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

Abstract

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 °C) in order to study their bifunctional catalytic performance in Fischer–Tropsch synthesis. The samples were characterized by ICP-AES, XRD, ²⁷Al MAS NMR, N₂ 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 (C₁₃+) and much higher selectivities of olefins and iso-paraffins were found in the products.