Cobalt catalysts (2-10 wt% Co) supported on silica-rich MCM-22 zeolites have been prepared by impregnation with aqueous Co(NO3)(2) solutions. The catalysts are characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), nitrogen adsorption, solid state nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The catalytic properties for the Fischer-Tropsch synthesis (FTS) at 280 degrees C, 12.5 bar and H-2/CO = 2 are evaluated. The catalysts supported on MCM-22 exhibit the highest selectivity to long-chain (C5+) hydrocarbons when MCM-22 supports are synthesized with the appropriate SUM ratio. (c) 2005 Elsevier B.V. All rights reserved.