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Surface characterization of the deactivation of alumina catalysts used for COS synthesis
Author(s) -
Mink G.,
Bertóti I.,
Németh L.,
Gáti G.,
Mohai M.,
Székely T.
Publication year - 1988
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.740120407
Subject(s) - catalysis , chemistry , adsorption , chemisorption , gravimetric analysis , x ray photoelectron spectroscopy , carbon fibers , deposition (geology) , impurity , sulfur , inorganic chemistry , chemical engineering , organic chemistry , materials science , paleontology , sediment , composite number , engineering , composite material , biology
One of the possible routes of producing COS, an important material in organic synthese, is the CO 2 + CS 2 ⇄ 2COS reaction, preferably over gamma‐alumina catalysts. Under long‐term loading, however, a remarkable loss of the catalytic activity occurs. The nature of the ageing process was studied by a multi‐technique apporach on high purity [I] and on a commerical grade [II] gamma‐alumina, which latter contained Na, Ca, and S as surface impurities. On catalyst [I] weak chemisorption of CO 2 , CS 2 and COS was observed by the volumetric method, as characterized by the isosteric heats of adsorption. Catalyst [II] chemisorbed CO 2 and COS but not CS 2 and showed much less catalytic activity. Gravimetric measurements have shown that adsorption of CS 2 and COS leads to the surface deposition of side products. XPS studies on new, loaded and aged samples have revealed that the ageing of the catalyst is primarily caused by the deposition of sulphur and carbon with carbon in excess, presumably in CS, CS and CC environements.