Preparation and characterization of NiO-Ag nanofibers, NiO nanofibers, and porous Ag: towards the development of a highly sensitive and selective non-enzymatic glucose sensor

Following a facile two-step synthesis route, NiO-Ag hybrid nanofibers, NiO nanofibers, and porous Ag were prepared. Scanning electron microscopy and transmission electron microscopy were employed to characterize the morphology of the as-prepared samples. Fourier transform infrared spectroscopy was used to confirm the complete degradation of the polymer matrix and the conversion of metal salts to metal oxides. X-Ray diffraction and X-ray photoelectron spectroscopy were performed to investigate the crystal structures and compositions of the final products. The as-prepared samples were then applied to construct non-enzymatic sensors for glucose detection. The NiO-Ag hybrid nanofiber-based sensor shows much higher sensitivity, lower detection limit and wider linear range in glucose detection compared to the NiO nanofibers or the porous Ag based sensor. A synergistic effect was achieved between NiO and Ag. High selectivity against uric acid and ascorbic acid was also achieved from the NiO-Ag nanofibers and NiO nanofiber-based sensors at an applied potential of 0.6 V. A mechanism of the excellent selectivity was proposed for the first time. The application of NiO-Ag nanofibers for selective glucose detection was also demonstrated using human serum sample, and the result is in good agreement with that of commercial glucose meter. The excellent performance of the developed inorganic nanofiber-based glucose sensor, combined with good reproducibility, low cost and inherent stability of inorganic materials, indicates great commercial value in clinical diagnosis of diabetes.