Oxygen adatoms and vacancies on the (110) surface of CeO2

The behavior of oxygen on ceria surfaces is closely related with the applications of ceria as a catalyst and oxygen conductor in solid-oxide fuel cells. Here, the atomic configurations of oxygen adatoms and vacancies on the (110) surface of CeO2 have been studied combining aberration-corrected transmission electron microscopy and first-principles calculations. The oxygen adatoms were estimated to be located on top of Ce atoms with 50% coverage, forming a c(2x2) reconstruction. The oxygen vacancies can form stable configuration, with the Ce atoms partly reduced.