Vanadium Oxide Nanotubes: Characterization and Electrochemical Behavior

2001 ◽  
Vol 703 ◽  
Author(s):  
Samuel T. Lutta ◽  
Arthur Dobley ◽  
Katana Ngala ◽  
Shoufeng Yang ◽  
Peter Y. Zavalij ◽  
...  
Keyword(s):  
Vanadium Oxide ◽  
Sol Gel ◽  
Interlayer Spacing ◽  
Inert Atmosphere ◽  
X Ray Diffraction ◽  
Ion Exchange Reaction ◽  
Transmission Electron ◽  
Redox Active ◽  
Vanadium Oxide Nanotubes ◽  
Tubular Morphology

ABSTRACTVanadium oxide nanotubes (VONT) were formed from vanadium (V) oxide and the dodecylamine templating agent by a sol-gel reaction and subsequent hydrothermal treatment. The nanotubes were characterized by transmission electron microscopy (TEM), electron diffraction, thermogravimetric analysis (TGA), infrared spectroscopy and powder X-ray diffraction (XRD). The nanotubes consist of VO2.4[C12H28N] 0.27 and range in diameter from 100 nm to150 nm. The study further reveals that the compound maintained the tubular morphology when heated at 430o C in an inert atmosphere. However, the tubular morphology is destroyed when the compound is heated at about 130°C in oxygen. Organic free manganese intercalated vanadium oxide nanotubes (MnVONT) were synthesized by an ion exchange reaction. The previously mentioned techniques were used to characterize MnVONT. Mn0.86V7O16+δ. nH2O layers have 2D tetragonal cell with a=6.157(3) Å, while interlayer spacing is 10.52 (3) Å. VONT, heated VONT and Mn0.86V7O16+δ. nH2O are redox - active and can insert lithium reversibly. This study reveals that the electrochemical performance of VONT is enhanced by removing the organic template by heating in an inert atmosphere or exchanging with Mn2+ ions.

Vanadium Oxide Nanotubes with Diamine Templates

1999 ◽  
Vol 581 ◽  
Author(s):  
F. Krumeich ◽  
H.-J. Muhr ◽  
M. Niederberger ◽  
F. Bieri ◽  
M. Reinoso ◽  
...  
Keyword(s):  
Vanadium Oxide ◽  
Hydrothermal Treatment ◽  
Sol Gel ◽  
Exchange Reactions ◽  
Thin Walls ◽  
Synthesis Routes ◽  
High Yields ◽  
Vanadium Oxide Nanotubes ◽  
Tubular Morphology

ABSTRACTDiamine vanadium oxide nanotubes (DA-VOx-NTs) have been prepared in high yields applying two different synthesis routes, namely either a sol-gel reaction followed by a hydrothermal treatment or an exchange reaction. The first route is analogous to the well-known preparation of VOx-NTs containing monoamines: a vanadium(V) alkoxide is mixed with an α, ω- diamine (H2N[CH2]nNH2 with 12≤n≤20), the resulting adduct is hydrolyzed, and, after aging, a hydrothermal treatment leads to the nanotubes in pure form. The exchange of the monoamine template in VOx-NTs against diamines represents an alternative access to DA-VOx-NTs. This reaction occurs readily and is also applicable for diamines with short CH 2 chains like, e.g., in ethylene diamine. The TEM characterization of the DA-VOx-NTs confirms the tubular morphology which is widely preserved in the products of the exchange reactions. The characteristic feature of as-synthesized DA-VOx-NTs is a thick tube wall with many VO, layers while the exchange products are tubes comprising thin walls or bent packs of layers.

Vanadium Oxide Nanotubes: New Synthesis Route and Mechanism of Formation.

