In situ preparation and determination of CeO2 high-index surface atomic structures

Understanding the properties regarding the high-index surfaces of the oxide nanocrystals is of great importance, but it remains challenging to obtain atomic-level information due to the lack of efficient preparation methods for high-index surfaces. Herein, we presented a work to in situ prepare and determine the intrinsic atomic structures of nanocrystalline CeO2 high-index surfaces via in situ spherical aberration (Cs)-corrected scanning transmission electron microscopy (STEM). By utilizing a reshaping process driven by the Wulff reconstruction, high-index surfaces of CeO2 nanocrystals including {210} {311}, and {533} were successfully prepared. Combined STEM with the density functional theory calculations, these high-index surface structures were determined with atomic precision, and interestingly {533} exhibited a unique atomic pit feature with low-coordinated Ce atoms exposure and unique electrical properties. This work has revealed new information about CeO2 high-index surfaces through experiments, enhancing our understanding of these surfaces, and also providing a new route for preparing high-index surfaces.