Background: The Fischer–Tropsch synthesis (FTS) is an industrial process using metal catalysts allows the conversion of the syngas (CO + H2) to mixture of hydrocarbons such as naphta, light olefins, alcohols, diesel and other substances. Objective: The purpose of this study was to investigate the role of key parameters of co-precipitation procedure in synthesis of unsupported Fe-Co-Ni ternary catalysts, including the ageing time; temperature and pH of the precipitation as well as their effects on the morphology, structure and catalytic performance of samples. Results: The catalyst containing a molar ratio of Fe: Co: Ni= 1:1:1 aged for 1 h, precipitated at 70 °C, pH of 9.3 performed optimally for the conversion of synthesis gas to light olefins specially ethylene and propylene in a fixed bed micro-reactor. Conclusion: Ageing time, precipitation temperature and pH were identified to be important variables influencing, the performance, morphology and structure of the precursors and calcined catalysts in CO hydrogenation via FTS.
