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Influence of the co-precipitation pH on the physico-chemical and catalytic properties of vanadium aluminum oxide catalyst

par Blangenois, Nathalie;Florea, Mihaela;Prada Silvy, Ricardo;Grange, Paul;Chenakin, Sergiy ;Bastin, Jean Marie ;Kruse, Norbert ;Barbero, Bibiana P.;Cadús, Luis
Référence Applied catalysis. A, General, 263, page (163)
Publication Publié, 2003-12-03

Article révisé par les pairs

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Résumé :

Vanadium-aluminum oxide catalysts for propane oxidative dehydrogenation (ODH) are investigated with respect to their physico-chemical properties and catalytic activity as a function of the co-precipitation pH. Modifications of the specific surface area, the particle size distribution, and the chemical nature of the active phase are found. At co-precipitation pH 5.5, an amorphous V-Al-Ox mixed phase was formed by condensation of tetrahedral polymeric [VOx]n n− and amorphous aluminum hydroxide species. At pH between 7.5 and 8.5, the catalyst consists of [VOx]n n− species supported on amorphous aluminum hydroxide. At pH = 10, V2O7 4− ions are presumably adsorbed on boehmite surface. The propane conversion and the rate of propylene formation per gram-atom of vanadium are higher for the samples prepared at pH ≥8.5. A correlation exists between the reduction temperature of the vanadium species and the catalytic activity for the propane oxidative dehydrogenation reaction.