Authors: Antonio Rodolfo dos Santos Marcelo Carmo Almir OliveiraNeto Estevam V Spinacé João G Rocha Poço Christina Roth Hartmut Fuess Marcelo Linardi
Publish Date: 2007/07/25
Volume: 14, Issue: 1, Pages: 43-51
Abstract
This works report results of the structural and the electrochemical characterization of membrane electrode assemblies MEA for proton exchange membrane fuel cells PEMFC under various cell conditions using different MEA production processes Electrochemical impedance spectroscopy EIS was applied “online” in situ as a tool for diagnosis concerning the cell performance MEA with a 25cm2 surface area were prepared using Pt/C and Pt–Ru/C commercial electrocatalysts from ETEK and Pt–Ru/C electrocatalysts produced by the alcohol reduction process The catalytic ink was applied directly onto the carbon cloth or alternatively onto the Nafion® membrane Two carbon cloth thicknesses were tested as diffusion layers in the MEA 0346 mm common and 0424 mm ELAT An increase of the electrocatalytic activity can be obtained by pH control in the alcohol reduction process possibly due to the better particle dispersion and the smaller particle sizes observed In addition a slower current decay in the ohmic region was observed using the thinner carbon cloth This can be related to a lower resistance of the gas flow through the cloth to the catalytic active layer Different types of methanol feed were employed in the experiments by humidification and by evaporation The results showed that the choice of suitable methods for catalyst preparation as well as for MEA production enhance PEMFC performance
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