Changes in the surface hydrophobicity degree of a MCM-41 used as iron support: a pathway to improve the activity and the olefins production in the Fischer–Tropsch synthesis

• DOI: 10.1007/s10934-016-0342-5
• Publication Date: 2016-12-17T02:52:01Z
• Authors: N. A. Fellenz; J. F. Bengoa; M. V. Cagnoli; S. G. Marchetti
• Keywords: 01 natural sciences; 7. Clean energy; 0104 chemical sciences

The effect of surface hydrophobicity degree of MCM-41 support on activity and selectivity in Fischer–Tropsch synthesis has been studied. The Fe/MCM-41 catalyst was prepared by impregnation of the mesoporous support with iron. A portion of this product was silylated with hexamethyldisilazane. The samples were characterized by atomic absorption spectroscopy, X ray diffraction at low angles, N2 adsorption at 77 K, Fourier transform infrared spectroscopy and Mossbauer spectroscopy at 25 and 298 K in controlled atmosphere. Catalytic tests were performed simulating industrial operating conditions and showed that the silylated system presents higher activity, lower selectivity toward methane and higher olefin/paraffin ratio. The higher methane production and the lower amount of olefins observed for the non-silylated catalyst indicate that this system has a larger amount of hydrogen on its surface than the silylated one. A detailed discussion about the relationship among surface chemistry, stability, selectivity and the changes in iron species of the catalysts is presented.