title: Delamination of layered zeolite precursors under mild conditions: synthesis of UCB-1 via fluoride/chloride anion-promoted exfoliation.
abstract: New material UCB-1 is synthesized via the delamination of zeolite precursor MCM-22 (P) at pH 9 using an aqueous solution of cetyltrimethylammonium bromide, tetrabutylammonium fluoride, and tetrabutylammonium chloride at 353 K. Characterization by powder X-ray diffraction, transmission electron microscopy, and nitrogen physisorption at 77 K indicates the same degree of delamination in UCB-1 as previously reported for delaminated zeolite precursors, which require a pH of greater than 13.5 and sonication in order to achieve exfoliation. UCB-1 consists of a high degree of structural integrity via (29)Si MAS NMR and Fourier transform infrared spectroscopies, and no detectable formation of amorphous silica phase via transmission electron microscopy. Porosimetry measurements demonstrate a lack of hysteresis in the N(2) adsorption/desorption isotherms and macroporosity in UCB-1. The new method is generalizable to a variety of Si:Al ratios and leads to delaminated zeolite precursor materials lacking amorphization.
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of California at Berkeley, Berkeley, California 94720, United States.
authors.forename: Isao
authors.initials: I
authors.lastname: Ogino
authors.forename: Michael M
authors.initials: MM
authors.lastname: Nigra
authors.forename: Son-Jong
authors.initials: SJ
authors.lastname: Hwang
authors.forename: Jeong-Myeong
authors.initials: JM
authors.lastname: Ha
authors.forename: Thomas
authors.initials: T
authors.lastname: Rea
authors.forename: Stacey I
authors.initials: SI
authors.lastname: Zones
authors.forename: Alexander
authors.initials: A
authors.lastname: Katz