Spectroscopic characterization of gold supported on tungstated zirconia

Date
2012
Authors
Kantcheva, M.
Milanova, M.
Avramova, I.
Mametsheripov, S.
Advisor
Supervisor
Co-Advisor
Co-Supervisor
Instructor
Source Title
Catalysis Today
Print ISSN
0920-5861
Electronic ISSN
1873-4308
Publisher
Elsevier
Volume
187
Issue
1
Pages
39 - 47
Language
English
Type
Article
Journal Title
Journal ISSN
Volume Title
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Abstract

Gold catalysts supported on tungstated zirconia (containing 5–20 wt% WO3) are prepared by cationic adsorption from aqueous solution of [Au(en)2]Cl3 complex. The materials are characterized by XRD, DRUV–vis spectroscopy and XPS. The nature of the deposited gold species is studied by FT-IR spectroscopy of adsorbed CO. It is concluded that the gold particles occupy preferentially the WOx-free zirconia surface and the dispersion of gold depends on the amount of coodinatively unsaturated (cus) Zr4+ ions. Modification of zirconia by tungsten increases the gold uptake but at the same time causes decrease in the concentration of (cus) Zr4+ ions thus lowering the dispersion of gold clusters. According to the results of in situ FT-IR spectroscopy, the Au/WOx ZrO2 catalysts display higher activity in the CO oxidation in the low-temperature range (up to 150 ◦C) than the WOx-free Au/ZrO2 sample. The low-temperature activity of the W-containing catalysts could be associated with decreased basicity of the support oxide ions resulting in reduced accumulation of stable carbonate species.

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Keywords
DR-UV-vis spectroscopy, Gold supported on tungstated zirconia, In situ FT-IR spectroscopy of adsorbed CO, XPS, XRD, CO + O 2
Citation
Published Version (Please cite this version)