Electrochemical non-enzymatic glucose sensor based on hierarchical 3D Co3O4/Ni heterostructure electrode for pushing sensitivity boundary to a new limit

In this study, 3D Co3O4/Ni heterostructures were synthesized on the porous Ni substrate by hydrothermal method for electrochemical non-enzymatic glucose detection. Both structure and morphology of fabricated 3D Co3O4/Ni heterostructures were characterized by X-ray diffraction (XRD), Fourier transformed infrared (FTIR) and scanning electron microscopy (SEM) techniques. The results showed that the pure Co3O4 cluster nanofibers with the diameter of ca. 50 nm have grown layer by layer on the 3D Ni substrate. They provided high surface-to-volume ratio resulting in the high specific surface area of 17,886 m2/g. The electrochemical non-enzymatic sensor based on fabricated 3D Co3O4/Ni heterostructures enabled the highest sensitivity of 13,855 μA mM−1 cm−2 towards glucose reported-to-date. This sensor also exhibited fast response time (less than 1 s), detection limit as low as 1 μM (S/N = 3) and excellent selectivity to glucose at the presence of ascorbic acid, uric acid, sodium chloride, dopamine, cysteine and d-fructose.