Comparison of preparation methods for carbon nanotubes supported iron Fischer-Tropsch catalysts

Carbon nanotubes supported iron catalysts were prepared by incipient wetness, deposition/precipitation using K2CO3, and deposition/precipitation using urea. The incipient wetness method and the deposition/precipitation technique using urea yielded highly dispersed Fe3+ on the carbon nanotubes support. The deposition/precipitation technique using K2CO3 also yielded larger Fe2O3-crystallites. After reduction the three catalysts had similar metal surface areas. Nevertheless, the activity of these catalysts in the Fischer-Tropsch synthesis differed significantly with the catalyst prepared by incipient wetness being the most active one. It is speculated that the differences in the performance of the catalysts might be attributed to the different crystallite size distributions, which would result in a variation in the amount of the different phases present in the catalyst under reaction conditions. The selectivity in the Fischer-Tropsch synthesis over the three catalysts seems to be independent of the method of preparation. (C) 2002 Elsevier Science B.V. All rights reserved.