Structural evolution upon thermal heating of nanostructured inorganic-organic hybrid materials to binary oxides MO2-SiO2 (M = Hf, Zr) as evaluated by solid-state NMR and FTIR spectroscopy
| Autor: | Silvia Gross, Lidia Armelao, and Otgontuul Tsetsgee, Eugenio Tondello, Andrea Zattin, Giuseppe Pace, Klaus Müller |
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| Jazyk: | angličtina |
| Rok vydání: | 2006 |
| Předmět: |
Materials science
biology General Chemical Engineering Thermal decomposition Oxide Analytical chemistry binary oxides General Chemistry Nuclear magnetic resonance spectroscopy Hafnia biology.organism_classification Thermogravimetry structural evolution chemistry.chemical_compound Solid-state nuclear magnetic resonance chemistry Chemical engineering FTIR hybrid materials Materials Chemistry Fourier transform infrared spectroscopy Hybrid material hybrid materials structural evolution binary oxides FTIR |
| Popis: | The structural and compositional evolution of inorganic−organic silica-based hybrid materials and their conversion to mixed oxides, consisting of host silica with variable amounts of zirconia or hafnia (1:1 Si:M, 40:1 Si:M, M = Zr, Hf), was studied by multinuclear solid-state NMR spectroscopy, FTIR spectroscopy, and thermogravimetry. It is shown that the as-prepared materials, composed of M4O2(OMc)12 oxoclusters (M = Zr, Hf; OMc = methacrylate) and methacryloxymethyltriethoxysilane (MAPTMS), are not completely polymerized. Rather, a finite number of double bonds remain independent of the actual sample composition. Thermolysis between 300 and 500 °C is accompanied by drastic changes in the structural composition, as reflected by the complete loss of all organic components. The incorporation of oxoclusters is found to catalyze the cleavage of Si−C bonds. At the same time, continuous alterations in the inorganic/oxide part are registered. The degree of condensation, as derived from the 29Si NMR data, increas... |
| Databáze: | OpenAIRE |
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