EPR Studies of the Coverage Effects in TiO2(B)-Supported Vanadia Catalysts for Toluene Ammoxidation
(1992) In Journal of Catalysis 138(1). p.79-89- Abstract
- EPR spectroscopy has been employed to determine the nature of vanadium (+4) species in the TiO2(B)-supported vanadia catalysts. IR and EPR studies show that multiple vanadia species are observed as a function of loading. At coverages greater than 3.5 theoretical layers, the EPR signal is reminiscent of bulk V205. At lower coverages, a different magnetic species dominates the resonance and may be attributable to tetrahedral states of vanadium at the oxide interface. The spin concentration and (g) suggest two distinct vanadia phases as a function of coverage. In this study, we have also analyzed catalysts after use in ammoxidation of toluene. These samples show strikingly different features compared with the freshly prepared samples. Changes... (More)
- EPR spectroscopy has been employed to determine the nature of vanadium (+4) species in the TiO2(B)-supported vanadia catalysts. IR and EPR studies show that multiple vanadia species are observed as a function of loading. At coverages greater than 3.5 theoretical layers, the EPR signal is reminiscent of bulk V205. At lower coverages, a different magnetic species dominates the resonance and may be attributable to tetrahedral states of vanadium at the oxide interface. The spin concentration and (g) suggest two distinct vanadia phases as a function of coverage. In this study, we have also analyzed catalysts after use in ammoxidation of toluene. These samples show strikingly different features compared with the freshly prepared samples. Changes in both the g-anisotropy and hyperfine coupling were observed relative to the fresh catalysts. Though EPR is not surface sensitive, inference into the nature of the catalytic surface can be made by comparison of catalysts of different coverage and studies of monolayer samples. A study of the TiO2(B)-vanadia interface was made by comparing monolayer catalysts prepared from slightly different technique. Our measurements show strikingly different features in V4+ species as a function of preparation. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/2017970
- author
- Jansen, Susan ; Tu, Yanping ; Palmieri, Michael J ; Sanati, Mehri LU and Andersson, Arne LU
- organization
- publishing date
- 1992
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Journal of Catalysis
- volume
- 138
- issue
- 1
- pages
- 79 - 89
- publisher
- Elsevier
- external identifiers
-
- wos:A1992JU77700007
- scopus:0002416187
- ISSN
- 1090-2694
- DOI
- 10.1016/0021-9517(92)90008-6
- language
- English
- LU publication?
- yes
- id
- 5ab4c541-c335-4170-b406-08a174fc6b4d (old id 2017970)
- date added to LUP
- 2016-04-04 11:36:57
- date last changed
- 2023-09-06 11:07:45
@article{5ab4c541-c335-4170-b406-08a174fc6b4d, abstract = {{EPR spectroscopy has been employed to determine the nature of vanadium (+4) species in the TiO2(B)-supported vanadia catalysts. IR and EPR studies show that multiple vanadia species are observed as a function of loading. At coverages greater than 3.5 theoretical layers, the EPR signal is reminiscent of bulk V205. At lower coverages, a different magnetic species dominates the resonance and may be attributable to tetrahedral states of vanadium at the oxide interface. The spin concentration and (g) suggest two distinct vanadia phases as a function of coverage. In this study, we have also analyzed catalysts after use in ammoxidation of toluene. These samples show strikingly different features compared with the freshly prepared samples. Changes in both the g-anisotropy and hyperfine coupling were observed relative to the fresh catalysts. Though EPR is not surface sensitive, inference into the nature of the catalytic surface can be made by comparison of catalysts of different coverage and studies of monolayer samples. A study of the TiO2(B)-vanadia interface was made by comparing monolayer catalysts prepared from slightly different technique. Our measurements show strikingly different features in V4+ species as a function of preparation.}}, author = {{Jansen, Susan and Tu, Yanping and Palmieri, Michael J and Sanati, Mehri and Andersson, Arne}}, issn = {{1090-2694}}, language = {{eng}}, number = {{1}}, pages = {{79--89}}, publisher = {{Elsevier}}, series = {{Journal of Catalysis}}, title = {{EPR Studies of the Coverage Effects in TiO2(B)-Supported Vanadia Catalysts for Toluene Ammoxidation}}, url = {{http://dx.doi.org/10.1016/0021-9517(92)90008-6}}, doi = {{10.1016/0021-9517(92)90008-6}}, volume = {{138}}, year = {{1992}}, }