Catalytic performance of zirconium-modified Co/Al2O3 for Fischer-Tropsch synthesis

A series of zirconium-modified Co/AlO3 catalysts were prepared with a two-step impregnation method using the incipient wetness technique. XRD, XPS, TPR. H-2-TPD and oxygen titration were used for the characterization of the catalysts. The catalytic performance was performed in a fixed bed reactor for Fischer-Tropsch synthesis (1717 S). The CoAl2O4 spinel phase was detected on the prepared catalysts and its content on the catalysts decreased with the increase of zirconium loading, indicating that Zr-added could inhibit CoAl2O4 formation. The addition of zirconium to the Co catalyst caused the increase of cobalt cluster size. Zr addition has been shown to improve the activity and C5+ selectivity of Co/Al2O3 catalyst for Fischer-Tropsch synthesis. This could be explained by the increase of active metal cobalt site and reducibility. The increase of zirconium loading on Co/Zr/Al2O3 Catalyst resulted in the increase of olefin/paraffin ratio in the products. (c) 2005 Elsevier B.V. All rights reserved.