Fischer−Tropsch Synthesis:  Assessment of the Ripening of Cobalt Clusters and Mixing between Co and Ru Promoter via Oxidation−Reduction-Cycles over Lower Co-Loaded Ru−Co/Al2O3 Catalysts

A 2% Ru-promoted 15% Co/Al2O3 catalyst was tested after reduction and after being subjected to oxidation−reduction cycles. The catalysts were characterized over four oxidation−reduction cycles by XANES/EXAFS, TPR, HRTEM, and EDS elemental mapping. The oxidation−reduction treatments were found to ass...

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Bibliographic Details
Published in:Industrial & engineering chemistry research 2008-02, Vol.47 (3), p.672-680
Main Authors: Jacobs, Gary, Sarkar, Amitava, Ji, Yaying, Luo, Mingsheng, Dozier, Alan, Davis, Burtron H
Format: Article
Language:English
Subjects:
Applied sciences
Catalysis
Catalytic reactions
Chemical engineering
Chemistry
Exact sciences and technology
General and physical chemistry
Reactors
Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
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Summary:A 2% Ru-promoted 15% Co/Al2O3 catalyst was tested after reduction and after being subjected to oxidation−reduction cycles. The catalysts were characterized over four oxidation−reduction cycles by XANES/EXAFS, TPR, HRTEM, and EDS elemental mapping. The oxidation−reduction treatments were found to assist in sintering the metallic clusters to a larger size, and to promote mixing on at least the order of the nanoscale. The larger crystallites in closer proximity to the Ru promoter led to a more facile reduction of the cobalt crystallites. In addition, a catalyst exposed to two oxidation−reduction cycles resulted in slightly higher conversion, higher α-value product, slightly lower methane selectivity, and greater stability over a reduced freshly calcined catalyst.
ISSN:0888-5885
1520-5045
DOI:10.1021/ie0709988