超声辅助液相剥离制备石墨烯及其应用研究

发布时间：2018-04-06 01:35

本文选题：石墨烯　切入点：超声　出处：《合肥工业大学》2017年硕士论文

【摘要】：石墨烯作为高导热、高导电、高比表面积的二维材料,在物理、化学等诸多领域具有重要应用价值。目前高品质石墨烯的低成本宏量制备,仍是阻碍下游产业化应用的关键瓶颈。液相剥离石墨制备石墨烯具有工艺简单、成本低、易于放大等特点,是当前规模化制备领域研究的热点。本论文运用超声辅助液相剥离的方法,主要探讨了不同石墨原料和液相体系对石墨烯制备的影响。主要分为有机体系和水相体系两种方法制备石墨烯,其中有机体系选用不同预处理石墨在聚咔唑的甲苯溶液中超声剥离制备石墨烯,并将优选的石墨烯用于环氧树脂基复合材料的抗静电研究;水相体系主要探究了四种原料石墨经三氧化铬插层和化学膨胀后对石墨烯品质和产率的影响,并优选了两种石墨烯用作超级电容器电极材料进行电化学性能表征。主要研究结果如下:有机体系制备石墨烯的实验中,过硫酸钠和浓硫酸自剥离处理的热膨胀石墨(TEG)引入了较高的氧化缺陷且剥离效果不如TEG直接作为前驱体制备的石墨烯。以TEG为前驱体超声输出能量为10 Wh/mL时,制备的石墨烯浓度约25.58μg/mL,且制备的少层单晶石墨烯片径大小约2μm,厚度3 nm左右。溶液法制备的石墨烯/环氧树脂复合材料,当石墨烯的质量分数为0.5%时,复合材料的表面电阻率为9.17×106Ω/□,并表现出渗流行为。水相体系制备石墨烯的实验中,天然鳞片石墨(NFG)、阿拉丁石墨粉A(GP-A)和阿拉丁石墨粉B(GP-B)三种原料石墨经三氧化铬插层可以形成三阶的三氧化铬-石墨插层化合物(CrO3-GIC),而TEG没有明显的三阶CrO3-GIC特征衍射峰。四组化学膨胀石墨(CEG)在脱氧胆酸钠(NaDC)的水溶液中经超声剥离、离心分层后,均能得到低缺陷的寡层石墨烯(FLG),其中FLG(NFG)和FLG(TEG)的片径明显大于FLG(GP-A)和FLG(GP-B)。GP-A和GP-B为原料制备的石墨烯产率分别为20.7%和12.3%,在NaDC/水溶液中的分散浓度分别高达0.26 mg/m L和0.15 mg/m L,且静置两个月仍无明显沉降。其中FLG(GP-A)经统计分析厚度小于3 nm的高达78%,片径大小在1~6μm之间的约占74%。FLG(GP-A)和FLG(GP-B)分散液抽滤、洗涤制备的石墨烯纸电导率分别为0.96×104 S/m和1.72×104 S/m,三电极测试电化学性能表现出较好的双电层电容特性。
[Abstract]:Graphene, as a two-dimensional material with high thermal conductivity, high conductivity and high specific surface area, has important application value in many fields such as physics, chemistry and so on.At present, the low cost macropreparation of high-quality graphene is still the key bottleneck of downstream industrial application.The preparation of graphene by liquid phase stripping graphite has the advantages of simple process, low cost and easy amplification, so it is a hot spot in the field of large-scale preparation.In this paper, ultrasonic assisted liquid stripping was used to investigate the effects of different graphite raw materials and liquid systems on the preparation of graphene.Graphene was prepared by two methods: organic system and aqueous system, in which graphene was prepared by ultrasonic stripping of different pretreatment graphite in polycarbazole toluene solution.The selective graphene was used in the antistatic study of epoxy resin matrix composites, and the effects of four kinds of raw materials graphite on the quality and yield of graphene were studied in aqueous phase system after the graphite was intercalated with chromium trioxide and chemically expanded.Two kinds of graphene were selected as electrode materials of supercapacitor to characterize their electrochemical properties.The main results are as follows: in the experiment of preparing graphene by organic system, the thermal expanded graphite (Teg) treated by sodium persulfate and concentrated sulfuric acid self-stripping introduced higher oxidation defects and the exfoliation effect was not as good as the graphene prepared by TEG as precursor directly.When the ultrasonic output energy of TEG was 10 Wh/mL, the concentration of graphene was 25.58 渭 g / mL, and the diameter of graphene sheet was about 2 渭 m and the thickness of graphene was about 3 nm.The surface resistivity of graphene / epoxy resin composites prepared by solution method is 9.17 脳 10 ~ 6 惟 / -when the mass fraction of graphene is 0.5 and shows percolation behavior.Preparation of graphene from aqueous phase system,Natural flake graphite (NFG), Aladdin graphite (Agna GP-A) and Aladdin graphite (BGP-B) can be intercalated with chromium trioxide to form a third-order Cr _ 2O _ 3-graphite intercalation compound, while TEG has no obvious third-order CrO3-GIC characteristic diffraction peak.Four groups of chemically expanded graphite (CEG) in aqueous solution of sodium deoxycholate (NaDC) were separated by ultrasonic and centrifuged and stratified.All of the oligosacene flags with low defects were obtained, in which the diameters of FLGG (NFG) and FLGG (TEG) were significantly larger than those of FLGG GP-A) and the yields of graphene prepared by FLG(GP-B).GP-A and GP-B were 20.7% and 12.3%, respectively. The dispersion concentrations in aqueous NaDC/ solution were as high as 0.26 mg/m L and 0.15 mg/m L, respectively.There was no significant settlement for two months.Among them, FLGG GP-A (less than 3 nm in thickness) was 78.The diameter of the film was between 1 渭 m and 6 渭 m, and about 74.FLGG GP-A) and FLGGGP-B) dispersions were filtrated.The conductivity of graphene paper prepared by washing is 0.96 脳 104s / m and 1.72 脳 104s / m, respectively.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ127.11

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