在Nafion與Pt/C觸媒混合製備電極上的氫氣氧化反應動力學分析

Kinetics of Hydrogen Oxidation Reaction on Electrodes Prepared with Nafion and Pt/C Catalysts

徐瑞甫(Rui-Fu Hsu) ； 謝宗達(Tzung-Da Shie) ； 施信民(Shin-Min Shih) ； 林仁斌(Ren-Bin Lin)

《華岡工程學報》 27期 (2011/01) Pp. 71-76

https://doi.org/10.29987/CCUHKJE.201101.0009

摘要

本研究以旋轉電極及循環伏安法探討Nafion與Pt/C觸媒混合製備電極上的電催化氫氣氧化反應動力學。結果顯示，Nafion會阻擋白金的活性位置，隨著Nafion/Pt比例的增加，電化學活性表面積會下降。在相同Nafion/Pt比例下，電化學活性表面積會隨著白金負載量增加而呈線性關係增加。而白金負載量與Nafion/Pt比例的改變則對氫氣氧化的電流密度幾乎沒有影響。藉由伏安圖譜，應用修正的Koutecky-Levich方程式，可求出反應動力學參數。本研究顯示，氫氣在電極上的氧化反應皆非常快速，因此反應受電解質溶液中氫氣的質傳速率所控制，所測得之電流密度皆為質傳速率。

關鍵字

電催化 ； 氫氣氧化 ； 白金 ； Nafion ； 燃料電池

並列摘要

The reaction kinetics of hydrogen oxidation on the electrodes prepared with Nafion and Pt/C catalysts were investigated by the rotating disk electrode and cyclic voltammetry techniques. The results indicated that the active sites of Pt were blocked by th Nafion coating, and the electrochemical active surface decreased with the increasing Nafion/Pt ratio. At the same Nafion/Pt ratio, the electrochemical active surface increased in a linear relationship with the Pt-loading. The current density of hydrogen oxidation was hardly influenced by the Pt-loading and the Nafion/Pt ratio. The hydrodynamic voltammograms were analyzed to determine the kinetic parameters by using the modified Koutecky-Levich equation. The results showed that the oxidation reaction of hydrogen on the electrodes was very fast, and thus the reactions were controlled by the diffusion of hydrogen in the electrolyte. The measured current densities here were all the mass transfer rates.

並列關鍵字

electrocatalysis ； hydrogen oxidation ； platinum ； Nafion ； fuel cell