Study of Nickel Catalysts Supported on MnO_x–CeO₂ Mixed Oxides in Dry Reforming of Methane¹

Abstract—Nickel-containing (10 wt % Ni) catalysts supported on CeO₂–MnO_х oxides with different Ce/Mn ratios (0.25, 1, and 9) have been synthesized and studied in dry reforming of methane (DRM). The low-temperature N₂ sorption, XRD, and H₂-TPR methods have been used to study the effect of the Ce/Mn ratio on the phase composition of the catalysts and the size and distribution of the Ni-containing oxide precursor to determine the role of MnO_x phases and the Ce_{1 − x}Mn_xO_{2 − δ} solid solution in the formation of the active surface of the catalysts. The addition of manganese oxide contributes to the incorporation of Niⁿ⁺ cations into the surface structure to form solid solutions, which leads to a decrease in the size of NiO crystallites on the support surface. The synthesized catalysts have been studied in the DRM process in the long-run temperature testing mode for 24 h. The catalyst based on a support with a Ce/Mn weight ratio of 0.25 has exhibited the highest activity and stability in DRM (X(CH₄)/X(CO₂) = 47/70); this fact has been attributed to the existence of a developed MnO_x interface and the presence of fine Ni and MnNiO_x particles on the surface.