<i>In situ</i> formation of Co <sub>3</sub> O <sub>4</sub> hollow nanocubes on carbon cloth-supported NiCo <sub>2</sub> O <sub>4</sub> nanowires and their enhanced performance in non-enzymatic glucose sensing
Qi Guo, Wen Zeng, Shilin Liu, Yanqiong Li
Abstract
Abstract 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 NiCo 2 O 4 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 NiCo 2 O 4 nanowires to form a hybrid nanoarchitecture. The hierarchical structure was transformed into a Co 3 O 4 /NiCo 2 O 4 /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 Co 3 O 4 /NiCo 2 O 4 /CC electrode exhibited outstanding sensing properties towards glucose, including terrific sensitivity (12.835 mA mM −1 cm −2 ), a wide linear range (from 1 μ M to 1.127 mM), a low detection limit (0.64 μ M) 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 Co 3 O 4 hollow nanocubes, can be attributed to the NiCo 2 O 4 nanowire arrays affording fast channels for electron transfer between CC and Co 3 O 4 . 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.