The effect of binders on structure and chemical properties of Fe-K/γ-Al2O3 catalysts for CO2 hydrogenation Original Research Article

The study is focused on investigating catalytic behavior with and without binder in CO2 hydrogenation. It was found that Fe-K/γ-Al2O3 with alumina binder (FA-A catalyst) had excellent capability of CO2 hydrogenation, whereas Fe-K/γ-Al2O3 with silica binder (FS-A catalyst) showed dramatically decreased capability compared with those of other catalysts. The product selectivity for catalysts with and without binder was compared at the same reaction conditions. The selectivity and activity of Fe-K/γ-Al2O3 with polyvinylalcohol (PVA) binder (FP catalyst) tended to be similar to those of Fe-K/γ-Al2O3 without binder (FN catalyst). FS-A catalyst exhibited higher methane (16 mol%) and C2–C4 selectivity (43.5 mol%) than FN catalyst. For FA-A catalyst, the main products were higher hydrocarbons such as C5+ hydrocarbon. This phenomenon can be explained if the structure and porosity of catalysts with alumina binder have differences in spite of the similarities of main chemical composition. This would mean that the higher hydrocarbon selectivity of FA-A is increased as the amounts of strong acid sites increase.