Article,
Fe-containing carbon obtained from ferrocene: Influence of the preparation procedure on the catalytic performance in FTS reaction
CHEMICAL ENGINEERING JOURNAL, (2017)
DOI: 10.1016/j.cej.2017.02.047
Abstract
Four different preparation routes were applied to obtain Fe-containing
carbon catalysts for Fischer Tropsch Synthesis (FTS) including copolymer
assisted co-precipitation of iron precursor, chemical modification of
ferrocene, sol-gel and wetness impregnation of iron on polymeric carbon.
The effects of the FTS reaction temperature and pressure were also
examined. Using ferrocene as a starting precursor and applying sol-gel
method to prepare the solid, the syngas is readily converted to C-10(+)
hydrocarbons with a conversion of up to 56% and a productivity of 34 mg
(hyarocarboa).g(cat)(-1).h(-1) at 240 degrees C and 20 atm. Impregnation
method gave a Fe/C based catalyst with the highest exposure of active
sites, including surface Fe3+ and Fe2+ redox sites with great properties
in FTS. Chemical modification of ferrocene route enables the formation
of hematite and maghemite nanoparticles on carbon, which were in situ
reduced to magnetite and iron carbides, being the latter mostly active
for the water gas shift reaction. It is found that copolymer assisted
co-precipitation of ferrocene facilitates the production of large
crystals of magnetite, which suffered from sintering and coking
exhibiting low performance in FTS. Among these methods, sol-gel based
catalyst proved to have superior performance due to the good dispersion
of Fe, stable magnetite and iron carbide and Fe-doped nitrogen carbon
phases production. Based on spent catalysts characterizations, the
synergetic effect between magnetite and the iron carbides phases in the
sol-gel based catalyst plays an important role in heavy hydrocarbon
formation. (C) 2017 Elsevier B.V. All rights reserved.
