單電流脈衝電鍍製備不同原子比鉑釕於碳之伏安研究

Single current pulse plating different atomic ratio platinum- ruthenium on carbon for voltammetric investigation

林漢威(Han-Way Lin)

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(2006年)

摘要

直接甲醇燃料電池之陽極觸媒其Pt-Ru原子比對甲醇氧化之影響甚鉅，鑑於此，本研究乃使用單電流脈衝電鍍，藉由改變鍍浴條件(包含前驅物Pt-Ru原子比:3/7、1/1、4/3、5/2及4/1，支持電解質濃度: 0.1、0.5、0.9、1.3及1.7M及甲醇濃度:0.5、1、1.5、2M)與電鍍操作參數(總通電量:0.5-8C與電流密度:30-120mA/cm2)期研製最佳性能之Pt-Ru/C。實驗結果發現，在25°C下，鍍浴為前驅物鉑釕原子比濃度4/3、 1.3M HCl及1.5M甲醇時所製備之觸媒電極具有最大之觸媒活性。當總通電量為6C C/cm2及電流密度提高至100mA/cm2時，所製備之觸媒具有最佳的氧化能力。而SEM圖發現，鍍層的結構受鍍浴中之甲醇成份影響甚大,對本實驗而言甲醇是個良好的晶粒細化劑。循環伏安法隨著掃瞄次數的增加，吸附在鉑上的釕會逐漸脫落，使得甲醇氧化電流增加，亦再次印證鉑的前驅物比例高於釕較符合雙功模式(bifunction model)。綜合本研究獲得之實驗結果:通電時間(ton)0.1秒，斷電時間(toff)0.3秒，固定通電量6C/cm2，電流密度100mA/cm2之操作參數下，鍍浴配方為0.01M H2PtCl6、0.0075M RuCl3、1.3M HCl及1.5M 甲醇等之條件下，可獲催化性能最佳之Pt-Ru/C觸媒。

關鍵字

單電流脈衝電鍍 ； 燃料電池 ； 鉑-釕原子比

並列摘要

The ratio of Pt-Ru on the anode of direct methanol fuel cell have much effect on methanol oxidation. In the view of this, we changed the plating bath compositions (including Pt-Ru precursor atomic ratios: 3/7 , 1/1 , 4/3 , 5/2 , 4/1 , supporting electrolyte concentrations:0.1,0.5,0.9,1.3,1.7M, and methanol concentrations: 0.5 , 1, 1.5 ,2M ) and plating operation parameter(including electrical input: 0.5-8C and current density: 30-120mA/cm2) by single current pulse plating .In order to produce Pt-Ru/C with the best performance in this study, the experiments indicate the catslyst with the bset performance of methanol oxidation was produced by these conditions : Pt-Ru precursor atomic ratio 4/3, the concentrations of HCl 1.3M and CH3OH 1.5M at 25°C in the plating bath, and the best plating operation parameters were 100mA/cm2,and 6C/cm2 .By the figures of SEM ,the component of methanol in the plating bath has a great influence on the structure of plating layer. It is a good grain refiner for this study. When the times of scaning by cyclic voltammograms increases, the Ru absorbing on Pt will desorb by degrees and made the peak of methanol oxidation current increase .It can prove that the precursor ratio of Pt is higher than Ru .According to the result, we can get a result corresponding with the bifunction model. In the words , we not only obtain the result of the experiments in the plating operation parameter which are on-time 0.3s,off-time 0.1, 6C/cm2,current density 60mA/cm2 and the plating bath compositions of 0.01M H2PtCl6,0.0075M RuCl3, 1.3M HCl and 1.5M CH3OH,but also produce the Pt-Ru/C with best performance of methanol oxidation.

並列關鍵字

single current pulse plating, ； fuel cell ； Pt-Ru atomic ratio

參考文獻

【84】衣寶廉，燃料電池原理與應用，五南文化事業，2005年

【2】 黃炳照，”PEMFC燃料電池陽極材料之發展及方向，化工第49卷第3期(2002)70-81

【66】鄒威民，定電流脈衝電鍍製備奈米鉑釕/碳雙金屬陽極之甲醇電氧化研究

【7】Ho Seok Park，”physical and electrochemical property of Nafion/polypyrrole composite membrane for DMFC”，J.membrane science 272(2006)28-36

【8】J.G.Liu et al.，”effect of membrane thickness on the performance and efficiency of passive direct methanol fuel cells”，J.power source 153(2006)61-67