利用脈衝式電鍍法製備高燃料氧化效能及抗一氧化碳毒化之新穎奈米結構鉑觸媒

Enhanced Catalytic Efficiency and CO Tolerance of Novel Pt Nanostructures Prepared by Pulsed Electrodeposition for Fuel Oxidation

莊宸綱(Chuang, Chen Kang)

指導教授 ： 葉宗洸

國立清華大學/原子科學院/工程與系統科學系/碩士(2015年)

摘要

本研究利用脈衝式電化學沉積法在乾淨碳紙上製備新型態鉑觸媒作為質子交換膜燃料電池之觸媒。此新型態鉑觸媒之特殊形貌可增加觸媒反應活性，在無其它碳載體的情況下具有較多的觸媒表面積，進而提升觸媒催化效率及降低觸媒承載量。經由循環伏安法於硫酸及甲醇溶液下進行電化學測試，並利用X光粉末繞射儀(XRD)、掃描式電子顯微鏡(SEM)、穿透式電子顯微鏡(TEM)以及電感耦合等離子體質譜(ICP-MS)對試片做進一步的分析。透過掃描式電子顯微鏡照片發現此新型態鉑觸媒的結構為樹枝狀結構，其主幹長度約為0.3至3 μm，而寬度約為400至600 nm。半電池電化學測試結果顯示，甲醇測試電流可達277.5 mA/cm2，其if/ib值為1.4，顯示鉑樹枝狀結構觸媒具有良好的抗一氧化碳毒化能力。使用最佳參數製備出的鉑樹枝狀觸媒在經由氫氣單電池測試，其功率密度可達506.7 mW/cm2，顯示鉑樹枝狀觸媒具有高催化性及耐久性。

關鍵字

鉑 ； 觸媒 ； 電化學沉積法 ； 質子交換膜燃料電池 ； 樹枝狀結構

並列摘要

Innovative support-free platinum (Pt) nanostructures were developed in this study for enhancing the anode catalyst activities for proton exchange membrane fuel cell (PEMFC) application. The platinum nanostructures were directly grown on carbon paper by a pulsed electrodeposition technique. The morphology of Pt nanostructures were investigated by SEM, and shown as dendritic structures instead of nanoparticles. The sizes of the dendritic structures are ranged from 0.3 to 3 μm in length and 400 to 600 nm in diameter. A cyclic voltammetry analysis was carried out for characterizing the behavior of methanol oxidation on specimen bearing the Pt dendritic nanostructures in mixed 1 M methanol and 0.5 M sulfuric acid solutions. It was found that the peak current density of methanol oxidation obtained from the cyclic voltammogram on the new Pt dendritic nanostructures specimen was 277.5 mA/cm2. Due to its unique morphology, the Pt dendritic nanostructures could exhibit a good carbon monoxide tolerance and high efficiency without the joined Ruthenium (Ru) catalyst. The catalytic efficiency of prepared Pt dendritic nanostructures was much better than that of a commercial Pt-black catalyst. It is noteworthy that the if/ib value of the Pt dendritic nanostructures is higher than 1.4, which is very different from pure Pt nanoparticles. The outcome signified that the novel catalyst morphology of the Pt dendritic nanostructures have remarkable CO tolerance even if Ru or other metal catalyst were not joined.

並列關鍵字

Platinum ； Catalyst ； Electrodeposition ； PEMFC ； Dendrite Structure

參考文獻

[21] 張育鳴，「改善電鍍技術製備以奈米碳管為載體之直接甲醇燃料電池陽極觸媒層」，國立清華大學碩士論文，2007

[23] J. Y. Sun, J. S. Huang, Y. X. Cao, and X. G. Zhang, "Hydrothermal synthesis of Pt-Ru/MWCNTs and its electrocatalytic properties for oxidation of methanol," International Journal of Electrochemical Science, vol. 2, pp. 64-71, Jan 2007.

[1] W. R. Grove, "On voltaic series and the combination of gases by platinum", Phil. Mag., vol. 14, pp. 127-130, 1839

[2] J. Larminie and A. Dicks, Fuel cell systems explained, 2nd ed. Chichester, West Sussex: J. Wiley, 2003.

[3] B. Wickman, "Nanostructured Model Electrodes for Studies of Fuel Cell Reactions", Chalmers University of Technology, 2010