Electrocatalytic Reduction of CO₂ to Acetic Acid by a Molecular Manganese Corrole Complex

Abstract

The controlled electrochemical reduction of carbon dioxide to value added chemicals is an important strategy in terms of renewable energy technologies. Therefore, the development of efficient and stable catalysts in an aqueous environment is of great importance. In this context, we focused on synthesizing and studying a molecular MnIII‐corrole complex, which is modified on the three meso‐positions with polyethylene glycol moieties for direct and selective production of acetic acid from CO2. Electrochemical reduction of MnIII leads to an electroactive MnII species, which binds CO2 and stabilizes the reduced intermediates. This catalyst allows to electrochemically reduce CO2 to acetic acid in a moderate acidic aqueous medium (pH 6) with a selectivity of 63 % and a turn over frequency (TOF) of 8.25 h−1, when immobilized on a carbon paper (CP) electrode. In terms of high selectivity towards acetate, we propose the formation and reduction of an oxalate type intermediate, stabilized at the MnIII‐corrole center.

Recent advances in single atom catalysts for the electrochemical carbon dioxide reduction reaction

“…As there are no neighbouring active sites, *OCHO is more likely to bind to the SAC via only one O atom as shown in Fig. 4 [63][64][65][66] As discussed above, the C 2 pathways involve two close active sites to adsorb intermediates, which are severely limited in SACs. Consequently, very few groups have reported the generation of C 2 products on SACs via the CO 2 RR.…”

Tuning Electronic Structures of Covalent Co Porphyrin Polymers for Electrocatalytic CO 2 Reduction in Aqueous Solutions

“…Molecular catalysts have clear and controllable structures and thus have benefits to study structure-function relationships for catalysis. 24,25 A variety of metal complexes of polypyridines, [26][27][28] cyclams, [29][30][31] porphyrins, [32][33][34][35][36][37][38] and corroles, 39,40 have been identified as efficient CO 2 RR electrocatalysts in non-aqueous solutions. By studying these molecular catalysts, knowledge of improving catalyst performance has been gained, including tuning electronic structures, 41,42 installing proton relays, 43,44 and introducing hydrogen-bonding and electrostatic interactions.…”

Photocatalytic Reduction of CO2 to CO in Aqueous Solution under Red-Light Irradiation by a Zn-Porphyrin-Sensitized Mn(I) Catalyst

“…Such systems have been realized for other transition metals, such as Ni, Fe, and Co, 38−42 . 43 Other studies overcome the lack of water solubility of Mn catalysts by immobilizing them on graphene, 44 TiO 2 nanoparticles, 45 carbon nanotubes, graphitic carbon nitride, 12,22,46,47 carbon paper or cloth, 48,49 or polymers. 50 Light activation of Mn catalysts is precluded by the photosensitivity of typical [MnX(NN)(CO) 3 ] compounds, for which excitation even into the lowest energy absorption bands corresponding to the metal-to-ligand (MLCT) or halide-to-ligand (XLCT) charge-transfer transitions results in decomposition through ligand dissociation.…”