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Tailored Mesoporosity Development in Zeolite Crystals by Partial Detemplation and Desilication
Author(s) -
PérezRamírez Javier,
Abelló Sònia,
Bonilla Adriana,
Groen Johan C.
Publication year - 2009
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200800871
Subject(s) - materials science , zeolite , calcination , mesoporous material , chemical engineering , leaching (pedology) , aqueous solution , pyrolysis , catalysis , nanotechnology , organic chemistry , chemistry , environmental science , soil science , engineering , soil water
Abstract Partial detemplation of zeolites followed by desilication in alkaline medium is demonstrated as a powerful and elegant approach to design hierarchical zeolites with tailored degree of mesoporosity. This achievement, illustrated for large beta crystals, is based on the fact that the template‐containing zeolite is virtually inert to Si leaching upon treatment in aqueous NaOH solutions. Partial removal of the structure‐directing agent creates regions in the crystal susceptible to mesopore formation by subsequent desilication, while template‐containing regions are protected from silicon extraction. Variation of the calcination temperature in the range 230–550 °C determines the amount of template removed and enables control of the extent of mesopore formation in the zeolite (20–230 m 2 g −1 ) upon alkaline treatment. The functionality of the introduced mesoporosity in the hierarchical beta crystals is demonstrated by the improved performance in the catalytic pyrolysis of low‐density polyethylene. The partial detemplation–desilication treatment enhances the tuning options of this demetallation method.