Direct 4-Electron Reduction of Molecular Oxygen to Water Mediated by Cu-10-(4-aminophenyl)-5,15-dimesitylcorrole-modified Electrodes

Abstract

At pH 3 and 7, a glassy carbon electrode modified by deposition of a physio-adsorbed Cu-10-(4-aminophenyl)-5,15-dimesitylcorrole reduces molecular oxygen to water through a 4-electron direct transference. In the case of a glassy carbon electrode modified by electropolymerizing the same corrole on the surface, the reduction occurs by two parallel ways giving peroxide and water simultaneously. However at pH 7 this electrode gives peroxide as the unique product. This indicates that the way of modifying the electrode affects the product of reduction of oxygen. At pH 12, both modified electrodes catalyze the reduction to peroxide. It is noticeable that a Cu-azamacrocycle reduces oxygen to water. At all the studied pH values, the modified electrodes are unstable and lose activity after a first cycle in the presence of oxygen.