G. S. Zakharova

Enhanced gas sensing properties of V2O5 nanowires decorated with SnO2 nanoparticles to ethanol at room temperature

V2O5 nanowires decorated with SnO2 nanoparticles are prepared by two-step mild hydrothermal reaction, and the gas sensor device is fabricated by coating the nanowires as a thick film on the alumina tube. The pure V2O5 nanowires have almost no response to ethanol at room temperature, however, the sensitivity of V2O5 nanowires decorated with SnO2 nanoparticles is 1.46 upon exposure to 1000 ppm ethanol gas. The highest sensitivity of gas sensor based on V2O5 nanowires decorated with SnO2 nanoparticles to 1000 ppm ethanol is about 14, which is 2–3 times of pure V2O5 nanowires. The improved sensing performance of the composite is due to the increased depletion width and active sites along the nanowires, the energy gap between V2O5 nanowires and SnO2 nanoparticles promotes the electrons transport. Moreover, the gas sensor based on V2O5 nanowires decorated with SnO2 nanoparticles possesses a good selectivity to ethanol compared with other gases, such as CO2, H2O and NH3, and the stability of gas sensing performance is quite good, which implies that it would be a good candidate in the potential application.

Interpenetrating network V2O5 nanosheets/carbon nanotubes nanocomposite for fast lithium storage

Rapid charge and discharge cathode materials for lithium-ion batteries have been commonly researched for the development of electrical mobility applications. Here, an interpenetrating network vanadium pentoxide (V2O5) nanosheets/carbon nanotubes (CNTs) nanocomposite was fabricated by a freeze-drying process. Field emission scanning electron microscopy and transmission electron microscopy tests indicated that the CNTs and V2O5 nanosheets form an interpenetrating network structure. X-ray diffraction and X-ray photoelectron spectroscopy analyses confirmed that the V2O5 nanosheets exhibit orthorhombic crystal structure and mixed element states in the nanocomposite. The electrochemical properties of the V2O5 nanosheets/CNTs nanocomposite were studied by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge–discharge measurements. The results indicated that the V2O5 nanosheets/CNTs nanocomposite exhibits high specific capacity and good cycling stability. The initial specific capacity of the V2O5 nanosheets/CNTs nanocomposite is 130.7 mA h g−1 for a current density up to 5.0 A g−1 and remains at 100.1 mA h g−1 after 100 cycles.

Synthesis of vanadium pentoxide nanoneedles by physical vapour deposition and their highly sensitive behavior towards acetone at room temperature

V2O5 nanoneedles were synthesized using a facile physical vapour deposition approach. The XRD patterns confirmed the good crystallinity of the as prepared nanoneedles. The chemical states of the V2O5 nanoneedles were confirmed through XPS analysis. Gas sensor based on the V2O5 nanoneedles was investigated for four types of gases (acetone, ammonia, ethanol and propylamine) at room temperature. A high reproducible response and a good selective behavior towards acetone were observed in both low and high concentration zones with a low detection limit of 941 ppb, which was explained on the basis of the energy band model. A sensing mechanism has also been suggested.

Effect of the titanium glycerolate precursor heat treatment procedure on the morphology and photocatalytic properties of TiO2 nanopowder

We have studied the effect of titanium glycerolate precursor heat treatment on the morphology, structure, and photocatalytic properties of titanium dioxide nanopowders.

Ion state of atoms and the properties of perovskite-like compound CaCu3V4O12

The binding energies and valence state of atoms in the perovskite-like compound CaCu3V4O12 have been determined using XPS spectroscopy. The stoichiometry of this phase is formulated as Ca2+Cu2+Cu2+(V25+V24+O12). Under an air atmosphere, the phase interacts with water vapor and oxygen. As a result, Ca(OH)2 is formed on its surface, the Cu+ and V4+ ion concentrations decrease, and the Cu2+ and V5+ concentrations increase in association. Raman spectra show shortened cation-anion bond lengths and cation-anion-cation bond angles in CaCu3V4O12 compared to perovskite CuVO3; the two structures are alike. The electrical conductivity, magnetic susceptibility, thermal and sensor properties of CaCu3V4O12 in aqueous salt solutions have been studied.

Fabrication of TiO2 nanotube arrays and their application in flexible dye-sensitized solar cells

TiO2 nanotube arrays have been widely used as the photoelectrode in dye-sensitized solar cells (DSSCs). In this work, free-standing TiO2 nanotube arrays were prepared by two-step electrochemical anodization of titanium foils, then the TiO2 nanotube arrays were transferred to a flexible ITO/PEN substrate using titania slurries. SEM images showed that the TiO2 nanotube arrays with different lengths (10, 14, 20 and 30 μm) were successfully obtained. The photovoltaic properties for incident photon to current efficiency (IPCE) and photovoltaic conversion efficiency were also studied, showing that the best photovoltaic conversion efficiency of DSSCs based on 20 μm length TiO2 nanotube arrays was 3.44%.

High-pressure defect phase CexCu3V4O12

AbstractNonstoichiometric perovskite oxide CexCu3V4O12 (space group Im

Enhanced ultra-stable n-propylamine sensing behavior of V2O5/In2O3 core–shell nanorods

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