The O vacancy formation on the CeO2(110) surface was studied by ab initio electronic structure calculations. Embedded-cluster calculations with explicit treatment of the electron correlation from Møller–Plesset perturbation theory (MP2) provided an alternative description of the surface O vacancy compared to previously reported periodic density functional theory calculations. The electronic structure at the MP2 level revealed a complete localization of the excess electrons on the two surface Ce ions neighboring the vacancy, contrary to the delocalized description seen in the periodic density functional theory calculations for the CeO2(110) surface (but more in line with DFT+U results recently reported for the partially reduced CeO2 bulk and (001)-surface). The calculations predicted a vacancy formation energy of 3.1 to 3.3eV at the MP2 level; including basis-set superposition error correction, and a geometrical structure which was in qualitative agreement with the periodic density functional theory results, where the surface O ion next to the vacancy assumed a bridging position between the reduced Ce ions.

Electronic Structure of the CeO2(110) Surface Oxygen Vacancy. B.Herschend, M.Baudin, K.Hermansson: Surface Science, 2005, 599[1-3], 173-86