Catalytic probe for alloy formation in supported PtRe catalysts: isotope exchange and hydrogenolysis of cyclopentane

Journal Article · Sat Aug 01 04:00:00 EDT 1987 · J. Catal.; (United States)

DOI:https://doi.org/10.1016/0021-9517(87)90254-5· OSTI ID:5204285

Augustine, S M; Sachtler, W M.H.

The H/D isotope exchange and the hydrogenolysis of cyclopentane (CP) as catalyzed by alumina- or silica-supported Pt, Re, their alloys, and physical mixtures have been studied. The number of surface-exposed metal atoms is determined by chemisorbing deuterium and exchanging it with hydrogen. The CP exchange reaction is found to be nonspecific for the composition of the catalyzing ensembles: PtRe alloys exhibit the same rate and exchange pattern as a physical mixture of these metals with the same number of metal atoms exposed. The exchange rate can therefore be used to count exposed metal atoms. The exchange patterns over Pt and PtRe show partial maxima for d/sub 5/ and d/sub 10/; over PtRe all products are formed in quantities intermediate to those obtained over Pt and Re respectively. CP hydrogenolysis is highly ensemble-specific. The TOF (turnover frequency) for methane formation over PtRe exceeds that over the separate metals by a factor of 40. This finding is used to estimate the extent of alloy formation in supported bimetallic PtRe catalysts. Even in physical mixtures of Pt and Re, initially supported on separated support particles, some alloy formation can be detected.

• Research Organization: Northwestern Univ., Evanston, IL (USA)
• OSTI ID: 5204285
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 106:2; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020400* -- Petroleum-- Processing
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400202 -- Isotope Effects
Isotope Exchange
& Isotope Separation
ALKANES
ALLOYS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
BIMETALS
CATALYST SUPPORTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHEMISORPTION
COMPARATIVE EVALUATIONS
CYCLOALKANES
DEUTERIUM
ELEMENTS
HYDROCARBONS
HYDROGEN
HYDROGEN ISOTOPES
HYDROGENATION
ISOTOPES
ISOTOPIC EXCHANGE
KINETICS
LIGHT NUCLEI
METALS
METHANE
MINERALS
NONMETALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PENTANE
PLATINUM
PLATINUM ALLOYS
PLATINUM METAL ALLOYS
PLATINUM METALS
REACTION KINETICS
RHENIUM
RHENIUM ALLOYS
SEPARATION PROCESSES
SILICA
SILICON COMPOUNDS
SILICON OXIDES
SORPTION
STABLE ISOTOPES
SYNTHESIS
TRANSITION ELEMENTS