Uniform NiO mesoporous nanowalls are easily fabricated on reduced graphene oxide (RGO) nanosheets coated three dimensional nickel foams (3D NF-G) through a simple aqueous deposition with successive annealing. The structure and morphology of the resulting NiO nanowalls supported on 3D NF-G composites (3D NF-G-NiO) are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDX). The 3D NF-G-NiO composites are directly used as binder-free electrodes for supercapacitors and biosensors. For supercapacitor, the electrode delivers high specific capacitance of about 950 F g(-1) at a current density of 5A g(-1) with excellent cycling stability. As glucose sensor, the 3D NF-G-NiO electrode can detect glucose with an ultrahigh sensitivity of 3.23 mAmM(-1) cm(-2) and a superior selectivity with a remarkable lower detection limit towards 10 mu M. (C) 2016 Elsevier Ltd. All rights reserved.