Cubic fluorite phase of samarium doped cerium oxide (CeO₂)_0.96Sm_0.04 for solid oxide fuel cell electrolyte

Nanocrystalline samarium doped cerium oxide of (CeO₂)_0.96Sm_0.04 was synthesized by using a simple and environment-friendly sol–gel method via hydrolysis process. The synthesized cubic fluorite phase of (CeO₂)_0.96Sm_0.04 solid electrolytes was confirmed by powder X-ray diffraction. Incorporation of samarium into the cerium lattice improved the redox ability of ceria. The fourier transform infrared (FT-IR) spectrum of samarium doped cerium oxide exhibits strong band below 700 cm⁻¹ which is due to the δ(Ce–O–C) mode. The observed red shift in the UV–Vis absorption spectra confirmed the promoted electron–phonon interaction in samarium doped cerium oxide solid electrolytes. Scanning electron microscopy images of (CeO₂)_0.96Sm_0.04 appeared as coral rock structure with slight agglomeration. Narrower particle distribution and the tightly packed surface morphology of the particles is a benefit for the efficient charge carrier formation. The electrochemical properties were examined by electrochemical impedance spectroscopy, cyclic voltammetry and chronoamperometry. Sm³⁺ ions involved a crucial role to decrease the ionic band between the Ce and O, which makes the oxygen flexible. Hence, (CeO₂)_0.96Sm_0.04 solid electrolytes can be a suitable material for solid oxide fuel cell device applications.