Characterization of bulk and surface composition of polycrystalline Co3O4 synthesized at 400 degrees C for electrocatalysis

Co3O4 cubic spinel was prepared by thermal decomposition of cobalt nitrate at 400 degrees C. Their properties were characterized by X-ray diffraction (XRD), infrared spectroscopy (IRS), thermogravimetric analysis (TG), scanni ng electron microscopy (SEM), magnetic susceptibility (chi) and oxidation p ower (q) measurements. Using the physicochemical characterization results a nd a structural refinement performed with the Rietveld method, it has been confirmed as cationic structure Co2+[Co-2(III)] with 3% of water hydration. From X-ray photoelectron spectroscopy (XPS) studies, in addition to previo us work, the Co3O4 surface shows Co3+/Co2+ = 0.59 while for the same oxide but prepared by spray pyrolysis, Co3+/Co2+ = 1.20 showing the effect of pre paration method.