Nickel Supported on Alkaline Earth Metal-Doped γ-Al2O3-La2O3 as Catalysts for Dry Reforming of Methane

Nickel catalysts supported on gamma-Al2O3 doped with La2O3 and alkaline earth oxides (MgO, CaO, and SrO) were investigated in the dry reforming of methane. The samples were prepared with wet impregnation method and characterized by BET surface area, X-ray diffraction (XRD), and scanning electron microscopy (SEM) techniques. The results showed that addition of these dopants decrease the specific surface area (S-BET) of oxides and/or catalysts. XRD results revealed the presence of different phases of Al2O3, as well as La(OH)(3), La2O2CO3, MgO, CaCO3 and SrCO3. The addition of alkaline earth promoters (MgO, CaO, and SrO) increased the catalytic activity and stability of the catalysts. The Ni/SrLaAl catalyst presented the best activity and stability, which is explained by the strong basicity of strontium. SEM analysis after reaction indicates formation of carbon over the spent catalyst and that addition of strontium stabilized the surface of the catalyst by homogeneous dispersion of the particles.