Upscaled model for diffusion and serial reduction pathways in porous electrodes
Langue
EN
Article de revue
Ce document a été publié dans
Journal of Electroanalytical Chemistry. 2019, vol. 855
Résumé en anglais
Multiscale modelling of coupled diffusion and serial reduction reactions
in porous micro-electrodes is developed in this work. The governing cou-
pled equations at the pore scale in the case of two reduction reactions, ...Lire la suite >
Multiscale modelling of coupled diffusion and serial reduction reactions
in porous micro-electrodes is developed in this work. The governing cou-
pled equations at the pore scale in the case of two reduction reactions, as
for instance, the serial reaction pathway for oxygen reduction to hydrogen
peroxide and subsequently to water, are upscaled to obtain a macroscopic
model describing the process in an effective medium at the electrode scale.
This new macroscopic model, obtained from the volume averaging technique,
is validated through comparisons with results of 3D Direct Numerical Sim-
ulations of the pore-scale model. The excellent agreement between the two
approaches proves the relevance of the macroscale model which reduces to a 1D problem in the configuration under concern, providing a drastic speedup in the computation of the solution. Numerical results obtained with the macroscopic model are successfully compared to experimental data obtained by voltammetry with porous gold electrodes of different thicknesses operating the serial pathway of oxygen reduction to water. Results highlight the ability of this new macroscopic model to predict the electrode behavior and show that the second reduction reaction of hydrogen peroxide plays an important role in the current production.< Réduire
Mots clés en anglais
Porous micro-electrode
Oxygen reduction reaction
Diffusion reaction macroscopic model
Upscaling
Volume averaging method