Formation of [ital V][sub 2]O[sub 5]-based mixed oxides in flames
- Department of Chemical Engineering, The Johns Hopkins University, Baltimore, Maryland 21218 (United States)
V[sub 2]O[sub 5]--TiO[sub 2] and V[sub 2]O[sub 5]--Al[sub 2]O[sub 3] mixed oxide powders were synthesized in a hydrogen-oxygen flame using VOCl[sub 3], TiCl[sub 4], and Al(CH[sub 3])[sub 3] as precursors. The particle formation processes were investigated as a function of VOCl[sub 3] concentration by laser light-scattering and by collecting particles directly onto transmission electron microscopy grids. In the V[sub 2]O[sub 5]--TiO[sub 2] system, the oxides condense as an intimate mixture at all three VOCl[sub 3] concentrations. Spherical particles, 40 to 70 nm in diameter, are obtained. In the V[sub 2]O[sub 5]--Al[sub 2]O[sub 3] system, chain-like particles composed of an intimate mixture of V[sub 2]O[sub 5] and Al[sub 2]O[sub 3] form at the lowest VOCl[sub 3] concentration. At high VOCl[sub 3] concentrations, the chain-like particles have a core-mantle structure (a core mainly of Al[sub 2]O[sub 3] and a mantle mainly of V[sub 2]O[sub 5]). The crystalline form and 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 VOCl[sub 3] concentrations, and V[sub 2]O[sub 5] is obtained at the higher VOCl[sub 3] concentrations. The structure of the amorphous vanadium oxide matches that published for vanadium oxide supported'' catalysts.
- DOE Contract Number:
- FG02-88ER45356
- OSTI ID:
- 6148914
- Journal Information:
- Journal of Materials Research; (United States), Journal Name: Journal of Materials Research; (United States) Vol. 8:9; ISSN JMREEE; ISSN 0884-2914
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360201* -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
AMORPHOUS STATE
CHALCOGENIDES
COHERENT SCATTERING
DIFFRACTION
DISPERSIONS
FLAMES
FOURIER TRANSFORM SPECTROMETERS
INFRARED SPECTRA
MEASURING INSTRUMENTS
MIXTURES
MORPHOLOGY
OXIDES
OXYGEN COMPOUNDS
POWDERS
SCATTERING
SPECTRA
SPECTROMETERS
SYNTHESIS
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
VANADIUM COMPOUNDS
VANADIUM OXIDES
X-RAY DIFFRACTION