(307f) Electrochemical CO2 Reduction to Formic Acid with High Carbon Efficiency

Storing intermittent energy sources in the form of chemical bonds through the electrochemical CO₂ reduction (CO₂RR) to formic acid has proven its high technology readiness level, given the high CO₂RR partial current density towards formic acid, with reported system stabilities for hundreds of hours at industrially relevant current densities. However, neutral and alkaline CO₂RR systems still suffer from low CO₂ utilization efficiency due to carbonate formation. Previous efforts to recover the lost CO₂ and improve the CO₂RR single-pass conversion efficiency (SPCE) have primarily focused on gas products. Herein, we optimize the SPCE by tuning the local reaction environment and use a three-chamber porous solid electrolyte (PSE) reactor to illustrate pure formic acid generation with high SPCE (>90%) at 100 mA cm^-2 current density. To prove the practical application of our approach, we use a sequential system to report the continuous conversion of simulated flue gas to pure formic acid.