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Monitoring the states of vanadium oxide during the transformation of TiO2 anatase-to-rutile under reactive environments: H2 reduction and oxidative dehydrogenation of ethane

Paper ID Volume ID Publish Year Pages File Format Full-Text
51824 46855 2009 5 PDF Available
Title
Monitoring the states of vanadium oxide during the transformation of TiO2 anatase-to-rutile under reactive environments: H2 reduction and oxidative dehydrogenation of ethane
Abstract

The influence of vanadium oxide on the TiO2 (anatase) to rutile transformation for supported VOx/TiO2 catalysts under different environments (oxidizing, reducing and ethane oxidative dehydrogenation (ODH)) was investigated. The supported VOx/TiO2 catalysts were synthesized by incipient wetness impregnation and characterized with XPS surface analysis, Raman spectroscopy and temperature-programmed oxidation and reduction. The XPS surface analysis and Raman spectroscopy demonstrate that the supported vanadium oxide phase is initially present as surface VOx species on the titania (anatase) support below monolayer coverage (∼9 V/nm2) and that crystalline V2O5 nanoparticles are also present above monolayer coverage. The TiO2 anatase-to-rutile transformation is found to depend both on the gaseous environment and presence of vanadia. The anatase-to-rutile transformation is accelerated by the presence of vanadium oxide and the incorporation of V+4 cations into the TiO2 (rutile) lattice. The incorporation of the V+4 cations decreases the catalytic activity since the active sites are removed from the surface into the bulk, which is not accessible to the reactant gases. Although the titania anatase-to-rutile transformation readily occurs in oxidizing environments (O2 and ODH reaction), the solid-state transformation does not take place under reducing environments (H2) since large V3+ ions form prior to the transition temperature and cannot enter the titania lattice.

Keywords
Titania-supported vanadium oxide catalysts; Ethane oxidative dehydrogenation; In situ TP-Raman; Surface and bulk structure
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Monitoring the states of vanadium oxide during the transformation of TiO2 anatase-to-rutile under reactive environments: H2 reduction and oxidative dehydrogenation of ethane
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Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Communications - Volume 11, Issue 1, 10 October 2009, Pages 15–19
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us