Remarkable effect of the preparation method on the state of vanadium in BEA zeolite: Lattice and extra-lattice V species
✍ Scribed by S. Dzwigaj; E. Ivanova; R. Kefirov; K. Hadjiivanov; F. Averseng; J.M. Krafft; M. Che
- Publisher
- Elsevier Science
- Year
- 2009
- Tongue
- English
- Weight
- 467 KB
- Volume
- 142
- Category
- Article
- ISSN
- 0920-5861
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✦ Synopsis
in dealuminated BEA from an aqueous VOSO 4 solution, used as V(IV) precursor. However, despite the combined deployment of different techniques, it was difficult to obtain precise information concerning oxidation state and location of vanadium ions in BEA zeolite after different pre-treatments.
In this paper, we report on the effect of the preparation method on the state of vanadium ions in BEA zeolite and provide data on (1) the nature and environment of the V species formed, and (2) the reactivity of V(IV) (VOSO 4 ) precursor with vacant T-sites of SiBEA zeolite in anaerobic conditions. The combined deployment of XRD, FT-IR, DR UV-vis and EPR used for characterization of activated (outgassed at 773 K), oxidized (calcined in flowing oxygen at 773 K) and reduced (treated with hydrogen at 873 K) V-containing BEA zeolite allows to distinguish different kinds of V(V), V(IV) or V(III) species present in lattice and extra-lattice position.
Experimental
2.1. Materials
A tetraethylammonium BEA (TEABEA) zeolite was provided by RIPP (China). A portion of it was calcined (15 h, 823 K) to obtain Catalysis Today 142 (2009) 185-191