Development and Optimization of Gas Diffusion Electrodes for Electrochemical CO2 Reduction at High Current Density

Abstract

The electrochemical reduction of CO2 to valuable compounds is a promising approach for its substantial utilization and the storage of electricity in chemical form. At present, the main challenges impeding technical realization are i) low production rates due to mass transport limitations deriving from the low solubility of CO2 in the electrolyte, ii) high overpotentials and poor energetic efficiency, necessitating development of more active catalysts, as well as iii) the demonstration of its continuous production which combines the above with low ohmic losses and long-term stability. Furthermore, hydrogen evolution occurs in the same potential range, and becomes dominating at current densities above 10 mA∙cm 2 on conventional metallic electrodes when diffusion of CO2 to the electrode surface becomes rate-determining.