Effects of metallic cobalt crystal phase on catalytic activity of cobalt catalysts in Fischer-Tropsch synthesis (FTS) were investigated in a continuous spinning basket reactor. The cobalt catalysts were prepared by impregnation of cobalt active phase in microemulsion system on multiwall carbon nanotubes support. A series of cobalt catalysts with different Co particle size were prepared by variation the water-to-surfactant molar ratio (W/S) from 2 to 12 in microemulsion system. The X-ray diffraction (XRD) results validate a complex composition of cobalt phases contains cobalt oxides and metallic cobalt with hexagonal close-packed (hcp) and face-centered-cubic (fcc) phases are existed in our cobalt catalysts. The results show that, larger cobalt particles exhibit more fcc and less hcp metallic cobalt. The experimental results show that the catalysts with higher fractions of hcp phase exhibited higher conversion in FTS reaction.

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