A series of ultrafine Mo Co K catalysts with different Co/Mo ratios but constant potassium content were characterized by TPD technique and their catalytic performance for higher alcohol synthesis was investigated The results indicated that there are two kinds of adsorption sites, ie, low temperature adsorption sites (LTAS) around 90?℃ and high temperature adsorption sites (HTAS) above 400?℃ for H 2 and CO on the surface of the catalysts The desorption temperature of HTAS for H 2 and CO as well as the desorption amount of HTAS for H 2 were strongly influenced by the Co/Mo ratio of the catalysts It was found that the addition of Co into the ultrafine Mo K catalyst resulted in a decrease of the HTAS desorption temperature and an increase of the HTAS desorption amount for H 2 As the Co/Mo ratio increased further, the HTAS desorption amount for H 2 increased accordingly while the HTAS desorption temperature remained constant However, the HTAS desorption temperature for CO was found to be mainly influenced by the Co/Mo ratio, and the HTAS desorption temperature got its minimum at the Co/Mo ratio of 1∶7 It was found that a weaker adsorption of H 2 and CO on the HTAS and an appropriate H 2 adsorption amount were favourable for the formation of higher
Co based catalysts supported on silica from two different sources were tested in F T synthesis and characterized by ICP, H 2 TPD and FT IR. It was found that the Co catalyst supported on home made silica was superior to the commercial silica. One reason was that the latter had a higher content of Na impurity, which was harmful to the catalytic activity owing to its alkaline effect. The other one might be that the silica source exerted an unfavorable effect on metal dispersion. A maximum C 5+ yield of 140g/Nm 3 (2H 2+CO) was obtained over Co/Si(3).
