Oxygen stoichiometry and transport properties of cerium niobate

Abstract

CeNbO4 + δ has been synthesized by both solid state and wet chemical routes and characterized with respect to electrical conductivity and oxygen stoichiometry between 900 °C and 1100 °C and pO2 from 1 bar to 0.002 bar. CeNbO4 + δ was shown to exhibit mixed conductivity with oxygen interstitials and electron holes being the major charge carriers. The activation energies for chemical diffusion (Dchem) and surface exchange coefficient (kchem), determined by electrical relaxation measurements, were 55.8 ± 3.7 and 198 ± 20 kJ/mol, respectively. Finally, both Dchem and kchem were reduced with decreasing partial pressure of oxygen.