CeNixOy and CeAlzNixOy solids studied by electron microscopy, XRD, XPS and depth sputtering techniques

Abstract

Mixed oxides based on nickel, cerium and aluminum, effective in the catalytic hydrogenation of unsaturated compounds, were prepared by a coprecipitation route and studied by XRD, TEM, XPS and ion sputtering techniques. The CeNi_xO_y mixed oxides (0⩽x⩽1) can be described as a mixture of nickel oxide and ceria modified by the insertion of nickel cations in its lattice. Ion sputtering followed by XPS analysis has been very useful for estimating the size of NiO clusters present in the compounds, too small to be detected by XRD and TEM. Among the different CeNi_xO_y catalysts studied, the CeNi_0.5O_y solid presents the highest number of interactions between Ce⁴⁺ cations and Ni²⁺ cations, located either in the solid solution of cerium–nickel and/or at the NiO/CeO₂ interface. In the CeAl_zNi_xO_y series (0<x⩽5 and 0⩽z⩽1), the addition of aluminum leads to a disorganization of the previous structure with favored interactions between Al³⁺ cations and Ni²⁺ cations.