2004 ◽  
Vol 847 ◽  
Author(s):  
Maguy Jaber ◽  
Nathalie Steunou ◽  
Thierry Azaïs ◽  
Jacques Livage
Keyword(s):  
Vanadium Oxide ◽  
X Ray Diffraction ◽  
Mechanism Of Formation ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Transmission Electron ◽  
New Synthesis ◽  
In Situ Experiments ◽  
Vanadium Oxide Nanotubes

ABSTRACTThe synthesis of vanadium oxide nanotubes containing phosphorus (VPOx-NT) is described. A mixture of V2O5.nH2O gels, phosphoric acid and hexadecylamine was heated under hydrothermal conditions at 180°C for 7 days. The VPOx nanotubes were characterized by X-ray diffraction, scanning and transmission electron microscopy, 51V and 31P solid state NMR. In-situ experiments were performed in order to get a better understanding of the mechanism of these nanotubes formation.

scholarly journals The Influence Of NO/O2 On The NOx Storage Properties Over A Pt-Ba-Ce/γ-Al2O3 Catalyst

2019 ◽  
Vol 17 (1) ◽  
pp. 1459-1465
Author(s):  
Xuedong Feng ◽  
Jing Yi ◽  
Peng Luo
Keyword(s):  
Sol Gel ◽  
Chemical Properties ◽  
No Oxidation ◽  
Test Results ◽  
X Ray Diffraction ◽  
Storage Performance ◽  
Transmission Electron ◽  
Temperature Programmed ◽  
Physical And Chemical ◽  
Al2o3 Catalyst

AbstractWith the purpose of studying the influence of NO/O2 on the NOx storage activity, a Pt-Ba-Ce/γ-Al2O3 catalyst was synthesized by an acid-aided sol-gel method. The physical and chemical properties of the catalyst were characterized by X-ray diffraction (XRD) and Transmission Electron Microscope (TEM) methods. The results showed that the composition of the catalyst was well-crystallized and the crystalline size of CeO2 (111) was about 5.7 nm. The mechanism of NO and NO2 storage and NOx temperature programmed desorption (NO-TPD) experiments were investigated to evaluate the NOx storage capacity of the catalyst. Pt-Ba-Ce/γ-Al2O3 catalyst presented the supreme NOx storage performance at 350℃, and the maximum value reached to 668.8 μmol / gcat. Compared with O2-free condition, NO oxidation to NO2 by O2 had a beneficial effect on the storage performance of NOx. NO-TPD test results showed that the NOx species stored on the catalyst surface still kept relatively stable even below 350℃.

scholarly journals V2O3/C composite fabricated by carboxylic acid-assisted sol–gel synthesis as anode material for lithium-ion batteries

2021 ◽  
Author(s):  
G. S. Zakharova ◽  
E. Thauer ◽  
A. N. Enyashin ◽  
L. F. Deeg ◽  
Q. Zhu ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Lithium Ion Batteries ◽  
Sol Gel ◽  
Carbon Sources ◽  
Lithium Ion ◽  
X Ray Diffraction ◽  
Electron Microscopies ◽  
Transmission Electron ◽  
Battery Electrode ◽  
Sol Gel Synthesis

AbstractThe potential battery electrode material V2O3/C has been prepared using a sol–gel thermolysis technique, employing vanadyl hydroxide as precursor and different organic acids as both chelating agents and carbon sources. Composition and morphology of resultant materials were characterized by X-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopies, physical sorption, and elemental analysis. Stability and electronic properties of model composites with chemically and physically integrated carbon were studied by means of quantum-chemical calculations. All fabricated composites are hierarchically structured and consist of carbon-covered microparticles assembled of polyhedral V2O3 nanograins with intrusions of amorphous carbon at the grain boundaries. Such V2O3/C phase separation is thermodynamically favored while formation of vanadium (oxy)carbides or heavily doped V2O3 is highly unlikely. When used as anode for lithium-ion batteries, the nanocomposite V2O3/C fabricated with citric acid exhibits superior electrochemical performance with an excellent cycle stability and a specific charge capacity of 335 mAh g−1 in cycle 95 at 100 mA g−1. We also find that the used carbon source has only minor effects on the materials’ electrochemical performance.

