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Lookup NU author(s): Dr Hua Cheng,
Emeritus Professor Keith Scott
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In order to improve the performance of direct methanol fuel cells, carbon-supported RuSeW nano-electrocatalysts were prepared using an impregnation method with RuO2, SeO2 and WO2 as precursors. The novel electrocatalyst was evaluated for oxygen reduction in 0.5 M H 2SO4 media in half cells, either as a gas diffusion electrode or as an ink-type rotating disk electrode. The most striking feature was that the tungsten participation significantly enhanced the kinetics of oxygen reduction, exhibiting greater apparent rate constants (up to 35%) and lower apparent activation energy (15% less) than those at the RuSe cathode. The oxygen reduction on the RuSeW electrode was a first-order reaction with respect to oxygen with the Tafel slopes of -0.07 and -0.12 V dec-1 at high and low potential regions, respectively. The enhancement effect was corroborated in direct methanol fuel cells. The electrochemical impedance spectra obtained insitu of fuel cells displayed reduced ohmic and cathode activation resistances as a consequence of the tungsten modification. The electrocatalytic effect was related to a change in the electrocatalyst structure, which was discussed based on the SEM and XRD data. © J. New Mat. Electrochem. Systems.
Author(s): Cheng H, Yuan W, Scott K, Browning DJ, Lakeman JB
Publication type: Article
Publication status: Published
Journal: Journal of New Materials for Electrochemical Systems
Print publication date: 01/07/2008
ISSN (print): 1480-2422
Publisher: Ecole Polytechnique de Montreal