The kinetics of O removal from CeO2 were investigated by using thermogravimetric analysis, at high temperatures, under a reducing atmosphere of Ar–6%H2. A chemical diffusivity model was developed that took account of the compositional dependence of both the pre-exponential factor and the activation energy. According to this model, the diffusivity could be described by:

D (cm2/s) = 22.32exp[-0.22x] exp[-(194.5-173.9x)(kJ/mol)/RT]

where x was the non-stoichiometry of CeO2–x. The model well described the O removal kinetics over the entire time range (100min). This demonstrated its superiority to 2 other models that could fit only part of the experimental data.

Kinetics of Oxygen Removal from Ceria. M.Stan, Y.T.Zhu, H.Jiang, D.P.Butt: Journal of Applied Physics, 2004, 95[7], 3358-61