Preparation involving dealumination of a BEA zeolite connected with its impregnation with a diluted, highly acidic aqueous solution of NH 4 VO 3, followed by thermal activation under vacuum, results in abundant generation of an intrazeolite di-oxovanadium(IV) radical species (VO 2 ), not observed before in any catalytic or other related systems. Their identification was based on characteristic EPR spectra and ascertained by DFT calculation of the magnetic parameters. The VO 2 active sites exhibit high reactivity toward NO and O 2, via spin pairing and electron-transfer reactions, in decomposition of N 2 O via oxygen transfer as well as oxygen insertion to the double bond of hydrocarbon molecules. These make the VO 2 −BEA a versatile functional system for model molecular level studies of many elementary processes, such as interfacial electron and oxygen transfer or spin pairing when contacted with reactants of catalytic relevance.
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Pietrzyk et al. (2007) studied this question.