12035-98-2Relevant academic research and scientific papers
Crossed-beam chemiluminescent reactions of titanium and vanadium with O2
Parson, J. M.,Geiger, L. C.,Conway, T. J.
, p. 5595 - 5605 (1981)
Titanium and vanadium have been reacted with O2 under crossed-beam conditions to form the TiO A 3Φ, B 3Π, C 3Δ, and E 3Π states and the VO B 4Π state.By heating and seeding the O2 nozzle beam the Ti reaction has been studied at relative collision energies of 4.0, 7.6, and 13.3 kcal/mol, and the V reaction at 3.9, 6.9, 7.6, and 13.1 kcal/mol.Computer simulations of the spectra yield relative rates for formation of TiO(A) and VO(B) vibrational states, which are slightly more excited than the prior model predictions.Increasing the relative collision energy does increase the production of all the electronically excited states, but the VO B state population does not increase as quickly as expected from the prior model.The dependence of the chemiluminescent signals on the metal source temperature suggests reaction of ground state Ti to formTiO(A), but metastable V to form VO (B).
A clean process of preparing VO as LIBs anode materials via the reduction of V2O3 powder in a H2 atmosphere: Thermodynamic assessment, isothermal kinetic analysis, and electrochemistry performance evaluation
Jin, Xin,Lv, Xuewei,Pei, Guishang,Xiang, Junyi,Zhong, Dapeng
, (2020)
VO is one of the most promising anode materials for lithium ion batteries (LIBs). Herein, we present the clean preparation of VO powder via reduction of V2O3 powder under high-purity H2. Thermodynamic calculation and V–O phase diagram analysis were carried out to ensure reasonable oxygen potential conditions. Isothermal reduction experiments and kinetic analysis using thermogravimetric analysis (TGA) were then performed at 1623 K, 1648 K, and 1673 K under a pure H2 gas flow. The reduction of V2O3 powder appears to obey an unreacted shrinking core model and can be divided into two steps. The first step was controlled by a chemical reaction, the kinetics of which can be described as G(α) = [-ln(1-α)]1/3 with an apparent activation energy of 107.3 kJ·mol?1. The second stage was controlled by gas diffusion, the kinetics of which can be described as G(α) = [1-(1-α)1/3]1/2 with an apparent activation energy of 45.5 kJ·mol?1. Powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) also were employed for characterizing the morphology of the prepared VO powder. As a result, when the VO was served as the LIBs anode material, the resulting electrodes exhibited a high specific capacity (843 mAh·g?1 after 30 cycles) and remarkable cyclic stability.
Reactions of Atomic Scandium, Titanium, and Vanadium with Molecular Water at 15 K
Kauffmann, J. W.,Hauge, R. H.,Margrave, J. L.
, p. 3547 - 3552 (1985)
Scandium, titanium, and vanadium metal atoms were cocondensed with water molecules in an argon matreix at 15 K.The atomic metals were observed to insert spontaneously into the OH bond of water to form the HMOH molecule, which was found to be nonlinear in
Kinetics of Neutral Transition-Metal Atoms in the Gas Phase: Oxidation of Sc(a2D), Ti(a3F), and V(a4F) by NO, O2, and N2O
Ritter, David,Weisshaar, James C.
, p. 4907 - 4913 (1990)
The oxidation kinetics of gas-phase, ground-state Sc(a2D), Ti(a3F), and V(a4F) atoms by NO, O2, and N2O is studied in 0.80 Torr of He buffer gas at 300 +/- 5 K.The metal atoms are created in a hollow cathode sputtering source before entering a fast flow reactor.The reactions are monitored by laser-induced fluorescence of the metal atom reactant.All nine M + OX -> MO + X bimolecular oxygen atom transfer reactions are inefficient at 300 K with rate constants in the range 0.45 x 10-12 to 10 x 10-12 cm3s-1.This indicates activation energies not larger than2-4 kcal mol-1 in all cases.The substantial range of reaction rates for a particular metal with the three different oxidants contrasts with the remarkable similarity of rates for all three metal atoms with each oxidant.The rate constants for reaction of each metal with the three oxidants fall in the order kNO > kO2 > kN2O, opposite to the normal expectation of decreasing activation energy with increasing exothermicity.The rate constant ordering kSc > kV > kTi for each oxidant and the small activation energies are interpreted in terms of an electron-transfer mechanism from neutral M + OX reactant surfaces to ion-pair M+O- + X product surfaces.
Reactions of V2O5, Nb2O5, and Ta2O5 with AlN
Chumarev,Mar'evich,Larionov,Dubrovskii, A. Ya.
