Fischer Tropsch reaction from a mixture similar to biosyngas. Influence of promoters on surface and catalytic properties of Co/SiO2 catalysts

Fischer Tropsch reaction using a mixture similar to that obtained from biomass transformation (biosyngas) has been studied on promoted Co/SiO2 catalysts. As promoters, Cu, Zn, Re and Ru at two different contents were analysed. The promoter affects both the reducibility and the dispersion of Co species, which have an important effect in the activity and selectivity of the studied catalysts. Re and Ru significantly increase both the activity and the selectivity to long chain hydrocarbons, whereas in those promoted by Cu and Zn the effect is strongly affected by the amount of promoter. In those with higher amount of promoter (0.5 wt%), the formation of surface spinels or the blocking of the Co active sites by the copper itself produces a drop in the catalytic activity. The product distribution of the liquid extract reveals the presence of hydrocarbons from C6 to higher than C14+, in most of the catalysts.