PREPARATION, CHARACTERIZATION AND ELECTROCHEMICAL STABILITY EVALUATION OF Ti/Co3O4-xIrO2 ELECTRODES

Abstract

Cobalt spinel is a good material for the manufacture of electrodes for the electrochemical
oxidation of azo dyes; however, it has poor electrochemical stability in electrolytes with
chlorides ion, suffering severe corrosion. This work focuses on the preparation and evaluation
of spinel cobalt electrode doped with iridium oxide supported on titanium foil, Ti/Co3O4-
xIrO2 and their evaluation as stable to corrosion by chloride electrodes. The influence of
IrO2 into cobalt spinel electrode was evaluate, the spinel was doped with 1,25%; 2,5% and
5,0% (atomic percent) iridium. The electrodes were characterized using cyclic voltammetry
techniques (VC), scanning electron microscopy (SEM), energy dispersive microanalysis
(EDX) and X-ray diffraction (XRD). The test of the stability of the electrodes was subjected
to electrolysis in a solution of sodium chloride to 6% (w/v), at room temperature, maintaining
pH 5,8 and a current of 0,5A.cm-2. The results showed that the electrodes increased their
electrochemical stability relative to IrO2 increased content of cobalt in the spinel.