Electrocatalytic reduction of dioxygen on the surface of glassy carbon electrodes modified with cobalt porphyrin complexes

The preparation and electrocatalytic behavior of glassy carbon electrodes modified with three different cobalt porphyrin complexes were investigated. The electrocatalytic ability of the modified electrodes for the reduction of dioxygen to hydrogen peroxide and water in air-saturated aqueous solutions was examined by cyclic voltammetry and chronoamperometry techniques. The porphyrin-adsorbed glassy carbon electrodes possess excellent electrocatalytic abilities for dioxygen reduction with overpotential about 0.5 V lower than that at a plain glassy carbon electrode. The experimental parameters were optimized and the mechanism of the catalytic process was discussed. The possible effects of the electron-donating properties of groups in the meso-position of the porphyrin ring were investigated.