Loading...
Search for: vanadium-oxide
0.006 seconds

    Photo-degradation of methelyne blue over V2O5- TiO2 nano-porous layers synthesized by micro arc oxidation

    , Article Catalysis Letters ; Volume 134, Issue 1-2 , 2010 , Pages 162-168 ; 1011372X (ISSN) Bayati, M. R ; Golestani Fard, F ; Zaker Moshfegh, A ; Sharif University of Technology
    Abstract
    V2O5-TiO2 porous layers were synthesized via micro-arc oxidation for the first time. The effect of the applied voltage on morphology, composition, and photo-activity of the layers was investigated. The layers, which consisted of anatase, rutile, and vanadium pentoxide phases, revealed an enhanced photo-activity. About 93% of methylene blue solution was degraded on the synthesized layers after 120 min UV-irradiation with a reaction rate constant of k = 0.0228 min-1. The band gap energies of the vanadia-titania and pure titania layers were calculated as 2.56 and 3.39 eV, respectively  

    Synthesis and Charecterization of Nanosized vanadium Oxide

    , M.Sc. Thesis Sharif University of Technology Asjodi, Fateme (Author) ; Sadrnezhad, Khatiboleslam (Supervisor)
    Abstract
    This work examines the dissolution kinetics of Sodium meta vanadate in water medium. The effects of temperature, solid/liquid ratio, agitation speed on the leaching kinetics were investigated. the dissolution kinetics was controlled by the internal diffusion at the surface of the Sodium metavanadate particles. The activation energy for the leaching was2/13 kJ/mol. In the current project, we report the preparation of VO_2 nanorods crystals using a ethylenediaminetetracetic acid assisted and Cetyl Trimethyl Ammonium Bromide hydrothermal synthesis route. NH_4 Cl and NaVO_3 solution were used as the starting materials and vanadiumoxide crystals were obtained following growth at 180 °C for 24... 

    Pulsed laser deposition of W-V-O composite films: preparation, characterization and gasochromic studies

    , Article Solar Energy Materials and Solar Cells ; Volume 92, Issue 8 , 2008 , Pages 878-883 ; 09270248 (ISSN) Ranjbar, M ; Mahdavi, S. M ; Iraji zad, A ; Sharif University of Technology
    2008
    Abstract
    Modified tungsten oxide films by vanadium oxide provide neutrally coloring electrochromic electrodes for smart windows technology. In this study W-V-O mixed oxide films were fabricated by Nd:YAG pulsed laser deposition (PLD), λ=1064 nm, from mixed pressed powders of (WO3)1-x(V2O5)x, x=0, 0.09, 0.17, 0.23, 0.29 and 0.33, at 13.3 Pa oxygen partial pressure and 200 °C temperature on glass substrates. X-ray photoelectron spectroscopy (XPS) revealed V5+, V4+, W6+ and W5+ surface oxide states, where the ratio of W5+/W6+ enhances by the amount of vanadium in the films. Surface morphology was studied by scanning electron microscope (SEM) and optical properties by transmission-reflection spectra.... 

    One step electrodeposition of V2O5/polypyrrole/graphene oxide ternary nanocomposite for preparation of a high performance supercapacitor

    , Article International Journal of Hydrogen Energy ; Volume 42, Issue 33 , 2017 , Pages 21073-21085 ; 03603199 (ISSN) Asen, P ; Shahrokhian, S ; Iraji zad, A ; Sharif University of Technology
    Abstract
    A new ternary nanocomposite based on graphene oxide (GO), polypyrrole (PPy) and vanadium pentoxide (V2O5) is obtained via one-step electrochemical deposition process. Electrochemical deposition of V2O5, PPy and GO on a stainless steel (SS) substrate is conducted from an aqueous solution containing vanadyl acetate, pyrrole and GO to get V2O5/PPy/GO nanocomposite. Characterization of the electrode material is carried out by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM). The electrochemical performance of the as-prepared nanocomposite is evaluated by... 

