Effect of potassium addition to the TiO2 support on the structure of V2O5/TiO2 and its catalytic properties in the oxidative dehydrogenation of propane
| العنوان: | Effect of potassium addition to the TiO2 support on the structure of V2O5/TiO2 and its catalytic properties in the oxidative dehydrogenation of propane |
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| المؤلفون: | Monique Rigole, Michel Guelton, Barbara Grzybowska, Dominique Courcot, Anne Ponchel, Yolande Barbaux |
| المصدر: | Journal of the Chemical Society, Faraday Transactions. 92:1609 |
| بيانات النشر: | Royal Society of Chemistry (RSC), 1996. |
| سنة النشر: | 1996 |
| مصطلحات موضوعية: | chemistry.chemical_compound, Anatase, chemistry, X-ray photoelectron spectroscopy, Propane, Potassium, Inorganic chemistry, chemistry.chemical_element, Dehydrogenation, Physical and Theoretical Chemistry, Selectivity, Vanadium oxide, Catalysis |
| الوصف: | Vanadium oxide has been deposited by a grafting technique onto TiO2 anatase, both pure and doped with potassium [(1.2 and 2.5) atoms nm–2]. The V content varied between 0.1 and 20 atoms nm–2[0.01–2 V2O5 monolayers (ML)]. The prepared samples were characterized by X-ray photoelectron spectroscopy (XPS), 51V magic-angle spinning (MAS) NMR and a surface potential (SP) technique and tested as catalysts in the oxidative dehydrogenation (ODH) of propane and propan-2-ol decomposition, a probe reaction for acid–base properties. From the XPS and SP data it has been inferred that VOx are located beside the K centres on the bare surface of TiO2 with the lower K content sample, whereas they cover the K-doped fraction of the surface for the sample with higher K content. Monomeric and polymeric VOx species and V2O5 were detected by 51V NMR on pure and K-doped catalysts. For the K-doped samples the polymeric species were observed only at high V content and new tetrahedral VOx species and traces of KVO3 appeared. It has been found that the presence of K on the TiO2 surface leads to (a) a decrease in the reducibility of the vanadia phase at low V content; (b) a decrease in the surface potential (electronic work function); (c) a decrease in acidity and increase in basicity and (d) a decrease in the total activity for ODH of propane. The pattern of the activity and selectivity changes with the total V content depends on the amount of K on the support surface: with K 1 ML) are required to obtain the same catalytic performance. Polymeric [VOx] species seem to be more active and selective in the ODH of propane than monomeric species or bulk V2O5. |
| تدمد: | 1364-5455 0956-5000 |
| DOI: | 10.1039/ft9969201609 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_________::5a6b41c9c67d8918ab2518c8681ffc0c https://doi.org/10.1039/ft9969201609 |
| رقم الانضمام: | edsair.doi...........5a6b41c9c67d8918ab2518c8681ffc0c |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 13645455 09565000 |
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| DOI: | 10.1039/ft9969201609 |