石墨烯氧化过程中官能团分布的研究

发布时间：2018-06-11 21:48

本文选题：氧化石墨烯 + 氧化位点　；参考：《扬州大学》2017年硕士论文

【摘要】：氧化石墨烯(GO)含有一系列氧官能团,如羧基、酮、环氧和羟基,使其在光电子纳米器件、催化、复合材料和药物传递中有着良好的应用。尽管在实验和理论上已经做了大量的研究,但GO的精确结构仍然未知且存争议。最近的理论研究采用DFT方法研究高锰酸盐氧化石墨烯的过程发现,GO上有大面积的氧化区域与未氧化区域共存的现象,且氧化位点有高度的相关性,这与实验观察一致[Angewandte Chemie International Edition 53,10190(2014)].。在本论文中,我们进一步研究了石墨烯的起始氧化过程,考虑了羟基、环氧、羧基和酮等氧化官能团。通过研究这些官能团及它们的混合构型,我们认为,在石墨烯氧化过程中,初始的氧化位点是随机的。然而,接下来,相较于近中心,近边缘的位点更容易被氧化。尤其是环氧和羟基,它们更容易处于靠近边缘的区域。此外,石墨烯上的氧化位点趋向于聚集在一起,有高度的相关性,但它们的聚集程度存在上限,这是因为相邻官能团的空间效应,包括单个环氧的空间吸引、单个羟基的空间排斥和混合官能团的空间位阻等效应。其中,空间位阻和排斥通过使分子形变抑制临近位点的氧化,而空间吸引使氧化位点倾向于聚集。如上所述,我们研究了石墨烯的起始氧化过程,发现近边缘的位点比近中心的位点更易被氧化。在氧化过程中官能团趋向于聚集,氧化位点有高度相关性。然而,由于官能团自身的多种空间效应,氧化位点聚集程度并非无限。
[Abstract]:Graphene oxide (GOO) contains a series of oxygen functional groups, such as carboxyl, ketone, epoxy and hydroxyl groups, which make them have good applications in photoelectron nanodevices, catalysis, composite materials and drug delivery. Although a lot of experimental and theoretical studies have been done, the exact structure of go is still unknown and controversial. The recent theoretical study on the process of studying graphene permanganate oxide by using DFT method shows that there exists a large area of oxidized and unoxidized regions coexisting in go, and the oxidation sites are highly correlated, which is consistent with the experimental observation [Angewandte Chemie International Edition 53C101902014]. In this thesis, we further studied the initial oxidation process of graphene, including hydroxyl group, epoxy group, carboxyl group and ketone group. By studying these functional groups and their mixed configurations, we consider that the initial oxidation sites are random in the process of graphene oxidation. Next, however, the near-edge sites are more likely to be oxidized than near-center sites. Epoxy and hydroxyl groups, in particular, are more likely to be near the edge. In addition, oxidation sites on graphene tend to gather together with a high degree of correlation, but there is an upper limit to their aggregation because of the spatial effects of adjacent functional groups, including the spatial attraction of individual epoxy, The spatial repulsion of a single hydroxyl group and the steric hindrance of a mixed functional group. Among them, steric hindrance and exclusion inhibit the oxidation of adjacent sites by molecular deformation, while spatial attraction makes oxidation sites tend to aggregate. As mentioned above, we have studied the initial oxidation process of graphene and found that the near edge sites are more likely to be oxidized than the near central sites. In the oxidation process, the functional groups tend to aggregate, and the oxidation sites are highly correlated. However, due to various spatial effects of functional groups themselves, the degree of oxidative site aggregation is not infinite.
【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O613.71

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