Abstract: Three catalysts, NiO-MgO, NiO-La2O3-MgO and NiO-CeO2-MgO containing 10％(w) Ni were prepared by the co-precipitation method. The effects of La2O3 and CeO2 on physico-chemical properties and catalytic performance of NiO-MgO catalysts were studied by means of BET, XRD, TPR, XPS, TG and reaction activity evaluation. It was found that NiO formed a nickel-magnesia solid solution with MgO, and La2O3 and CeO2 promoters improved the resistance to sintering of the nickel-magnesia solid solution, which was attributed to the higher specific surface area and smaller size of crystallites of the Nickel-magnesia solid solution. Besides, La2O3 and CeO2 could promote reduction of nickel species in nickel-magnesia solid solution, especially CeO2. Under reaction conditions of CH4/CO2=1(molar ratio), 0.1 MPa, 1023 K and 1073 K, 18 L•g-1•h-1, NiO-La2O3-MgO and NiO-CeO2-MgO showed higher activity than NiO-MgO. However, the three catalysts had similar activity at 1123 K because the reaction was close to the thermodynamic equilibrium under these reaction conditions. La2O3 and CeO2 act as a structural promoter and an electronic promoter respectively to improve the properties of NiO-MgO.

Key words: Methane reforming with carbon dioxide, Nickel-magnesian solid solution