Fischer-Tropsch synthesis over Ru-Group Ib/SiO sub 2 catalysts
- Iowa State Univ., Ames (USA)
Reaction studies probing the catalytic activity and selectivity of the Fischer-Tropsch synthesis reaction have been performed for a series of chlorine-free, silica-supported Ru-group Ib (Ag, Au, Cu) bimetallic catalysts. The goal of this work was to isolate ensemble effects, electronic effects, or the influence of the metal particle structure on catalytic behavior. The rate per surface Ru atom, or turnover frequency, was used to correlate catalytic activity with surface composition. The turnover frequencies for the series of Ru-Cu catalysts declined by a factor of about two when the relative Cu composition increased form 0% to 10% (at constant Ru loading). Increasing the Cu loading beyond this level did not affect the turnover frequency. Similar behavior was noted for the Ru-Ag catalysts where the turnover frequency declined until a Ag loading of about 25% was obtained. Increased Ag content did not further change the turnover frequency. As the segregating element (Ib) preferentially goes to the low-coordination, defect-like sites, the observed turnover frequency declines. Once all low-coordination sites are filled, no variation in turnover frequency with composition was observed, indication a lack of ensemble effects. This result contrasts with previously reported investigations of the Ru-Cu system. The overall rate changed modestly and the turnover frequency did not change significantly with composition over the series of Ru-Ag catalysts. The product distribution shifted to smaller molecules with increasing Cu content in the Ru-Cu series but remained constant over the entire composition range for the Ru-Ag and Ru-Au catalysts.
- DOE Contract Number:
- W-7405-ENG-82
- OSTI ID:
- 5724898
- Journal Information:
- Journal of Catalysis; (USA), Journal Name: Journal of Catalysis; (USA) Vol. 126:2; ISSN 0021-9517; ISSN JCTLA
- Country of Publication:
- United States
- Language:
- English
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BIMETALS
CATALYSIS
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL COMPOSITION
CHEMICAL REACTIONS
COMPARATIVE EVALUATIONS
COPPER
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
ELEMENTS
FISCHER-TROPSCH SYNTHESIS
GOLD
METALS
MICROSTRUCTURE
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
QUANTITY RATIO
RUTHENIUM
SILICON COMPOUNDS
SILICON OXIDES
SILVER
SURFACE PROPERTIES
TRANSITION ELEMENTS