System Design Rules for Intensifying the Electrochemical Reduction of CO2 to CO on Ag Nanoparticles

Electroreduction of CO2 (eCO2RR) is a potentially sustainable approach for carbon‐based chemical production. Despite significant progress, performing eCO2RR economically at scale is challenging. Here we report meeting key technoeconomic benchmarks simultaneously through electrolyte engineering and process optimization. A systematic flow electrolysis study ‐ performing eCO2RR to CO on Ag nanoparticles as a function of electrolyte composition (cations, anions), electrolyte concentration, electrolyte flow rate, cathode catalyst loading, and CO2 flow rate ‐ resulted in partial current densities of 417 and 866 mA/cm2 with faradaic efficiencies of 100 and 98 % at cell potentials of −2.5 and −3.0 V with full cell energy efficiencies of 53 and 43 %, and a conversion per pass of 17 and 36 %, respectively, when using a CsOH‐based electrolyte. The cumulative insights of this study led to the formulation of system design rules for high rate, highly selective, and highly energy efficient eCO2RR to CO. Top performer: Revealing mechanistic insights into the role of electrolyte composition allows for optimization of key performance metrics simultaneously. Resulting generalized insights lead to system design rules for intensified electroreduction of CO2 to CO on Ag nanoparticles under ambient conditions.