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The Energetics of Surfactant‐Templating of Zeolites
Author(s) -
Linares Noemi,
Jardim Erika O.,
Sachse Alexander,
Serrano Elena,
GarcíaMartínez Javier
Publication year - 2018
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201803759
Subject(s) - pulmonary surfactant , thermogravimetry , chemistry , mesoporous material , adsorption , zeolite , synchrotron , chemical engineering , crystallization , in situ , activation energy , inorganic chemistry , organic chemistry , catalysis , biochemistry , physics , engineering , nuclear physics
Mesoporosity can be conveniently introduced into zeolites by treating them in basic surfactant solutions. The apparent activation energy involved in the formation of mesopores in USY by surfactant‐templating was determined using a combination of in situ synchrotron X‐ray diffraction and ex situ gas adsorption. Additionally, techniques such as pH measurement and thermogravimetry/differential thermal analysis were employed to determine OH − evolution and cetyltrimethylammonium ion (CTA + ) uptake during the development of mesoporosity, thereby providing information about the different steps involved. The combination of both in situ and ex situ techniques has allowed determination of the apparent activation energies of the different processes involved in the mesostructuring of USY zeolites for the first time. Apparent activation energies are of the same order of magnitude (30–65 kJ mol −1 ) as those involved in the crystallization of zeolites. Hence, important mechanistic insight into the surfactant‐templating method was obtained.