Porous carbon-supported Ag catalysts enable high-current-density CO₂ electroreduction to CO with enhanced mass transport

Silver nanoparticles are typically utilized for the electrochemical reduction of CO₂ to CO, which usually undergo aggregation and deactivation during the reaction. In this study, four types of carbon black with distinct specific surface areas were used to fabricate carbon-supported silver catalysts, aiming to enhance the dispersion of silver nanoparticles. It has been found that the ECP-600JD sample has the most-developed porous structure and the largest specific surface area, and the resulting carbon-supported silver catalyst (Ag/ECP-600JD) has the most homogeneous and the smallest particle size. In an electrolytic cell of membrane electrode assembly, the Ag/ECP-600JD can deliver a maximum current density of 524 mA·cm⁻² at 3 V with a Faradaic efficiency of 74% at 200 mA·cm⁻². CO₂ adsorption tests and simulation calculations have shown that Ag/ECP-600JD has the highest CO₂ enrichment efficiency and the fastest CO₂ mass transfer rate.