Effects of molecular shapes, molecular weight, and types of edges on peak positions of C1s X-ray photoelectron spectra of graphene-related materials and model compounds
Effects of molecular shapes, molecular weight, and types of edges on peak positions of C1s X-ray photoelectron spectra of graphene-related materials and model compounds
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DOI：
10.1007/s10853-022-07599-6
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发表时间：
2022-08
影响因子：
4.5
通讯作者：
Kumiko Mori;Jungpil Kim;Shingo Kubo;Yasuhiro Yamada
中科院分区：
文献类型：
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作者：
Kumiko Mori;Jungpil Kim;Shingo Kubo;Yasuhiro Yamada
纳米碳材料如石墨烯和石墨烯纳米带（gnr）已被研究用于各种应用，如电极和催化剂。对于纳米碳材料的精确分析，除了传统使用的分析，如拉曼光谱和红外光谱和显微镜分析是必不可少的。C1s - x射线光电子能谱（XPS）是分析碳材料结构的常用技术之一。然而，XPS还没有被广泛地用于详细研究碳材料的结构。在这项工作中，揭示了分子形状、分子大小和边缘类型与C1s XPS光谱峰位置的相关性。例如，在相同H/C原子比下，gnr等矩形类石墨烯结构的C1s光谱调整峰位往往高于三角形或六角形类石墨烯结构，这主要是因为gnr的矩形结构比石墨烯相关材料的六角形和三角形结构更能增强共轭作用。此外，通过测量燃烧元素分析、质谱、C1s XPS光谱和最高占据分子轨道，并比较其H/C比和分子量随C1s XPS光谱调整峰位的变化趋势，可以在不使用显微镜的情况下估计出石墨烯相关材料的结构，如具有之字形或扶手形边缘的矩形结构、三角形结构、六边形结构等。此外，实验C1s XPS光谱发生位移和展宽的原因是由于被分析化合物的粉末尺寸较大而引起的带电效应。图形抽象
Nanocarbon materials such as graphene and graphene nanoribbons (GNRs) have been studied for various applications such as electrodes and catalysts. For precise analyses of nanocarbon materials, analyses other than conventionally used analyses such as Raman and infrared spectroscopies and microscopies are essential. C1s X-ray photoelectron spectroscopy (XPS) is one of the general techniques used to analyze the structures of carbon materials. However, XPS has not been commonly utilized to investigate the structures of carbon materials in detail. In this work, the relevance of molecular shapes, molecular sizes, and types of edges on peak positions of C1s XPS spectra were revealed. For example, adjusted peak positions of C1s spectra of rectangular graphene-like structures such as GNRs tended to be higher than those of triangle or hexagonal graphene-like structures at the same atomic ratio of H/C mainly because rectangular structures of GNRs enhanced the conjugation more than those of hexagonal and triangle structures of graphene-related materials. Besides, the structures of graphene-related materials, such as rectangular with either zigzag or armchair edges, triangle, hexagonal, and the other structures, can be estimated without using a microscope by measuring combustion elemental analysis, mass spectrometry, C1s XPS spectra, and the highest occupied molecular orbital and comparing them with the tendencies of H/C ratio and molecular weight versus adjusted peak positions of C1s XPS spectra. Moreover, the reasons for the shift and the broadening of experimental C1s XPS spectra have been revealed to be the charge-up effect caused by the large size of the powder of analyzed compounds.Graphical abstract