Investigation of Gas Diffusion Electrode Systems for the Electrochemical CO2 Conversion

Electrochemical CO2 reduction is a promising carbon capture and utilisation technology. Herein, continuous flow gas diffusion electrode (GDE)-cell configuration has been studied to convert via electrochemical under atmospheric conditions. To this purpose, Cu-based electrocatalysts immobilised on porous conductive GDE have tested. Many system variables evaluated find the most conditions able lead increased production of liquid products, specifically: applied potentials, catalyst loading, Nafion content, KHCO3 electrolyte concentration, presence metal oxides, like ZnO or/and Al2O3. In particular, CO productivity at lowest content 15%, leading syngas with an H2/CO ratio ~1. Meanwhile, highest (45%), C2+ products formation increased, selectivity decreased by 80%. The reported results revealed that crossover through highly impacts active sites, thus reducing conversion efficiency. Through mathematical modelling, it confirmed increase local pH, coupled electrode-wetting, promotes bicarbonate species deactivate catalysts surface, hindering mechanisms for generation. These want shine spotlight kinetics transport limitations, shifting focus from catalytic activity materials other involved factors.