A series of Co-Fe catalysts supported on TiO2-SiO2 were prepared by the sol-gel method. This research investigated the effects of (Co/Fe) wt.%, the solution pH, different Co/Fe molar ratio, calcination conditions and different promoters on the catalytic performance of cobalt-iron catalysts for the Fisher-Tropsch synthesis (FTS). It was found that the catalyst containing 35 wt.% (Co-Fe)/TiO2-SiO2 (Co/Fe molar ratio is 80/20) promoted with 1.5 wt.% Cu and calcined in air atmosphere at 600 degrees C for 7 h with a heating rate of 3 degrees C min(-1) is an optimal nano catalyst for converting synthesis gas to light olefins and C-5-C-12 hydrocarbons. The effects of operational conditions such as the H-2/CO ratio, gas hourly space velocity (GHSV), different reaction temperature, and reaction pressure were investigated. The results showed that the best operational conditions for optimal nano catalyst are 250 degrees C, GHSV = 2000 h(-1), H-2/CO molar ratio 1/1 under 5 bar total pressure. Catalysts and precursors were characterized by, X-ray diffraction (XRD), scanning electron microcopy (SEM), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), temperature program reduction (TPR) and N-2 adsorption-desorption measurements. (C) 2015 Elsevier Ltd. All rights reserved.