Modeling and upscaling analysis of gas diffusion electrode-based electrochemical carbon dioxide reduction systems

As an emerging technology for CO2 utilization, electrochemical CO2 reduction reaction (ECO2RR) systems incorporating gas diffusion electrodes (GDE) have the potential to transform CO2 to valuable products efficiently and environment-friendly. In this work, a two-dimensional multiphase model capturing the details of the catalyst layer in a GDE that produces formate with byproducts is established and quantitatively validated against experimental data. This model is capable of describing the mixture gas and aqueous species transportation, electron conduction processes, and a series of interrelated chemical and electrochemical reactions. Specific electrical energy consumption (SEEC) and product yield (PY) have been introduced and used to examine the GDE scalability and evaluate the system performance. The results predict the optimal values for applied cathode potential and catalyst loading and porosity. The effect of inlet gas composition and velocity is also evaluated. Moreover, this study predicts that the GDE is scalable as it retains a stable performance as its geometrical surface area varies. This model together with the simulation findings contributes to the improved understanding of GDE-based CO2 conversion as needed for the future development toward successful industrial applications.