Modeling basic components of solid oxide fuel cells using density functional theory: Bulk and surface properties of CeO_2

摘要

In this paper, the structural and electronic properties of CeO_2 are studied using conventional and hybrid den sity functional theory. A computational protocol, based on the parameter-free hybrid functional PBEO coupled with a 4f in-valence basis set for Ce atoms based on a 28 electrons small core pseudopotential is able to rea sonably reproduce both structural and electronic experimental data. Such a protocol is then applied to the modeling of true 2-D periodic CeO_2 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/m~2), with a substantial rumbling in the outermost planes of this latter. Finally, as a first step toward reactivity at CeO_2 surfaces involved in solid oxide fuel cells, the importance of electrostatic effects in the adsorption of chemical species such as CO is pre sented. These results will allow for a detailed study of catalytic reactions at ceria surface.