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

Abstract

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.