Direct observation of oxygen configuration on individual graphene oxide sheets
Direct observation of oxygen configuration on individual graphene oxide sheets
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DOI：
10.1016/j.carbon.2017.10.100
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发表时间：
2018-02-01
期刊：
影响因子：
10.9
通讯作者：
Hassenkam, Tue
中科院分区：
文献类型：
--
作者：
Liu, Zilong;Norgaard, Kasper;Hassenkam, Tue
氧化石墨烯（GO）是一种具有广泛应用潜力的有趣材料。这些应用的关键是氧键的类型及其在各个GO片上的空间分布。这种分布还没有得到很好的理解。很少有技术能够提供足够高的分辨率来明确识别氧的构型。我们使用了一种新的无标记光谱技术来映射GO上的氧键合，具有纳米的空间分辨率和高化学特异性。AFM-IR，原子力显微镜与红外光谱相结合，克服了传统的红外衍射限制，从特定点产生红外光谱以及与地形相结合的化学图。我们已经直接观察到氧键合优先在石墨烯折叠的区域上、在离散域中和在GO的边缘上。根据这些观察，我们提出了一个更新的结构模型GO，其边缘和平面上的C=O，这证实了早期提出的模型的一部分。这些结果有着有趣的含义。通过精确成像确定原子的位置和构型，可以将纳米级结构和组成与材料功能联系起来，为离子、聚合物和生物材料的靶向束缚铺平道路。(C)2017爱思唯尔有限公司版权所有
Graphene oxide (GO) is an interesting material that has the potential for a wide range of applications. Critical for these applications are the type of oxygen bond and its spatial distribution on the individual GO sheets. This distribution is not yet well understood. Few techniques offer a resolution high enough to unambiguously identify oxygen configuration. We used a new, label free spectroscopic technique to map oxygen bonding on GO, with spatial resolution of nanometres and high chemical specificity. AFM-IR, atomic force microscopy coupled with infrared spectroscopy, overcomes conventional IR diffraction limits, producing IR spectra from specific points as well as chemical maps that are coupled to topography. We have directly observed oxygen bonding preferentially on areas where graphene is folded, in discrete domains and on edges of GO. From these observations, we propose an updated structural model for GO, with C=O on its edge and plane, which confirms parts of earlier proposed models. The results have interesting implications. Determining atomic position and configuration from precise imaging offers the possibility to link nanoscale structure and composition with material function, paving the way for targeted tethering of ions, polymers and biomaterials. (C) 2017 Elsevier Ltd. All rights reserved.