The Studies of Anode Impedance and CNT-supported Pt-Ru Catalyst for Direct Methanol Fuel Cells
Date Issued
2006
Date
2006
Author(s)
Hsu, Ning-Yih
DOI
en-US
Abstract
Abstract
In this work, electrochemical impedance was used to analyze the reaction kinetics and interfacial characteristics of an anode in a direct methanol fuel cell (DMFC). An advanced equivalent-circuit model is proposed. The new model incorporates constant phase elements (CPEs) rather than conventional capacitors in the equivalent-circuits taking into account the porous structure of the anode, particularly that in the catalyst layer and at the anode/membrane interface. It effectively simulated the electrochemical characteristics of a DMFC porous anode. The impedance model incorporates the interface factor, resulting in excellent matches between the simulation results and the experimental data in the Nyquist and the Bode plots over a wide range of frequencies. In addition, the differences among methanol electrooxidation reaction kinetics at various operating potentials are clearly observed and satisfactorily explained using electrochemical impedance spectroscopy and the CPE-based equivalent-circuit model.
The performance of a single-cell direct methanol fuel cell (DMFC) using carbon nanotube-supported Pt-Ru (Pt-Ru/CNT) as an anode catalyst has been investigated. In this study, the Pt-Ru/CNT electrocatalyst was successfully synthesized using a modified polyol approach with a controlled composition very close to 20wt%Pt-10wt%Ru, and the anode was prepared by coating Pt-Ru/CNT electrocatalyst on a wet-proof carbon cloth substrate with a metal loading of about 4 mg cm-2. A commercial gas diffusion electrode (GDE) with a platinum black loading of 4 mg cm-2 obtained from E-TEK was employed as the cathode. The membrane electrode assembly (MEA) was fabricated using Nafion
Subjects
直接甲醇燃料電池陽極
奈米碳管
陽極觸媒
交流阻抗
動態氫電極
固定相角元件
Direct methanol fuel cell
CNT
Carbon nanotube
electrochemical impedance spectroscopy
dynamic hydrogen electrode
constant phase element
Type
thesis
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