Support effects in high temperature Fischer-Tropsch synthesis on iron catalysts

• Iron catalysts were studied in Fischer-Tropsch reaction over silica and carbon supports.
• CO pre-treatment results in conversion of Fe2O3 and Fe3O4 into mainly χ-Fe2C5 carbide.
• The type of support affect iron particle size, iron carbidisation and catalyst phase.
• Iron supported on carbon nanotubes and activated carbon show the highest activity.
• This high activity might be due to the formation of magnetite–carbide composite.

The paper addresses the effects of silica and carbon supports on the structure and catalytic performance of iron catalysts for high temperature Fischer-Tropsch synthesis. Iron phase composition and dispersion in both calcined and activated catalysts were strongly affected by the support. Hematite was the major iron phase in calcined silica supported catalysts, while carbon supported counterparts contain magnetite. Catalyst activation in carbon monoxide leads to carbidisation of iron oxides to principally Haag iron carbide. Higher Fischer-Tropsch reaction rates were observed on carbon supported iron catalysts compared to silica supported counterparts. The catalytic performance principally depended on iron phase composition rather than on iron dispersion. Iron catalysts supported on carbon nanotubes and activated carbon showed highest activity in Fischer-Tropsch, which could be attributed to the formation of composites of iron carbide and residual magnetite.

Figure optionsDownload high-quality image (167 K)Download as PowerPoint slide