Breaking a Molecular Scaling Relationship Using an Iron–Iron Fused Porphyrin Electrocatalyst for Oxygen Reduction
Daiki Nishiori, Jan Paul Menzel, Nicholas R. Armada, Edgar A. Reyes Cruz, Brent L. Nannenga, Víctor S. Batista, Gary F. Moore
Abstract
″ of electrocatalysis arises from synthetic design strategies, where structural alterations to a catalyst must balance nucleophilic versus electrophilic character. Efforts to circumvent this fundamental impasse have focused on bioinspired applications of extended coordination spheres and charged sites proximal to a catalytic center. Herein, we report evidence for breaking a molecular scaling relationship involving electrocatalysis of the oxygen reduction reaction (ORR) by leveraging ligand design. We achieve this using a binuclear catalyst (a diiron porphyrin), featuring a macrocyclic ligand with extended electronic conjugation. This ligand motif delocalizes electrons across the molecular scaffold, improving the catalyst's nucleophilic and electrophilic character. As a result, our binuclear catalyst exhibits low overpotential and high catalytic turnover frequency, breaking the traditional trade-off between these two metrics.