First-principles Studies on Electronic Structure and Chemical Properties of Al-doped Ceria

The geometric and electronic structures of the unreduced and reduced Al-doped ceria are systematically studied using the first principle method based on the density functional theory(DFT) within generalized gradient approximation(GGA) and with the inclusion of on-site Coulomb interaction(DFT+U).The projector-augmented wave method(PAW) is applied to treat the interaction of the core electrons with the valence electrons.It is shown that Al-doping substantially reduces the reduction energies,i.e.makes the reduction easier.The mechanisms that the Al dopant lowes the reduction energies are studied in detail from atomic and electronic structure analysis.