Cerium dioxide oxygen vacancies

Cerium oxide based catalysts have been widely studied during the last two decades. Main catalytic application was the elimination of automotive exhaust emissions (1,2). The catalytic properties of this oxide has often been related with the mobility of oxygen vacancies in the solid (3,4) and hence with its capacity to release stored oxygen under reducing conditions tests (5,6).Moreover, A.F. Ahlstrom and C.U.I. Odenbrand (7) reported the deactivation by sulphur dioxide of supported copper oxide during the oxidation of soot. 

Examine the influence of a curvature radius on the ojgrgen vacancy concentration in cerium dioxide in the presence of oxygen. The reaction is ... 

All the lanthanide elements form +3 oxides which are strongly basic. Cerium, Pr and Tb also form formally +4 oxides, but only the Ce oxide approaches 1 2 stoichiometry. The oxides of Pr and Tb are non-stoi-chiometric and approximate to the formulae Pr O, and Tb O, both showing oxygen deficiencies. The three dioxides have the fluorite (CaF,) structure with oxide ion vacancies. They are basic in character. Three of the lanthanide elements, Sm, Eu and Yt, form +2 oxides with sodium chloride structures. They are basic. 

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