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Full-Text Articles in Chemical Engineering
Ga And In Modified Ceria As A Support For Cobalt Fischer-Tropsch Synthesis, Muthu Kumaran Gnanamani, Gary Jacobs, Wilson D. Shafer, Michela Martinelli, Donald C. Cronauer, A. Jeremy Kropf, Christopher L. Marshall, Burtron H. Davis
Ga And In Modified Ceria As A Support For Cobalt Fischer-Tropsch Synthesis, Muthu Kumaran Gnanamani, Gary Jacobs, Wilson D. Shafer, Michela Martinelli, Donald C. Cronauer, A. Jeremy Kropf, Christopher L. Marshall, Burtron H. Davis
Center for Applied Energy Research Faculty and Staff Publications
Ceria modified by the addition of gallium or indium (20 mol%) was used as a support for cobalt Fischer-Tropsch synthesis. The addition of gallium to ceria improved the CO conversion for cobalt, whereas indium tended to decrease it. A similar trend was observed with the Ag-promoted cobalt/ceria catalysts that were doped with Ga or In. For Ag promoted catalysts, doping with Ga or In decreased methane and increased the product selectivities of olefins and alcohols. The sum of olefins and alcohols in terms of product selectivity for the Ag-promoted catalysts decreased in the following order: Ag-Co/Ce-Ga > Ag-Co/Ce-In > Ag-Co/Ce. The H2-TPR-XANES …
Influence Of Reduction Promoters On Stability Of Cobalt/Γ-Alumina Fischer-Tropsch Synthesis Catalysts, Gary Jacobs, Wenping Ma, Burtron H. Davis
Influence Of Reduction Promoters On Stability Of Cobalt/Γ-Alumina Fischer-Tropsch Synthesis Catalysts, Gary Jacobs, Wenping Ma, Burtron H. Davis
Center for Applied Energy Research Faculty and Staff Publications
This focused review article underscores how metal reduction promoters can impact deactivation phenomena associated with cobalt Fischer-Tropsch synthesis catalysts. Promoters can exacerbate sintering if the additional cobalt metal clusters, formed as a result of the promoting effect, are in close proximity at the nanoscale to other cobalt particles on the surface. Recent efforts have shown that when promoters are used to facilitate the reduction of small crystallites with the aim of increasing surface Co0 site densities (e.g., in research catalysts), ultra-small crystallites (e.g., < 2–4.4 nm) formed are more susceptible to oxidation at high conversion relative to larger ones. The choice of promoter is important, as certain metals (e.g., Au) that promote cobalt oxide reduction can separate from cobalt during oxidation-reduction (regeneration) cycles. Finally, some elements have been identified to promote reduction but either poison the surface of Co0 (e.g., Cu), or produce excessive light gas selectivity (e.g., Cu and Pd, or Au at …