Oxygen stoichiometry and transport properties of cerium niobate

Abstract

CeNbO 4 + 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 pO 2 from 1 bar to 0.002 bar. CeNbO 4 + δ was shown to exhibit mixed conductivity with oxygen interstitials and electron holes being the major charge carriers. The activation energies for chemical diffusion ( D chem) and surface exchange coefficient ( k chem), determined by electrical relaxation measurements, were 55.8 ± 3.7 and 198 ± 20 kJ/mol, respectively. Finally, both D chem and k chem were reduced with decreasing partial pressure of oxygen.