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Generalized synthesis of core–shell structured nano-zeolite@ordered mesoporous silica composites

Paper ID Volume ID Publish Year Pages File Format Full-Text
54883 47030 2013 6 PDF Available
Title
Generalized synthesis of core–shell structured nano-zeolite@ordered mesoporous silica composites
Abstract

Novel core–shell structured composite molecular sieves comprising mono-dispersed nano-sized zeolite single-crystals (i.e., nano-zeolite Y) as cores and ordered mesoporous silica as shells were synthesized via a surfactant-directed sol–gel process in basic media by using cetyltrimethylammonium bromide (CTAB) as a template and tetraethyl-orthosilicate (TEOS) as a precursor. Uniform mesoporous silica shells are coated on the mono-dispersed nano-zeolites to form the hierarchical porous structures, the thickness of which can be tailored depending on the adding amount of TEOS. The composite molecular sieves with the thickness of 20 nm possess ultra high surface area of 1198 m2/g, ordered mesopores (∼3.5 nm in diameter) from the silica shell and uniform micropores (∼0.9 nm) from nano-zeolite core. The ordered mesopore channels in the shells are annularly vertical to the nano-zeolite crystal-faces. On the other hand, the nano-zeolite@mesoporous silica composite molecular sieves with such high surface area and opened hierarchical pores, can provide sufficient voids for capturing reactant molecules and also promote molecule diffusion from mesopores to micropores. Thus, the composite molecular sieves show greatly enhanced adsorption capacity (4.7 mmol/g) for large molecules such as benzene relative to that of pristine nano-zeolites (3.0 mmol/g), ascribing to the large contribution from mesopores in the shell.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (220 K)Download as PowerPoint slideHighlights► The nano-zeolite@ordered mesoporous silica core–shell structured composite molecular sieves were synthesized novelly. ► The composite molecular sieves possess ultra high surface area, ordered mesopores and uniform micropores. ► The highly opened hierarchical composites show greatly enhanced adsorption capacity for benzene than nano-zeolite.

Keywords
Zeolite; Mesoporous silica; Core–shell; Synthesis
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Generalized synthesis of core–shell structured nano-zeolite@ordered mesoporous silica composites
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Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 204, 15 April 2013, Pages 2–7
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us