Separation of graphene oxide by density gradient centrifugation and study on their morphology-dependent electrochemical properties

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• 作者：Sha Li ; Fengsen Zhu ; Fanjun Meng ; Haibo Li ; Lei Wang ; Jingjing Zhao ; Qiaoli Yue ; Jifeng Liu ; Jianbo Jia
• 关键词：Graphene oxide ; Morphology-dependent properties ; Nitrogen doping ; Oxygen reduction reaction
• 刊名：Journal of Electroanalytical Chemistry
• 出版年：2013
• 出版时间：15 August, 2013
• 年：2013
• 卷：703
• 期：Complete
• 页码：135-145
• 全文大小：2371 K

文摘

Graphene oxide (GO) made from graphite oxidation by Hummer¡¯s method is a mixture of GO sheets with different size and thickness. Previous work has shown that these GO sheets have different electrophoretic properties and can be separated via capillary electrophoresis according to their surface charge (J. Zhao et al., Anal. Chem. 83 (2011) 9100-9106). Herein, the GO sheets were separated by density gradient centrifugation to achieve preparation of bulk GO materials. GO sheets were separated by their thicknesses and the as-obtained sheets were characterized for their spectroscopic, electronic and electrochemical properties. After treated by hydrazine, GO was derivatized with N element and become active toward oxygen reduction reaction. The thin layer GO sheets incorporated with more hydrazine and the atomic ratio of N/C was higher than thick layer GO sheets. This work suggested that the physicochemical properties of GO sheets were N of layer related and it is necessary to separate GO sheets to prepare suitable materials for device fabrication or catalysts use.