單電流脈衝電鍍製備奈米鉑-釕/碳陽極 之甲醇電氧化研究

Single Current Pulse Electrodeposition of Nanostructured Pt-Ru/C Anodes for Methanol Electrooxidation

鄒威民(Wei-Min Tsou)

指導教授 ： 黃進益

國立臺北科技大學/工程學院/化學工程所/碩士(2005年)

摘要

直接甲醇燃料電池(DMFC)以質子交換膜為電解質，用甲醇水溶液為進料注入電池內進行電催化發電，具有高能量密度、燃料補充方便及低污染等優點。然而，發展直接甲醇燃料電池的主要瓶頸之一，為昂貴的觸媒價格。因此，如何製備奈米級的Pt- Ru 來大幅降低成本，和增加陽極甲醇氧化的反應速率為主要課題之ㄧ。本研究在0.05M H2PtCl6、0.05M RuCl3、1M HCl 鍍液中，使用單電流脈衝法，通電時間(ton)為0.1 秒，斷電時間(toff)為0.3 秒，分別以電流密度：20、40、50、60、70、80 mA cm-2，固定通電量2.27 庫倫，製備奈米Pt-Ru 觸媒。然後將其置於0.5M H2SO4 溶液中，以循環伏安法檢查是否有Pt-Ru 觸媒的析鍍。電鍍前後的鍍液經分析，其電鍍電流效率約為83％。並使用高解析度場發射式電子顯微鏡（FE-SEM）檢測Pt-Ru 觸媒的粒徑約為5 ~ 30 nm。再將不同電流密度製備的PtRu/C 電極置於0.5M ~ 4M CH3OH 溶液中，探討其甲醇電氧化反應。综合實驗結果發現，以電流密度在50 ~ 60 mA cm-2 製備之奈米PtRu/C 電極表現為最佳。

關鍵字

電流脈衝 ； 鉑-釕觸媒 ； 甲醇電氧化

並列摘要

The direct methanol fuel cell (DMFC) using a solid electrolyte membrane as an electrolyte which pours aqueous methanol into the fuel cell directly for electrocatalysis to generate electric power, has good energy efficiency, complement fuel comvenient and no pollution problem etc. . However, a main problem in the development of a DMFC is expensive catalysts price. To fabricate nano scale Pt-Ru
can lower the catalyst cost materially and promote the anode kinetics of methanol oxidation. For lower the catalyst loadings, electrodeposition is used to fabricate
electrodes for DMFC. The platinum- ruthenium alloy (PtRu) catalysts were prepared by changing applied current density : 20、40、50、60、70、80 mA cm-2 and the total
charges are controlled under 2.27 C/cm2 with 0.1s on-time(ton) and 0.3s off-time(toff) which have been investigated in 0.05M H2PtCl6、0.05M RuCl3、1M HCl solution. Cyclic voltammetry (CV)of electrodes in 0.5M H2SO4 after deposition were used to evaluate the loading of metal catalysts. The efficiency of is about 83％ and the
particle sizes range of Pt-Ru catalyst measured by field emission scanning electron microscopy (FE-SEM) from 5 to 30 nm. The electrocatalytical properties of PtRu/C
electrode in 0.5M ~ 4M CH3OH prepared under different conditions for methanol electrooxidation was studied. The results showed that electro- catalytic PtRu/C
electrode prepared by applied current density of 50 ~ 60mA cm-2 was better than that of catalysts prepared at any other applied current.

並列關鍵字

galvanostatic pulses ； Platinum-Ruthenium catalysts ； Methanol electrooxidation

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