From sphere to polyhedron: A hypothesis on the formation of high-index surfaces in nanocrystals

Yan Zhou1 , Junyan Zhang1 , Gang Su2 & Jiangong Li3

1 State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China, 2 School of Physics, University of Chinese Academy of Sciences, Beijing 100049; China, 3 Institute of Materials Science and Engineering, Lanzhou University, Lanzhou 730000, China. The morphology of tetrahexahedral nanocrystals could be understood on the basis of a hypothesis that the atoms or molecules on or near spherical surfaces can migrate till reaching their equilibrium positions. Such migration of atoms/molecules is shown to be closely related to the formation of high-index surfaces in nanopolyhedrons. On account of this hypothesis, a theoretical calculation about the indices of the surfaces in tetrahexahedrons is found in good agreement with the empirical results. A group of high-index surfaces for nanocrystals that can be formed under certain environments are thus predicted. This study may provide a novel idea for preparing the catalysts at nanoscale.