Kinetic lattice Monte Carlo model was developed for investigating oxygen vacancy diffusion in praseodymium-doped ceria. The current approach uses a database of activation energies for oxygen vacancy migration, calculated using first-principles, for various migration pathways in praseodymium-doped ceria. Since the first-principles calculations revealed significant vacancy-vacancy repulsion, an investigation was made of the importance of that effect by conducting simulations with and without a repulsive interaction. Initially, as dopant concentrations increase, vacancy concentration and thus conductivity increased. However, at higher concentrations, vacancies interfere and repel one another, and dopants trap vacancies, creating a traffic jam that decreased conductivity, which was consistent with the experimental findings. The modeled effective activation energy for vacancy migration slightly increased with increasing dopant concentration in qualitative agreement with the experiment. The current methodology comprising a blend of first-principle calculations and kinetic lattice Monte Carlo model provided a very powerful fundamental tool for predicting the optimal dopant concentration in ceria related materials.

Kinetic Lattice Monte Carlo Model for Oxygen Vacancy Diffusion in Praseodymium Doped Ceria: Applications to Materials Design. P.P.Dholabhai, S.Anwar, J.B.Adams, P.Crozier, R.Sharma: Journal of Solid State Chemistry, 2011, 184[4], 811-7