https://scholars.lib.ntu.edu.tw/handle/123456789/178788
標題: | 直接甲醇燃料電池用鈀-碳-鐵合金觸媒之開發及其特性研究 Development and Characterization of Pd-C-Fe Electrocatalysts Used in Direct Methanol Fuel Cells |
作者: | 葉雲傑 Yeh, Yun-Chieh |
關鍵字: | X光吸收光譜;非鉑觸媒;鈀碳鐵;直接甲醇燃料電池;PdCFe;non-platinum electrocatalyst;X-ray absorption spectroscopy;DMFCs | 公開日期: | 2008 | 摘要: | 目前全球能源需求日益提升,於取得能源同時對於環境之威脅亦相提升,有鑑於此,目前世界各國正極力投入燃料電池相關研究藉以發新型之綠色能源。料電池乃藉化學反應以產生電能,其中電化學觸媒於燃料分解反中扮演不可或缺之角色。傳統甲醇燃料電池用觸媒乃為鉑金屬及其關合金粒子並使用不同碳材做為載體以增加該觸媒之催化效能,然鉑金屬價格高昂、蘊藏量短少且於操作過程中具甲醇毒化之缺點,對該觸媒之普及無疑為一大威脅,因此,非鉑觸媒之發展以逐漸受重視。據目前文獻指出鈀金屬觸媒具高抗甲醇毒化特性,該特性對甲醇燃料電池壽命之延長具相當之助益;為提升鈀金屬之催化活,於鈀金屬中參雜不同之過渡金屬乃為一有效之方法,然而對於電學活性提升之現象目前仍未有一正確之機制提出。研究以含浸法製備PdCFe/C 觸媒,並以X 光吸收光譜進行樣品構分析以建立觸媒合成機制;觸媒氧氣還原活性及甲醇穿透測試方乃以循環伏安電位儀進行測試,並配合理論計算以建立氧氣於還原程中之行為;由於觸媒於酸性電解質下操作觸媒粒子及碳材將因酸作用而流失,有鑑於此,本研究分別以含浸法及逐滴添加法還原金層(Au monolayer)於PdCFe/C 表層以期觸媒抗酸能力之提升並以感應合電漿原子吸收光譜儀測試觸媒抗酸能力,由研究結果顯示,藉金子層之保護,觸媒抗酸能力得以提升顯示其為一有效保護觸媒並延期使用壽命之方式。 With global energy demand growth and human impacts on thenvironment, to raise the requirements of each country on fuel cell researchnd development is increasing. fuel cell is a device that generates electricity by a chemical reaction.ith the help of electrocatalyst, efficient decomposition of fuel could beltized. Platinum and its alloys supported on different kind of carbonupports were used as traditional electrocatalyst in direct methanol fuelells (DMFCs). However, the high cost and the limited abundance arehowing potential threat for further application in real life. Moreover,latinum-based catalyst suffered serious methanol-poisonoing problemuring cell operation. In this regard, non-platinum catalyst has received areat attention during these years. Recent research has shown that Pd-basedatalyst has higher tolerance to methanol than Pt-based catalyst. It mayenerate higher operational efficiency and can prolong the operation periodo the DMFCs. Most of recent investigations on Pd-based catalyst focus onow alloying effect between Pd and other kinds of transition metalsffected the catalytic efficiency. However, the real reason for themprovement of catalytic efficiency to these Pd-M alloy (M= transitionetal) is so far not fully understood.n the present thesis, PdCFe/C electrocatalyst was facilitated bympregnation method. X-ray absorption spectroscopy (XAS) was appliedor the structural investigations. The electrochemical behaviours towardsxygen reduction reaction (ORR) and the methanol crossover effect weretudied by cyclic voltammery (CV). The formation mechanism of PdCFe/Clectrocatalyst and its catalytic activity were facilitated by above studiesnd theoretical calculations. The corrosion of electrocatalysts and damagef carbon support are commonly occuring during the operation of fuel cells.o increase the acid tolerance and prolong the life time of electrocatalyst,u monolayer was deposited on the surface of PdCFe/C by modifiedmpregnation (IM) method and drop-by-drop (DBD) method. To performhe acid tolerance test, the Inductively couple plasma- atomic emissionpectroscopy (ICP-AES) was applied. Based on ICP-AES test results, theuppression of metal leaching was observed. It has also been proved thathe Au deposition method is the effective method for catalyst protectionuring the cell operation under acid electrolytic conditions. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/187485 |
顯示於: | 化學系 |
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ntu-97-R96223110-1.pdf | 23.32 kB | Adobe PDF | 檢視/開啟 |
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