Modeling basic components of solid oxide fuel cells using density functional theory: Bulk and surface properties of CeO2

In this paper, the structural and electronic properties of CeO₂ are studied using conventional and hybrid density functional theory. A computational protocol, based on the parameter-free hybrid functional PBE0 coupled with a 4f in-valence basis set for Ce atoms based on a 28 electrons small core pseudopotential is able to reasonably reproduce both structural and electronic experimental data. Such a protocol is then applied to the modeling of true 2-D periodic CeO₂ slabs of non polar low-index surfaces. The obtained results show that the (111) surface is more stable than the (110) one (0.73 vs 0.81 J/m²), with a substantial rumbling in the outermost planes of this latter. Finally, as a first step toward reactivity at CeO₂ surfaces involved in solid oxide fuel cells, the importance of electrostatic effects in the adsorption of chemical species such as CO is presented. These results will allow for a detailed study of catalytic reactions at ceria surface.