Modulating C5+selectivity for Fischer-Tropsch synthesis by tuning pyrolysis temperature of MOFs derived Fe-based catalyst

Abstract

BackgroundFischer-Tropsch synthesis have been of great importance since decades to yield efficient catalysts for C5+ products. High C5+ selectivity is often at the expense of reduced CO conversion which is tried to overcome. MethodsIn this research, the Fe@C catalysts were successfully synthesized through direct pyrolysis of Fe-MIL-88B with MOFs structure at high temperature (600, 700 and 800 °C), then reduced and tested the FTS performance. Furthermore, pyrolysis temperature effects on textural properties and FTS performance were studied via TEM, SEM, XRD, N2 physisorption, Raman spectroscopy Significant findingsThe result indicated that the obtained catalysts depicted high Fe loading and transformation from needle-like precursor to highly porous sponge shaped crystalline. Moreover, the catalyst Fe@C-800 pyrolyzed at 800 °C achieved an exceptionally high C5+ hydrocarbon selectivity near 90% with good reaction stability. Meanwhile, the catalyst Fe@C-700 showed the highest CO conversion among these catalysts that can be credited to more Fe5C2 carbide phase which is a known active phase for FTS system. This demonstrates that the MOFs derived Fe-based catalysts are potential for high C5+ selectivity toward FTS without reduction of CO conversion.