Crystalline ZrO2 Monoliths with Well-Defined Macropores and Mesostructured Skeletons Prepared by Combining the Alkoxy-Derived Sol–Gel Process Accompanied by Phase Separation and the Solvothermal Process
Autor: | Kazuyuki Hirao, Satoshi Oiwa, Koji Fujita, Junko Konishi, Kazuki Nakanishi |
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Rok vydání: | 2008 |
Předmět: | |
Zdroj: | Chemistry of Materials. 20:2165-2173 |
ISSN: | 1520-5002 0897-4756 |
DOI: | 10.1021/cm703351d |
Popis: | We have successfully prepared multiscale porous crystalline zirconia (ZrO2) monoliths by combining the alkoxy-derived sol–gel process accompanied by phase-separation and the solvothermal process. The gelation can be controlled by the addition of N-methylformamide to the starting solution, while the phase separation is induced by the incorporation of poly(ethylene oxide). Amorphous ZrO2 monolithic gels with well-defined bicontinuous macropores and microstructured skeletons are obtained when the transient structure of polymerization-induced phase separation is fixed by the gelation. The size of the macropores is controlled in the range of 300 nm to 2 µm by adjusting the amount of poly(ethylene oxide). The solvent exchange of the mother liquor in the as-gelled wet specimens with absolute ethanol, followed by the solvothermal treatment at temperatures above 210 °C, brings about the formation of mesopores and stabilizes tetragonal ZrO2 nanocrystals without disturbing the macroporous morphology. The resultant m... |
Databáze: | OpenAIRE |
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