Study of Co/SBA-15 catalysts prepared by microwave and conventional heating methods and application in Fischer–Tropsch synthesis

• Molecular sieve SBA-15 was prepared under microwave and conventional heating.
• Cobalt was deposited on SBA-15 support by wet impregnation.
• The catalysts were evaluated for the Fischer–Tropsch reaction.
• Co/SBA-15 catalyst was active and selective to C5+, due the synergistic effect between Co and SBA-15.
• Co/SBA-15 catalysts may be potentially useful for FT synthesis.

The aim of this work was to produce a 20% (w/w) cobalt catalyst supported in SBA-15 molecular sieve, analyze it and evaluate its use in Fischer–Tropsch (FT) reaction. Two synthesis methods for the SBA-15 molecular sieves were evaluated: microwave (Co/SBA15-MW) and conventional heating (Co/SBA15-CH). The Co/SBA-15 catalysts were prepared by humidity impregnation and were characterized by X-ray diffraction, X-ray energy dispersion spectrophotometer, N2 adsorption–desorption, temperature-programmed reduction, and transmission electron microscopy. Fischer–Tropsch synthesis was carried out to evaluate the activity of the catalyst. The synthesis was carried out in a slurry reactor operating at 513 K, 20 atm, and 1:1 CO:H2 molar ratio. X-ray diffraction showed that the calcined cobalt catalyst did not modify the structure of SBA-15 and that Co was present under the form of Co3O4 in the precursor. The addition of cobalt in the SBA-15 decreased the specific surface area of the molecular sieve. Fischer–Tropsch synthesis activity and C5+ hydrocarbon selectivity increased with the Co/SBA15-MW. The increase in activity and selectivity were attributed to the increased number of active sites as a result of the higher reducibility. The Co/SBA-15 catalysts showed moderate conversion (40%) and high selectivity towards the production of C5+ (79%, w/w).

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