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The effect of water on the acidity of TiO2 and sulfated titania

Paper ID Volume ID Publish Year Pages File Format Full-Text
44560 46041 2006 9 PDF Available
Title
The effect of water on the acidity of TiO2 and sulfated titania
Abstract

Temperature-programmed desorptions (TPD) of isopropylamine (IPA), NH3, and pyridine were compared with diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) of pyridine to determine the effect of H2O on the acidities of three titania catalysts. Brønsted acidity increased in the following order: Degussa P-25 TiO2 < TiO2 synthesized in our laboratory (p-TiO2) < sulfated titania (SO42−/TiO2). Although the traditional interpretation of pyridine infrared spectra showed an apparent increase in Brønsted acidity upon treating SO42−/TiO2 with H2O, IPA TPD spectra showed that H2O displaced IPA from approximately one-third to one-half of the Brønsted sites. Similarly, H2O treatment prior to TPD displaced significant amounts of both NH3 and pyridine. The primary effect of H2O is displacement of strongly adsorbed basic probe molecules from Brønsted sites, rather than the conversion of Lewis sites to Brønsted sites.

Keywords
Sulfated titania; TPD; Isopropylamine; Brønsted; Lewis; Ammonia; Pyridine; DRIFTS; Acidity
First Page Preview
The effect of water on the acidity of TiO2 and sulfated titania
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 302, Issue 2, 11 April 2006, Pages 274–282
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis