(369d) Development of a New Packed-Bed Type Electrolyzer for the Production of CO or Syn-Gas through Electrochemical CO2 Reduction Reaction

Electrochemical CO₂ reduction (eCO₂R) is a promising alternative method for producing CO or syn-gas in a sustainable manner. Nonetheless, numerous obstacles must be surmounted prior to the realization of commercial viability. Many studies focused on the direct conversion of CO₂-captured amine solutions, which utilize amine absorbents to capture CO₂ from flue gas emissions, into value-added compounds are receiving increased interest because considerable thermal energy must be provided to regenerate the absorbed CO₂ to obtain pure CO₂. Here, we present a packed-bed type electrolyzer designed to allow CO₂-captured amine solutions, as a catholyte, to pass through a flow path packed with three-dimensional electrodes made of carbon felt-binder-silver (Cfelt-b-Ag). For these three-dimensional electrodes, the local hydrophobicity inside the carbon felt can be controlled by adjusting the type and amount of binders. A well-controlled hydrophobicity of the three-dimensional electrodes can facilitate the formation of an instantaneous three-phase interface around the silver surface, which promotes eCO₂R. In a system with counter anodes of only 10 cm_­² scale, we achieved a total current of 15 A while maintaining over 50% faradaic efficiency of the CO.