NiO-CoO Hybrid Nanostructures: Preparation, Characterization and Application in Methanol Electro-Oxidation

NiO-CoO hybrid nanostructures with improved electrocatalytic activity for methanol oxidation reaction were successfully synthesized via a simple two-step route. Ni/beta-Co(OH)(2) precursor was first prepared by a hydrothermal route at 100 A degrees C for 24 h, employing Ni nanospheres, CoSO4 center dot 7H(2)O and l-lysine as the reactants; Then, NiO-CoO hybrid nanostructures were obtained by calcining the above precursor in air at 450 A degrees C for 2 h. The as-obtained products were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. Cyclic voltammograms investigations showed that the as-obtained NiO-CoO hybrid nanostructures presented better electrochemical behavior in 1 M KOH solution than single NiO and CoO in the absence/presence of 0.5 M CH3OH. In the system containing 1 M KOH and 0.5 M CH3OH, the maximum current densities of various modified electrodes were in turn 175 mu A cm(-2) for the NiO-CoO/Ni foam (NF) electrode, 85 mu A cm(-2) for the NiO/NF electrode, 80 mu A cm(-2) for the CoO/NF electrode and 15 mu A cm(-2) for the Ni foam electrode at the potential of 0.6 V. Simultaneously, NiO-CoO hybrid nanostructures still exhibited the lower over-potential and higher stability. The above facts indicated that the as-prepared NiO-CoO hybrid nanostructures were potential candidates as the electrocatalyst for methanol oxidation reaction.