On the mechanism of the Fischer-Tropsch synthesis involving unreduced iron catalyst

Abstract Iron oxide (Fe2O3) dispersed on silica aerogel exhibits a catalytic activity at the steady state in the Fischer-Tropsch synthesis which is about 300 times higher (per g of iron) than the activity of the conventional fused iron reduced catalyst, and it does not deactivate by carburization or by deposition of inactive carbon. The non-supported iron oxide or the xerogel-type silica-supported iron oxide (Fe2O3) shows an intermediate behaviour. The less active catalysts of any type (unsupported, xerogel or aerogel) are those pre-reduced in H2 at 500°C. They deactivate by carburization and by carbon deposition. A mechanism of the Fischer-Tropsch reaction which takes into account these characteristics is proposed.