Ca Doping of Nanosize Ce−Zr and Ce−Tb Solid Solutions: Structural and Electronic Effects

Abstract

Ceria-based ternary oxides are novel materials with potential use in many areas of chemistry, physics, and materials science. Synchrotron-based time-resolved X-ray diffraction (TR-XRD), X-ray absorption near-edge spectroscopy (XANES), Raman and infrared spectroscopies (RS and IR), and density-functional (DF) calculations were used to study the structural and electronic properties of Ce−M−Ca (M = Zr, Tb) oxide nanoparticles. The nanoparticles were synthesized following novel microemulsion and citrate methods and had sizes in the range of 3−6 nm. The atoms in these nanoparticles adopted a Fluorite-type structure and exhibited cell parameters with deviations with respect to the values predicted by Vegard's rule for ideal solid solutions. The simultaneous presence of Zr/Tb and Ca creates strain in the Fluorite-type lattice which correlates with the presence and number of oxygen vacancies through the Ce−M−Ca samples. The oxygen vacancy and cation distributions of the nanoparticles are strongly affected by the ...