NiCo–NiCoO2/carbon hollow nanocages for non-enzyme glucose detection

Abstract

Hybrid transition metals/metal oxides/carbon bases with adjustable structures are becoming more and more important and attractive as electrode materials for electrocatalysis of glucose. Herein, we demonstrate the fabrication of carbon encapsulated hollow cage NiCo-NiCoO2 composite (NiCo-NiCoO2/C), which were synthesized by a two-step procedure involving preparation of nickel-cobalt Prussian blue analogue (Ni-Co PBA) derivative (NiO-NiCo2O4) and an organic carbon source, and the synthesis of the nanocomposite at 400°C for direct carbonization and reduction process in an Ar atmosphere. As a multi-component electrocatalyst for glucose oxidation in alkaline solution, the unique structure provides a large accessible surface area, while the uniformly distributed NiCoO2, NiCo, and C effectively catalyze and facilitate the glucose reaction. The sensitivity of the catalyst were 340.4 μA mM−1 cm−2 and 56.1 μA mM−1 cm−2 in the linear concentration ranges of 0.1 μM-600 μM and 0.9 mM-6.3 mM, respectively, and the LOD was 0.03 μM with good reproducibility and long-term stability. Besides, the effective performance of the sensor material in detecting glucose in real human serum has been recognized. The NiCo-NiCoO2/C annealed at an appropriate temperature has high electronic conductivity, large surface area, and faster ion/electron transfer at the electrode and electrolyte-electrode interface, resulting in a higher electrocatalytic oxidation of glucose ability.