A cobalt corrole with a biologically relevant imidazolium pendant for boosted electrocatalytic oxygen reduction

Developing electrocatalysts with high activity and selectivity for the oxygen reduction reaction (ORR) has attracted increasing interest in the past decades. The many imidazole residues located at the active site of cytochrome c oxidases (CcOs) play crucial roles in facilitating the selective reduction of dioxygen to water. As inspired by nature, we herein reported on the synthesis of Co-III corrole 1 hanged with a biologically relevant imidazolium group and its electrocatalytic ORR features in both acidic and alkaline solutions. Complex 1 is more active and selective than its imidazolium-free analogue for electrocatalytic four-electron ORR. Importantly, 1 displayed ORR activities with the half-wave potentials at E-1/2 = 0.65 V versus RHE in 0.5 M H2SO4 solution and at E1/2 = 0.81 V versus RHE in 0.1 M KOH solution. This work presents a strategy to simultaneously improve catalytic ORR activity and selectivity by hanging a cationic imidazolium unit over molecular catalytic sites.