Electrocatalytic reduction of CO2 to CO by Fe(iii) carbazole–porphyrins in homogeneous molecular systems

Abstract

Iron porphyrins have demonstrated remarkable catalytic activity as electrocatalysts for the carbon dioxide reduction reactions (CO₂RR). To enhance their catalytic activity, iron(III) tetrakis(4-(diphenylamino)phenyl)porphyrin (FeTDPP) and iron(III) tetrakis(carbazol-9-ylphenyl)porphyrin (FeTCPP) were synthesized by incorporating triphenylamine and phenylcarbazole substituents at the meso position. Both FeTDPP and FeTCPP were able to electrocatalytic reduce CO₂ to CO with a Faraday efficiency exceeding 90%. Compared with the benchmark catalyst, iron(III) tetra(meso-phenyl)porphyrin (FeTPP), FeTDPP and FeTCPP exhibit lower overpotentials that are positively shifted by approximately 10 mV and 90 mV, respectively.