Simulation-based guidance for improving CO 2 ${\rm CO}_{2}$ reduction on silver gas diffusion electrodes

Abstract

The reduction of ${\mathrm{CO}}_2$ in an electrochemical reactor using electrical energy is a promising approach to implement a more sustainable carbon economy and to replace fossil fuels with renewable carbon sources. Conventionally used solid plate electrodes are limited by poor mass transport of the reactants. Gas diffusion electrodes (GDEs) can overcome this limitation and have gained industrial relevance during the last decades. A comprehensive understanding of transport and conversion phenomena within such porous electrodes is not yet well developed. Here, we report a one-dimensional steady state model of the GDE to investigate the influence of relevant operational parameters and GDE properties on ${\mathrm{CO}}_2$ reduction. The results indicate the importance of controlling the local reaction environment, that is, the reactant concentration and the pH value, by tuning the electrolyte and gas composition, and flow rate as well as the catalyst layer properties.