Ru catalysts supported on Al-SBA-15 with high aluminum content and their bifunctional catalytic performance in Fischer-Tropsch synthesis

Highly ordered mesoporous Al-SBA-15 materials with high Al/Si ratios (0.2, 0.5 and 1.0) have been synthesized by a modified "pH-adjusting" method, and ruthenium catalysts supported on the Al-SBA-15 were prepared by incipient wetness impregnation and tested in a fixed bed reactor at high temperature (250 degrees C) in order to study their bifunctional catalytic performance in Fischer-Tropsch synthesis. The samples were characterized by ICP-AES, XRD, Al-27 MAS NMR, N-2 physisorption, NH3-TPD, TEM, TPR and IR spectroscopy of adsorbed pyridine. The results showed that the selectivities of hydrocarbons were significantly influenced by Al/Si ratio in the support. The 4Ru(1.0) catalyst with Al/Si ratio of 1.0 exhibited typical bifunctional properties in Fischer-Tropsch synthesis, lower selectivity (24.9%) of heavy hydrocarbons (C-13+) and much higher selectivities of olefins and iso-paraffins were found in the products.