Isotopic and chemical titration of acid sites in tungsten oxide domains supported on zirconia

Article Abstract:

Temporary acid sites formed by H2 dissociation and adsorption on basic oxygens in WOx domains lead to very active Bronsted acid sites, which catalyze 0-xylene isomerization with turnover rates much higher than on H-ZSM5. The surface and acid properties of WOx-ZrO2 acid catalysts were characterized in the presence of H2, and related to changes in the surface density and reducibility of WOx species.

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Structural characterization of molybdenum oxide supported on zirconia

Article Abstract:

The structure of dispersed and crystalline structures in MoO(sub x)/ZrO2 catalysts useful in the oxidative dehydrogenation of alkanes is determined by X-ray diffraction and X-ray absorption and Raman spectroscopies. The evolution of pre-edge and near edge features in the X-ray absorption spectra of these high surface density samples confirms the structural evolution observed.

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Extent of reduction of vanadium oxides during catalytic oxidation of alkanes measured by in-Situ UV-Visible spectroscopy

Article Abstract:

The method for measuring the extent of reduction during catalysis using pre-edge features in the UV-visible spectrum is described. It is proved that this method provides greater sensitivity than x-ray absorption and UV visible spectroscopic methods based on near-edge spectral features.

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