtained by high-temperature thermal pyrolysis and atmospheric bipolar plasma pyrolysis. Thermal pyrolysis experiments were conducted at 925–1150 °C with methane flow rates of 8–50 LPM. Higher temperatures and lower flow rates increased methane conversion, which reached 67–69.3% at 1142–1150 °C and 8 LPM. Gas chromatography showed a decrease in the methane signal and an increase in the relative hydrogen signal to 82–85%, indicating enhanced methane decomposition and hydrogen production under these conditions. Carbon products were collected from the reaction zone, dust collectors, and pipelines. Scanning electron microscopy revealed predominantly near-spherical particles several hundred nanometers in size. The average particle diameters of carbon collected from the filter bag and cyclone collectors were 482.3 ± 80.2 nm and 566.7 ± 127.2 nm, respectively. X-ray diffraction and Raman spectroscopy indicated low-crystallinity graphitic or turbostratic carbon with abundant defects. Overall, this work demonstrates hydrogenation and carbonization phenomena in the high-pressure Pd–H system and shows that methane pyrolysis can produce hydrogen and solid carbon whose properties depend on the reaction conditions and collection method.

[1] Bardeen, J., Cooper, L. N., & Schrieffer, J. R. (1957). Theory of superconductivity. Physical Review, 108(5), 1175–1204. https://doi.org/10.1103/PhysRev.108.1175
[2] Meissner, W., & Ochsenfeld, R. (1933). Ein neuer Effekt bei Eintritt der Supraleitfähigkeit. Naturwissenschaften, 21, 787–788. https://doi.org/10.1007/BF01504252
[3] Ginzburg, V. L., & Landau, L. D. (1950). On the theory of superconductivity. Zhurnal Eksperimental'noi i Teoreticheskoi Fiziki, 20, 1064–1082.
[4] Ashcroft, N. W. (1968). Metallic hydrogen: A high-temperature superconductor? Physical Review Letters, 21(26), 1748–1749. https://doi.org/10.1103/PhysRevLett.21.1748
[5] Drozdov, A. P., Eremets, M. I., Troyan, I. A., Ksenofontov, V., & Shylin, S. I. (2015). Conventional superconductivity at 203 kelvin at high pressures in the sulfur hydride system. Nature, 525, 73–76. https://doi.org/10.1038/nature14964
[6] Somayazulu, M., Ahart, M., Mishra, A. K., Geballe, Z. M., Baldini, M., Meng, Y., Struzhkin, V. V., & Hemley, R. J. (2019). Evidence for superconductivity above 260 K in lanthanum superhydride at megabar pressures. Physical Review Letters, 122, 027001. https://doi.org/10.1103/PhysRevLett.122.027001
[7] Drozdov, A. P., Kong, P. P., Minkov, V. S., Besedin, S. P., Kuzovnikov, M. A., Mozaffari, S., Balicas, L., Balakirev, F. F., Graf, D. E., Prakapenka, V. B., Greenberg, E., Knyazev, D. A., Tkacz, M., & Eremets, M. I. (2019). Superconductivity at 250 K in lanthanum hydride under high pressures. Nature, 569, 528–531. https://doi.org/10.1038/s41586-019-1201-8
[8] Skośkiewicz, T. (1972). Superconductivity in the palladium-hydrogen and palladium-nickel-hydrogen systems. Physica Status Solidi (a), 11(2), K123–K126. https://doi.org/10.1002/pssa.2210110256
