Electrocatalytic CO2 reduction at low overpotentials using iron(III) tetra(meso-thienyl)porphyrins

The optical and electrochemical properties, as well as the CO 2 reduction capability of two different iron(III) thienyl-porphyrins, iron(III) tetra( meso -thien-2-yl)porphyrin ( FeTThP ) and iron(III) tetra( meso -5-methylthien-2-yl)porphyrin ( FeTThMeP ), are directly compared to those of iron(III) tetra( meso -phenyl)porphyrin ( FeTPP ). Through exploitation of mesomeric stabilization effects, FeTThP and FeTThMeP both reduced CO 2 to CO with comparable faradaic efficiencies and TON CO relative to FeTPP , with an overpotential 150 mV lower than the benchmark catalyst.