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

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 O2 and CO2 . 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 O2 and CO2 reduction electrocatalysts, with an emphasis on contrasting homogeneous and heterogeneous electrocatalysis. Comparisons for proposed reaction mechanisms are provided for both CO2 and O2 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.