Three-Dimensional Structure of CeO2 Nanocrystals

Visualization of three-dimensional (3D) structures of materials at the nanometer scale can shed important information on the performance of their applications and provide insight into the growth mechanism of shape-controlled nanomaterials. In this paper, the 3D structures and growth pathway of CeO2 nanocrystals prepared by the hydrothermal method were investigated by electron tomography and high-resolution transmission electron microscopy (HRTEM). Two typical shapes (regular truncated octahedrons and irregular compressed truncated octahedron with {111} and {001} as the major facets) were identified in samples synthesized under different conditions. The homogeneous growth environment in solution with polyvinylpyrrolidone (PVP) molecules led to the formation of regular octahedral CeO2 nanocrystals with small {001} facet truncations. When the PVP surfactant was removed, the aggregation of regular truncated octahedral CeO2 particles through a lattice matched interface generated irregular compressed truncated ...