乙二醇還原法製備鉑/碳觸媒之研究

Study of the preparation of Pt/C catalyst by ethylene glycol reduction

江昇壕(Sheng-Hao Chiang)

指導教授 ： 黃進益

國立臺北科技大學/工程學院/化學工程研究所/碩士(2008年)

摘要

燃料電池之電極氧化還原反應，係藉助觸媒反應來降低活化能以利電化學反應的進行。其中，觸媒著重於顆粒尺度大小、載體表面的分散性及控制成本等方面。利用化學還原法簡單且直接的化學反應能夠使得鉑前驅物與碳載體形成均勻的混合。
本研究以0.05M的氯鉑酸做為前驅物於乙二醇溶液還原在Vulcan XC-72R碳載體表面，製備20wt%載量及40wt%載量的鉑/碳觸媒。另外添加不同莫耳比率的硼氫化鈉(莫耳比率為乙二醇:硼氫化鈉=10：1、15：1)，於室溫下(25℃)進行化學還原反應4小時，藉此觀察利用乙二醇還原鉑/碳觸媒以及添加NaBH4對還原反應的影響。本實驗製備鉑/碳觸媒後利用XRD進行金屬晶體結構分析；定量分析使用SEM觀察鉑/碳觸媒表面的分布情形，發現在添加NaBH4濃度(莫耳比率為乙二醇:硼氫化鈉=10：1)製備之鉑觸媒分散性最佳，顆粒大小最佳為6~7nm。最後在0.5M H2SO4、1M CH3OH中利用循環伏安法(Cyclic voltammetry)進行鉑觸媒對甲醇之電氧化行為。實驗結果發現利用乙二醇溶液添加NaBH4所製備出具有高分散性且良好催化活性之觸媒，其對甲醇氧化反應能夠得到最佳之波峰電流。

關鍵字

乙二醇 ； 鉑觸媒

並列摘要

The oxidation reaction of electrode in the fuel cell is used Pt catalyst to make lower activation energy and is better to make electrochemical reaction happened. The basis of catalyst design is in dimension of particle and dispersible on carrier’s surface and decrease the cost. In many preparation methods, chemical reduction method is the broad used at present, simple and direct chemical reaction make Pt can mix well with carbon carrier.
In this research, 0.05M H2PtCl6 plus ethylene glycol solution and different molar ratio of NaBH4 (molar ratio of EG:NaBH4=10：1、15：1) to reduce 20wt% loading and 40wt%loading Pt on the surface of Vulcan XC-72R carbon，and the reaction continue with 4h at 25℃. After the Pt catalyst completed, the catalyst is characterized by X-ray diffraction (XRD).The catalyst surface is observed by scanning electron microscope (SEM).Under the condition molar ratio of EG:NaBH4=10：1, it can get the Pt particle at 6 to 7 nm. The electrochemical behaviors are analyzed by cyclic voltammetry (CV) under 0.5M H2SO4 and 1M CH3OH. In this result, the catalyst reduced by ethylene glycol with NaBH4 that are higher dispersion and better catalysis activation then only used ethylene glycol or NaBH4 and got the better methanol oxidation current.

並列關鍵字

ethylene glycol ； platinum catalyst

參考文獻

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