Membrane‐electrode assembly design parameters for optimal CO ₂ reduction

Commercial-scale generation of carbon-containing chemicals and fuels by means electrochemical CO2 reduction (CO2R) requires electrolyzers operating at high current densities product selectivities. Membrane-electrode assemblies (MEAs) have been shown to be suitable for this purpose. In such devices, the cathode catalyst layer controls both rate CO2R distribution products. study, we investigate how ionomer-to-catalyst ratio (I:Cat), loading, catalyst-layer thickness influence performance a containing Ag nanoparticles supported on carbon. paper, explore these parameters affect cell establish role exchange solution (water vs. CsHCO3) behind anode in performance. We show that total density is best achieved using an I:Cat 3 loading 0.01–0.1 mgAg/cm2 with 1.0 M CsHCO3 circulated layer. For conditions, optimal CO partial depends voltage applied MEA. The work also reveals limited combination electrochemically active surface area degree which mass transfer transport OH− anions away from it limit overall activity. Hydration ionomer found not issue when solution. insights gained allowed MEA operates between 200 mA/cm2 1 A/cm2 faradaic efficiencies 78–91%, findings understanding herein should applicable broad range MEA-based devices.