V-Ti oxide catalysts prepd. by different methods (flash drying, copptn., wet impregnation, grafting) were investigated. Three V species are present in addn. to cryst. V2O5 (found at coverages higher than the theor. monolayer): VIV and VV strongly interacting with the Ti surface and a weakly interacting VV species. The prepn. procedure strongly influences the relative ratio of these 3 V species. Prepns. in which an oxo-hydrated Ti gel is involved instead of preformed TiO2 give rise to the formation of a greater amt. of strongly interacting V species. A comparison of catalytic properties in ortho-xylene selective oxidn. suggests that all these species are involved in the mechanism of oxidn.; in particular, VIV in the activation stage and VV in the selective step. [on SciFinder(R)]
Preparation chemistry of vanadium-titanium-oxygen mixed oxides. Comparison of coprecipitation, grafting and impregnation methods
CENTI, Gabriele;
1987-01-01
Abstract
V-Ti oxide catalysts prepd. by different methods (flash drying, copptn., wet impregnation, grafting) were investigated. Three V species are present in addn. to cryst. V2O5 (found at coverages higher than the theor. monolayer): VIV and VV strongly interacting with the Ti surface and a weakly interacting VV species. The prepn. procedure strongly influences the relative ratio of these 3 V species. Prepns. in which an oxo-hydrated Ti gel is involved instead of preformed TiO2 give rise to the formation of a greater amt. of strongly interacting V species. A comparison of catalytic properties in ortho-xylene selective oxidn. suggests that all these species are involved in the mechanism of oxidn.; in particular, VIV in the activation stage and VV in the selective step. [on SciFinder(R)]Pubblicazioni consigliate
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