Promotion of Co/carbon sphere Fischer–Tropsch catalysts by residual K and Mn from carbon oxidation by KMnO4

The effect of functionalising agents (KMnO4 and HNO3) on the surface properties of carbon spheres (CSs) produced from acetylene gas by a chemical vapour deposition method, was examined. Cobalt was loaded onto the differently functionalised CSs using the deposition precipitation (DPU) method and the Co/CS catalysts were tested for Fischer–Tropsch (FT) activity. FT studies, revealed differences in activity and selectivity for the HNO3 and KMnO4 functionalised catalysts. Investigation of the role of Mn (0.05%) and K (0.05%) on Co/CS FT catalysts functionalised with HNO3 revealed that these differences were due to the presence of residual MnO4− ions remaining after the surface functionalisation reaction.

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► Carbon spheres (CSs) preparation by a direct chemical vapour deposition method.
► CSs functionalisation by KMnO4 and HNO3 functionalising agents.
► 5% Co/CS KMnO4 functionalised and 5% Co/CS HNO3 functionalised catalyst evaluation in FTS.
► Investigation of K and Mn promoter effects on 5% Co/CS HNO3 catalysts in FTS.