The Kinetics of the Electroreduction Reaction of Molecular Oxygen in a Series of Quinoline Media

The quantitative investigations of the electroreduction of O2 to O2− at Au electrode in Q, IQ and a series of methylquinoline solvents were carried out using cyclic voltammetry (CV) and normal pulse voltammetry (NPV). The relevant kinetic parameters (i.e., the standard rate constant, ko, and the cathodic transfer coefficient, αc) were evaluated by NPV. Results show that there is an inverse relationship of the formal potential (Eo,) to lowest unoccupied molecular orbital (LUMO) energy, indicating that O2− is more stabilized in a solvent with lower LUMO; and a proportional relationship of ko to diffusion coefficient (D), indicating the solvent dynamics control of the electrode reactions.