Effect of Silylation of SBA-15 on Its Supported Cobalt Catalysts for Fischer-Tropsch Synthesis

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.