Photocatalytic System using Iron-Based Catalysts: Effect of External Ions on CO2-to-CO Conversion

Herein, we report four self-assembly Iron(II/III) complex consisting triethanolamine (TEOA) as ligand and an FeIII(TPA)Cl3 (TPA= 3-(2-pyridine methyl) amine) as contrast catalyst, for photochemical reduction of CO2 to CO under visible light. The photocatalytic systems were assembled by [Ru(bpy)3]Cl2 as photosensitizer, and 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo-[d]-imidazole (BIH) as electron donor. Experiments are conducted to study the relationship between CO production and the external ions. Different external counterions are provided to assist the discussion of the influence of these external ions on catalysis. Density functional theory calculations confirmed that the external ions have an effect on the CO yield. Moreover, a mechanism involving proton-coupled electron transfer is proposed.