A combined in situ XAS/Raman and WAXS study on nanoparticulate V2O5 in zeolites ZSM-5 and Y

作者：Boyesen Katrine Lie^*; Meneau Florian; Mathisen Karina

来源：Phase Transitions, 2011, 84(8): 675-686.

DOI：10.1080/01411594.2010.550177

• vanadium pentoxide
• zeolites
• nanoparticles
• propene oxidation
• combined EXAFS/Raman

Nanoparticles (NPs) of vanadium pentoxide (V2O5) were introduced into zeolites H-ZSM-5 and H-Y by an ion exchange/co-precipitation procedure. Wide Angle X-ray Scattering confirms the presence of V2O5 NPs in ZSM-5, but the particles formed in zeolite Y were too small to be detected. The local vanadium environment was studied by combined X-ray Absorption Spectroscopy and Raman. The vanadium coordination in V2O5/ZSM-5 is distorted square pyramidal, similar to that in bulk V2O5. The vanadyl group is absent in zeolite Y, which is mainly comprised of symmetrical VOx surface groups. The size of the NPs is clearly limited by the shape selective properties of the chosen 3-D support system. Only V2O5/ZSM-5 is active in oxidising propene over a wide temperature range. Variations in the pre-edge height of the 1s-3d pre-edge feature suggests that continuous breakage and restoration of the V=O bond occurs in V2O5/ZSM-5 during reaction.

• 出版日期2011