Journal ArticleDOI
Formation of V2O5-based mixed oxides in flames
TLDR
In this article, the particle formation processes were investigated as a function of VOCl3 concentration by laser light-scattering and by collecting particles directly onto transmission electron microscopy grids.Abstract:
V2O5–TiO2 and V2O5–Al2O3 mixed oxide powders were synthesized in a hydrogen-oxygen flame using VOCl3, TiCl4, and Al(CH3)3 as precursors. The particle formation processes were investigated as a function of VOCl3 concentration by laser light-scattering and by collecting particles directly onto transmission electron microscopy grids. In the V2O5–TiO2 system, the oxides condense as an intimate mixture at all three VOCl3 concentrations. Spherical particles, 40 to 70 nm in diameter, are obtained. In the V2O5–Al2O3 system, chain-like particles composed of an intimate mixture of V2O5 and Al2O3 form at the lowest VOCl3 concentration. At high VOCl3 concentrations, the chain-like particles have a core-mantle structure (a core mainly of Al2O3 and a mantle mainly of V2O5). The crystalline form and the surface area of these mixed oxides were determined by x-ray diffractometry, FT-IR spectroscopy, and BET analysis by nitrogen desorption. These measurements indicate that amorphous vanadium oxide forms at low VOCl3 concentrations, and V2O5 is obtained at the higher VOCl3 concentrations. The structure of the amorphous vanadium oxide matches that published for vanadium oxide “supported” catalysts.read more
Citations
More filters
Journal ArticleDOI
Flame aerosol synthesis of smart nanostructured materials
TL;DR: In this article, the authors classified flame processes into vapour-fed and liquid-fed ones depending on the employed state of the metal precursor, and distinguished them for their flexibility in producing materials of various compositions and morphologies that result in unique product functionalities.
Journal ArticleDOI
Aerosol flame synthesis of catalysts
TL;DR: In this article, a review of synthesis and performance of flame-made catalytic materials is presented, focusing on flame technology for its dominance in aerosol manufacturing of materials of high purity with minimal liquid byproducts.
Journal ArticleDOI
Gas-phase combustion synthesis of particles
TL;DR: In this paper, the fundamental processes governing gas-phase combustion synthesis of particles are summarized and compared for different growth regimes, including homogeneous nucleation, agglomeration, and coalescence.
Journal ArticleDOI
Aerosol flame reactors for manufacture of nanoparticles
TL;DR: In this article, the synthesis of nanoparticles using dry flame technology has been studied in the context of heterogeneous catalysts, which can be used to produce highly active nanoparticles with closely controlled morphology and composition.
Journal ArticleDOI
Flame Aerosol Synthesis of Vanadia–Titania Nanoparticles: Structural and Catalytic Properties in the Selective Catalytic Reduction of NO by NH3
TL;DR: In this article, a flame aerosol synthesis has been used to prepare vanadia-titania nanoparticles with high activity for the selective catalytic reduction of NO by NH3.
References
More filters
Journal ArticleDOI
The ultraviolet bands of OH Fundamental data
G.H. Dieke,H.M. Crosswhite +1 more
TL;DR: In this paper, a new survey of the infrared and visible-light bands of the Earth's ozone (OH) is presented, which is used for temperature measurements in flames and other combustion processes.
Journal ArticleDOI
Morphology of flame-generated soot as determined by thermophoretic sampling
TL;DR: In this article, the authors describe mesures sont effectuees sur une flamme a diffusion d'ethylene laminaire et asymetrique, permettant une amelioration de la qualite des informations.
Journal ArticleDOI
Laser raman spectroscopy of supported vanadium oxide catalysts
TL;DR: In this paper, the effects of vanadia loading and support composition on the structure of the dispersed vanadia species were studied by Raman spectroscopy to establish the effect of supporting vanadia catalysts.
Journal ArticleDOI
Solid-state vanadium-51 NMR structural studies on supported vanadium(V) oxide catalysts: vanadium oxide surface layers on alumina and titania supports
Hellmut Eckert,Israel E. Wachs +1 more
TL;DR: In this paper, two main surface vanadium oxide species with different bonding environments are detected, which are, on the basis of their anisotropic chemical shift and nuclear electric quadrupolar coupling properties, assigned to 4-and 6-coordinate V-O environments.
Journal ArticleDOI
Vanadium oxide monolayer catalysts. 3. A Raman spectroscopic and temperature-programmed reduction study of monolayer and crystal-type vanadia on various supports
Fred Roozeboom,MC Mittelmeijer-Hazeleger,Jacob A. Moulijn,J Medema,de Vhj Vincent Beer,P.J. Gellings +5 more
TL;DR: In this article, a combination of Raman spectroscopy and temperature-programmed reduction (TPR) was used for qualitative and quantitative structural analysis of vanadium(V) oxide supported on 7-A1203, GO2, Cr2O3, Si02, Ti02, and Zr02.