Abstract High-oxidation-degree graphene oxide particles were synthesized using a modified Hummers' method. Six different types of particles were synthesized by varying the operating conditions, including the temperature, the reactant ratios, and the oxidation time. The oxidation degree, represented by the oxygen content, and the atomic oxygen/carbon (O/C) ratio were determined using CHNSO elemental analysis, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy-universal attenuated total reflectance sensor (FTIR-UATR) and Raman spectroscopy. The structural morphology of graphene oxide was evaluated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The thermal stability of the particles was studied using thermogravimetric analysis (TGA). The SEM images showed that the prepared GO samples had different graphitic layer structures. The TEM images showed different stacking levels and transparency of GO flakes caused by the difference in oxidation level. The oxygen content and O/C ratios ranged between 34.7 and 50.0 wt% and 0.43 and 0.8, respectively. The highest oxygen content and O/C ratio were found to be 50 wt% and 0.8, respectively, for GO prepared at 95 °C with a 1-hr reaction time (GO2-a). A quantitative analysis on the FTIR-UATR spectra was performed and was in reasonable agreement with the CHNSO analysis results. The Raman spectra showed two characteristic bands (D and G) with different relative intensities, as characterized by the ID/IG ratio, suggesting that the prepared samples had different crystallite sizes and defects. The crystallite size (La) of the prepared GO particles was estimated using the Tuinstra-Koenig model and were ranging between 9 and 24 nm. The TGA results were correlated with the elemental analysis results and showed a clear dependence of the weight loss on the GO elemental compositions. GO2-a exhibited the lowest thermal stability because of a high oxygen content, whereas GO1-b exhibited the highest thermal stability.

中文翻译：

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使用改进的 Hummers 方法合成高氧化度氧化石墨烯颗粒

摘要 采用改进的 Hummers 方法合成了高氧化度氧化石墨烯颗粒。通过改变操作条件，包括温度、反应物比率和氧化时间，合成了六种不同类型的颗粒。使用 CHNSO 元素分析、X 射线光电子能谱 (XPS)、傅里叶变换红外光谱 - 通用衰减全反射传感器 (FTIR) 测定以氧含量表示的氧化度和原子氧/碳 (O/C) 比-UATR) 和拉曼光谱。使用扫描电子显微镜 (SEM) 和透射电子显微镜 (TEM) 评估氧化石墨烯的结构形态。使用热重分析（TGA）研究颗粒的热稳定性。SEM 图像显示制备的 GO 样品具有不同的石墨层结构。TEM 图像显示氧化水平的差异导致 GO 薄片的不同堆积水平和透明度。氧含量和 O/C 比分别在 34.7 和 50.0 重量％和 0.43 和 0.8 之间。对于在 95°C 和 1 小时反应时间 (GO2-a) 下制备的 GO，发现最高的氧含量和 O/C 比分别为 50 wt% 和 0.8。对 FTIR-UATR 光谱进行了定量分析，结果与 CHNSO 分析结果一致。拉曼光谱显示两个具有不同相对强度的特征带（D 和 G），以 ID/IG 比为特征，表明制备的样品具有不同的微晶尺寸和缺陷。使用 Tuinstra-Koenig 模型估计所制备的 GO 颗粒的微晶尺寸 (La)，其范围在 9 到 24 nm 之间。TGA 结果与元素分析结果相关，并显示出重量损失对 GO 元素组成的明显依赖性。由于氧含量高，GO2-a 表现出最低的热稳定性，而 GO1-b 表现出最高的热稳定性。