VOLTAMMETRIC AND PHOTOELECTRON SPECTRAL ELUCIDATION OF THE ELECTROCATALYTIC OXIDATION OF HYDROGEN-PEROXIDE AT SCREEN-PRINTED CARBON ELECTRODES CHEMICALLY-MODIFIED WITH COBALT PHTHALOCYANINE

The interplaying mechanisms involved in the electrocatalytic oxidation of hydrogen peroxide (H2O2) have been studied using cyclic and differential-pulse voltammetry and X-ray photoelectron spectroscopy (XPS). Cobalt phthalocyanine (CoPC) modified screen-printed carbon electrodes (SPCEs) were used as base transducers in the voltammetric studies, and for XPS experiments a mixture of the printing ink containing CoPC was coated onto a steel stub. These investigations have shown that CoPC is initially in the Co2+ oxidation state, and that in plain supporting electrolytes it is subsequently electrochemically oxidized to Co3+. A postulated sequence of events for the mediated oxidation of H2O2 at CoPC-SPCEs has been derived from the XPS and voltammetric data generated.