    In situ growth of vanadia-titania nano/micro-porous layers with enhanced photocatalytic performance by micro-arc oxidation

    , Article Electrochimica Acta ; Volume 55, Issue 9 , 2010 , Pages 3093-3102 ; 00134686 (ISSN) Bayati, M. R ; Moshfegh, A. Z ; Golestani Fard, F ; Sharif University of Technology
    2010
    Abstract
    Micro-arc oxidation process was used to synthesize V2O5-TiO2 porous layers for the first time. Surface morphology and topography of the layers were investigated by scanning electron microscope (SEM) and atomic force microscope (AFM). X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques were also employed to evaluate phase structure and chemical composition of the layers. It was found that the V2O5-TiO2 layers consisted of anatase, rutile, and vanadium pentoxide phases fraction of which varied with the applied voltage and the electrolyte concentration. It was also revealed that pore size and surface roughness increased with the applied voltage and the electrolyte... 

    Synthesis of narrow band gap (V2O5)x-(TiO2)1-x nano-structured layers via micro arc oxidation

    , Article Applied Surface Science ; Volume 256, Issue 9 , 2010 , Pages 2903-2909 ; 01694332 (ISSN) Bayati, M. R ; Moshfegh, A. Z ; Golestani Fard, F ; Sharif University of Technology
    Abstract
    V2O5-TiO2 layers with a sheet-like morphology were synthesized by micro arc oxidation process for the first time. Surface morphology and topography of the layers were investigated by scanning electron microscope (SEM) and atomic force microscope (AFM). Phase structure and chemical composition of the layers were also studied by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. It was revealed that the composite layers had a sheet-like structure average thickness of which was about 100 nm depending on the applied voltage. The layers consisted of anatase, rutile, and vanadium pentoxide phases fractions of which varied with the applied voltage. The optical properties... 

    An investigation of the oxidative dehydrogenation of propane kinetics over a vanadium-graphene catalyst aiming at minimizing of the COx species

    , Article Chemical Engineering Journal ; Vol. 250 , 2014 , Pages 14-24 ; ISSN: 13858947 Fattahi, M ; Kazemeini, M ; Khorasheh, F ; Rashidi, A ; Sharif University of Technology
    Abstract
    Application of the DOE with the ANN in kinetic study of the ODHP was investigated.•The catalyst of vanadium/graphene synthesized through the hydrothermal technique.•The ANN and RSM's simulations were utilized to generate the extra data points.•Power law models and corresponding parameters determined to describe the reactions.•The optimization conducted in order to minimize the COx production. In the current investigation, an application of the design of experiments (DOE) along with the artificial neural networks (ANN) in a kinetic study of oxidative dehydrogenation of propane (ODHP) reaction over a synthesized vanadium-graphene catalyst at 400-500. °C presented aiming at minimizing the CO. x... 

    A strategy for single-step elaboration of V2O 5-grafted TiO2 nanostructured photocatalysts with evenly distributed pores

    , Article Journal of Alloys and Compounds ; Volume 509, Issue 21 , 2011 , Pages 6236-6241 ; 09258388 (ISSN) Bayati, M. R ; Molaei, R ; Moshfegh, A. Z ; Golestani-Fard, F ; Sharif University of Technology
    2011
    Abstract
    V2O5-TiO2 nanostructured porous layers were grown through micro arc oxidation of titanium in vanadate containing electrolytes. This study sheds light on the effect of the electric current type on the photocatalytic performance of the layers. Surface morphology of the layers was investigated by SEM. The results revealed a porous structure with a pores size of 30-180 nm depending on the frequency and the duty cycle. A uniform porous structure was obtained under the pulse-DC regime. Topographical investigations revealed a rough surface which is favorable for catalytic applications. Our XRD and XPS results showed that the layers consisted of anatase, rutile, and vanadium oxide phases whose...