Abstract: Cobalt catalysts supported on unsilylated and silylated SBA-15 were prepared by incipient wetness impregnation and characterized by elemental analysis, N₂ adsorption-desorption, X-ray diffraction, H₂ temperature-programmed reduction, H₂ temperature-programmed desorption, and oxygen titration. Their catalytic properties for Fischer-Tropsch synthesis were evaluated in a fixed-bed reactor. The results show that the interaction between cobalt and the support was decreased, and the reducibility of the cobalt oxide species was more facile on the silylated Co/SBA-15 catalyst. With increasing (CH₃)₃SiCl loading, the surface coverage of the trimethylsilyl group increased, and the cobalt cluster size was larger. The higher activity of the silylated 10%Co/SBA-15 catalysts was ascribed to its improved reducibility. The increase in selectivity for C₅₊ hydrocarbons was attributed to the increase in cobalt cluster size.

Key words: silylation, SBA-15, cobalt-based catalyst, Fischer-Tropsch synthesis, trimethylsilyl