An heterogeneous diffusion model was developed in order to describe the kinetics of O incorporation into nanostructured oxides. Nanodomain boundaries were assumed to be the high-diffusivity paths for O transport, whereas diffusion into the ordered domains proceeded much more slowly. The model was applied to the qualitative evaluation of O diffusion parameters from data on the wet electrochemical oxidation of nanostructured perovskite SrCo0.5Fe0.2Ta0.3O3−y samples. Using Laplace transform methods, an exact solution was found for a ramped step-wise potential; permitting fitting of the experimental data to theoretical curves (in Laplace transforms). A further model generalization was considered by introducing additional parameters for the size-distribution of domains and particles.

Oxygen Diffusion in Nanostructured Perovskites. I.L.Zhogin, A.P.Nemudry, P.V.Glyanenko, Y.M.Kamenetsky, H.J.M.Bouwmeester, Z.R.Ismagilov: Catalysis Today, 2006, 118[1-2], 151-7