Ordered Mesoporous Materials as Supports for Stable Iron Catalysts in the Fischer–Tropsch Synthesis of Lower Olefins

The Fe-catalyzed Fischer–Tropsch to olefins (FTO) synthesis is a non-oil-based route for the production of C₂–C₄ olefins. The understanding of the interplay between the catalytically active species, promoters, and support materials has improved over the last years, but the nanostructures of the various supports used are often not comparable. Several ordered mesoporous materials with a comparable pore size and pore symmetry are used as model supports for Fe-based FTO catalysts. Ammonium iron citrate is used as the Fe source for all supports, and Na and S are added as promoters. The formation of catalytically active iron carbide species is suppressed within the strongly interacting mesoporous silica support, but the weakly interacting carbon and silicon carbide supports yield highly active FTO catalysts. Carbon-supported catalysts show a high selectivity towards lower olefins, low methane production, and stable operation for up to 140 h under industrially relevant FTO conditions.