Modeling gas-diffusion electrodes for CO₂ reduction.

Area of Science:

• Electrochemistry
• Chemical Engineering
• Materials Science

Background:

• Electrochemical CO2 reduction is hindered by mass transport limitations in aqueous electrolytes with planar electrodes.
• Vapor-fed gas-diffusion electrodes (GDEs) offer a pathway to significantly higher current densities by mitigating these transport barriers.

Purpose of the Study:

• To develop a multiphysics model for gas diffusion electrodes (GDEs) used in CO2 reduction.
• To investigate the complex interplay between species transport and electrochemical reaction kinetics within GDEs.
• To identify key parameters influencing GDE cell performance for optimized CO2 reduction.

Main Methods:

• Development of a multiphysics computational model for GDEs.
• Simulation of species transport and electrochemical reactions under various operating conditions.
• Parametric study of catalyst layer properties (hydrophobicity, loading, porosity) and electrolyte flowrate.

Main Results:

• The model quantifies how the local environment near the catalyst layer, influenced by operating conditions, impacts cell performance.
• Demonstrated significant improvements in current density using GDEs compared to planar electrodes.
• Identified critical parameters for optimizing GDE performance in CO2 reduction.

Conclusions:

• Multiphysics modeling provides crucial insights into GDE performance for CO2 reduction.
• Optimizing GDE design and operating parameters is essential for efficient electrochemical CO2 conversion.
• This work guides experimental efforts in developing advanced vapor-fed CO2 reduction cells.