Mn-Decorated CeO2 nanorod supported iron-based catalyst for high-temperature Fischer–Tropsch synthesis of light olefins

Abstract

CeO₂ nanorods with a mean width of 11.9 nm were synthesized via a facile hydrothermal method. Subsequently, Fe/CeO₂ and Fe/CeO₂@xMnO₂ catalysts were prepared from the CeO₂ nanorods and applied in the high-temperature Fischer–Tropsch synthesis of light olefins. Results show that the CeO₂ support donates electrons to Fe species, which promotes the dissociation of CO while suppressing the hydrogenation reaction, and then improves the selectivity to light olefins. The synergistic effect between Mn and Ce can improve the oxygen mobility on the catalyst surface and promote the electron-donating ability of Ce, thereby promoting the formation of χ-Fe₅C₂ and further improving the selectivity to light olefins. However, excess Mn hinders the contact between CeO₂ and Fe species and the migration of O atoms, and electron transfer from Ce to Fe can be blocked. Additionally, the reduction of iron oxides was suppressed and subsequently the CO conversion was reduced. The best hydrocarbon distribution for light olefins was 40.4% at a CO conversion of 39.9% over the Fe/CeO₂@0.2MnO₂ catalyst.