کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1612405 1516309 2014 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Structure and properties of cerium oxides in bulk and nanoparticulate forms
ترجمه فارسی عنوان
ساختار و خواص اکسید سریم در شکل های فله و نانوذرات
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد فلزات و آلیاژها
چکیده انگلیسی
The experimental and computational studies on the cerium oxide nanoparticles, as well as stoichiometric phases of bulk ceria are reviewed. Based on structural similarities of these phases in hexagonal aspect, electroneutral and non-polar pentalayers are identified as building blocks of type A sesquioxide structure. The idealized core/shell structure of the ceria nanoparticles is described as dioxide core covered by a single pentalayer of sesquioxide, which explains the exceptional stability of subsurface vacancies in nanoceria. The density functional theory (DFT) predictions of the lattice parameters and elastic moduli for the Ce(IV) and Ce(III) oxides at the hybrid DFT level are also presented. The calculated values for both compounds agree with available experimental data and allow predicting changes in the lattice parameter with decreasing size of the nanoparticles. The lattice parameter is calculated as equilibrium between contraction of sesquioxide structure in the core, and expansion of dioxide structure in the shell of the nanoparticle. This is consistent with available XRD data on ceria NPs obtained in mild aqueous conditions. The core/shell model, however, breaks down when applied to the size dependence of lattice parameter in NPs obtained by the laser ablation techniques.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Alloys and Compounds - Volume 584, 25 January 2014, Pages 199-208
نویسندگان
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