The ultrafine V 2O 5 TiO 2 composite oxide particles have been prepared by the high energy ball milling method and characterized by X ray diffraction, transmission electron microscopy, laser Raman spectroscopy, temperature programmed reduction, and microreactor testing. It has been shown that the milling process induces the formation of ultrafine V 2O 5 TiO 2 composite oxide particles with dispersed vanadium oxide on the surface of anatase TiO 2, accompanied by a decrease in particle size of V 2O 5 and TiO 2. The TPR results indicate that the strong interaction between dispersed V O species and TiO 2 increases the reducibility of the vanadium oxide. The catalytic properties of the catalysts for the selective oxidation of o xylene were evaluated. Under the similar o xylene conversion (58%), the ultrafine V 2O 5 TiO 2 composite oxide catalyst exhibits a higher selectivity for phthalic anhydride (44%) than the catalyst prepared by the conventional impregnation method (23%), and the catalyst composition has a great influence on the catalytic properties.
The structure and catalytic properties of V Ti O ultrafine particle catalyst for selective oxidation of o xylene have been studied. TEM and XRD results show that the particle size is in the range of 20～40 nm, and vanadium oxide is highly dispersed in TiO 2 (anatase). The catalytic activity of the V Ti O ultrafine particle catalyst for selective oxidation of o xylene to phthalic anhydride(PA) is higher than that of the larger oxide particles with the same catalyst composition prepared by impregnation and coprecipitation methods, indicating that the ultrafine V Ti O oxide particles are potentially new catalytic materials for the selective oxidation of o xylene to phthalic anhydride.
