Oxygen reduction and water oxidation are two key processes in fuel cell applications. The oxidation of water to dioxygen is a 4 H+/4 e- process, while oxygen can be fully reduced to water by a 4 e-/4 H+ process or partially reduced by fewer electrons to reactive oxygen species such as H2O2 and O2-. We demonstrate that a novel manganese corrole complex behaves as a bifunctional catalyst for both the electrocatalytic generation of dioxygen as well as the reduction of dioxygen in aqueous media. Furthermore, our combined kinetic, spectroscopic, and electrochemical study of manganese corroles adsorbed on different electrode materials (down to a submolecular level) reveals mechanistic details of the oxygen evolution and reduction processes.
Doppelleben: Ein Mangan‐Corrol‐Komplex vermittelt als difunktioneller Katalysator in wässriger Lösung die elektrokatalytische Erzeugung von Disauerstoff ebenso wie seine Reduktion. In schwach bis mäßig alkalischem Medium oxidiert der Komplex Hydroxidionen über einen Vier‐Elektronen‐Prozess zu molekularem Sauerstoff, und er reduziert O2 über einen Zwei‐Elektronen‐Prozess zu Wasserstoffperoxid.
Keywords: Corrole; Elektrochemie; Mangan; Sauerstoffentwicklung; Sauerstoffreduktion.