Regulating Steric Effect of Cobalt Corroles for Promoted Oxygen Electrocatalysis

Regulating catalyst steric effects is commonly used in organic chemistry but is relatively much less explored in O2 activation. Herein, we report on the steric effect of Co corroles on O2 reduction. Three Co corroles with different meso-substituents to regulate steric effects were synthesized. With bulky meso-substituents, Co corroles became more efficient, from both thermodynamic and kinetic points of view, to bind and activate O2. We confirmed that upon O2 binding, the resulted superoxo unit can be stabilized due to the steric protection of bulky meso-substituents. With this improvement, Co corrole with bulky meso-substituents displayed significantly improved oxygen electrocatalysis.