The Energetics of Surfactant‐Templating of Zeolites. Issue 28 (7th June 2018)

• Record Type: Journal Article
• Authors: Linares, Noemi; Jardim, Erika O.; Sachse, Alexander; Serrano, Elena; García‐Martínez, Javier
• Is Part Of: Angewandte Chemie international edition. Volume 57:Issue 28(2018)
• Page Start: 8724
• Page End: 8728
• Publication Date: 2018-06-07
• Subjects: apparent activation energy -- kinetics -- mesoporous zeolites -- surfactant-templating -- synchrotron characterization; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201803759
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: 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. Abstract : Big pores, small energy : Mesostructuring of zeolites with surfactants occurs under time and temperature conditions typically used to synthesize zeolites. A systematic study of mesopore formation in USY zeolite at different temperatures using both in situ and ex situ techniques reveals the kinetics of the underlying formation process. Apparent activation energies are similar (30–65 kJ mol −1 ) to those involved in the crystallization of zeolites.