AuPt nano-alloys as reduction promoters for Co/TiO₂ Fischer-Tropsch catalysts
Cobalt-based catalysts for the Fischer-Tropsch synthesis are typically promoted with noble metals to achieve a more facile reduction of Co₃O₄ to the catalytically active metal, Co⁰. Hydrogen spillover is thought to be the dominant mechanism for the functioning of noble metals during the reduction process. Platinum is a well-known reduction promoter and its functioning as a reduction promoter is thought to occur via H₂ - spillover mechanism. This process is switched off during the Fischer-Tropsch synthesis, when platinum is used as a reduction promoter, since platinum has been shown to be catalytically inert under these conditions, due to strong adsorption of CO. Some hydrogen spill-over during the Fischer-Tropsch synthesis might be desired to obtain more stable catalysts (less coking), but this effect has to be balanced against increased methanation activity.
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