, p. 267 - 272 (2011)
Reactions of vanadium, niobium, and tantalum pentoxides with aluminum nitride have been studied using X-ray diffraction. At temperatures from 1000 to 1600°C, we have identified various V, Nb, and Ta nitrides. The composition of the niobium and tantalum ni
Refinement of the V-O phase diagram in the range 25-50 at % oxygen
Davydov,Rempel
, p. 47 - 54 (2009)
The boundaries of the V14O6 + V x O z two-phase region in the V-O system at temperatures from ? 1050 to ? 1650 K have been determined experimentally. The V-O phase diagram has been refined in the range 25-50 at
Phase transitions and electrical transport in the mixed-valence V 2+/V3+ oxide BaV10O15
Bridges,Greedan
, p. 1098 - 1110 (2004)
BaV10O15 can be regarded as a Ba-doped V 2O3 in which the Ba2+ ions substitute in the O2- close-packed layers. The Ba2+ ions order within these layers and direct the occupation of the octahedral sites by V2+ and V3+ ions resulting in a structure with subtle differences from that of V2O3 which can be described in Cmca at room temperature. Magnetic susceptibility data show evidence for two phase transitions at 135 and 40K. The higher temperature transition at 135K is shown to be structural in origin to another orthorhombic form, Pbca. The structural transition temperature, Ts, decreases with decreasing V2+ content to a minimum value of 105K. Crystallographic and DSC data support a first-order transition driven by partial bond formation which results in a 7% reduction in the distance between two of the five crystallographically distinct V atoms. There is no conclusive crystallographic evidence for V 2+/V3+ charge ordering in either the Cmca or Pbca forms. Electrical conductivity data show semiconducting behavior above Ts which can be fitted to a small polaron hopping model for the most reduced samples (Ts=135K). The same sample shows a sharp but not discontinuous decrease in conductivity below Ts, consistent with carrier removal due to bond formation. More oxidized materials with T s=105K show a more subtle anomaly. Evidence for correlated (Efros-Shklovskii) variable-range hopping at low temperatures is seen in the Ts=105K sample from analysis using a Hill-Zabrodski (logdE vs. logT) plot. Thermopower data on the Ts=135K material show an anomalously small value of S～+1μV/K at room temperature which increases to >+200μV/K upon cooling to 90K. Plots of dS/dT show evidence for the T s=135K phase transition. These results are not consistent with a simple one carrier model for small polaron hopping assuming that the V 2+ ions are the carriers, which would predict S～-100μV/K, but seem to demand a two carrier model with n～p at room temperature for which n-type carriers are trapped as a result of bond formation at the phase transition as temperature is lowered. The lower temperature phase transition near 40K is magnetic in origin and will be discussed in a subsequent publication.
Magnetic properties of (Mn1-xVx)Sb2O4 with one-dimensional magnetic arrays
Abe,Yoshii,Kitazawa
, p. 429 - 432 (2002)
The magnetic properties of mangan-vanadium antimonate solid solution (Mn1-xVx)Sb2O4 (x = 0 to 0.6) with the tetragonal TX2O4 structure (T = Pb4+, Sn4+; X = Pb2+ or T = Mn2+, Fe2+, Co2+, Ni2+; X = Sb3+, As3+) were investigated. Magnetic measurements on the polycrystalline specimens have shown that characteristic ferromagnetic behavior appears in the case that x is larger than 0.1, whereas the final compound MnSb2O4 is an antiferromagnet with the Neel temperature TN = 60.5 K. The magnetic isotherms of the solid solution at low temperatures show ferromagnetic jumps at low fields but do not tend to saturate up to 5 T. The zero-field cooling magnetic susceptibility has a maximum at Tc = 57 K, which is independent of both the vanadium concentration x and the frequencies of the applied external fields.
Trends in the Optical Signatures for Transition-Metal Oxide Carbonyl Complexes. Evaluation of Transition-Metal Carbonyl, M(CO)x, Binding Energies
McQuaid, M. J.,Morris, K.,Gole, J. L.
, p. 5280 - 5285 (1988)
Transition-metal atoms entrained in argon, helium, and CO are oxidized with ozone (O3) and nitrogen dioxide (NO2) to study the nature of the metal atom complexation with CO.We establish a method for evaluating M-CO binding energies through comparison of the chemiluminescent emission from the oxidation of argon- and CO-entrained transition-metal atoms.These studies have thus far yielded Ebinding(Ti(CO)x) ca. 1.75 eV and Ebinding(NiCO) ca. 1.10 eV, the latter in excellent agreement with previous experimental and theoretical evaluations of the Ni-CO bond energy.We identify the optical signatures for transition-metal oxide carbonyl (MOCO) complexes formed in the oxidation of M(CO) complexes.We outline trends in the nature of the observed metal oxide complex emissions.The current study suggests a method for obtaining the spectra of transition-metal carbonyl (M(CO)x, x=1,2) complexes.
Preparation of nanocrystalline VOy by high-energy ball milling
Valeeva,Schroettner,Rempel
, p. 408 - 411 (2011)
We report high-energy milling of macrocrystalline nonstoichiometric cubic vanadium monoxide (V Oy) powder in a planetary ball mill lined with stabilized zirconia. The results indicate that milling of macrocrystalline VOy powder at 500 rpm for more than 2 h considerably broadens diffraction line profiles, with no changes in the crystal structure of the vanadium monoxide, VO1.00. Microstructural examination of vanadium monoxide powder by high-resolution scanning electron microscopy and X-ray diffraction indicates that highenergy ball milling can be used to produce vanadium monoxide powder with an average crystallite size within 23 nm.
