Titanium in MFI-Type Zeolites: A Characterization by XANES, EXAFS, IR, and 74, 49Ti and 17O MAS NMR Spectroscopy and H2O Adsorption
✍ Scribed by A. Lopez; M.H. Tuilier; J.L. Guth; L. Delmotte; J.M. Popa
- Publisher
- Elsevier Science
- Year
- 1993
- Tongue
- English
- Weight
- 405 KB
- Volume
- 102
- Category
- Article
- ISSN
- 0022-4596
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✦ Synopsis
The location and chemical environment of titanium in MFI-type zeolites synthesized in (\mathrm{OH}^{-})or in (\mathrm{F}^{-}) media was determined by XANES, EXAFS, IR, and ({ }^{47.49}) 'Ti and "O MAS-NMR spectroscopy. Water adsorption and its influence on the coordination of Ti was studied in the calcined zeolites. Titanium is incorporated into the framework by substitution for silicon, but a significant amount of Ti can also be present in the form of extracrystalline or intracrystalline inclusions of (\mathrm{TiO}_{2}) depending on the (\mathrm{F} / \mathrm{Ti}) ratio in the synthesis mixture. In the absence of water. Ti in the framework is essentially tetrahedrally coordinated; in the presence of water its coordination becontes octahedral. O 1993 Academic Press. Inc.