[9] McLachlan, D. S., Doyle, T. B., & Burger, J. P. (1977). The superconducting properties of PdHx≈1. Journal of Low Temperature Physics, 26, 589–607. https://doi.org/10.1007/BF00655218
[10] Kato, R., Koga, R., Miyakawa, K., Shiga, M., Inagaki, Y., & Kawae, T. (2023). Superconducting properties of palladium hydride systems prepared by low-temperature absorption. JPS Conference Proceedings, 38, 011033. https://doi.org/10.7566/JPSCP.38.011033
[11] Kato, R., Yoshida, T., Iimori, R., Tai, Z., Shiga, M., Inagaki, Y., Kimura, T., Ienaga, K., & Kawae, T. (2025). New quantum state formed by highly concentrated protons in superconducting palladium hydride. arXiv:2505.01960. https://doi.org/10.48550/arXiv.2505.01960
[12] Caputo, R., & Alavi, A. (2003). Where do the H atoms reside in PdHx systems? Molecular Physics, 101(11), 1781–1787. https://doi.org/10.1080/0026897031000094489
[13] Meninno, A., & Errea, I. (2023). Ab initio study of metastable occupation of tetrahedral sites in palladium hydrides and its impact on superconductivity. Physical Review B, 107, 024504. https://doi.org/10.1103/PhysRevB.107.024504
[14] Geballe, Z. M., Somayazulu, M., Armanet, N., Mishra, A. K., Ahart, M., & Hemley, R. J. (2021). High-pressure synthesis and thermodynamic stability of PdH1±ε up to 8 GPa. Physical Review B, 103, 024515. https://doi.org/10.1103/PhysRevB.103.024515
[15] Hong, J., Bae, J.-H., Jo, H., et al. (2022). Metastable hexagonal close-packed palladium hydride in liquid cell TEM. Nature, 603, 631–636. https://doi.org/10.1038/s41586-021-04391-5
[16] Liu, Z., Ahuja, R., Li, H., & Luo, W. (2020). Mechanical and electronic properties of van der Waals layered hcp PdH2. Scientific Reports, 10, 8037. https://doi.org/10.1038/s41598-020-61385-5
[17] Tsuppayakorn-aek, P., Majumdar, A., Ahuja, R., Bovornratanaraks, T., & Luo, W. (2023). Superconducting state of the van der Waals layered PdH2 structure at high pressure. International Journal of Hydrogen Energy, 48(42), 16769–16778. https://doi.org/10.1016/j.ijhydene.2022.12.312
[18] Gavello, G., Tofani, G., De Fazio, D., Lettieri, S., Mezzetta, A., Guazzelli, L., Pomelli, C. S., Gonnelli, R. S., Piatti, E., & Daghero, D. (2024). Facile synthesis of palladium hydride via ionic gate-driven protonation using a deep eutectic solvent. arXiv:2410.15452. https://doi.org/10.48550/arXiv.2410.15452
[19] Liu, Q., Xu, W., Huang, H., et al. (2024). Spectroscopic visualization of reversible hydrogen spillover between palladium and metal-organic frameworks toward catalytic semihydrogenation. Nature Communications, 15, 2562. https://doi.org/10.1038/s41467-024-46923-3
[20] Sherman, R. (1978). Raman studies of hydrogen vibrational modes in palladium. Master's thesis, University of Illinois at Urbana-Champaign.
[21] Tsuchiya, K., Watanabe, A., Ozaki, M., & Sasabe, S. (2008). Observation of optical phonon in palladium hydrides using Raman spectroscopy. Proceedings of ICCF-14 International Conference on Condensed Matter Nuclear Science.
