MnO2 coated Fe2O3 spindles designed for production of C5+ hydrocarbons in Fischer–Tropsch synthesis

•Fe2O3@MnO2 spindles were designed for use in Fischer–Tropsch synthesis.•Different from the conventional Fe–Mn catalysts, no Fe–Mn spinel oxide was formed.•Mn promoter was used to weaken the C–O band and thus favoring chain growth.•The prepared novel catalysts displayed excellent selectivity to C5+ hydrocarbons.

Manganese served as promoter for the Fe-based catalysts has been considered to have great potential in Fischer–Tropsch (FT) synthesis. However, many previous researchers mainly focus on the enhancement of lower olefins, primarily because the previous reported Fe–Mn spinel oxide hindered its wide applications. In this article, Fe2O3@MnO2 spindles were fabricated by coverage of hematite with MnO2 via a hydrothermal reaction and applied in FT synthesis reaction. Different from the conventional Fe–Mn catalysts, the synthesized core–shell catalysts exhibited enhanced catalytic performance, especially in C5+ hydrocarbons selectivity. It demonstrated that Mn promoter could accelerate the dissociation of CO and thus enhanced the concentration of active intermediates for chain growth. Compared with the pure Fe2O3 (Mn-free) catalyst, the selectivity toward C5+ hydrocarbons over Fe2O3@MnO2 (Mn-9) catalyst was increased from 44.6 to 66.6 wt%. Meanwhile, the undesired CH4 was decreased from 16.8 to 8.9 wt%.

Graphical abstractFe2O3@MnO2 spindles were designed as catalysts for use in Fischer–Tropsch synthesis. Different from the conventional Fe–Mn catalysts, the synthesized catalysts displayed excellent selectivity to C5+ hydrocarbons and poor to CH4 as a side product.Figure optionsDownload full-size imageDownload as PowerPoint slide