Abstract

Oxygen reduction reaction mediated by electrodes composed of graphite powder, octylpyridinium hexafluorophosphate as a binder, and cobalt and iron metal octaethylporphyrins is studied. Morphological and composition changes of the electrodic surfaces are observed employing the ionic liquid (IL) as a binder by scanning electron microscopy along with X-ray microanalysis. Cyclic voltammetry and electrochemical impedance spectroscopy studies indicate that both the ILs and porphyrins are capable of generating an electrocatalytic effect in terms of current and/or potential toward this reaction, as well as increasing the conductive ability of the systems, presenting a synergistic effect between the ILs and the porphyrins. Scan rate studies determine that with the mixing of Co-Fe porphyrins, an oxygen reduction close to four electrons, either directly or through the production of a hydrogen peroxide intermediate, is generated.