膨胀石墨氧化制备石墨烯

Preparation of graphene oxide based on expanded graphite

在氧化还原法制备石墨烯的工艺中,氧化石墨的制备尤为重要。以大鳞片石墨制备的膨胀石墨为原料,采用改进的Hummers法制备氧化程度高、可剥离度高的氧化石墨稀,研究中温氧化时间、氧化剂用量及高温反应对氧化石墨烯结构、形貌及氧化程度的影响,对样品进行扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)表征。结果表明:硫酸与膨胀石墨用量比为75 mL∶1 g,高锰酸钾与石墨用量比为4 g∶1 g,35℃水浴反应24 h,制备得到氧化程度高的大片氧化石墨烯。该方法工艺简单、反应温度低,无须进行高温反应,可以解决大鳞片石墨制备氧化石墨烯难度大,氧化效率低的问题。

This paper is motivated by the recognition that the preparation of oxide graphite is vital to preparing graphene by oxidation and reduction. The paper introduces the preparation of graphene oxide with a higher oxidation degree and higher peeling degree,employing modified Hummers method and using expanded graphite prepared from larger flakes of graphite; the investigation into the effect of oxidation time,oxidant dosage and high temperature reaction on the structure and degree of oxidation of graphene oxide; and the characterization of the morphology and structure of graphene oxide by X-ray diffraction, Fourier transform infrared spectroscopy,scanning electron microscope and transmission electron microscopy. Results suggest that the preparation of large flakes of graphene oxide with a high oxidation degree and is possible with the conditions： the sulfuric acid-EG ratio of 75 mL ∶ 1 g,potassium permanganate-expanded graphite ratio of 4 g ∶ 1 g and the 35 ℃ oxidation time of 24 h. The method is accompanied by the advantages of a simpler process,lower reaction temperature,and no high-temperature reaction and thus provides an improved alternative to the greater technological difficulty and lower oxidation efficiency,produced by the preparation of graphene oxide using larger flakes of graphite.