Alkoxy-derived multiscale porous TiO2 gels probed by ultra-small-angle X-ray scattering and small-angle X-ray scattering
| Autor: | Shotaro Nishitsuji, Mikihito Takenaka, Kazuki Nakanishi, Junko Konishi, Koji Fujita, Kazuyuki Hirao, Kiyotaka Miura |
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| Rok vydání: | 2008 |
| Předmět: |
Materials science
Spinodal decomposition Small-angle X-ray scattering Scattering Evaporation Mineralogy General Chemistry Microporous material Condensed Matter Physics Electronic Optical and Magnetic Materials Biomaterials Chemical engineering Materials Chemistry Ceramics and Composites Porous medium Porosity Sol-gel |
| Zdroj: | Journal of Sol-Gel Science and Technology. 46:63-69 |
| ISSN: | 1573-4846 0928-0707 |
| DOI: | 10.1007/s10971-008-1694-3 |
| Popis: | Titania (TiO2) monoliths with well-defined bicontinuous macropores and gel skeletons were prepared through the alkoxy-derived sol–gel process accompanied by spinodal decomposition, and the structural evolution during evaporation drying and heat treatment was probed by a combination of ultra-small-angle X-ray scattering and small-angle X-ray scattering. X-ray scattering profiles of wet and dried gels revealed that microporous structures related to the existence of primary particles are present in the gel skeletons at the wet stage and are preserved during drying. Additionally, it is found that the primary particles swollen in the wet condition are dried to compact aggregates to produce the smooth surface of gel skeletons. Upon heating at 400 °C, the particle–particle correlation associated with regularity of mesostructures is enhanced. From nitrogen adsorption–desorption measurements, the average pore size is less than 1 nm in the dried gel and increases to 3.1 nm by the heat treatment. Homogeneous growth of primary particles due to interparticle-polycondensation reaction is responsible for the increased size and uniform distribution of mesopores in the heat-treated gel. |
| Databáze: | OpenAIRE |
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