Effect of Calcinations on Characterizations of Fabricated Nano Manganese Ferrite

2013 ◽  
Vol 634-638 ◽  
pp. 2150-2154 ◽  
Author(s):  
Rita Sundari ◽  
Tang Ing Hua ◽  
M. Rusli Yosfiah
Keyword(s):  
Sol Gel ◽  
Volatile Components ◽  
Manganese Ferrite ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Reflectance Analysis ◽  
Transmission Electron Microscope Analysis ◽  
Electron Microscope Analysis ◽  
Nano Size

A citric acid anionic surfactant has been applied for nano manganese ferrite (MnFeO3) fabrication using sol gel method. The calcinations have been varied for 300, 600 and 800oC. The UVDR (UV-Vis Diffused Reflectance) analysis shows a high absorptive band gap after 400 nm for the 600oC calcinated MnFeO3. The DTA (Differential Thermal Analysis) profiles exhibit remarkably trapped volatile matters (H2O, CO2, and NO2) in the fabricated MnFeO3 under sol gel heat treatment at 100oC and the peaks disappeared as the calcination increased to 600oC. As the temperature elevated from 100 to 300oC, the absorption peaks of volatile components are disappeared as demonstrated clearly by the FTIR (Fourier Transform Infrared) spectra of the fabricated material, which 3393 cm-1 corresponded to OH group, 1624 cm-1 to CO group, and 1384 cm-1 to NO group. The XRD (X-Ray Diffraction) spectra show clearly the alteration process from amorphous to crystalline structure as the calcinations increased from 300 to 600oC. In addition, the TEM (Transmission Electron Microscope) analysis exhibits parts of the fabricated MnFeO3 found in cubic nano size of 15-40 nm under interested calcinations and the result is in agreement with that obtained by XRD investigation.

Synthesis of Novel Vanadium Oxide Nanotubes and Nanofibers

2002 ◽  
Vol 740 ◽  
Author(s):  
Samuel T. Lutta ◽  
Hong Dong ◽  
Peter Y. Zavalij ◽  
M. Stanley Whittingham
Keyword(s):  
Thermal Analysis ◽  
Vanadium Oxide ◽  
Electrochemical Behavior ◽  
Redox Reactions ◽  
Sol Gel ◽  
Vanadium Oxides ◽  
Organic Polymer ◽  
Fibrous Morphology ◽  
Surfactant Templates ◽  
Vanadium Oxide Nanotubes

ABSTRACTWe are exploring the synthesis and properties of structured vanadium oxides mainly nanotubes and nanorods. Nanotubes initially formed with surfactant templates have been readily exchanged with simple cations without change of the basal-plane structure. These compounds contain d-like vanadium oxide layers with the vanadium in VO6 octahedra. This structure is particularly suitable for redox reactions. In this paper we report on synthesis of vanadium oxide, (NH4)xV2O5-d·nH2O rods using organic polymer as template. This compound has been synthesized by sol-gel reaction and subsequent hydrothermal treatment. TGA, SEM, XRD and FTIR were used to characterize this compound. Thermal analysis of this compound shows that the fibrous morphology is maintained when it is heated in nitrogen and oxygen above 300 °C. However, in both cases the size of the fibers decreases. Performance of this compound as cathode material in secondary electrolyte has been investigated using LiPF6 as electrolyte. A capacity of 140 mAh/g was obtained which remained fairly constant with up to at least 10 cycles. We also investigated electrochemical behavior of thermal products.

