Surface structures of cerium oxide nanocrystalline particles from the size dependence of the lattice parameters

Cerium oxide nanocrystalline particles are synthesized and monodispersed in the size range from 2 to 8 nm in diameter. The dependence of the lattice parameters on particle size is obtained by x-ray and electron diffraction analyses. The size dependence well coincides with the estimation based on the assumption that the surface is composed of one layer of Ce₂O ₃ and the inside consists of CeO₂. The effect of particle size on lattice parameters is discussed from the differences in the fabrication method and the surface structure.