Structure of vanadium oxide on supports as measure by the benzaldehyde-ammonia titration method

Journal Article · Thu Aug 13 04:00:00 EDT 1987 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100301a020· OSTI ID:5527789

Niwa, M; Matsuoka, Y; Murakami, Y

In order to clarify the structure of vanadium oxide on supports, the benzaldehyde-ammonia titration (BAT) method was applied to various supported vanadium oxide catalysts. Prior to the measurements, an infrared study of the adsorbed benzoate ion on TiO/sub 2/, ZrO/sub 2/, and CeO/sub 2/ was carried out to justify the BAT method to measure surface cus sites. The exposed surface area of the supports Al/sub 2/O/sub 3/, TiO/sub 2/, and ZrO/sub 2/ with different crystal phases was then measured, and the surface area of vanadium oxide supported was calculated by the difference between BET and exposed surfaced areas. On the other hand, the surface area of vanadium oxide on SiO/sub 2/ was measured after reduction on 773 K, because benzaldehyde was adsorbed on the reduced V/sub 2/O/sub 3/ but not on SiO/sub 2/. Based on these measurements, the relationship between percent coverage on support and surface V/sub 2/O/sub 5/ concentration was obtained. The structure of supported V/sub 2/O/sub 5/ thus determined depended on the kind of support, but not significantly on the crystal phase. Except in small concentration on Al/sub 2/O/sub 3/ and SiO/sub 2/, vanadium oxide formed a multilayer. The support surface at Al/sub 2/O/sub 3/(..gamma..) was covered most effectively, and the average thickness of V/sub 2/O/sub 5/ in 100% of the coverage was 3 layers. To the contrary, the SiO/sub 2/ surface was not covered effectively, and the average thickness attained up to 50 layers. Furthermore, ZrO/sub 2/ and TiO/sub 2/ showed intermediate behavior between these supports. It is shown that the coverage efficiency and thickness of the formed metal oxides are correlated with the electronegativity of the cations of supports.

• Research Organization: Nagoya Univ., Japan
• OSTI ID: 5527789
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 91:17; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALDEHYDES
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
AMMONIA
BENZALDEHYDE
CATALYSIS
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
CRYSTAL STRUCTURE
DATA
DEPOSITION
EXPERIMENTAL DATA
HYDRIDES
HYDROGEN COMPOUNDS
INFORMATION
INFRARED SPECTRA
MOLECULAR STRUCTURE
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
SPECTRA
SURFACE COATING
SURFACE PROPERTIES
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
VANADIUM COMPOUNDS
VANADIUM OXIDES
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES