Synthesis of carbon nanofibers supported cobalt catalysts for Fischer-Tropsch process

In this paper, CNFs prepared at three different temperatures (1023, 873 and 723 K, called CNF-1, CNF-2 and CNF-3, respectively) were used as supports for cobalt-based catalysts in the Fischer-Tropsch Synthesis (FTS). The supports and cobalt catalysts were characterized by nitrogen adsorption-desorption, temperature-programmed reduction (TPR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA) techniques; the metal content of the cobalt-based catalysts was analyzed by atomic absorption. The activity and selectivity of the CNFs supported catalysts were studied at 523 K, 20 bar and H2/CO = 2. Co/CNF-1 and Co/CNF-2 were very active and showed high selectivity to CH4 and CO2, without further deactivation, whereas the less active catalyst Co/CNF-3 led to the highest selectivity to long-chained hydrocarbons (C5+) and under was a remarkable deactivation. Used catalysts were characterized by nitrogen adsorption-desorption, XRD and TGA. Results confirmed that all the catalysts underwent catalyst fouling as a consequence of C5+ hydrocarbons formation whereas catalyst Co/CNF-3 presented a notably metal sintering by coalescence.