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Titolo:
METAL-SUPPORT INTERACTION IN SILICA-SUPPORTED COBALT CATALYST
Autore:
HO SW;
Indirizzi:
NATL CHENG KUNG UNIV,DEPT CHEM TAINAN 701 TAIWAN
Titolo Testata:
Journal of the Chinese Chemical Society (Taipei)
fascicolo: 4, volume: 45, anno: 1998,
pagine: 569 - 575
SICI:
0009-4536(1998)45:4<569:MIISCC>2.0.ZU;2-#
Fonte:
ISI
Lingua:
ENG
Soggetto:
CO HYDROGENATION; O-2-H-2 TREATMENTS; RESTORATION; REDUCTION;
Keywords:
SILICA-SUPPORTED COBALT CATALYST; METAL-SUPPORT INTERACTION; EFFECT OF REDUCTION TEMPERATURE; ADSORPTION AND DESORPTION OF H-2 AND CO;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
14
Recensione:
Indirizzi per estratti:
Citazione:
S.W. Ho, "METAL-SUPPORT INTERACTION IN SILICA-SUPPORTED COBALT CATALYST", Journal of the Chinese Chemical Society (Taipei), 45(4), 1998, pp. 569-575

Abstract

The variations in catalytic properties for CO hydrogenation and adsorptive properties for H-2 and CO of silica-supported cobalt catalyst asa function of reduction temperature (400 to 700 degrees C) were investigated. A mild sintering of cobalt metal from 130 Angstrom to 145 Angstrom occurred only when the reduction temperature was further increased from 600 to 700 degrees C. However, a monotone decrease in the activity (per gram Co) for CO hydrogenation was observed with increasing reduction temperature. This is accompanied with a decrease in methane and an increase in olefin formation. The decrease in activity can not be accounted for by the variation of crystallite size of cobalt metal. A concurrent suppression in the amount of hydrogen and CO adsorptions was observed after reduction temperature was raised to 700 degrees C. The turnover frequencies, based on cobalt dispersion estimated from H-2 and CO chemisorption, remained, more or less, similar with increasing reduction temperature from 400 to 600 degrees C, but increased ca. 3and 1.5 times, respectively, at 700 degrees C. The relative amount ofsubcarbonyl species (2062 cm(-1)) with respect to the linear adsorbedCO (2010 cm(-1)) was found to increase as well. Furthermore, reduction of silica surface at 700 degrees C was indicated by the presence of similar to Si-H, which was detected by infrared spectroscopy at 2294 cm(-1). This shows the presence of metal-support interaction for silica-supported cobalt systems after reduction treatment at 700 degrees C.

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Documento generato il 02/12/20 alle ore 17:14:45