Surface rhenium oxide-support interaction for supported Re[sub 2]O[sub 7] catalysts

Journal Article · Tue Jun 01 04:00:00 EDT 1993 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1006/jcat.1993.1151· OSTI ID:5990236

Kim, D S; Wachs, I E ^[1]

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1. Lehigh Univ., Bethelehem, PA (United States)

The molecular structures of the two-dimensional rhenium oxide overlayers on different oxide supports (Al[sub 2]O[sub 3], TiO[sub 2], SiO[sub 2], and MgO) under ambient and dehydrated conditions were determined by Raman spectroscopy. The surface rhenium oxide species under ambient conditions are hydrated by adsorbed moisture and are essentially in an aqueous medium. Consequently, the surface rhenium oxide species under ambient conditions resemble the ReO[sub 4][sup [minus]] ion in an aqueous solution independent of the specific oxide support. Upon dehydration at elevated temperatures, the surface rhenium oxide species interact with the oxide support by a bridged oxygen (with exception of the Re[sub 2]O[sub 7]/MgO system). The molecular structures of the dehydrated surface rhenium oxide species possess an isolated, four-coordinated rhenium oxide species with three terminal Re[double bond]O bonds and one bridging Re-O-support bond. For the Re[sub 2]O[sub 7]/MgO systems, the surface rhenium oxide species is primarily present as a compound(s) formed by a strong acid-base interaction between the supported rhenium oxide catalysts revealed that the activity is strongly dependent on the specific oxide support and increases with increasing reducibility of the surface rhenium oxide species. The activity and reducibility of the supported rhenium oxide catalysts are attributed to the difference in the Re[sup 7+]-O-support bond strength. 47 refs., 4 figs., 2 tabs.

• OSTI ID: 5990236
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 141:2; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
HYDRATES
LASER SPECTROSCOPY
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
MOLECULAR STRUCTURE
OXIDES
OXYGEN COMPOUNDS
RAMAN SPECTROSCOPY
REDUCTION
REFRACTORY METAL COMPOUNDS
RHENIUM COMPOUNDS
RHENIUM OXIDES
SILICON COMPOUNDS
SILICON OXIDES
SPECTROSCOPY
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS