Y. K. Xie

Electrochemical determination of L-cysteine using polyaniline/CuGeO3 nanowire modified electrode

The 10 wt % polyaniline/CuGeO3 nanowire modified glassy carbon electrode has been used for the electrochemical determination of L-cysteine. The electrochemical behavior of L-cysteine at the 10 wt % polyaniline/CuGeO3 nanowire modified glassy carbon electrode has been investigated. The intensities of the anodic cyclic voltammogram (CV) peaks of L-cysteine at the modified electrode increase linearly with the increase of the L-cysteine content in the range of 0.001–2 mM and scan rate ranging from 25 to 200 mV s−1. 10 wt % polyaniline/CuGeO3 nanowire modified glassy carbon electrode exhibits good reproducibility, stability and low detection limit of 1.7 and 0.44 μM for cvpl and cvp2, respectively. The polyaniline combined with the CuGeO3 nanowires can improve the electrochemical detection ability of L-cysteine.

Single crystalline Sr germanate nanowires and their photocatalytic performance for the degradation of methyl blue

Single crystalline Sr germanate nanowires have been synthesized by a facile hydrothermal process without any surfactants at a low temperature. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), Fourier transform infrared (FTIR) and ultraviolet-visible (UV-vis) diffusion reflectance spectra have been used to characterize the structure, morphology, size and optical properties of the Sr germanate nanowires. The nanowires with the orthorhombic SrGeO3 phase have the diameter of 50 to 200 nm. The morphology and size of the Sr germanate nanowires can be controlled by adjusting the hydrothermal temperature, reaction time and surfactant species. The photocatalytic activity of the Sr germanate nanowires has been evaluated by the degradation of methylene blue (MB) under UV-vis light irradiation. The roles of the irradiation time, the content of the Sr germanate nanowires and the MB concentration on the MB degradation have been investigated. The Sr germanate nanowires present a degradation ratio of 83.22% after irradiation for 4 h over 10 mg Sr germanate nanowires in a 10 ml 10 mg L−1 MB solution.

Synthesis and characterization of manganese vanadate nanorods as glassy carbon electrode modified materials for the determination of L-cysteine

Manganese vanadate nanorods with a single crystalline triclinic Mn2V2O7 phase have been synthesized through a hydrothermal process using sodium lauryl sulfonate (SDS) as the surfactant. The manganese vanadate nanorods have a typical length in the range of 5 to 20 μm and a diameter of about 50 to 300 nm. The morphology of the manganese vanadate products is influenced by SDS concentration, hydrothermal temperature and duration time. SDS promotes the phase transformation of the products from irregular particles with an orthorhombic MnV2O5 phase to nanorods with a triclinic Mn2V2O7 phase. The growth process has been proposed as a nucleation and SDS adsorption growth process based on the analysis of the influence of growth conditions on the morphology of the manganese vanadate products. The manganese vanadate nanorods are used as glassy carbon electrode modified materials to analyze the electrochemical responses of L-cysteine. The manganese vanadate nanorod modified glassy carbon electrode exhibits a good analytical performance for the electrochemical determination of L-cysteine with a detection limit of 0.026 μM and linear range of 0.00005–2 mM.

Electrochemical determination of benzoic acid using CuGeO3 nanowire modified glassy carbon electrode

Copper germanate (CuGeO3) nanowires are applied as the electrochemical modified materials for the electrochemical determination of benzoic acid (BA) in neutral solution. The electrochemical responses of BA at the CuGeO3 nanowire modified glassy carbon electrode (GCE) show two pairs of electrochemical cyclic voltammogram peaks (cvp) which originate from the nanowires. The linear range is 0.01–2 mM and detection limit is 6.3 µM for cvp1 at a signal-to-noise ratio of 3. The linear range and detection limit, respectively, are 0.001–2 mM and 0.91 µM for cvp2. Scan rate plays an important role on the electrochemical behavior of BA at the CuGeO3 nanowire modified GCE. There is a linear correlation between the anodic current and scan rate in the range of 25–200 mV s−1. The CuGeO3 nanowire modified GCE exhibits good stability and reproducibility. The good analytical performance indicates that the CuGeO3 nanowires have a potential application for the determination of BA.

Polyvinyl pyrrolidone-assisted synthesis of crystalline manganese vanadate microtubes

Manganese vanadate microtubes have been synthesized by a facile polyvinyl pyrrolidone-assisted hydrothermal route. X-ray diffraction pattern confirms that the microtubes are composed of monoclinic MnV2O6, tetragonal V2O5 and orthorhombic MnO2 phases. The outer diameter and inner diameter of the microtubes are about 300 nm-3 µm and 200 nm-1 µm, respectively. The tube wall thickness of the microtubes is about 50 nm-1 µm. The possible formation process of the manganese vanadate microtubes has been proposed as a polyvinyl pyrrolidone-assisted growth mechanism.

Copper germanate nanowire electrode for the electrochemical detection of glyoxalic acid using cyclic voltammetry method

Glyoxalic acid was determined by electrochemical cyclic voltammetry method using copper germanate (CuGeO3) nanowires as the modified glassy carbon electrode (GCE) materials. The CuGeO3 nanowire modified GCE exhibited good detection performance for glyoxalic acid in neutral solution. The intensities of two anodic peaks vary linearly with the increase of the scan rate from 25 to 200 mVs−1 and glyoxalic acid concentration from 0.001 to 2 mM. The detection limit was 8.5 μM and 0.78 μM for cvp1 and cvp2 with the correlation coefficient of 0.991 and 0.998, respectively. The CuGeO3 nanowire modified GCE exhibited good reproducibility and stability.

Synthesis and formation process of zirconium dioxide nanorods

Crystalline zirconium dioxide nanorods have been prepared by a simple hydrothermal process using zirconium hydroxide as the zirconium raw material. Zirconium dioxide nanorods are composed of monoclinic zirconium dioxide phase, which has been confirmed by the X-ray diffraction analysis. Electron microscopy observations show that the zirconium dioxide nanorods have a single crystal structure, with the rod diameter of less than 100 nm and length of 1–2 μm. Hydrothermal temperature and reaction time play essential roles in the formation and growth of the zirconium dioxide nanorods. Nucleation and crystal growth process are proposed to explain the formation and growth of the zirconium dioxide nanorods.