Three-dimensional NiO/Co₃O₄@C composite for high-performance non-enzymatic glucose sensor

In this study, a new enzyme-free glucose sensor was constructed using the transition metal-based composite material. The synthesis of ZIF-67 entailed the addition of NiO with high catalytic performance. Two-dimensional NiO/Co₃O₄@C heterojunctions were obtained via pyrolysis of NiO@ZIF-67 in the air at a temperature of 500 ℃. The enzyme-free glucose sensor Nafion/NiO/Co₃O₄@C/GCE was constructed by modifying NiO/Co₃O₄@C on a glassy carbon electrode (GCE). The performance of the modified electrode was tested via cyclic voltammetry (CV) and a time-current curve (i-t curve). The linear ranges of the modified electrode were 5 -1000 μM and 1.0- 4.0 mM with sensitivities of 690 and 215.4 μA mM^-1 cm^-2, respectively. The detection limit was 2.28 μΜ (S/N = 3). The recoveries were in the range of 98.9-99.7% during the detection of real samples. The prepared sensor Nafion/NiO/Co₃O₄@C/GCE showed excellent electrocatalytic properties with superb reproducibility, stability and anti-interference capability. The sensor has been successfully utilized to determine glucose in real serum samples.