[EN] Graphene materials containing different functional groups were prepared from a natural graphite, by means of two different oxidation methods (Hummers and Brodie). It was observed that the differences in the structure of the resultant graphite oxides (GOs) greatly affect the structure of the graphenes resulting from their thermal exfoliation/reduction. Although the oxidation of the graphite was more effective with the modified Hummers method than with Brodie’s method (C/O of 1.8 vs 2.9, as determined by XPS), the former generated a lower residual oxygen content after thermal exfoliation/reduction and a better reconstruction of the 2D graphene structure (with fewer defects). This is explained by the presence of conjugated epoxy and hydroxyl groups in the GO obtained by Brodie’s method, which upon thermal treatment, lead to the incorporation of oxygen into the carbon lattice preventing its complete restoration. Additionally, graphene materials obtained with Brodie’s method exhibit, in general, smaller sheet size and larger surface area.
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机译:[EN]通过两种不同的氧化方法(悍马(Hummers)和布罗迪(Brodie)),由天然石墨制备含有不同官能团的石墨烯材料。观察到,所得石墨氧化物(GOs)的结构差异极大地影响了由石墨烯的热剥落/还原导致的石墨烯的结构。尽管改良的Hummers方法比Brodie方法更有效地氧化石墨(CPS为1.8 vs 2.9,由XPS确定),但前者在热剥离/还原后产生的残余氧含量较低,并且重建效果更好2D石墨烯结构的数量(缺陷较少)。通过Brodie方法获得的GO中存在共轭环氧基和羟基,可以解释这一点,热处理后会导致氧掺入碳晶格中,从而阻止其完全还原。另外,用布罗迪(Brodie)方法获得的石墨烯材料通常具有较小的薄片尺寸和较大的表面积。
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