V sub 2 O sub 5 /SiO sub 2 catalysts modified by Na sup + ions: Surface characterization by spectroscopic methods and photoassisted oxidation of 2-propanol and propene

Silica-supported vanadium oxide prepared by impregnation of silica with a mixed solution of NaOH and NH{sub 4}VO{sub 3} exhibits a high activity in the photooxidation of 2-propanol and propene as well as improves selectivities to propane from 2-propanol and to acraldehyde from propene. The amount of...

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Bibliographic Details
Published in:Journal of catalysis 1989-08, Vol.118:2
Main Authors: Tanaka, Tsunehiro, Nishimura, Yasuo, Kawasaki, Shin-Ichi, Ooe, Masaharu, Funabiki, Takuzo, Yoshida, Satohiro
Format: Article
Language:English
Subjects:
02 PETROLEUM
020400 - Petroleum- Processing
10 SYNTHETIC FUELS
100200 - Synthetic Fuels- Production- (1990-)
ADDITIVES
ALCOHOLS
ALKALI METALS
ALKENES
CATALYST SUPPORTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL PREPARATION
CHEMICAL REACTIONS
CRYSTAL STRUCTURE
DECOMPOSITION
ELEMENTS
HYDROCARBONS
HYDROXY COMPOUNDS
METALS
MINERALS
ORGANIC COMPOUNDS
OXIDATION
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PHASE STUDIES
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
PROPANOLS
PROPYLENE
SILICA
SILICON COMPOUNDS
SILICON OXIDES
SODIUM
SPECTRA
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS
ULTRAVIOLET SPECTRA
VANADIUM COMPOUNDS
VANADIUM OXIDES
VISIBLE SPECTRA
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Summary:Silica-supported vanadium oxide prepared by impregnation of silica with a mixed solution of NaOH and NH{sub 4}VO{sub 3} exhibits a high activity in the photooxidation of 2-propanol and propene as well as improves selectivities to propane from 2-propanol and to acraldehyde from propene. The amount of sodium ions added affected the selectivity in the photooxidation of propene significantly but did not affect that of 2-propanol. In both reactions, the highest activity was observed for the catalyst containing 1 wt% Na{sub 2}O. UV-Vis spectra of the catalysts show that there are three different phases of vanadates on the silica surface, namely a polymeric phase and two tetrahedral phases. One of the tetrahedral phases exhibits an absorption band at 315 nm, which is an active species in the photocatalysis. By comparison of the results of the reactions, it is concluded that the addition of sodium ions alters the composition of surface phases. Addition of an appropriate amount of sodium ions maximizes the fraction of the active phase on the surface and enhances photocatalytic activity.
ISSN:0021-9517
1090-2694
DOI:10.1016/0021-9517(89)90321-7