Formation of the Ni-CrOx/MgO and Ni/MgO catalysts for carbon dioxide reforming of methane

Temperature-programmed reduction by hydrogen, temperature-programmed desorp tion Of O-2, local X-ray spectral analysis, and scanning electron microscop y are used to study redox processes occurring on the Ni-Cr2O3/MgO and Ni/Mg O catalysts for carbon dioxide reforming of methane. The reduction of Ni/Mg O 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. R eoxidation leads to the oxidized structures NiO, NiCr2O4, and NiCrO4.