Formation of the Ni–CrOx/MgO and Ni/MgO Catalysts for Carbon Dioxide Reforming of Methane

Temperature-programmed reduction by hydrogen, temperature-programmed desorption of O2, local X-ray spectral analysis, and scanning electron microscopy are used to study redox processes occurring on the Ni–Cr2O3/MgO and Ni/MgO catalysts for carbon dioxide reforming of methane. The reduction of Ni/MgO leads to the formation of nickel clusters distributed over the surface of MgO. During the reduction of NiO–Cr2O3/MgO, chromates are transformed into chromites, and then nickel is formed by the reduction of spinel NiCr2O4. Reoxidation leads to the oxidized structures NiO, NiCr2O4, and NiCrO4.