A CuOx/Cu/C electrocatalyst-based gas diffusion electrode for the electroreduction of CO2 with high selectivity to C2H4

Abstract

Electrochemical conversion of CO₂ (CO₂RR) has received significant attention since it could provide pathways for renewable energy storage to energy-dense chemicals and synthetic fuels. We developed a novel CuO_x/Cu/C type electrocatalyst via pyrolysis, which we used to convert CO₂ at industrially relevantly current densities using gas diffusion electrodes. The influence of the pyrolysis conditions on the electrocatalytic CO₂RR activity and selectivity was evaluated. Optimization of the electrode structure to mitigate electrowetting was done by mixing the catalyst with polytetrafluoroethylene (PTFE). We found that mixing the most active catalyst with PTFE in a mass ratio of 1 to 0.25 substantially increased the formation of C₂H₄ displaying 41% Faradaic efficiency (FE) at –240 mA cm^–2. Prolonged CO₂RR at different current densities shows that the electrode containing 25 wt.% PTFE in the catalyst layer display FE_C2H4 > 40% at –280 mA cm^–2 for 2 h.