Ni foam supported-Co3O4 nanowire arrays are prepared by a template-free growth method, followed by a thermal treatment in air, and are characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, infrared spectroscopy, and thermogravimetric and differential thermal analysis. The Co3O4 nanowires have a diameter of about 250 nm, a length up to 15 μm, and a Brunauer-Emmett-Teller surface area of 78.4 m2 g−1. They grow almost vertically from the surface of Ni foam skeleton, pack densely, and uniformly cover the entire surface of Ni foam skeleton. Electroreduction of H2O2 on Co3O4 nanowire arrays in alkaline medium is investigated by cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. The Co3O4 nanowire electrode exhibits superior activity, stability, and mass transport property for H2O2 electroreduction. A current density of 90 mA cm−2 is achieved at −0.4 V in 0.4 mol dm−3 H2O2 and 3.0 mol dm−3 NaOH at room temperature. The per gram current...