Cyclic Voltammetric Measurement of Catalyst Surface Area for Pt-Black/Nafion Electrodes

以循環伏安法量測鉑黑／Nafion電極之觸媒表面積

林仁斌(Ren-Bin Lin) ； 施信民(Shin-Min Shih)

《Journal of the Chinese Institute of Chemical Engineers》 37卷4期 (2006/07) Pp. 311-319

https://doi.org/10.6967/JCICE.200607.0311

摘要

本研究以循環伏安法量測浸沒在0.5M硫酸溶液中的鉑黑／Nafion薄膜電極之電化學表面積。在高電位掃描速率下觸媒表面利用率減少，是由於不完全的氫吸附程序所致，溶液電阻所造成的歐姆電位降使得在負電位方向掃描時所測得的電極電位低於其真實值。當電極粗糙度或掃描速率增加時，歐姆電位降將隨著相應的電流增加而更為顯著。Nafion膜的厚度(≦8μm)對表面積量測幾無影響。在掃描速率未造成大幅歐姆電位降的情況下，電極觸媒的表面積可以被精確地測定；適當的掃描速率將隨電極粗糙度增加而減小。

並列摘要

The electrochemical surface areas of Pt-black/Nafion thin-film electrodes immersed in 0.5 M H2SO4 were measured using the cyclic voltammetry (CV) technique. The decrease in the catalyst surface utilization measured at high potential scan rates was due to the incomplete H-adsorption process caused by the ohmic potential drop in the solution, which resulted in the measured electrode potential being lower than the real one during the cathodic scan. The ohmic potential drop became more appreciable when the roughness factor of an electrode or the scan rate increased, due to the increase in the current. The Nafion film coating (≦8μm) had a negligible effect on the surface area measurements. The real catalyst surface area of an electrode can be accurately estimated through CV, if a scan rate that does not cause appreciable ohmic potential drops is used; the appropriate scan rate becomes lower as the roughness factor of the electrode increases.

並列關鍵字

Pt-black ； Cyclic voltammetry ； Catalyst surface utilization ； Porous electrode ； Fuel cells