Transformations of gold nanoparticles investigated using variable temperature high-resolution transmission electron microscopy
Transformations of gold nanoparticles investigated using variable temperature high-resolution transmission electron microscopy
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DOI：
10.1016/j.ultramic.2009.12.010
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发表时间：
2010-04-01
期刊：
影响因子：
2.2
通讯作者：
Kirkland, A. I.
中科院分区：
文献类型：
--
作者：
Young, N. P.;van Huis, M. A.;Kirkland, A. I.
最近设计的用于透射电子显微镜 (TEM) 的先进原位样品架已用于金纳米粒子的研究。我们报告了变温 TEM 实验的结果，其中结构转变与样品温度相关，从而可以识别总体趋势。对于大多数颗粒，无论其初始结构如何，都观察到尺寸范围为 5-12 nm 的颗粒向十面体形态的转变。原位退火后，发现十面体在室温下稳定，证实这是平衡形态，与最近计算的相图一致。除了表面粗糙化之外，还观察到了低温下的其他转变，并与相同的纳米级相图相关联。对高温下金颗粒的研究揭示了固相和液相共存的证据。总的来说，这些结果对于更精确地理解催化金纳米粒子的结构和作用以及理论计算的实验验证具有重要意义。 (C) 2010 Elsevier B.V. 保留所有权利。
Recently designed advanced in-situ specimen holders for transmission electron microscopy (TEM) have been used in studies of gold nanoparticles. We report results of variable temperature TEM experiments in which structural transformations have been correlated with specimen temperature, allowing general trends to be identified. Transformation to a decahedral morphology for particles in the size range 5-12 nm was observed for the majority of particles regardless of their initial structure. Following in-situ annealing, decahedra were found to be stable at room temperature, confirming this as the equilibrium morphology, in agreement with recently calculated phase diagrams. Other transitions at low temperature in addition to surface roughening have also been observed and correlated with the same nanoscale phase diagram. Investigations of gold particles at high temperature have revealed evidence for co-existing solid and liquid phases. Overall, these results are important in a more precise understanding of the structure and action of catalytic gold nanoparticles and in the experimental verification of theoretical calculations. (C) 2010 Elsevier B.V. All rights reserved.