Abstract: SiO2 was modified by various organic groups before the impregnation of the cobalt precursor. These modified supports and the corresponding catalysts were characterized by IR spectroscopy,X-raydiffraction, and temperature-programmed reduction. The results showed that the organic modification of SiO2 reduced the surface silanol (Si-OH) concentration of SiO2 support, suppressed the interaction between cobalt and silica, enhanced the reduction of the supported cobalt, and thus increased the catalytic activity of Co catalysts for Fischer-Tropsch synthesis. Moreover, SiO2 modified by different organic groups had different surface silanol concentration due to steric hindrance and the catalytic activity increased with the decrease of surface silanol concentration.

Key words: cobalt, silica, organic modification, Fischer-Tropsch synthesis