Effect of Calcination Conditions on the Dispersion of Cobalt Over Re, Ru and Rh Promoted Co/γ-Al2O3 Catalysts

Abstract

The effects of catalyst calcination conditions, such as calcination temperature and calcination atmosphere composition on the dispersion of cobalt particles over Co/γ-Al2O3 catalysts for Fischer–Tropsch conversion of synthesis gas are studied. A number of catalysts were prepared by incipient wetness impregnation of 20-wt% of cobalt onto γ-Al2O3 and promoted with 0.5 wt% ruthenium, rhenium, and rhodium. Metal dispersions of active metals were studied by chemisorption of carbon monoxide. The highest dispersion for Co/γ-Al2O3 catalyst was achieved by calcination at 400 °C in a flow of N2. Co metal dispersion seem to be increased in the calcination steps if a flowing gas was used instead of static calcination conditions. The addition of promoter metals like Ru, Re or Rh enhances the dispersion of the active metal.