Studies on Fe-Co spinel electrodes

Abstract

FeCo2O4 spinel oxide pelleted electrodes were prepared from the respective powders, obtained by low-temperature coprecipitation method. X-ray diffraction studies suggest the coexistence of two spinel phases, with different a-cell parameters. The samples show semiconductor-type behaviour, in the range 530-340 K. The estimated activation energy for conduction is about 0.7 eV. These phases are stable, after being used as electrode materials, as the XRD and SEM/EDS results show. Cyclic voltammetry has been used to investigate the electrochemical behaviour of the FeCo2O4 electrodes in 1 mol dm-3 KOH aqueous solutions. The voltammetric data allowed finding out the redox reactions occurring at the electrode surface, namely Fe3O4.4H2O/Fe(OH)2 or Fe3O4/Fe2O3 and CoO2/CoOOH by comparing the experimental results with those referred in the literature.