For the Co (II) complex, the high overpotential (-4.95V) indicates a substantial energy barrier for initiating and propagating the reaction. This high barrier suggests suboptimal binding of intermediates, particularly the hydroxyl ion (OH -) and oxygen atom (O * ) which are critical in the mechanistic pathway. The excessive energy required to overcome this barrier slows down the reaction kinetics, making the rate-determining step energetically prohibitive and less efficient.