Iron porphyrin for selective electrochemical reduction of CO2: Synthesis, characterization and effect of electrolyte

The electrochemical CO2 reduction reaction to form valued by-products is a challenging and a sustainable process. In general, CO2 reduction to carbon neutral fuels requires selective and well-designed catalysts. Herein, we report perfluorinated iron porphyrin (FeFPor) for CO2-to-CO electroreduction in different bicarbonate electrolytes, byproducts distribution in lithium, sodium, potassium and cesium were analyzed. The immobilized FeFPor on the carbon microporous layer of the carbon cloth exhibited a high selectivity for carbon monoxide production over a wide range of potentials from −0.5 to −1 V vs. RHE in all bicarbonate solution with the NaHCO3 being the best catalytic medium. The highest conversion efficiency to CO production reached 97% at −0.5 V vs. RHE in 0.5 M NaHCO3 in near neutral aqueous solution (pH = 7.2). The CO electrosynthesis dropped when using lithium, potassium and cesium bicarbonates, which was due to the CO2 concentration and reactions at the inner electrode-solution reactions.