کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1490194 | 992319 | 2012 | 9 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Steam-assisted crystallization of TPA+-exchanged MCM-41 type mesoporous materials with thick pore walls Steam-assisted crystallization of TPA+-exchanged MCM-41 type mesoporous materials with thick pore walls](/preview/png/1490194.png)
Hierarchical MCM-41/MFI composites were synthesized through ion-exchange of as-made MCM-41 type mesoporous materials with tetrapropylammonium bromide and subsequent steam-assisted recrystallization. The obtained samples were characterized by powder X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis, FT-IR, 1H–13C CP/MAS and nitrogen adsorption–desorption. The XRD patterns show that the MCM-41/MFI composite possesses both ordered MCM-41 phase and zeolite MFI phase. SEM and TEM images indicate that the recrystallized materials retained the mesoporous characteristics and the morphology of as-made mesoporous materials without the formation of bulky zeolite, quite different from the mechanical mixture of MCM-41 and MFI structured zeolite. Among others, lower recrystallization temperature and the introduction of the titanium to the parent materials are beneficial to preserve the mesoporous structure during the recrystallization process.
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► Mesoporous Ti-containing silica with thicker pore walls was synthesized.
► Ion-exchange and steam-assisted crystallization led to MCM-41/MFI composite.
► The introduction of Ti inhibited the formation of separated MFI particles.
► Lower temperature favored retaining mesoporous characteristics and morphology.
Journal: Materials Research Bulletin - Volume 47, Issue 7, July 2012, Pages 1774–1782