Alloy formation and metal oxide segregation in Pt-Re/. gamma. -Al/sub 2/O/sub 3/ catalysts as investigated by temperature-programmed reduction

Journal Article · Mon Oct 15 00:00:00 EDT 1979 · J. Catal.; (United States)

OSTI ID:5585261

Wagstaff, N; Prins, R

Temperature-programmed reduction has been used to characterize the finely dispersed metal compounds in a series of Pt-Re/..gamma..-Al/sub 2/O/sub 3/ catalysts. Strong evidence has been obtained that zerovalent Pt and Re atoms are in intimate contact with each other after catalyst reduction. The formation of bimetallic clusters supports the alloy explanation for the improved performance of this type of bimetallic reforming catalyst. Treatment of the reduced catalysts with oxygen above about 200/sup 0/C causes segregation of platinum and rhenium oxides. Adsorption of oxygen at temperatures up to 100/sup 0/C leaves the bimetallic clusters largely intact, but subsequent high-temperature treatment in the absence of extra oxygen leads to segregation of Pt and Re species. This suggests that in the presence of adsorbed oxygen the Pt-Re clusters are thermodynamically unstable, but that under mild conditions the rate of segregation is slow. 10 figures, 4 tables.

• Research Organization: Koninklijke/Shell-Laboratorium, Amsterdam, Netherlands
• OSTI ID: 5585261
• Journal Information: J. Catal.; (United States), Vol. 59:3
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CATALYSTS
PLATINUM
CATALYTIC EFFECTS
PLATINUM OXIDES
SEGREGATION
RHENIUM
RHENIUM OXIDES
ALLOYS
ALUMINIUM OXIDES
HIGH TEMPERATURE
OXYGEN
REDUCTION
SYNTHESIS
TEMPERATURE DEPENDENCE
ALUMINIUM COMPOUNDS
CHALCOGENIDES
CHEMICAL REACTIONS
CRYOGENIC FLUIDS
ELEMENTS
FLUIDS
METALS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PLATINUM COMPOUNDS
PLATINUM METALS
REFRACTORY METALS
RHENIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
400201* - Chemical & Physicochemical Properties