Electronic Structures and Oxygen Ion Migration Energies of Metal Doped CeO2Systems：A DFT+U Study

Doping energies of Ca, Ba, Sm and Zr in CeO2 systems and influences of dopings on oxygen ion migration ener- gies and vacancy formation energies were studied using DFT and DFT+U methods. The calculated results showed that the doping energies increased with doping cation radius for doped CeO2 systems without oxygen vacancies, and for doped CeO2 systems with oxygen vacancies, the doping energies were related to the valence of the doping cations besides their radius. Calculations on electronic structures of various doped CeO2 systems showed that Fermi level shifted to the high energy in reduced CeO2, Zr- and Sm-doped CeO2 systems, however, in Ca- and Ba-doped CeO2 systems, negative charges due to the substitution of Ca 2 +