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Textural and morphology changes of mesoporous SBA-15 silica due to introduction of guest phase

Authors: Bulánek Roman | Čičmanec Pavel

Year: 2017

Type of publication: článek v odborném periodiku

Name of source: Pure and Applied Chemistry

Page from-to: 481-491

Titles:

Language	Name	Abstract	Keywords
cze	Texturní a morfologické změny mezoporézní SBA-15 siliky způsobené zavedením sekundární fáze	Výzkum byl zaměřen na studium vlivu sekundární fáze na specifický povrch a objem pórů SBA-15. Změny v těchto vlastnostech jsou zřejmé z N-2 adsorpčních izoterem Vox-SBA-15 vzorků, a to i pro nízký obsah sekundární fáze.	dispergovaný VOx; oxidativní dehydrogenace; katalytické chování; adsorpce; struktura pórů
eng	Textural and morphology changes of mesoporous SBA-15 silica due to introduction of guest phase	The research focuses on study of guest phase effect on the surface area and pore volume of SBA-15 with the emphasis on elucidation of reasons for these changes. The changes of surface area and pore volume are evident from evaluated N-2 adsorption isotherms of VOx-SBA-15 even for samples with relative low content of supported guest phase, which is "atomically" spread on the surface in the form of anchored monomeric vanadyl species. These species cannot block the pore with diameter of 10 nm, nevertheless the presence of such phase causes decrease in adsorbed nitrogen during physisorption. Comparison of guest phase amount with differences in adsorbed amount of nitrogen led to conclusion that each vanadyl complex prevents adsorption of about one or two N-2 molecules in the layer and influences two adsorption layers. Significant pore blocking occurs in the VOx-SBA-15 materials only in the case of presence bulk oxide-like nanospecies. Re-structuralization of silica mimicking phase separation phenomena relying on spinodal decomposition of a system was observed by SEM/TEM analysis and adsorption isotherms inspection for materials with high vanadium content.	Dispersed vanadium-oxide; oxidatice dehydrogenation; catalytic behavior; adsoption; pore structure