[22] Eremets, M. I., & Troyan, I. A. (2011). Conductive dense hydrogen. Nature Materials, 10, 927–931. https://doi.org/10.1038/nmat3175
[23] Huang, X., Li, F., Huang, Y., Wu, G., Li, X., Zhou, Q., Liu, B., & Cui, T. (2016). High-pressure Raman study of solid hydrogen up to 300 GPa. Chinese Physics B, 25, 037401. https://doi.org/10.1088/1674-1056/25/3/037401
[24] Mao, H. K., Xu, J., & Bell, P. M. (1986). Calibration of the ruby pressure gauge to 800 kbar under quasi-hydrostatic conditions. Journal of Geophysical Research: Solid Earth, 91(B5), 4673–4676. https://doi.org/10.1029/JB091iB05p04673
[25] Fincke, J. R., Anderson, R. P., Hyde, T., Detering, B. A., Wright, R., Bewley, R. L., Haggard, D. C., & Swank, W. D. (2002). Plasma pyrolysis of methane to hydrogen and carbon black. Industrial & Engineering Chemistry Research, 41(6), 1425–1435. https://doi.org/10.1021/ie010722e
[26] Muradov, N. Z., & Veziroğlu, T. N. (2005). From hydrocarbon to hydrogen-carbon to hydrogen economy. International Journal of Hydrogen Energy, 30(3), 225–237. https://doi.org/10.1016/j.ijhydene.2004.03.033
[27] Hamdani, I. R., Ahmad, A., Chulliyil, H. M., et al. (2023). Thermocatalytic decomposition of methane: A review on carbon-based catalysts. ACS Omega, 8(32), 28945–28967. https://doi.org/10.1021/acsomega.3c01936
[28] Moghaddam, A. L., Hejazi, S., Fattahi, M., Kibria, M. G., Thomson, M. J., AlEisa, R., & Khan, M. A. (2025). Methane pyrolysis for hydrogen production: Navigating the path to a net zero future. Energy & Environmental Science, 18, 2747–2790. https://doi.org/10.1039/D4EE06191H
[29] Mašláni, A., Hrabovský, M., Křenek, P., Hlína, M., Raman, S., Sikarwar, V. S., & Jeremiáš, M. (2021). Pyrolysis of methane via thermal steam plasma for the production of hydrogen and carbon black. International Journal of Hydrogen Energy, 46(2), 1605–1614. https://doi.org/10.1016/j.ijhydene.2020.10.105
[30] Wnukowski, M., Jasiński, M., & Mizeraczyk, J. (2023). Methane pyrolysis with the use of plasma: Review. Energies, 16(18), 6441. https://doi.org/10.3390/en16186441
[31] Dors, M., Izdebski, T., Berendt, A., & Mizeraczyk, J. (2014). Chemical kinetics of methane pyrolysis in microwave plasma at atmospheric pressure. Plasma Chemistry and Plasma Processing, 34, 313–326. https://doi.org/10.1007/s11090-013-9510-4
[32] Wnukowski, M., et al. (2022). Shifts in product distribution in microwave plasma methane conversion. Plasma, 5(4), 567–583. https://doi.org/10.3390/plasma5040038
[33] Chen, X., et al. (2025). Plasma induced methane conversion: A review on COx-free production of hydrogen, valuable chemicals, and functional carbon materials. EES Catalysis. https://doi.org/10.1039/D5EY00054H
[34] Fridman, A. (2008). Plasma Chemistry. Cambridge University Press. https://doi.org/10.1017/CBO9780511546075
[35] 陳冠廷（2007）。常壓微波電漿裂解與蒸汽重組甲烷產氫之研究。國立高雄應用科技大學化學工程與材料工程系碩士論文。
[36] Ferrari, A. C., & Robertson, J. (2000). Interpretation of Raman spectra of disordered and amorphous carbon. Physical Review B, 61, 14095–14107. https://doi.org/10.1103/PhysRevB.61.14095
[37] Tuinstra, F., & Koenig, J. L. (1970). Raman spectrum of graphite. The Journal of Chemical Physics, 53, 1126–1130. https://doi.org/10.1063/1.1674108
[38] Ferrari, A. C., & Robertson, J. (2004). Raman spectroscopy of amorphous, nanostructured, diamond-like carbon, and nanodiamond. Philosophical Transactions of the Royal Society A, 362, 2477–2512. https://doi.org/10.1098/rsta.2004.1452
[39] Warren, B. E. (1941). X-ray diffraction in random layer lattices. Physical Review, 59, 693–698. https://doi.org/10.1103/PhysRev.59.693
[40] Sadezky, A., Muckenhuber, H., Grothe, H., Niessner, R., & Pöschl, U. (2005). Raman microspectroscopy of soot and related carbonaceous materials: Spectral analysis and structural information. Carbon, 43(8), 1731–1742. https://doi.org/10.1016/j.carbon.2005.02.018
[41] Cullity, B. D., & Stock, S. R. (2001). Elements of X-Ray Diffraction (3rd ed.). Prentice Hall.
[42] Goldstein, J. I., Newbury, D. E., Michael, J. R., Ritchie, N. W. M., Scott, J. H. J., & Joy, D. C. (2018). Scanning Electron Microscopy and X-Ray Microanalysis (4th ed.). Springer. https://doi.org/10.1007/978-1-4939-6676-9