In situ formation of CoO hollow nanocubes on carbon cloth-supported NiCoO nanowires and their enhanced performance in non-enzymatic glucose sensing.

Diabetes is a chronic disease that can seriously affect human health. Therefore it is important to develop a rapid and highly sensitive enzyme-free glucose sensor to aid the treatment of diabetes. In this work, homogeneous NiCoO nanowire arrays were synthesized in an orderly fashion on flexible carbon cloth (CC) by a facile hydrothermal method. Then well-structured zeolitic imidazolate framework (ZIF-67) nanocubes were grown in situ on the as-prepared NiCoO nanowires to form a hybrid nanoarchitecture. The hierarchical structure was transformed into a CoO/NiCoO/CC composite after annealing in the air. The as-prepared electrode was put into 0.1 M NaOH, and cyclic voltammetry and amperometry were employed to investigate its electrocatalytic properties at room temperature. It was found that the CoO/NiCoO/CC electrode exhibited outstanding sensing properties towards glucose, including terrific sensitivity (12.835 mA mM cm), a wide linear range (from 1 μM to 1.127 mM), a low detection limit (0.64 μM) and a fast response time (within 2 s). In addition, it also had excellent selectivity, reproducibility and stability. The improvement in enzyme-free glucose sensing, in addition to the high porosity and large specific surface area of metal organic framework-derived CoO hollow nanocubes, can be attributed to the NiCoO nanowire arrays affording fast channels for electron transfer between CC and CoO. Accordingly, this method, which directly prepares hierarchical composite nanomaterials on a conductive substrate, may open up a new perspective for the enhancement of non-enzymatic glucose-sensing properties.