Density functional methods were used to study the environmental dependence of O vacancy formation in CeO2. It was found that an O vacancy in the 2+ charged state has the lowest formation energy for a wide range of Fermi energies (EF) from 0 to ∼1.9 eV, while a neutral vacancy becomes the most stable at higher EF values. The O vacancy formation energy can be strongly affected by temperature (T) and the partial pressure of oxygen (P O2). The effect of T and P O2 on the equilibrium compositions of reduced ceria (CeO2-x) was also calculated and showed qualitative agreement with gravimetric experiments.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)