Researches on Preparation of Photosan Loaded Magnetic Silica Anoparticles and their Anti-Tumor Effects in Photodynamic Therapy

2012 ◽  
Vol 622-623 ◽  
pp. 821-826
Author(s):  
Yu Wen ◽  
Xiao Feng Deng ◽  
Liang Liang Liu ◽  
Shu Yun Shi ◽  
Li Xiong
Keyword(s):  
Drug Delivery ◽  
Photodynamic Therapy ◽  
Drug Delivery System ◽  
Delivery System ◽  
Sol Gel ◽  
Haematoporphyrin Derivative ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Good Biocompatibility ◽  
Low Solubility

Photodynamic therapy (PDT) is an effective, noninvasive and nontoxic therapeutics for cancer and some other diseases. It is becoming a alternative of traditional therapeutics for cancers. But the efficacy of PDT was restricted by insufficient selectivity and low solubility. In this study, novel multifunctional silica-based magnetic nanoparticles were prepared as targeting drug delivery system to achieve higher specificity and better solubility. Haematoporphyrin derivative (photosan) was used as photosensitizer. Magnetite nanoparticles (Fe3O4) and photosan were incorporated in silica nanoparticles by microemulsion and sol-gel methods. The prepared nanoparticles were characterized by X-ray diffraction, and transmission electron microscopy. The nanoparticles possessed good biocompatibility and could cause remarkable photodynamic anti-tumor effects. These suggested that photosan-Fe3O4 nanoparticles had great potential as effective drug delivery system in targeting photodynamic therapy.

Synthesis, Characterization, and Microwave Absorption Properties of SrFe12O19 Ferrites and FeNi3 Nanoplatelets Composites

2010 ◽  
Vol 148-149 ◽  
pp. 893-896 ◽  
Author(s):  
Ze Yang Zhang ◽  
Xiang Xuan Liu ◽  
You Peng Wu
Keyword(s):  
Electron Microscopy ◽  
Microwave Absorption ◽  
Composite Coatings ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Absorption Properties ◽  
Filling Fraction ◽  
Microwave Absorption Properties ◽  
Phase Reduction ◽  
Transmission Electron

M-typical SrFe12O19 ferrites and FeNi3 nanoplatelets were successfully prepared by the sol-gel method and solution phase reduction method, respectively. The crystalline and morphology of particles were studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The composite coatings with SrFe12O19 ferrites and FeNi3 nanoplatelets in polyvinylchloride matrix were prepared. The microwave absorption properties of these coatings were investigated in 2-18GHz frequency range. The results showed that the M-typical SrFe12O19 ferrites and FeNi3 nanoplatelets were obtained and they presented irregular sheet shapes. With the increase of the coating thickness, the absorbing peak value moves to the lower frequency. The absorbing peak values of the wave increase along with the increasing of the content of FeNi3 nanoplatelets filling fraction. When 40% SrFe12O19 ferrites is doped with 20% mass fraction FeNi3 nanoplatelets to prepare composite with 1.5mm thickness, the maximum reflection loss is -24.8 dB at 7.9GHz and the -10 dB bandwidth reaches 3.2GHz.

The effect of silver concentration and calcination temperature on structural and optical properties of ZnO:Ag nanoparticles

2015 ◽  
Vol 29 (01) ◽  
pp. 1450254 ◽  
Author(s):  
M. Shayani Rad ◽  
A. Kompany ◽  
A. Khorsand Zak ◽  
M. E. Abrishami
Keyword(s):  
Calcination Temperature ◽  
Sol Gel ◽  
Visible Emission ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
Zno Nps ◽  
Calcination Temperatures ◽  
Transmission Electron ◽  
Xrd Patterns ◽  
Average Size

Pure and silver added zinc oxide nanoparticles ( ZnO -NPs and ZnO : Ag -NPs) were synthesized through a modified sol–gel method. The prepared samples were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. In the XRD patterns, silver diffracted peaks were also observed for the samples synthesized at different calcination temperatures of 500°C, 700°C, 900°C except 1100°C, in addition to ZnO . TEM images indicated that the average size of ZnO : Ag -NPs increases with the amount of Ag concentration. The PL spectra of the samples revealed that the increase of Ag concentration results in the increase of the visible emission intensity, whereas by increasing the calcination temperature the intensity of visible emission of the samples decreases.

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