- [Show abstract] [Hide abstract] ABSTRACT: Nickel oxide microfibers (NiO-MFs) were directly immobilized onto the surface of fluorine tin oxide (FTO) electrode by electrospinning and calcination without using any immobilization matrix for nonenzymatic glucose sensor. Morphology and structure of NiO-MFs were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction pattern (XRD). The electrochemical and electrocatalytic performances of the NiO-MFs modified electrodes prepared at different calcination temperatures ranging from 300 to 500°C were evaluated by cyclic voltammetry (CV). The CV results have demonstrated that NiO-MFs modified electrode prepared at 300°C displayed distinct increase in electrocatalytic activity toward the oxidation of glucose, which is explored to develop an amperometric nonenzymatic glucose sensor. The NiO-MFs prepared at 300°C based amperometric nonenzymatic glucose sensor has ultrasensitive current (1785.41 μA mM(-1) cm(-2)) response and low detection limit of 3.3×10(-8) M (signal/noise ratio (S/N)=3), which are among the best values reported in literature. Additionally, excellent selectivity and stability have also been obtained.
- [Show abstract] [Hide abstract] ABSTRACT: Silver/polyaniline composite nanotubes have been successfully synthesized via a self-assembly process assisted by excess ammonium persulfate and silver nitrate as oxidant without using any acid molecule reagent or hard template. Scanning electron microscopy (SEM), energy-dispersive X-ray spectra (EDX), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), ultraviolet−visible absorption spectra (UV−vis), and X-ray photoelectron spectroscopy (XPS) were performed to characterize the resulting polyaniline samples. SEM and TEM images indicate that the as-obtained polyaniline composite entirely consists of uniform nanotubes in high yield with a diameter of about 100 nm. The TEM image shows that the average size of the dispersed silver nanoparticles decorated on the surface of the silver/polyaniline composite nanotubes is about 10 nm. A tentative mechanism is proposed in detail to elucidate the formation of the tubular nanostructures in such system. The composite nanotubes are immobilized on the surface of an indium tin oxide and applied to construct a sensor, which exhibits higher electrocatalytic activity toward reduction of dopamine than pure polyaniline. Furthermore, the high surface area, small diameter, and porous nature of the silver/polyaniline composite nanotubes and introduction of the silver nanoparticles give significantly better performance in both gas sensitivity and time response.