NiO mesoporous nanowalls grown on RGO coated nickel foam as high performance electrodes for supercapacitors and biosensors

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 5 A 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 μM.