Enhanced CO2 methanation activity over Ni/CeO2 catalyst by one-pot method

Carbon dioxide hydrogenation for value-added chemicals has been regarded as a promising way for CO2 utilization. This paper describes the preparation of Ni/CeO2 catalysts derived from Ce-MOF precursor by impregnation or one-pot method and their application in carbon dioxide methanation. Various techniques were employed to characterize the prepared catalysts, including N2 adsorption–desorption, X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (SEM), H2-temperature programmed reduction (H2-TPR), H2-temperature programmed desorption (H2-TPD) and CO2-temperature programmed desorption (CO2-TPD). The results showed that compared with commercial CeO2 and CeO2 prepared by precipitation, CeO2 derived from Ce-MOF exhibited more oxygen vacancies and lower temperature reducibility, making it more beneficial for the adsorption and activation of CO2. Consequently, nickel supported on rod-shaped CeO2 derived from Ce-MOF exhibited higher CO2 conversion and methane selectivity at low temperatures. Furthermore, the Ni/CeO2−M-1 catalysts prepared by one-pot method showed superior activity since nickel could be partially incorporated into ceria lattice, leading to the formation of Ce1-xNixO2-y solid solutions and oxygen vacancies. The effect of nickel loading on the properties of the catalysts by one-pot method was also investigated, and the optimum Ni loading was 15 wt.% owing to the maximum number of oxygen vacancies being reached.