Vanadium oxide catalysis

Attenlion should be drawn to ihe use of tin oxide systems as heterogeneous catalysts. The oldest and mosi extensively patented systems are the mixed lin-vanadium oxide catalysis for the oxidation of aromatic compounds such as benzene, toluene, xylenes and naphthalene in the. synthesis of organic acids and acid anhydride.s. More recenily mixed lin-aniimony oxides have been applied lo the selective oxidaiion and ammoxidaiion of propylene to acrolein, acrylic acid and acrylonilrile. 

Fig. 22. Relalioiiship between yields of photoformed CO2 on vanadium oxide catalysis anchored to SiOq and the relative yields of the phololuminescence spectra of catalrats having different vanadium contents at 280 K [reproduced with permission from Patterson et at (J25) ...

When heated in the presence of a carboxyHc acid, cinnamyl alcohol is converted to the corresponding ester. Oxidation to cinnamaldehyde is readily accompHshed under Oppenauer conditions with furfural as a hydrogen acceptor in the presence of aluminum isopropoxide (44). Cinnamic acid is produced directly with strong oxidants such as chromic acid and nickel peroxide. The use of t-butyl hydroperoxide with vanadium pentoxide catalysis offers a selective method for epoxidation of the olefinic double bond of cinnamyl alcohol (45). 

In the bulk form, vanadium oxides display different oxidation states and V—O coordination spheres and exhibit a broad variety of electronic, magnetic, and structural properties [96, 97], which make these materials attractive for many industrial applications. Prominent examples range from the area of catalysis, where V-oxides are used as components of important industrial catalysts for oxidation reactions [98] and environment pollution control [99], to optoelectronics, for the construction of light-induced electrical switching devices [100] and smart thermo-chromic windows. In view of the importance of vanadium oxides in different technological applications, the fabrication of this material in nanostructured form is a particularly attractive goal. 

Although much of the V NMR has been performed on model systems or catalytic materials containing vanadium, 29 >30 compounds such as V2O5 or VOPO4 are used in both the catalysis and lithium battery fields, and many of the results can be used to help elucidate the structures of vanadium-containing cathode materials. V NMR spectra are sensitive to changes in the vanadium coordination number and distortions of the vanadium local environments from regular tetrahedra or octahedra. >33 5>V isotropic chemical shifts of between —400 and —800 ppm are seen for vanadium oxides, and unfortunately, unlike... 

The important commercial process of sulfur dioxide oxidation has been studied by a number of investigators. A set of steps that has been proposed for both platinum and vanadium oxide-based catalysis by Horiuti (7) for the overall reaction 2SOz + 02 2SOs is as follows ... 

Andersson, A. (1982). An oxidized surface state model of vanadium oxides and its application to catalysis. /. Solid State Chem. 42, 263-75. 

Bond GC, Tahir SF. Vanadium oxide monolayer catalysts Preparation, characterization and catalytic activity. Applied Catalysis. 1991 71(1) 1—31. 

Iron vanadate, FeV04, is a prospective material for lithium rechargeable batteries and in catalysis. In [90] mechanical coactivation of iron and vanadium oxides was used to prepare intimate nanoscale mixture, similar to those prepared by soft chemistry. Reduction of this mixture at the same temperature and oxygen partial pressure conditions as of soft chemistry products (500°C and 10 Pa) leads to formation of a nanometric vanadium ferrite with the only spinel phase. The characterization of the powders thus prepared was perfomed by X-ray diffraction, SEM, IR spectrometry, thermogravimetry and colourimetry. It was shown that the homogeneity of grain size and chemical composition is achieved if the initial oxides have similar grain size. 

Structure and reactivity of surface vanadium oxide species on oxide supports. Applied Catalysis A General,... 

Chemistry, spectroscopy and the role of supported vanadium oxides in heterogeneous catalysis. Catalysis Today, 78 (1-4), 25 6. 

Cortez, G.G. and Banares, M.A. (2002) A Raman Spectroscopy Study of Alumina-Supported Vanadium Oxide Catalyst during Propane Oxidative Dehydrogenation with Online Activity Measurement. Journal of Catalysis, 209 (1), 197-201. 

Khodakov, A., Olthof, B., BeU, A.T. and Iglesia, E. (1999) Structure and catalytic properties of supported vanadium oxides support effects on oxidative dehydrogenation reactions. Journal of Catalysis,... 

Kanervo, J.M., Harlin, M.E., Krause, A.0.1. andBanares, M.A. (2003) Characterization of alumina-supported vanadium oxide catalysts by kinetic analysis of H2-TPR data. Catalysis Today, 78 (1-4) 171-80. 

Gao, X., Jehng, J.-M. and Wachs, l.E. (2002) In situ UV-vis-NlR diffuse reflectance and raman spectroscopic studies of propane oxidation over Zr02-supported vanadium oxide catalysts. Journal of Catalysis, 209 (1), 43-50. 

Ruitenbeek, M., Van Dillen, A.J., de Groot, E.M.F., Wachs, I.E., Geus, J.W. and Koningsberger, D.C. (2000) The structure of vanadium oxide spedes on. gamma-alumina an in situ X-ray absorption study during catalytic oxidation. Topics in Catalysis, 10 (3 ) 241-54. 

This review deals with the applications of photolurainescence techniques to the study of solid surfaces in relation to their properties in adsorption, catalysis, and photocatalysis, After a short introduction, the review presents the basic principles of photolumines-cence spectrosajpy in relation to the definitions of fluorescence and phosphorescence. Next, we discuss the practical aspects of static and dynamic photoluminescence with emphasis on the spectral parameters used to identify the photoluminescent sites. In Section IV, which is the core of the review, we discuss the identification of the surface sites and the following coordination chemistry of ions at the surface of alkaline-earth and zirconium oxides, energy and electron transfer processes, photoluminesccncc and local structure of grafted vanadium oxide, and photoluniinescence of various oxide-... 

The importance of supported vanadium oxide in catalysis and photocatalysis is attested to by the richness of information provided by the photolumi-... 

Nozaki F, Ohki K (1972) A study of catalysis by uranium oxide and its mixed catalysis, 3. Comparison of uranium oxide catalysts with vanadium oxide, molybdenum oxide and tungsten oxide catalysts for catalytic oxidation of carbon monoxide. Bull Chem Soc Jap 45 9473... 

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