Theoretical study of environmental dependence of oxygen vacancy formation in CeO2 -: art. no. 141917

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 (E-F) from 0 to similar to 1.9 eV, while a neutral vacancy becomes the most stable at higher E-F 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. (C) 2005 American Institute of Physics.