Studies on Fe–Co spinel electrodes

Abstract FeCo 2 O 4 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 FeCo 2 O 4 electrodes in 1 mol dm −3 KOH aqueous solutions. The voltammetric data allowed finding out the redox reactions occurring at the electrode surface, namely Fe 3 O 4 ·4H 2 O/Fe(OH) 2 or Fe 3 O 4 /Fe 2 O 3 and CoO 2 /CoOOH by comparing the experimental results with those referred in the literature.