Regulating Steric\nEffect of Cobalt Corroles for Promoted\nOxygen Electrocatalysis

Regulating catalyst steric effects is commonly used in\norganic\nchemistry but is relatively much less explored in O<sub>2</sub> activation.\nHerein, we report on the steric effect of Co corroles on O<sub>2</sub> reduction. Three Co corroles with different <i>meso</i>-substituents to regulate steric effects were synthesized. With bulky <i>meso</i>-substituents, Co corroles became more efficient, from\nboth thermodynamic and kinetic points of view, to bind and activate\nO<sub>2</sub>. We confirmed that upon O<sub>2</sub> binding, the resulted\nsuperoxo unit can be stabilized due to the steric protection of bulky <i>meso</i>-substituents. With this improvement, Co corrole with\nbulky <i>meso</i>-substituents displayed significantly improved\noxygen electrocatalysis.