Effect of preparation methods on activation of cobalt catalyst supported on silica fiber for Fischer-Tropsch synthesis

Silica fibers (SF) have been synthesized by facile combination of a sol-gel method and electrospinning technique and investigated as supports of cobalt catalysts for Fischer-Tropsch synthesis (FTS). Tetraethyl orthosilicate (TEOS) was used as precursors for the production of silica fibers. The cobalt supported on silica fibers (Co/SF) catalysts were prepared with the impregnation (IM), strong electrostatic adsorption (SEA), deposition precipitation (DP), and hydrothermal synthesis (HT) method and characterized by N₂ adsorption, SEM, TEM, XRD, EDX, H₂-TPR and H₂-chemisorption. The results showed that the preparation methods significant affected the catalytic activity of Co/SF catalyst. The catalyst prepared by the SEA method showed the highest catalytic activity for FTS reaction, and their catalytic activities were varied in the order of SEA<DP<IM>HT. The XRD analysis showed that the Co₃O₄ particles on the Co/SF catalyst prepared by SEA method (9nm) were smaller than those on catalyst prepared by IM method (30nm). The size of the Co₃O₄ particles was controlled by the preparation method, with small particles formed in catalyst prepared by SEA, DP and HT method. The excellent catalytic activity of Co/SF-SEA may be attributed to the smaller size of cobalt particles and higher cobalt dispersion on this catalyst.