Abstract
The presence of different V V species in VSiBEA zeolite prepared by impregnation in air of dealuminated BEA zeolite with aqueous V IVOSO 4 solution is evidenced by diffuse reflectance UV–Visible and photoluminescence spectroscopies. The former technique shows that in as prepared VSiBEA with 0.26 and 0.68 wt%, V is present as lattice mononuclear tetrahedral species. In calcined-hydrated VSiBEA whatever the V content (0.26 and 0.68 wt%) and in as prepared VSiBEA with 1.36 V wt%, V is present both as lattice mononuclear tetrahedral and extra-lattice octahedral species. However, only photoluminescence spectroscopy is able to clearly distinguish three kinds of distorted lattice mononuclear tetrahedral V V species, whose relative amounts depend on V content and calcination–hydration treatments. Moreover, FT-IR demonstrates that the presence of V in dealuminated BEA zeolite generates Brønsted and Lewis acidic sites whose amounts increase with V content.
Published Version
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