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Morphology and Surface Analysis of Pure and Doped Cuboidal Ceria Nanoparticles

Year: 2013

Type: article

Abstract: Cuboidal nanoparticles of ceria are examined by high resolution imaging and analysis to explore their local morphology of faces, edges, and corners. Synthesized with and without Sm doping using a hydrothermal process, we find a high fraction of particles enclosed by {100} facets, which are normally energy-penalized compared to octahedral {111} facets. Electron tomography conducted at high magnification with lattice resolved imaging is combined with electron energy loss spectroscopy revealing oxidation states of Ce ions. It is found that extended {100} faces exist predominantly without local nanofaceting, except for {111} corner caps and subfacets on {110} edges. Reduced Ce is found on all {100} surfaces, while Sm doping does not lower the reduced Ce concentration. Molecular dynamics simulations are used to complement the microscopy, including the formation of {111} subfacets on {110} edges, formation of a {111} corner facet, and also the fact that reduced Ce ions prefer low coordinated positions like steps and corners along with more active {100} faces.

Source: The Journal of Physical Chemistry C

DOI: 10.1021/jp405993v