Insights into the nature of Zr-species in MFI-type Zr-metallosilicates by using bulk and surface techniques
Résumé
The purpose of this study is to prepare Zr-metallosilicates with MFI-type framework via direct hydrothermal approach, by varying Si and Zr precursors. First, a set of routine characterization techniques was applied to confirm the presence of the targeted structure as well as their intrinsic properties. Results suggest the formation of MFI-type materials with large specific surface areas (up to 421 m2 g−1). Then, a combination of advanced spectroscopic techniques (XPS, ToF-SIMS, EPR), high-resolution microscopy, and periodic Density Functional Theory (DFT) calculations were applied to study their bulk and surface properties as well as the nature and localization of Zr-species. It appears that the insertion of zirconium atoms within a MFI framework is energetically unfavorable, leading to the formation of an amorphous silica-zirconia shell coating the zeolite crystals.
| Origine | Publication financée par une institution |
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