Structural and Electrical Properties of Cerium Oxides Doped by Sb3+ and Bi3+ Cations.

The addition of low melting point trivalent ions in ceria-based electrolyte systems results in a new composite with better oxygen ion conduction at reduced temperature. The present work discusses the synthesis and characterization of co-doped ceramic electrolyte Ce_0.8Sm_0.1M_0.1O_2−δ (M = Bi, Sb) prepared by coprecipitation. This study mainly focuses on the effect of the ionic radius of the dopants on the structural and electrical properties of doped ceria. The structural studies of the samples by X-ray diffraction, field emission scanning electron microscopy and transmission electron microscopy show nanosized particles with a cubic fluorite structure. Raman spectroscopy confirmed the presence of O²⁻ vacancies introduced into the lattice due to the substitution of a large ionic radius of Bi³⁺ for Ce⁴⁺. The electrical survey by electrochemical impedance spectroscopy suggests that the dopant ionic radius has a significant influence on the ionic conductivity and activation energy of the doped ceria. There is an enhancement in conductivity noted for bismuth-co-doped samarium-doped ceria due to the larger ionic radius of the bismuth dopant compared to antimony-co-doped samarium-doped ceria. [ABSTRACT FROM AUTHOR]