The effect of dealumination on zeolite-supported Ru catalysts
- Univ. of Pittsburgh, PA (United States)
The physical and catalytic properties of a series Ru/dealuminated Y-zeolite catalysts prepared by ion exchange have been investigated in order to better understand the effect of the Si/Al ratio of a zeolite on the catalytic properties of a supported metal. Dealumination up to 52% was shown not to have affected the crystallinity of the zeolite. The reduced Ru catalysts exhibited increased metal dispersions, as measured by H[sub 2] chemisorption, with increased zeolite dealumination. Turnover frequency (TOF) for CO hydrogenation vs. Si/Al ratio showed a volcano shape. Maximum TOF occurred at a Si/Al ratio of about 5. While the overall product distribution was unaffected by Si/Al ratio, an increase in the selectivity for iso-C[sub 4] with increasing dealumination indicated that secondary reactions of the F-T primary products were enhanced by the presence of stronger acid sites. It is well known that the concentration of acid sites in a dealuminated Y-zeolite decreases with increasing Si/Al ratio, while the strength of the acid sites increases and reaches a maximum for Si/Al [approx]4.5. Since overall chain growth probability was not apparently affected by dealumination of the zeolite support, it is suggested that the increase in overall activity for CO hydrogenation on the dealuminated Ru catalysts may have been primarily due to an enhancement in secondary reactions as a result of the increase in acid strength lessening readsorption of olefinic primary products on Ru CO hydrogenation sites. 26 refs., 5 figs., 3 tabs.
- OSTI ID:
- 5649938
- Journal Information:
- Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 142:2; ISSN 0021-9517; ISSN JCTLA5
- Country of Publication:
- United States
- Language:
- English
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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYSIS
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISORPTION
COMPLEXES
ELEMENTS
FISCHER-TROPSCH SYNTHESIS
HETEROGENEOUS CATALYSIS
HYDROGEN
HYDROGENATION
INORGANIC ION EXCHANGERS
ION EXCHANGE
ION EXCHANGE MATERIALS
MATERIALS
MINERALS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
RUTHENIUM COMPLEXES
SEPARATION PROCESSES
SILICATE MINERALS
SORPTION
SORPTIVE PROPERTIES
SURFACE PROPERTIES
TRANSITION ELEMENT COMPLEXES
ZEOLITES