Modeling of a microfluidic electrochemical cell for the electro-reduction of CO2 to CH3OH

Abstract

This study focuses on developing a mathematical model for the electrochemical reduction of CO2 into CH3OH in a microfluidic flow cell. The present work is the first attempt to model the electro-reduction of CO2 to alcohols, which is a step forward toward the scale up of the process to industrial operation. The model features a simple geometry of a filter press cell in which the steady state isothermal reduction takes place. All significant physical phenomena occurring inside the cell are taken into account, including mass and charge balances and transport, fluid flow and electrode kinetics. The model is validated and fitted against experimental data and shows an average error of 20.2%. The model quantitatively demonstrated the dominance of the hydrogen evolution over the CH3OH production and the limitations imposed on the process due to the mass transfer of the reactants to the cathode, especially CO2. Also, the model shows that based on the flow pattern of CH3OH, more conductive membrane materials could be used to decrease the potential drop around the membrane in order to improve the process performance.