Morphology and Surface Analysis of Pure and Doped Cuboidal Ceria Nanoparticles
Morphology and Surface Analysis of Pure and Doped Cuboidal Ceria Nanoparticles
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DOI：
10.1021/jp405993v
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发表时间：
2013-11-21
影响因子：
3.7
通讯作者：
Moebus, Guenter
中科院分区：
文献类型：
--
作者：
Bhatta, Umananda M.;Reid, David;Moebus, Guenter
通过高分辨率成像和分析，研究了二氧化铈立方纳米颗粒的表面、边缘和角落的局部形态。在水热法合成和不掺杂Sm的情况下，我们发现与八面体{111}面相比，{100}面包围的颗粒比例很高。在高倍率下进行的电子断层扫描与晶格分辨成像结合了电子能量损失光谱，揭示了Ce离子的氧化态。研究发现，除了{111}角帽和{110}边缘上的子面外，扩展的{100}面主要存在没有局部纳米面。在所有{100}表面都发现了还原Ce，而Sm掺杂并没有降低还原Ce的浓度。分子动力学模拟用于补充显微镜，包括{110}边缘上{111}亚面的形成，{1111}角面的形成，以及还原Ce离子更喜欢台阶和角等低协调位置以及更活跃的{100}面。
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 {1 11} corner facet, and also the fact that reduced Ce ions prefer low coordinated positions like steps and corners along with more active {100} faces.