Revelation on the Complex Nature of Mesoporous Hierarchical FAU-Y Zeolites.

Mehlhorn D, Rodriguez J, Cacciaguerra T, Andrei RD, Cammarano C, Guenneau F, Gedeon A, Coasne B, Thommes M, Minoux D, Aquino C, Dath JP, Fajula F, Galarneau A (2018)


Publication Type: Journal article, Original article

Subtype: other

Publication year: 2018

Journal

Publisher: American Chemical Society

Book Volume: 34

Pages Range: 11414-11423-11423

Journal Issue: 38

DOI: 10.1021/acs.langmuir.8b03010

Abstract

The texture of mesoporous FAU-Y (FAUmes) prepd. by surfactant-templating in basic media is a subject of debate. It is proposed that mesoporous FAU-Y consists of: (1) ordered mesoporous zeolite networks formed by a surfactant-assisted zeolite rearrangement process involving local dissoln. and reconstruction of the cryst. framework, and (2) ordered mesoporous amorphous phases as Al-MCM-41, which coexist with zeolite nanodomains obtained by a dissoln.-reassembly process. By the present systematic study, performed with FAU-Y (Si/Al = 15) in the presence of octadecyltrimethylammonium bromide and 0 < NaOH/Si ratio < 0.25 at 115 °C for 20 h, we demonstrate that mesoporous FAU zeolites consist, in fact, of a complex family of materials with textural features strongly impacted by the exptl. conditions. Two main families have been disclosed: (1) for 0.0625 < NaOH/Si < 0.10, FAUmes are ordered mesoporous materials with zeolite walls, which coexist with zeolite nanodomains (100-200 nm) and (2) for 0.125 < NaOH/Si < 0.25, FAUmes are ordered mesoporous materials with amorphous walls as Al-MCM-41, which coexist with zeolite nanodomains (5-100 nm). The zeolite nanodomains decrease in size with the increase of NaOH/Si ratio. Increasing NaOH/Si ratio leads to an increase of mesopore vol., while the total surface area remains const., and to a decrease of strong acidity in line with the decrease of micropore vol. The ordered mesoporous materials with zeolite walls feature the highest acidity strength. The ordered mesoporous materials with amorphous walls present addnl. large pores (50-200 nm), which increase in size and amt. with the increase of NaOH/Si ratio. This alk. treatment of FAU-Y represents a way to obtain ordered mesoporous materials with zeolite walls with high mesopore vol. for NaOH/Si = 0.10 and a new way to synthesize mesoporous Al-MCM-41 materials contg. extra large pores (50-200 nm) ideal for optimal diffusion (NaOH/Si = 0.25). [on SciFinder(R)]

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APA:

Mehlhorn, D., Rodriguez, J., Cacciaguerra, T., Andrei, R.-D., Cammarano, C., Guenneau, F.,... Galarneau, A. (2018). Revelation on the Complex Nature of Mesoporous Hierarchical FAU-Y Zeolites. Langmuir, 34(38), 11414-11423-11423. https://dx.doi.org/10.1021/acs.langmuir.8b03010

MLA:

Mehlhorn, Dirk, et al. "Revelation on the Complex Nature of Mesoporous Hierarchical FAU-Y Zeolites." Langmuir 34.38 (2018): 11414-11423-11423.

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