Nanostructured Mixed Transition Metal Spinel Oxide as Efficient Electrocatalysts

CuxCo3-xO4 films with x values ranging from 0 to 1 have prepared in order to optimize their electrocatalytic properties for the oxygen evolution reaction (OER). Two methods have been used for the preparation of CuxCo3-xO4, namely thermal decomposition and co-precipitation methods. The prepared materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and cyclic voltammetry (CV). The SEM analysis shows that the prepared electrodes were very porous and EDX analysis proved that a good correlation exists between stoichiometric and EDX-derived copper to cobalt ratios. The formation of spinel structure was confirmed by XRD analysis. Cyclic voltammetric experiments were carried out on electrodes prepared by thermal decomposition method. Cu0.75Co2.25O4 showed the lowest overpotential for OER. The electrodes were found to be active for the electroreduction of H2O2. However, at a given potential Co3O4 has achieved higher current density compared to copper substituted cobalt spinel.