Structural and electronic properties of NM-doped ceria (NM = Pt, Rh): a first-principles study

The effects of noble metal (NM) dopants (NM = Pt, Rh) on the structural and electronic properties of ceria are studied using a density functional theory (DFT) method, with the inclusion of on-site Coulomb interaction (DFT + U). It is found that these NM dopants give rise to large perturbations of the atomic and electronic structures of ceria and induce metal-induced gap states at the Fermi level suitable for accommodating extra electrons, thereby lowering the reduction energy of ceria and making the NM-doped cerias more reducible than pure ceria. This mechanism for facilitating the reduction of ceria is different from that of Zr-doped ceria where the increased reducibility is largely due to the structural distortions and not to electronic modifications.