Structural, morphological and electrical properties of Ce<inf>1−x</inf>Ru<inf>x</inf>O<inf>2−</inf><inf>δ</inf> (x=0.005–0.02) solid solutions

Abstract

Nanoparticles of ceria–ruthenium oxide solid solutions with composition Ce1−xRuxO2−δ (x=0.005–0.02) were successfully produced by self–propagating room temperature synthesis using reaction between metal nitrates and sodium hydroxide. These compositions were characterized by X–ray powder diffraction (XRD), Raman spectroscopy, specific surface area, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X–ray spectroscopy (EDX). The experimental measurements were complemented by calculations based on the ion–packing model. XRD analysis revealed the presence of single–phase solid solutions with CeO2 fluorite structure (regardless of dopants concentration) and Raman spectroscopy confirmed the presence of the RuO2 phase. Electrochemical impedance spectroscopy (EIS) measurements of sintered samples at different temperatures showed that the small ionic radius dopant reduces oxygen vacancies mobility that is responsible for the conductivity of these ceramics.