Characterisation of as-synthesised MOx–MCM-41 (M=Mo, W) mesophases using Raman spectrometry and 29Si MAS NMR
| Autor: | Geneviève Chottard, Jean-Yves Piquemal, J.-M. Manoli, Emmanuel Briot, P. Tougne, Jean-Marie Brégeault |
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| Rok vydání: | 2003 |
| Předmět: |
Inorganic chemistry
chemistry.chemical_element General Chemistry Tungsten Condensed Matter Physics Molecular sieve law.invention Metal Crystallography symbols.namesake MCM-41 chemistry Mechanics of Materials Molybdenum law visual_art X-ray crystallography visual_art.visual_art_medium symbols General Materials Science Calcination Raman spectroscopy |
| Zdroj: | Microporous and Mesoporous Materials. 58:279-289 |
| ISSN: | 1387-1811 |
| DOI: | 10.1016/s1387-1811(02)00654-6 |
| Popis: | MCM-41 mesostructured silicas containing molybdenum and tungsten have been prepared in an acidic medium at room temperature. Two procedures were considered: the so-called oxo–peroxo route with low-nuclearity peroxo metal precursors (route A) and the oxo–polyoxo pathway, involving or generating polyoxometalates (route B). The native materials have been characterised by chemical analysis, powder X-ray diffraction, Raman spectrometry and 29 Si MAS NMR. The results show that, in route A, the use of peroxo compounds leads to a distribution of the low-nuclearity metal species throughout the silica-surfactant assembly whereas Keggin type polyoxometalates are generated in route B. The different dispersions of the MO x species (M=Mo, W) on and into the silica matrix and, hence, the formation of MO 3 (route B), previously observed for calcined materials, can be explained on the basis of different specific interactions in these organic–inorganic mesophases. |
| Databáze: | OpenAIRE |
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