Shrinking of hollow Cu2O and NiO nanoparticles at high temperatures

被引：51

作者：

Nakamura, R. ^{[1
]}

Tokozakura, D. ^{[1
]}

Lee, J. -G. ^{[2
]}

Mori, H. ^{[3
]}

Nakajima, H. ^{[1
]}

机构：

[1] Osaka Univ, Inst Sci & Ind Res, Osaka 5670047, Japan

[2] Korea Inst Mat Sci, Chang Won 641010, South Korea

[3] Osaka Univ, Res Ctr Ultra High Voltage Electron Microscopy, Osaka 5670047, Japan

来源：

ACTA MATERIALIA | 2008年 / 56卷 / 18期

关键词：

Nanoparticles; Oxides; Oxidation; Reduction; Transmission electron microscopy (TEM);

D O I：

10.1016/j.actamat.2008.07.004

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The structural stability of hollow CuO and NiO nanoparticles associated with reduction and oxidation reactions at high temperatures was studied by transmission electron microscopy (TEM). Hollow Cu2O and NiO in annealing under 5.0 x 10(-5) Pa was observed to have shrunk at 473 and 623 K, respectively, where the reduction reactions from oxides to metals started. As a result of shrinking associated with reduction, hollow oxides turned into solid metal nanoparticles after annealing at higher temperatures for a long time. In addition, hollow oxides shrunk and collapsed through high-temperature oxidation. It was found that shrinking of hollow oxides during oxidation occurs at temperature where the diffusion coefficients of slower diffusing species reach around 10(-22) m(2) s(-1). Annealing at high temperatures both in a vacuum and in air leads to atomic movement that results in the annihilation of nano-holes inside hollow nanoparticles, and a consequent reduction in the extra inner-surface energy. (C) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

引用

页码：5276 / 5284

页数：9

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