Comparison between Co/SiO2 and Co/La-SiO2 catalyst samples prepared via solvated metal atom impregnation method

The solvated metal atom impregnation (SMAI) method was used to prepare Co/S iO2 and Co/LaSiO2 catalyst samples with 5% Co content. The XPS results show ed that the cobalt particles both in SiO2 and in La-SiO2 existed in zero-va lent state (Co-0). The CO chemisorption results showed that the cobalt part icle size (5.3 nm) of Co/La-SiO2 sample was much smaller than that (8.1 nm) of Co/SiO2 sample. The turnover frequency (TOF) of CO on Co/La-SiO2 sample was higher than that on Co/SiO2 sample in F-T reaction (CO hydrogenation), which was probably due to the fact that the cobalt particle size in Co/La- SiO2 sample was much smaller than that in Co/SiO2 sample. The experimental results also showed that the selectivity of Co/La-SiO2 sample for long chai n paraffins was higher than that of Co/SiO2 sample.