Imaging of surface oxygen atoms and their defect structures on CeO2(1 1 1) by noncontact atomic force microscopy

Atomic-scale structures of CeO2(1 1 1) were examined by noncontact atomic force microscopy (NC-AFM). Hexagonally arranged surface oxygen atoms at an ideally oxygen-terminated surface, oxygen point vacancies, and multiple oxygen vacancies such as triangular defects and line defects formed depending on different oxidation states of CeO2−x were visualized by NC-AFM. These observations give a new insight to understand the special oxygen storage capacity with facile oxidation–reduction cycles for CeO2−x relevant to automotive exhaust catalysis.