Preparation of spinel nickel-cobalt oxide nanowrinkles/reduced graphene oxide hybrid for nonenzymatic glucose detection at physiological level

Nickel-cobalt oxide nanowrinkles with spinel-type crystal structure supported on reduced graphene oxide (NiCo 2 O 4 NWs-rGO) was prepared to develop a sensitive and stable nonenzymatic glucose sensor. The NiCo 2 O 4 NWs-rGO hybrid were prepared by a facile one-pot hydrothermal reaction, and sequential calcination in air. The morphology, composition and crystal structure of the NiCo 2 O 4 NWs-rGO hybrid were characterized by scanning electron microscope, transmission electron microscope, selected area electron diffraction, and energy-dispersive spectroscopy. The electrochemical behavior of the hybrid and its catalytic activity towards glucose oxidation were investigated by several electrochemical methods. Compared with single component NiO or Co 3 O 4 , spinel type NiCo 2 O 4 NWs displayed higher catalysis towards glucose oxidation. Further integration of NiCo 2 O 4 with graphene could reduce the overpotential and enhance the catalytic current due to the improved conductivity and dispersity of NiCo 2 O 4 . The NiCo 2 O 4 NWs-rGO based glucose sensor showed a wide linear range of 0.005-8.6   mM, a low detection limit of 2   μM (S/N   =   3), and an improved stability. A satisfactory recovery was also obtained for glucose detection in human serum at physiological level. Our results indicate rationally combine spinel type mixed metal oxide with graphene is a good alternative to fabricate advanced metal oxide based electrochemical sensors.