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Controlling_size_and_yield_of_zeolite_Y_nanocrystals_using
Controlling size and yield of zeolite Y nanocrystals using
tetramethylammonium bromide
Brett A. Holmberg, Huanting Wang, Joseph M. Norbeck, Yushan Yan *
College of Engineering––Center for Environmental Research and Technology (CE-CERT) and Department of Chemical
and Environmental Engineering, University of California, Riverside, CA 92521, USA
Received 7 October 2002; received in revised form 12 December 2002; accepted 7 January 2003
Abstract
In this study, we developed an alternative synthesis technique for the production of small colloidal zeolite Y
nanocrystals. By adding tetramethylammonium bromide as a second source of organic template, we were able to de-
couple and investigate the effect of two important synthesis parameters, tetramethylammonium concentration and
anion concentration. Optimizing these two parameters allowed us to hydrothermally synthesize highly crystalline zeolite
Y in a disperse nanocrystal form with a controllable particle size of 32–120 nm. Crystals hydrothermally synthesized
with a 1.00Al2O3–4.35SiO2–2.40(TMA)2O(2OH
)–1.2(TMA)2O(2Br)–0.048Na2O–249.00H2O (T3.6) solution com-
position were 45% smaller by volume after 54 h of crystallization at 100 C and were obtained with 73% more yield (g
zeolitic Al2O3 +SiO2/g synthesis Al2O3 + SiO2) than crystals synthesized with a 1.00Al2O3–4.35SiO2–2.40(TMA)2-
O(2OH)–0.048Na2O–249.00H2O (T2.4) composition. After 216 h, T3.6 syntheses contained 37 nm crystals with 180%
higher yield than that of T2.4 syntheses at 54 h (38 nm crystals, 0.044 g zeolitic Al2O3 + SiO2/g synthesis Al2O3 + SiO2).
The mechanisms involved in the observed crystal size decrease and yield improvement are discussed. A detailed
characterization of our zeolite Y nanocrystals is given, including powder X-ray diffraction (XRD), Fourier transform
infrared spectroscopy (FT-IR), N2 adsorption, dynamic light scattering (DLS), transmission electron microscopy
(TEM), thermogravimetric (TG) analyses, 29Si magic angle spinning nuclear magne
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