Mathematical modeling of direct ethanol fuel cells using a multi-step chemical kinetic mechanism Articles uri icon

publication date

  • October 2016

start page

  • 1

end page

  • 104

issue

  • 25

volume

  • 72

International Standard Serial Number (ISSN)

  • 1938-6737

Electronic International Standard Serial Number (EISSN)

  • 1938-5862

abstract

  • A 1D across-the-channel model is proposed for the anode of a Direct Ethanol Fuel Cell. The complex kinetics of the multi-step ethanol oxidation reaction is described using the reaction mechanism proposed by Meyer et al. [Electrochim. Acta, 56, 4299 (2011)], which considers free and adsorbed intermediate species on a Pt-based binary catalyst. The adsorbed species are modeled using coverage factors to account for the blockage of the active reaction sites on the catalyst surface. The reactions rates are described by Butler-Volmer equations, including the effect of ethanol and acetaldehyde crossover. A genetic algorithm is employed for determining the reaction constants for several catalyst types using polarization curves obtained from literature sources. By adjusting the reaction constants, different catalyst layers can be modeled and their selectivities can be partially reproduced. The discrepancies between the experimental and numerical results at low current densities suggest that Meyer's mechanism could be improved by adding acetaldehyde to the adsorbed intermediates.