Gamma-Alumina Nanotubes Prepared by Hydrothermal Method as Support of Iron, Cobalt and Nickel for Fischer-Tropsch Catalysts

Abstract

?-Alumina nanotubes have been synthesized by hydrothermal method from aluminium nitrate nonahydrate, CTAB, urea, and water with a molar ratio of 29:153:1:2028. The alumina has BET surface area of 203.73 m²/g, pore volume of 0.14 ml/g, and average pore diameter of 2.78 nm. The crystallite size calculated by Scherer equation was in the range of 9.8–11 nm. It has been employed as support of iron, cobalt, and nickel for Fischer-Tropsch synthesis catalyst. The three catalysts were prepared by incipient wetness impregnation method. It was found that they showed different catalytic behaviours and activity. The acidity of catalysts increased according to the order: Co/Al₂O₃<Fe/Al₂O₃<Ni/Al₂O₃. The reducibility, amount of active site and catalytic activity increased in the following order: Fe/Al₂O₃<Co/Al₂O₃<Ni/Al₂O₃.

Keywords: alumina nanotubes, hydrothermal method, iron, cobalt, nickel, Fischer-Tropsch catalyst.