Role of active metals Cu, Co, and Ni on ceria towards CO2thermo-catalytic hydrogenation

A series of CeO2supported Cu, Co, and Ni catalysts have been synthesized by the wet-impregnation method for CO2thermo-catalytic hydrogenation from 200 to 400 °C in the fixed bed reactor. All catalysts were characterized by XRD, N2-isotherms, and H2temperature-programmed reduction. XRD results have suggested that the incorporated Cu, Co, and Ni have uniformly distributed on the CeO2surface, N2-isotherm analysis confirmed that the pores of CeO2were blocked by incorporated metals and H2-TPR indicated strong interaction between active metal and CeO2. The CO2consumption rate and product selectivity depend on the type of active metal on CeO2and reaction temperature. The order of CO2consumption rate for 5 wt.% catalysts was 5Ni/CeO2> 5Co/CeO2> 5Cu/CeO2at 400 °C. The high CO2consumption rate for 5Ni/CeO2was attributed to the presence of more number of active metallic Ni during the reaction which dissociated H2molecule to H-atoms. The formed H-atoms reacted with active CO2molecule and formed CH4with 100% selectivity.