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Properties of surface‐modified alumina catalysts of COS synthesis
Author(s) -
Auroux A.,
Gervasini A.,
Németh L.,
Gáti G.,
Pap I. S.,
Mink G.
Publication year - 1992
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.740190198
Subject(s) - catalysis , adsorption , chemistry , monolayer , sodium , base (topology) , pyridine , inorganic chemistry , acceptor , organic chemistry , mathematical analysis , biochemistry , mathematics , physics , condensed matter physics
The surface electronic structure, the acid–base properties, the component adsorption and the catalytic activity of gamma alumina (CK‐300, Ketjen) modified with surface sodium as a donor‐type or iron as an acceptor‐type additive have been investigated. Alumina was loaded with 0.1 and 1 wt.% Na and Fe. The catalytic O/S exchange of CO 2 and CS 2 to form COS was applied as a model reaction, for which the kinetic parameters have also been determined. In the case of unloaded alumina and samples loaded with 0.1 wt.% Na and 0.1 or 1.0% Fe no characteristic differences in the shape and position of the O 1s and Al 2p lines were observed. However, 1.0 wt.% Na loading resulted in a broadening of the O 1s and Al 2p lines towards lower binding energies. Sodium, even in 1% monolayer coverage, and other donor‐type surface species, e.g. pre‐adsorbed NH 3 or pyridine, exhibited a readily detectable promoter effect which could be characterized by increased surface basicity, increased CO 2 and CS 2 adsorption and better catalytic performance. In contrast, on catalysts loaded with Fe an increase in surface acidic sites, a loss of basic sites, decreased component adsorption and lower catalytic activity were observed.