Temperature driven structural transitions in the graphitic-arrangement of carbon onions filled with FePd3 nano crystals
Temperature driven structural transitions in the graphitic-arrangement of carbon onions filled with FePd3 nano crystals
复制标题
填充 FePd3 纳米晶体的碳洋葱石墨排列中温度驱动的结构转变
DOI：
10.1016/j.carbon.2017.05.070
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发表时间：
2017-08-01
期刊：
影响因子：
10.9
通讯作者：
Zhang, Xiaotian
中科院分区：
文献类型：
--
作者：
Boi, Filippo S.;Ivaturi, Sameera;Zhang, Xiaotian
碳纳米洋葱（hocs）是一种富勒烯类结构，近年来在磁性数据记录、能量存储、生物医学等方面有着广泛的应用。在这项工作中，我们报告的观察新的温度驱动的结构转变，在近似球形hocs结构填充FePd 3纳米晶体通过温度依赖的X射线衍射分析。Rietveld精修方法被用来证明在25 ℃-400 ℃的温度范围内，hocs层之间的002晶面间距从大约0.35 nm的值增加到0.50 nm的值，从而导致石墨晶胞参数的畸变。这些观察结果也证实了额外的高分辨率透射电子显微镜和粒度分析，允许估计参与温度驱动的结构转变的HOCS层的数量。具体来说，我们发现，这种不寻常的效果是目前只为FePd 3填充hocs的情况下，但没有结构转变的情况下，发现其他类型的hocs填充Fe 3C在类似的实验条件下测量。(C)2017爱思唯尔有限公司版权所有
Carbon nano-onions (CNOs) are fullerene-like structures which have recently attracted a great attention for numerous applications, such as magnetic data recording, energy storage, biomedicine and others. In this work we report the observation of novel temperature-driven structural transitions in approximately spherical CNOs structures filled with FePd3 nano crystals through temperature dependent X-ray diffraction analyses. The Rietveld refinement method is used to demonstrate the presence of an anomalous temperature-driven increase of the 002 interplanar distance between CNOs layers from the value of approximately 0.35 nm to the value of 0.50 nm with a consequent distortion of the graphite unit-cell parameters in the temperature range of 25 degrees C-400 degrees C. These observations are confirmed also by additional high resolution transmission electron microscopy and grain-size analyses which allow to estimate the number of CNOs layers involved in the temperature driven structural transition. Specifically we find that such unusual effect is present only for the case of FePd3 filled CNOs, however no structural-transition is found for the case of other types of CNOs filled with Fe3C measured in similar experimental conditions. (C) 2017 Elsevier Ltd. All rights reserved.