(617dl) Promoter Effects of Residual K and Mn in Cobalt Supported Carbon Spheres Catalysts for Fischer Tropsch Synthesis

Carbon spheres (CSs) constitute a set of flexible and valuable properties when used as heterogeneous catalyst supports due to the inert nature of the Carbon spheres. These support materials may also be used as model support materials for the study of promoter effects in small amounts on the metal precursor. The surface of CSs must often contains N, O or H atoms in functional groups which may play pivotal roles in catalyst preparation by altering the acid-base and hydrophilic character of the carbon material hence creating metal anchoring sites. 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 and K⁺ ions remaining after the surface functionalisation reactions.