Praseodymium Doped Ceria: The Role of 4f-Electrons of Pr Dopant in Doped Ceria

Oxides like ceria (CeO₂) are very promising for solid electrolyte materials when doped by suitable aliovalent dopants, as they introduce high oxygen ion conduction leading to intermediate to low temperature operations (T ≤ 800°C ). Over the past decades, engineering new compositions aiming at high ionic conductivity at lower operating temperatures has been a key issue of developing solid oxide fuel cells. However, the understanding over the underlying physics on the oxygen ion conduction in this system remain unclear. In this study, we discuss DFT+U study on the effect of the 4f-electrons on Pr-doped CeO₂. We found that, regardless of their localized nature tendency, we found significant contributions from the Pr-dopant 4f-electrons to the oxygen vacancy formation energy as well as the preferential site of the oxygen vacancy formation in comparison with the model of fully localized 4f-electrons, though the geometrical properties for each local minimum structure remain unaffected.