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Title
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Supported vanadium oxide catalysts : quantitative spectroscopy, preferential adsorption of , and coating of Zeolite Y
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Author
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Abstract
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| A series of supported vanadium oxide catalysts were prepared by the incipient wetness method as a function of the support composition (Al2O3, SiO2, and USY), the metal oxide loading (0-1 wt %), and the impregnation salt (vanadyl sulfate and ammonium vanadate). These catalysts have been studied by combined DRS-ESR spectroscopies in order to quantify the amount of V4+ and V5+ and to unravel their coordination geometries. These spectroscopic fingerprints have been used to study the preferential adsorption of V4+/5+ ions on SiO2, Al2O3, and USY. Both V4+ and V5+ were preferentially adsorbed on Al2O3 and showed a much smaller preference for USY and SiO2. The observed preference orders are discussed in relation with the properties of the support. In addition, a novel method is proposed to coat the external surface of USY with a thin film of Al2O3 The method is based on the deposition of USY with the so-called Keggin ion, [Al13O4(OH)(24)(H2O)(12)](7+), which is too big to enter the USY channels or pores. The obtained Al2O3/USY material showed a preferential adsorption of V4+ Onto the Al2O3 film, suggesting that this method could be useful for vanadium passivation of FCC catalysts. |
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Language
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English
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Source (journal)
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The journal of physical chemistry : B : materials, surfaces, interfaces and biophysical. - Washington, D.C., 1997, currens
The journal of physical chemistry : B : condensed matter, materials, surfaces, interfaces and biophysical. - Washington, D.C.
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Publication
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Washington, D.C.
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1998
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ISSN
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1089-5647
[print]
1520-5207
[online]
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DOI
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10.1021/JP981482S
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Volume/pages
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102
:41
(1998)
, p. 8005-8012
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ISI
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000076617100011
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Full text (Publisher's DOI)
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