Evidence of correlation between electronic density and surface acidity of sulfated TiO2

Citation
Sm. Jung et P. Grange, Evidence of correlation between electronic density and surface acidity of sulfated TiO2, CATAL LETT, 76(1-2), 2001, pp. 27-30
Citations number
11
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physical Chemistry/Chemical Physics","Chemical Engineering
Journal title
CATALYSIS LETTERS
ISSN journal
1011-372X → ACNP
Volume
76
Issue
1-2
Year of publication
2001
Pages
27 - 30
Database
ISI
SICI code
1011-372X(2001)76:1-2<27:EOCBED>2.0.ZU;2-R
Abstract
Correlation between the electronic structure and surface acidity of TiO2-SO 42- with different SO42- amounts has been investigated by means of NH3-TPD, NH3-FT-IR and XPS. With the increase of sulfate loadings, the shift of bin ding energies of O 1s in hydroxyl and Ti 2p(2/3) increases and is proportio nal to total acidity. A linear relation is obtained between Ti 2p binding e nergy shift and Lewis acid sites, while the shift in O 1s binding energy is attributed both to the generation of NH3 hydrogen bond and of Bronsted aci d sites. Accordingly, the results obtained from XPS measurements provide ev idence that the ammonia adsorption sites are attributed to the decrease of electron density of O 1s in hydroxyl (Bronsted type and H bonded) and Ti 2p (2/3) (Lewis type) by inductive effect of the neighboring sulfate ion.