Potassium (1–5 wt.%)-promoted and unpromoted Co/SiO2 catalysts were prepared by impregnation method and characterized by nitrogen physisorption, temperature-programmed reduction (TPR), CO2 temperature-programmed desorption (TPD), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. They were evaluated for CO2 hydrogenation in a fixed bed reactor from 180 to 300 °C within a pressure range of 1–20 bar. The yield for hydrocarbon products other than methane (C2+) was found

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... to increase with an increase in the operating temperature and went through a maximum of approximately 270 °C. It did not show any significant dependency on the operating pressure and decreased at potassium loadings beyond 1 wt.%. Potassium was found to enhance the catalyst ability to adsorb CO2, but limited the reduction of cobalt species during the activation process. The improved CO2 adsorption resulted in a decrease in surface H/C ratio, the latter of which enhanced the formation of C2+ hydrocarbons. The highest C2+ yield was obtained on the catalyst promoted with 1 wt.% of potassium and operated at an optimal temperature of 270 °C and a pressure of 1 bar.