Characterization of surface acid sites in tin-silicalite-1 (Sn-MFI) molecular sieve by X-ray photoelectron spectroscopy

TitleCharacterization of surface acid sites in tin-silicalite-1 (Sn-MFI) molecular sieve by X-ray photoelectron spectroscopy
Publication TypeJournal Article
Year of Publication2011
AuthorsNiphadkar, PS, Patil, KR, Joshi, PN
JournalMicroporous and Mesoporous Materials
Volume141
Issue1-3
Pagination236-240
Date PublishedMAY
ISSN1387-1811
KeywordsLewis acidity, Pyridine chemisorption, SiO2/SnO2 molar ratio, Sn-MFI, XPS
Abstract

The nature, strength and density of surface acid sites in Sn-MFI molecular sieves with different Sn-content were characterized by N 1s high resolution photoelectron peak of chemisorbed pyridine in combination with pyridine-IR and TPAD. Two peaks emerged at 399.5 +/- 0.2 and 401.5 +/- 0.2 eV by deconvoluting composite N is peak were assigned to chemisorbed pyridine on weak and relatively strong Lewis acid sites, respectively. The relative percentage of strong Lewis acid sites was found to increase with the decrease of framework Sn content. A close agreement was observed between the ratios of weak Lewis acid sites to strong Lewis acid sites obtained from XPS and TPAD. (C) 2010 Elsevier Inc. All rights reserved.

DOI10.1016/j.micromeso.2010.10.036
Type of Journal (Indian or Foreign)Foreign
Impact Factor (IF)3.58
Divison category: 
Catalysis and Inorganic Chemistry
Center for Material Characterization (CMC)