Graphene oxide (GO) prepared from graphite powder using a modified Hummers method and reduced graphene oxide (rGO) obtained from GO using different reductants, i.e., sodium borohydride, hydrazine, formaldehyde, sodium hydroxide and L-ascorbic acid, were investigated using transmission electron microscopy, X-ray diffraction, Raman, infrared and electron spectroscopic methods. The GO and rGOs’ stacking nanostructure (flake) size (height x diameter), interlayer distance, average number of layers, distance between defects, elementary composition, content of oxygen groups, C sp3 and vacancy defects were determined. Different reductants applied to GO led to modification of carbon to oxygen ratio, carbon lattice (vacancy) and C sp3 defects with various in-depth distribution of C sp3 due to oxygen group reduction proceeding as competing processes at different rates between interstitial layers and in planes. The reduction using sodium borohydride and hydrazine in contrary to other reductants results in a larger content of vacancy defects than in GO. The thinnest flakes rGO obtained using sodium borohydride reductant exhibits the largest content of vacancy, C sp3 defects and hydroxyl group accompanied by the smallest content of epoxy, carboxyl and carbonyl groups due to a mechanism of carbonyl and carboxyl group reduction to hydroxyl groups. This rGO similar diameter to GO seems to result from a predominant reduction rate between the interstitial layers. The thicker flakes of a smaller diameter than in GO are obtained in rGOs prepared using remaining reductants and result from a higher rate of reduction of in plane defects.

中文翻译：

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还原氧化石墨烯的化学和结构特性——取决于还原剂

使用改进的 Hummers 方法由石墨粉制备的氧化石墨烯 (GO) 和使用不同还原剂（即硼氢化钠、肼、甲醛、氢氧化钠和 L-抗坏血酸）从 GO 获得的还原氧化石墨烯 (rGO) 使用透射电子进行了研究。显微镜、X 射线衍射、拉曼、红外和电子光谱方法。确定了 GO 和 rGO 的堆叠纳米结构（薄片）尺寸（高度 x 直径）、层间距离、平均层数、缺陷之间的距离、元素组成、氧基团含量、C sp3 和空位缺陷。将不同的还原剂应用于 GO 导致碳氧比的改变，碳晶格（空位）和 C sp3 缺陷具有 C sp3 的各种深度分布，这是由于氧基团还原在间隙层和平面内以不同速率作为竞争过程进行的。与其他还原剂相反，使用硼氢化钠和肼进行还原会导致空位缺陷的含量高于 GO。由于羰基和羧基还原为羟基的机制，使用硼氢化钠还原剂获得的最薄的薄片 rGO 显示出最大的空位、C sp3 缺陷和羟基含量，伴随着最小含量的环氧基、羧基和羰基。这种与 GO 相似的 rGO 直径似乎是由间隙层之间的主要还原率引起的。