Modeling gas-diffusion electrodes for CO 2 reduction

Modeling gas-diffusion electrodes for CO 2 reduction

TitleModeling gas-diffusion electrodes for CO 2 reduction
Publication TypeJournal Article
Year of Publication2018
AuthorsLien-Chun Weng, Alexis T Bell, Adam Z Weber
JournalPhysical Chemistry Chemical Physics
Volume20
Issue25
Pagination16973 - 16984
Date Published06/2018
ISSN1463-9076
Abstract

CO2 reduction conducted in electrochemical cells with planar electrodes immersed in an aqueous electrolyte is severely limited by mass transport across the hydrodynamic boundary layer. This limitation can be minimized by use of vapor-fed, gas-diffusion electrodes (GDEs), enabling current densities that are almost two orders of magnitude greater at the same applied cathode overpotential than what is achievable with planar electrodes in an aqueous electrolyte. The addition of porous cathode layers, however, introduces a number of parameters that need to be tuned in order to optimize the performance of the GDE cell. In this work, we develop a multiphysics model for gas diffusion electrodes for CO2 reduction and used it to investigate the interplay between species transport and electrochemical reaction kinetics. The model demonstrates how the local environment near the catalyst layer, which is a function of the operating conditions, affects cell performance. We also examine the effects of catalyst layer hydrophobicity, loading, porosity, and electrolyte flowrate to help guide experimental design of vapor-fed CO2 reduction cells.

DOI10.1039/C8CP01319E
Short TitlePhys. Chem. Chem. Phys.