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Vanadium Oxide (vanadium + oxide)

Distribution by Scientific Domains
Chemistry66%
Polymers and Materials Science33%

Selected Abstracts

ChemInform Abstract: Investigation of Yttrium and Polyvalent Ion Intercalation into Nanocrystalline Vanadium Oxide.

CHEMINFORM, Issue 45 2001
G. G. Amatucci
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Dehydration and Dehydrogenation of Alcohols with Mononuclear Cationic Vanadium Oxides in the Gas Phase and Energetics of VOnH0/+ (n = 2, 3),

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 17 2007
Marianne Engeser
Abstract The ion/molecule reactions of selected alcohols with the vanadium oxide cations VO+ and VO2+ are studied by Fourier-transform ion-cyclotron resonance (FT-ICR) mass spectrometry. Dehydrogenation is the dominating reaction pathway for methanol and allyl alcohols. With larger or less unsaturated alcohols, dehydration and carbocation formations prevail. While the valence in VO+ remains unchanged during alcohol dehydrogenation, VO2+ is reduced to VIII. Thermochemical data for VO2H0/+, VO3H and VO3H2+ are derived by means of ICR bracketing. The experimental results are further complemented by ab initio calculations using density functional theory. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]

Reduced Surfactant Uptake in Three Dimensional Assemblies of VOx Nanotubes Improves Reversible Li+ Intercalation and Charge Capacity

ADVANCED FUNCTIONAL MATERIALS, Issue 11 2009
Colm O'Dwyer
Abstract The relationship between the nanoscale structure of vanadium pentoxide nanotubes and their ability to accommodate Li+ during intercalation/deintercalation is explored. The nanotubes are synthesized using two different precursors through a surfactant-assisted templating method, resulting in standalone VOx (vanadium oxide) nanotubes and also "nano-urchin". Under highly reducing conditions, where the interlaminar uptake of primary alkylamines is maximized, standalone nanotubes exhibit near-perfect scrolled layers and long-range structural order even at the molecular level. Under less reducing conditions, the degree of amine uptake is reduced due to a lower density of V4+ sites and less V2O5 is functionalized with adsorbed alkylammonium cations. This is typical of the nano-urchin structure. High-resolution TEM studies revealed the unique observation of nanometer-scale nanocrystals of pristine unreacted V2O5 throughout the length of the nanotubes in the nano-urchin. Electrochemical intercalation studies revealed that the very well ordered xerogel-based nanotubes exhibit similar specific capacities (235,mA h g,1) to Na+ -exchange nanorolls of VOx (200,mA h g,1). By comparison, the theoretical maximum value is reported to be 240,mA h g,1. The VOTPP-based nanotubes of the nano-urchin 3D assemblies, however, exhibit useful charge capacities exceeding 437,mA h g,1, which is a considerable advance for VOx based nanomaterials and one of the highest known capacities for Li+ intercalated laminar vanadates. [source]

Smart sunglasses based on electrochromic polymers

POLYMER ENGINEERING & SCIENCE, Issue 11 2008
Chao Ma
Smart sunglasses based on electrochromic polymers are proposed and developed in this study. This article discusses the design, processing, and the optical and electrical performance of a prototype smart sunglasses based on cathodic electrochromic (EC) polymers, which show several merits compared with traditional materials for sunglasses lens as well as other smart window materials. It is a multilayer design of device. The conjugated polymer, poly[3,3-dimethyl-3,4-dihydro-2H-thieno [3,4-b] [1,4]dioxepine] (PProDOT-Me2), is utilized as the electrochromic working layer. The counter layer of the device is vanadium oxide (V2O5) film, which serves as an ion storage layer. There is also a polymer gel electrolyte acting as the ionic transport layer, sandwiched between the working and counter layers. The characteristics of the prototype device are reported, including transmittance (%T), driving power, response time, open circuit memory, and lifetime. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers [source]

X-ray powder diffraction and electron diffraction studies of the thortveitite-related L phase, (Zn,Mn)2V2O7

ACTA CRYSTALLOGRAPHICA SECTION B, Issue 2 2009
Kevin M. Knowles
The phase designated ,-Zn3(VO4)2 reported as a minor second phase in zinc oxide-based varistor materials doped with vanadium oxide and manganese oxide is shown to be the L phase, (Zn1,,,xMnx)2V2O7 (0.188 < x < 0.538), in the pseudo-binary Mn2V2O7,Zn2V2O7 system. Analysis of X-ray powder diffraction patterns and electron diffraction patterns of this phase shows that the previously published a, c and , values for this thortveitite-related phase are incorrect. Instead, Rietveld refinement of the X-ray powder pattern of the L phase shows that it has a monoclinic C lattice with Z = 6, with a = 10.3791,(1), b = 8.5557,(1), c = 9.3539,(1),Å and , = 98.467,(1)°. Although prior convergent-beam electron diffraction work of `,-Zn3(VO4)2' confirmed the C Bravais lattice, the space group was found to be Cm rather than C2/m, the difference perhaps arising from the inability of the X-rays to detect small displacements of oxygen. Attempts to refine the structure in Cm did not produce improved R factors. The relationship between the crystal structure of the L phase and the high-temperature C2/m,,-Zn2V2O7 thortveitite-type solid solution is discussed. [source]

Pb2.63Cd2V3O12, a cation-deficient garnet-type vanadate

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2007
Alexander A. Tsirlin
In the crystal structure of the cation-deficient garnet Pb2.63Cd2V3O12 (lead cadmium vanadium oxide), the Cd and V atoms fully occupy octahedral and tetrahedral sites, respectively, whereas the Pb atoms partially occupy a dodecahedral site. The total Pb and Cd content indicates that vanadium is slightly reduced from the +5 oxidation state. [source]