Fischer–Tropsch synthesis over alumina supported cobalt catalyst: Effect of promoter addition

Abstract In order to improve the activity of Co/Al 2 O 3 catalyst for FT synthesis, loading effect of metal promoter on Al 2 O 3 support was examined. In this study, total 13 kinds of metal (Mg, Ca, Sr, Ba, Y, La, Ce, Ti, V, Mn, Zn, Zr and Mo) were employed as promoters and θ-Al 2 O 3 prepared by the calcination of commercial boehmitewas used as support. Co/Al 2 O 3 catalysts loaded with various metal promoters were prepared by a sequential impregnation method. Loading of Mn, V and Mo on Al 2 O 3 support decreased Co reducibility and surface area of Co metal, but increased intrinsic activityper active Co metal sties (i.e. TOF). On the other hand, metal additives other than Mn, V and Mo varied Co reducibility and Co surface area, but did not influence TOF. High overall activity was obtained over Co/Al 2 O 3 catalysts loaded with rare earth elements (e.g. La and Ce), which was due to the high surface area of Co metal. We also examined the co-loading of La and V promoters on Al 2 O 3 support. Co/Al 2 O 3 catalysts loaded with both La and V (Co/La + V/Al 2 O 3 ) showed higher activity than those loaded with either La or V. CO conversion rate over the best Co/La(2) + V(0.5)/Al 2 O 3 catalyst was 1.6 times as high as that over bare Co/Al 2 O 3 catalyst. Over the Co/La + V/Al 2 O 3 catalyst, La and V promoters cooperatively improved Co reducibility, Co surface area and TOF, resulting in an increase of overall catalytic activity.