Recent Developments in Metalloporphyrin Electrocatalysts for Reduction of Small Molecules: Strategies for Managing Electron and Proton Transfer Reactions

Abstract

Porphyrins are archetypal ligands in inorganic chemistry. The last 10 years have seen important new advances in the use of metalloporphyrins as catalysts in the activation and reduction of small molecules, in particular O 2 and CO 2. Recent developments of new molecular designs, scaling relationships, and theoretical modeling of mechanisms have rapidly advanced the utility of porphyrins as electrocatalysts. This Minireview focuses on the summary and evaluation of recent developments of metalloporphyrin O 2 and CO 2 reduction electrocatalysts, with an emphasis on contrasting homogeneous and heterogeneous electrocatalysis. Comparisons for proposed reaction mechanisms are provided for both CO 2 and O 2 reduction, and ideas are proposed about how lessons from the last decade of research can lead to the development of practical, applied porphyrin-derived catalysts.

Metal‐Corrole‐Based Porous Organic Polymers for Electrocatalytic Oxygen Reduction and Evolution Reactions

“…Metal porphyrins are efficient electrocatalysts for ORR and OER [5, 42–46] . Porphyrin‐based frameworks usually display boosted activity and stability compared with respective monomers [35, 47–52] .…”

“…[35][36][37][38][39][40][41] Metal porphyrins are efficient electrocatalysts for ORR and OER. [5,[42][43][44][45][46] Porphyrin-based frameworks usually display boosted activity and stability compared with respective monomers. [35,[47][48][49][50][51][52] Like porphyrins, corroles provide metal ions with four-coordinated square-planar M-N 4 structure.…”

Synthesis and Electrochemistry of Free‐Base Porphyrins Bearing Trifluoromethyl meso‐Substituents

“…[4] These essential works have paved the way for applications in many different fields such as in catalysis, sensing, medicine and in energy related domains. [5,6] The introduction of electron-withdrawing groups (EWG) has proved particularly useful to enhance the axial binding ability of metalloporphyrins, [7] to tune the redox activity of porphyrins and the metal ion inserted in their cavities [8,9] or to enable the synthesis/stabilization of particular porphyrin analogs. [10,11] Such modifications are thus of paramount importance for synthetic purposes and to promote the applications of porphyrins in (electro)catalysis, [12] sensing [13] or in molecular magnetism.…”

CO2 to CO Electroreduction, Electrocatalytic H2 Evolution, and Catalytic Degradation of Organic Dyes Using a Co(II) meso-Tetraarylporphyrin

“…Inspired by nature that is using metalloporphyrins as antennae molecules, redox shuttles and redox and photo catalysts [ 1 ], researchers have tried to use artificial porphyrin complexes for various purposes in the last decades [ 2 , 3 , 4 , 5 , 6 , 7 , 8 ]. Cobalt porphyrins provide a rich electrochemistry consisting of both metal- (Co(I)/Co(II)/Co(III) and porphyrin-centred redox processes.…”

“…The potential of the CO 2 reduction is strongly connected to the presence of protons [ 7 , 40 ]. However, fine-tuning of the reduction potentials of Co porphyrins is easily possible through substitution on the ligand core.…”