Compositional and valent state inhomogeneities and ordering of oxygen vacancies in terbium-doped ceria

Intragranular distributions of composition and valent state in sintered Tb-doped ceria have been systematically investigated. Through detailed studies of electron energy loss spectroscopy and energy filtering transmission electron microscopy, both compositional and valent state inhomogeneities of Ce and Tb were confirmed, which are related to the existence of nanosized domains in Tb-doped ceria. Compared with their matrix, the domains have higher Tb concentration and Ce and Tb cations in the domains tend to be trivalent. Furthermore, ordering of oxygen vacancies in the domains, which increases with increasing doping concentration, has been determined by EELS.