Redox chemistry of the novel fast oxide ion conductor CeNbO4 + d determined through an in-situ spectroscopic technique

CeNbO4 + δ has been shown to undergo reversible redox processes as a function of both temperature and time. However the associated phase transitions are not fully reversible and this unusual feature is reflected in spectra obtained from near edge X-ray absorption spectroscopy of the Ce LIII edge. Two materials have been studied: CeNbO4.08 and CeNbO4.25 and it is found that the oxidation and reduction rates for these two materials differ significantly and that the thermal history of the material dramatically affects the extent and rate of redox activity.