A two-stage citric acid–sol/gel synthesis of ZnO/SiO2 nanocomposites: study of precursors and final products
| Autor: | Carla Cannas, Mariano Casu, Gabriella Pinna, Roberto Anedda, Giorgio Piccaluga, Anna Maria Giovanna Musinu |
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| Rok vydání: | 2007 |
| Předmět: |
Nanocomposite
Materials science Denticity Inorganic chemistry chemistry.chemical_element Bioengineering General Chemistry Zinc Condensed Matter Physics Atomic and Molecular Physics and Optics Matrix (chemical analysis) chemistry.chemical_compound chemistry Modeling and Simulation General Materials Science Carboxylate Fourier transform infrared spectroscopy Citric acid Sol-gel Nuclear chemistry |
| Zdroj: | Journal of Nanoparticle Research. 10:107-120 |
| ISSN: | 1572-896X 1388-0764 |
| DOI: | 10.1007/s11051-007-9235-5 |
| Popis: | ZnO nanoparticles, of average size of 10–15 nm, homogeneously dispersed in a silica matrix were prepared by a two stage citric acid/sol–gel process and thermal treatments up to 700 °C. The precursors formed at the early stages of the synthesis and their thermal evolution were investigated by FTIR, 29Si NMR MAS and CPMAS, 13C CPMAS and T1ρ(1H). A unidentate complex was revealed in the gel, together with other complexes in which citrate carboxylate groups are bound to one Zn2+ ion or act as a bridge between two Zn2+ ions. A comparison of the results from nanocomposite and silica samples prepared by the same method showed that chemical interactions between amorphous silica and zinc ions are not present either in the precursors or in the final materials. As a consequence, ZnO particles do not react with silica matrix when they are heated up to 700 °C. This result is ascribed to a nanophase segregation of zinc citrate complexes from the host matrix. |
| Databáze: | OpenAIRE |
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