利用脈衝雷射沉積成長燃料電池觸媒層

Growth of Carbon Support for Proton-Exchange-Membrane Fuel Cell by Pulsed-Laser Deposition (PLD)

陳亮吟(Liang-Yin Chen)

指導教授 ： 陳賜原 ； 林俊元

國立中正大學/理學院/物理學系/碩士(2014年)

摘要

摘要
關鍵字:燃料電池、脈衝雷射沉積法、碳奈米粒子、石墨化、拉曼光譜儀
隨著石化能源的大量開採，衍生出能源短缺和環境污染的問題，為尋求替代能源，開始發展燃料電池。燃料電池利用氫氣和氧氣所產生的化學能轉變成電能，產物是無汙染性的水，只要持續提供氫氣與氧氣，就有源源不絕的電能，因此燃料電池扮演著未來能源的重要角色。
燃料電池中的電極層是我研究的主要目標，電極層包含氣體擴散層(gas diffusion layer，GDL)和觸媒層(catalyst)，氣體擴散層能提供水和氣體的通道並支撐觸媒層，觸媒層則是催化氫氣反應產生氫離子和電子。觸媒又分為由碳奈米顆粒組成的微孔層和鉑奈米粒子。為解決碳原子的孤島效應，我使用脈衝雷射沉積法(pulsed laser deposition， PLD)來製作微孔層的碳粒子，此法為利用一道高功率雷射透過透鏡聚焦在靶材上，將靶材將熱至汽化而形成電漿蕈狀團(plasma plume)沉積在基板上形成薄膜。
在實驗中，我嘗試不同的壓力和碳紙(作為氣體擴散層)，比較不同條件下所製作的觸媒在燃料電池中的性能。實驗結果發現，在壓力比較高，微孔層的厚度較薄的條件下，燃料電池的性能較佳，從診斷結果推論出，在高壓時形成的碳顆粒，會明顯由小顆粒聚集成大顆粒，顆粒間有較多的孔隙，另外一個原因，則是石墨化程度比較好，所以有較好的導電度，能更有效率的傳送電子，由此可知，碳粒子的孔隙度與導電性是影響電池性能的重要因素。最後的實驗結果雖然效能不如商用的觸媒，但能預期往越高的壓力，增加碳粒子間的孔隙和石墨化程度，就能獲得更好的電池性能。

關鍵字

石墨化 ； 碳奈米粒子 ； 脈衝雷射沉積法 ； 燃料電池 ； 拉曼光譜儀

並列摘要

Abstract
key word: Fuel Cell、Pulsed Laser Deposition、Carbon Nano-particle、Degree of Graphitization、Raman Spectrum
With the large number of mining fossil fuels, the energy shortage and environmental pollution problems have become more and more serious. People begin to develop fuel cells for seeking alternative energy sources. Fuel cell use the chemical energy generated by hydrogen and oxygen transfer into electrical energy, and only produce water which is non-polluting products. As long as hydrogen was supplied continuously, there is an endless supply of electric power, so that the fuel cell plays an important role in future energy.
I did the research of gas diffusion electrode of fuel cell. Gas diffusion electrode include gas diffusion layer (GDL) and catalyst layer. Gas diffusion layer provide the passage for water and gas and support catalyst layer. Catalyst layer which urge hydrogen become ion and electron can divide into two parts, microporous layer formed by carbon nano-particle, and platinum nano-particle. For solving isolated effect, I use pulsed laser deposition( PLD) to make carbon nano-particle of catalyst layer. Pulsed laser deposition is a method that use a high power laser beam focus on the target through a lens and heat up the target to vapor to become plasma plume and finally become films and deposit on the substrate.
In the experiment, I make catalyst layer in different pressure and on different carbon paper(as gas diffusion layer), and compare the performance of fuel cell. From the experiment results, I find out that microporous layer made in higher pressure and has smaller thickness will have better performance. Deducing from diagnose result, carbon nano-particle grown in higher pressure will aggregate to each other and have bigger size, there will be more passage between particles. The other reason is that carbon nano-particle grown in higher pressure will have higher degree of graphitization, which means that conductivity is better, it can transfer electron more efficient. We can learn that morphology and conductivity of carbon nano-particle are two important matters that effect the performance of fuel cell. The final result doesn’t have better performance than commercial catalyst, but we can know that in higher pressure and increase the passage and degree of graphitization can have better performance.

並列關鍵字

Raman Spectrum ； Degree of Graphitization ； Carbon Nano-particle ； Pulsed Laser Deposition ； Fuel Cell

參考文獻

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[4] 蔡秉蒼, “應用金屬發泡材為流道之質子交換膜燃料電池之研究”, 國立中央大學機械系(2012)

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