The influence of cobalt loading and titania addition to the silica support on Fischer-Tropsch synthesis activity is investigated over two series of catalysts with Co loading of 6 wt% and 12 wt%. The pure silica support is prepared by sol-gel procedure in acid conditions. The modification by TiO2 is performed by grafting with titanium isopropoxide. The catalysts are prepared by wet-impregnation over amorphous SiO2 and over SiO2 modified by TiO2 (5 wt%). The samples, characterized by N-2-adsorption-desorption analyses, X-ray diffraction (XRD), temperature programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS), are tested in the low-temperature Fischer-Tropsch synthesis using the conditions of 483 K, 20 bar and H-2/CO = 2.1. The improved conversion rate and the increased SC5+ of the titania containing catalysts are discussed in terms of the stronger interaction between cobalt and titania affecting the cobalt oxide reducibility. (C) 2012 Elsevier B.V. All rights reserved.