低溫燃料電池用Pt/C觸媒之電催化特性分析

Electrocatalytic Characterization of Pt/C Catalysts Used in Low-Temperature Fuel Cells

何佩紋(Pei-Wen Ho) ； 李鴻達(Hung-Ta Li) ； 徐沛紳(Pei-Sheng Hsu) ； 施信民(Shin-Min Shih) ； 林仁斌(Ren-Bin Lin)

《華岡工程學報》 26期 (2010/06) Pp. 153-158

https://doi.org/10.29987/CCUHKJE.201006.0021

摘要

本研究以膠體先驅物法製備低溫燃料電池用碳黑負載之奈米級鉑（Pt/C）觸媒，並以循環伏安法（CV）及旋轉電極（RDE）探討Pt/C觸媒上化學吸附的一氧化碳（CO）對氫氣氧化反應（HOR）的影響。以X-ray繞射分析儀（XRD）和穿透式電子顯微鏡（TEM）量測所製備的5.4～27.2wt% Pt/C觸媒之Pt 粒徑範圍為3.1～8.9 nm，其值比商用Pt/C觸媒中的略大。藉由CO吸附降低觸媒活性面積，利用薄膜旋轉電極方法可求得Pt/C觸媒層氫氣氧化的電流密度，進而測得交換電流密度。在高CO覆蓋率下，Pt/C觸媒層的氫氣氧化反應為化學反應與擴散混合控制。本研究測得所製備之27.2wt% Pt/C觸媒的交換電流密度為5mA/cm^2（2A/mg（下標 Pt)）。

關鍵字

白金 ； 電催化 ； 氫氣氧化 ； 一氧化碳 ； 燃料電池

並列摘要

Platinum on carbon catalysts used in low-temperature fuel cells were prepared by using colloidal precursor technique. The influences of chemisorbed CO on the hydrogen oxidation reaction (HOR) on the catalyst were investigated by cyclic voltammetry (CV) and the rotating disk electrode (RDE) techniques. The particle size of Pt for 5.4~27.2 wt% Pt/C catalysts prepared, determined by X-ray diffraction (XRD) and transmission electron microscopy (TEM), was in the range of 3.1~8.9 nm, which are slightly larger than that of the commercial Pt/C catalyst. By reducing the electroactive surface area of the catalyst through the adsorption of CO, the current density in the catalyst layer and thus the exchange current density for HOR on the catalyst can be measured using the thin-film RDE methodology. At the higher CO coverage, the HOR in the Pt/C catalyst layer was the case of a mixture of reaction and diffusion control. The exchange current density of the prepared 27.2wt% Pt/C was determined to be 5mA/cm^2 (2A/mg(subscript Pt)).

並列關鍵字

platinum ； electrocatalysis ； hydrogen oxidation ； carbon monoxide ； fuel cells