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Title: | Direct Synthesis of Zr-containing Hybrid Periodic Mesoporous Organosilicas with Tunable Zirconium Conten |
Authors: | Zhai, Shang-Ru Park, Sung Soo Park, Mina Ullah, Md. Habib Ha, Chang-Sik |
Keywords: | Silicates / Template synthesis / Orangic–inorganic hybrid composites / Mesoporous materials |
Issue Date: | 2007 |
Publisher: | WILEY‐VCH Verlag |
Citation: | 16 |
Abstract: | Highly ordered Zr-containing periodic mesoporous organosilicas (ZrPMO) with different Zr/Si ratios were successfully synthesized, for the first time, by employing a ZrOCl2/NaCl combination as the promoting agent and by simply adjusting the molar ratio of the zirconium species to the organosilica precursor; no addition of mineral acids was necessary. The effect of preparation parameters on the structural and textural properties were carefully investigated by using different ratios of NaCl/Si and Zr/Si. It was found that both salts are essential for this system and highly ordered ZrPMOs can be prepared within fairly wide Si/Zr ratios (5–100) while keeping the NaCl/Si ratio constant. To prove the effectiveness of this synthetic pathway with a higher Zr incorporation, ZrPMO materials were also synthesized under strongly acidic conditions for the purpose of comparison. The synthesized ZrPMO materials were thoroughly characterized by ICP-AES, SAXS, N2 sorption, TEM, SEM, 13C CP/29Si MAS NMR spectroscopy, XPS, and TGA. Elemental analyses show that the amount of Zr incorporated into ZrPMO, which was synthesized under mild conditions, is greater than that obtained in a strongly acidic environment, and the Zr content, with a Si/Zr ratio up to 12, is close to that in the initial gel composition. A plausible assembly mechanism based on the synergistic effect of both “nonhydrolyzable” (NaCl) and “hydrolyzable” (ZrOCl2) inorganic salts was discussed in detail, where the “salting out” effect and self-generated acidity from both inorganic salts, respectively, are believed to be key factors for the formation of ordered SBA-15-type ZrPMO materials under the synthetic conditions. |
URI: | http://dspace.aiub.edu:8080/jspui/handle/123456789/1143 |
ISSN: | 1099-0682 |
Appears in Collections: | Publication: Journal |
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File | Description | Size | Format | |
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Direct Synthesis of Zr-containing Hybrid Periodic Mesoporous .pdf | Abstract | 74.12 kB | Adobe PDF | View/Open |
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