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

Abstract The effect of functionalising agents (KMnO 4 and HNO 3 ) 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 HNO 3 and KMnO 4 functionalised catalysts. Investigation of the role of Mn (0.05%) and K (0.05%) on Co/CS FT catalysts functionalised with HNO 3 revealed that these differences were due to the presence of residual MnO 4 − ions remaining after the surface functionalisation reaction.