Fe doping induced formation of crystalline/amorphous NiCo2O4 core/shell heterostructure for highly sensitive nonenzymatic detection of glucose

A novel strategy was reported to improve electrocatalytic activity of NiCo 2 O 4 by doping Fe. It is interesting to find that the doping of Fe induces formation of nanorod composing with crystalline core and thin amorphous shell. The composition, structure and properties of NiCo 2 O 4 are well characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry and amperometric method. The results display that the presence of thin amorphous shell is conducive to accelerating electron transfer rate and exposing more effective active sites, therefore making the sensor based on Fe-doped NiCo 2 O 4 detect glucose in a wide linear range from 0.2 μM to 3.1 mM with a high sensitivity of 3055.7 μA mM −1 cm −2 and a low detection limit of 0.19 μM. This unique crystalline core/amorphous shell-structured NiCo 2 O 4 demonstrates promising potential as an effective electrocatalyst for glucose sensing. • A unique NiCo 2 O 4 crystalline core/amorphous shell heterostructure is developed. • The doping of Fe induces the formation of crystalline core surrounding with thin amorphous shell. • The presence of thin amorphous shell is beneficial to improve electron transfer and increase active sites. • The sensor based on Fe-doped NiCo 2 O 4 exhibited remarkable catalytic performance for glucose detection.