Narrow Results

Halloysite nanotubes@polydopamine (HNTs@PDA) nanocomposites were successfully synthesized, and Au nanoparticles (Au NPs) were loaded on HNTs@PDA by electrostatic adsorption. The electrochemical sensor based on HNTs@PDA–Au nanocomposites was constructed. The effect of the composition, structure and property of HNTs@PDA–Au on the response performance of the sensor was explored. The morphology and composition of the nanocomposites were characterized by field emission scanning electron microscopy, transmission electron microscopic, X-ray diffraction, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. Electrochemical results revealed HNTs@PDA–Au as the sensing interface with good effect on electrocatalytic oxidation of N₂H₄. This sensor detected N₂H₄ in the range from 0.75$\mu$mol$\cdot$L${}^{-1}$ to 2.8mmol$\cdot$L${}^{-1}$, with a sensitivity of 171.7$\mu$A (mmol$\cdot$L${}^{-1}{)}^{-1}$cm${}^{-2}$ and a detection limit of 0.25$\mu$mol$\cdot$L${}^{-1}$ (S/N $=$ 3).

A novel titanium dioxide–graphene–polyaniline (TiO₂–RGO–PANI) hybrid was prepared by the one-pot method and used as a nonenzymatic electrochemical sensor for glucose detection. The composition and structural morphology of the as-prepared composites were determined by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The characterization results showed that TiO₂–RGO–PANI is mainly composed of Ti, O, C and N and their weight percentages are 67.68%, 21.57%, 10.70% and 0.05%, respectively, indicating that the TiO₂–RGO–PANI composite catalyst has been successfully prepared and presents a poriferous coral structure. A series of electrochemical tests such as cyclic voltammetry tests declared that TiO₂–RGO–PANI composite possessed a low limit of detection (LOD) (7.46$\mu$M), good repeatability, selectivity and stability. In the concentration range of 10–180$\mu$M, the hybrid presented linear diffusion, and the linear equation was $I_{pa}=0.21338+0.01392$ (C/mM), the correlation coefficient $R^2=0.9912$. In addition, the comparison of the merits of this proposed electrode with some recent nonenzymatic glucose sensors indicates that this highly sensitive TiO₂–RGO–PANI complex glucose sensor provides a simple, low-cost, nonenzymatic method for glucose detection, and has promising applications in clinical diagnostics and medical analysis.

Au nanoparticles anchored on core–shell $\alpha$-Fe₂O₃@SnO₂ nanospindles were successfully constructed through hydrothermal synthesis process and used for fabricating a novel nonenzymatic dopamine (DA) sensor. The structure and morphology of the Au/$\alpha$-Fe₂O₃@SnO₂ trilaminar nanohybrid film were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The electrochemical properties of the sensor were investigated by cyclic voltammetry and amperometry. The experimental results suggest that the composites have excellent catalytic property toward DA with a wide linear range from 0.5$\mu$M to 0.47mM, a low detection limit of 0.17$\mu$M (S/$\mathrm{\text{N}}=3$) and high sensitivity of 397.1$\mu$AmM${}^{-1}$cm${}^{-2}$. In addition, the sensor exhibits long-term stability, good reproducibility and anti-interference.

Ag nanoparticles dispersed on Co₃O₄/3D porous reduced graphene oxide (Ag/Co₃O₄/rGO) were successfully synthesized through sol–gel method and used for fabricating a novel nonenzymatic hydrogen peroxide (H₂O${}_2)$ sensor. The structure and morphology of anocomposites were characterized by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The electrochemical properties of the sensor were investigated by cyclic voltammetry and amperometry. The experimental results suggest that the composites have an excellent catalytic property toward dopamine with a wide linear range from 0.5$\mu$M–6.48mM, a low detection limit of 0.17$\mu$M ($\mathrm{\text{S/N}}=3$) and high sensitivity of 413.72$\mu$AmM${}^{-1}$ cm${}^{-2}$. In addition, the sensor exhibits long-term stability, good reproducibility and anti-interference.

The development of highly sensitive, long-lasting and cost-effective dual hydrogen peroxide (H₂O${}_2)$/glucose sensors is crucial for various industries, particularly in medical, clinical diagnostics, pharmaceuticals, environmental monitoring and food business. In our study titanium dioxide/copper oxide (TiO₂/CuO) hierarchical nanostructure electrodes have been grown using hydrothermal process and their nonenzymatic H₂O₂ sensing and glucose sensing properties have been demonstrated using cyclic voltammetry and amperometry measurements. The surface morphology of TiO₂ nanorods (TiO₂ NRs) and TiO₂/CuO hierarchical nanostructure was investigated using a scanning electron microscope (SEM). The TiO₂/CuO hierarchical nanostructure electrodes demonstrated sensitivity of 20.09 $\mu$A mM${}^{-1}$ cm${}^{-2}$ toward H₂O₂, in the concentration range 0.25–18.25 mM. The TiO₂/CuO hierarchical nanostructure electrodes demonstrated a sensitivity of 1.5 mA mM${}^{-1}$ cm${}^{-2}$ towards glucose, in the concentration range 0.05–5 mM. Furthermore, artificial neural networks (ANN) were used to model the observed experimental results.