Gold supported on ceria doped by Me3+ (Me = Al and Sm) for water gas shift reaction: Influence of dopant and preparation method
Author
Andreeva, D.
Kantcheva, M.
Ivanov, I.
Ilieva, L.
Sobczak, J. W.
Lisowski, W.
Date
2010Source Title
Catalysis Today
Print ISSN
0920-5861
Electronic ISSN
1873-4308
Volume
158
Issue
1-2
Pages
69 - 77
Language
English
Type
ArticleItem Usage Stats
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Abstract
Gold catalysts supported on ceria doped by Sm and Al were studied. The influence of the preparation method, as well as the nature of dopants on the structure, properties and WGS activity are investigated. The applied methods of preparation cause the modification of ceria in a different extent. In the sample prepared by co-precipitation (CP) and doped by Al, the vacancies are located within the bulk of ceria structure, whereas in the corresponding AuCeSmCP sample the vacancies are located most likely around Sm and the ceria structure seems to be better ordered than the Al doped ceria. There is no distinct correlation between the reducibility and WGS activity of the studied catalysts. The Au 4f XPS spectra of fresh samples reveal higher contribution of dispersed form of Au for Sm doped catalysts than for the corresponding Al doped samples. The Ce 3d XPS spectra disclose also a higher concentration of Ce3+ evaluated before the catalytic operation for Sm doped catalysts as compared with the Al doped fresh samples. The observations by "in situ" FT-IR spectroscopy agree well with the model of active sites and the, mechanism of the WGS reaction proposed recently by some of us. The amount of formate species observed on the AuCeSmCP is higher than that on the AuCeAlCP catalyst and parallels the catalytic activity. The higher concentration of active sites on the surface of the AuCeSmCP catalyst facilitates the dissociation of water.
Keywords
Catalytic activityPreparation methods
Sm and Al doped ceria
WGS activity and mechanism
Active site
Al doped
Ceria structure
FTIR spectroscopy
Gold catalysts
In-situ
Structure , properties
Water gas shift reactions
WGS reactions
XPS spectra
Aluminum
Catalyst activity
Cerium
Cerium compounds
Chemical shift
Doping (additives)
Gold
X ray photoelectron spectroscopy
Catalyst supports