查看文章

Three preparation methods of 5% Co/Nb₂O₅ were studied : Incipient wetness impregnation, deposition-precipitation with and without aging. Its effects over total area, mean pore diameter, cobalt species and acidity of reduced catalysts were investigated by BET, Hg porosimetry, XRD, DRS, TPR, TPO and NH₃ TPD. TPR results showed that the reduction proceeds as two steps (Co⁺³ → Co⁺² → Co^o). TPR and DRS indicated the presence of Co⁺² in the precipitated catalysts. The main phase was Co3O4 in all catalysts. The FTS selectivity showed good correlation with the strong acidity.