Morphology and Surface Analysis of Pure and Doped Cuboidal Ceria Nanoparticles

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• 作者：Umananda M. Bhatta ; David Reid ; Tamilselvan Sakthivel ; Thi X. T. Sayle ; Dean Sayle ; Marco Molinari ; Stephen C. Parker ; Ian M. Ross ; Sudipta Seal ; G眉nter M枚bus
• 刊名：Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：November 21, 2013
• 年：2013
• 卷：117
• 期：46
• 页码：24561-24569
• 全文大小：643K
• 年卷期：v.117,no.46(November 21, 2013)
• ISSN：1932-7455

文摘

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.