Porous Co3O4/NiO core/shell nanowire array with enhanced catalytic activity for methanol electro-oxidation

A self-supported Co3O4/NiO core/shell nanowire array is prepared by the combination of hydrothermal synthesis and electro-deposition methods. The Co3O4/NiO core/shell nanowire array shows a combined structure of mesoporous nanowire core and branch nanoflakes shell as well as hierarchically porous structure. The electro-oxidation properties of methanol of the Co3O4/NiO core/shell nanowire array are elucidated by cyclic voltammetry (CV) and chronoamperometry tests. Impressively, the Co3O4/NiO core/shell nanowire array exhibits much higher electro-catalytic activity, lower over-potential and much more stability for methanol electro-oxidation compared to the single Co3O4 nanowire array in alkaline medium. The enhancement of the electro-catalytic reactivity is due to the synergistic effect and unique porous core/shell nanowire architecture, which provides fast ion/electron transfer, sufficient contact between active materials and electrolyte, leading to faster kinetics, lower over-potential and higher electro-catalytic reactivity. (C) 2012 Elsevier B.V. All rights reserved.