Methods—A Potential–Dependent Thiele Modulus to Quantify the Effectiveness of Porous Electrocatalysts
Name
a-potential-dependent-thiele-modulus-to-quantify-the-effectiveness-of-porous-electrocatalysts.pdf
Description
Accepted version
Size
2.61 MB
Format
Adobe PDF
Checksum (MD5)
7a524dee3fdc345abe20ef92e9211abb
Author(s)
Wan, Charles Tai-Chieh
Greco, Katharine V
Alazmi, Amira
Darling, Robert M
Chiang, Yet-Ming
Brushett, Fikile R
Date Issued
2021
Journal
Journal of The Electrochemical Society
Publisher
The Electrochemical Society
Citation
Wan, Charles Tai-Chieh, Greco, Katharine V, Alazmi, Amira, Darling, Robert M, Chiang, Yet-Ming et al. 2021. "Methods—A Potential–Dependent Thiele Modulus to Quantify the Effectiveness of Porous Electrocatalysts." Journal of The Electrochemical Society, 168 (12).
Version
Author's final manuscript
Abstract
Electrochemical reactors often employ high surface area electrocatalysts to accelerate volumetric reaction rates and increase productivity. While electrocatalysts can alleviate kinetic overpotentials, diffusional resistances at the pore-scale often prevent full catalyst utilization. The effect of intraparticle diffusion on the overall reaction rate can be quantified through an effectiveness factor expression governed by the Thiele modulus parameter. This analytical approach is integral to the development of catalytic structures for thermochemical processes and has previously been extended to electrochemical processes by accounting for the relationship between reaction kinetics and electrode overpotential. In this paper, we illustrate the method by deriving the expression for the potential-dependent Thiele modulus and using it to quantify the effectiveness factor for porous electrocatalytic structures. Specifically, we demonstrate the application of this mathematical framework to spherical microparticles as a function of applied overpotential across catalyst properties and reactant characteristics. The relative effects of kinetics and mass transport are related to overall reaction rates, revealing markedly lower catalyst utilization at increasing overpotential. Subsequently, we generalize the analysis to different catalyst shapes and provide guidance on the design of porous catalytic materials for use in electrochemical reactors.
MIT Department
Massachusetts Institute of Technology. Department of Chemical Engineering
Massachusetts Institute of Technology. Department of Materials Science and Engineering
Terms of Use
Attribution-NonCommercial-ShareAlike 4.0 International
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1149/1945-7111/AC34CE
