共查询到17条相似文献,搜索用时 78 毫秒
1.
2.
采用高速剪切机液相剥离法, 在胆酸钠的水溶液中将鳞片石墨剥离, 离心得到石墨烯分散液。AFM、TEM、Raman表征结果发现, 剥离出的石墨烯厚度小于4层, 尺寸大约在2~3 μm, 高质量缺陷少(ID/IG≈0.15)。将石墨烯分散液冷冻干燥后与银粉共同添加到硅橡胶中, 制备出导热硅橡胶。利用稳态热流法测试导热硅橡胶的导热系数发现, 当添加3vol%石墨烯时, 复合材料的导热系数由未添加石墨烯时的4.900 W/(m·K)提高到12.367 W/(m·K)。综上所述, 通过液相剥离法成功制备出缺陷较少的少层石墨烯, 能够与银粉协同提高导热硅橡胶的导热系数。 相似文献
3.
4.
5.
6.
作为近年来的材料"明星"石墨烯,其制备方法的研究大多集中在化学方向,然而其许多本征物性的发现却来自于微机械剥离法制备的石墨烯。本文全面介绍了各类机械法诸如胶带法,"纳米铅笔"法,超薄切片法,超声波法,行星式球磨法,搅拌球磨法,低能纯剪切磨法和三辊磨剥法制备石墨烯的研究进展,评述了以上制备方法的特点及其面临的问题,并展望了机械法制备石墨烯的未来发展前景。 相似文献
7.
探索了N,N-二甲基甲酰胺和正丁醇、N,N-二甲基甲酰胺和乙醇两种二元体系剥离制备石墨烯的效果,得到了最佳剥离配比,提高了石墨烯分散液的浓度以及稳定性,并引入氢键的相关知识解释了该现象,指出了Hansen溶解度理论并不适合本研究所选的二元体系。通过原子力显微镜、透射电子显微镜、拉曼光谱等对样品的形貌和结构进行了表征,并通过石墨烯分散液的吸光度回归得到了其吸光度系数。经6 000r/min高速离心分离后,所得石墨烯分散液大部分为单层。 相似文献
8.
《中国粉体技术》2016,(1):56-62
为了研究石墨在机械剥离法制备石墨烯过程中剥离与团聚的力学性能,以天然超细石墨为原料,采用具有高剪切效果的机械剥离法,在无分散剂的去离子水介质中制备层数不超过5的石墨片体积分数为18.5%的石墨烯悬浮液;采用原子力显微镜、扫描电子显微镜和粒度分布测试仪表征被剥离的石墨片,获得被剥离石墨片的整体层数分布,并基于层间相互作用能计算石墨厚度变化过程中的剥离能与团聚能。结果表明:当研磨、剥离6 h时,层数不超过5的石墨片含量最多;石墨片层变化释放的团聚能是消耗的剥离能的4倍;石墨片层的剥离使层间接触面积被释放,导致团聚能被激活并不断增大;石墨层间范德华能是阻碍石墨剥离和导致团聚的主要能量,库仑能的作用十分微弱。 相似文献
9.
采用氧化石墨和七水合硫酸锌作为初始反应物, 在低温下(80℃)合成了氧化石墨/ZnO, 然后通过低温剥离法制备了高质量石墨烯/ZnO (GNS/ZnO)复合材料. 采用X射线衍射(XRD)、傅里叶变换红外(FTIR)光谱、热重分析仪(TG)、X射线光电子能谱(XPS)、拉曼光谱(RS)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)等分析手段对石墨烯/ZnO样品进行了表征. 结果表明: 氧化石墨还原彻底, 纳米ZnO成功地负载到了石墨烯上, 有效地减少了石墨烯片层间的团聚现象. 通过对ZnO和石墨烯/ZnO荧光性能测试, 结果表明: 石墨烯/ZnO发生了荧光淬灭现象, 在光电子领域拥有广阔的应用前景. 相似文献
10.
采用Hummers法液相氧化合成了氧化石墨(GO),通过高真空低温热膨胀法制备得到了高比表面积的石墨烯(GNS)材料。采用X射线衍射(XRD)、傅里叶变换红外(FT-IR)光谱、X射线光电子能谱(XPS)、拉曼光谱(RS)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等分析手段对石墨烯样品进行了表征。结果表明,石墨烯还原彻底,呈褶皱的片层状结构,缺陷少;BET测试及氢气高压吸附实验结果表明,通过高真空低温热剥离法制备的石墨烯材料比表面积高达908.3m2/g,并且拥有丰富的孔道结构;在温度为25、40和55℃,压力2500kPa条件下,氢气的吸附量分别达到了1.81%、0.995%和0.44%(质量分数),表明了石墨烯在储氢领域拥有着广阔的应用前景。 相似文献
11.
目的探究和比较制备石墨烯的两种常见方法,即氧化还原法和液相剥离法。方法采用液相剥离法,在N-甲基吡咯烷酮中超声剥离膨胀石墨制备单层和多层石墨烯,与氧化还原法制备得到的石墨烯在微观形貌和结构表征方面进行比较,并在此基础上比较不同有机溶剂液相剥离制备的石墨烯分散液的浓度和稳定性。结果液相剥离法得到的石墨烯具有更好的片层结构,分子结构含有较少的杂团和含氧基团,石墨烯片层间距较宽,热稳定性更好。在N-甲基吡咯烷酮中液相剥离制备的石墨烯质量浓度可达0.15 mg/m L,稳定性相对较好,该方法在一系列应用中也更易制备导电薄膜和复合材料。结论相较氧化还原法,液相剥离法制备的石墨烯性能更好。 相似文献
12.
探索了N,N-二甲基甲酰胺和正丁醇、N,N-二甲基甲酰胺和乙醇两种二元体系剥离制备石墨烯的效果,得到了最佳剥离配比,提高了石墨烯分散液的浓度以及稳定性,并引入氢键的相关知识解释了该现象,指出了Hansen溶解度理论并不适合本研究所选的二元体系.通过原子力显微镜、 透射电子显微镜、 拉曼光谱等对样品的形貌和结构进行了表征,并通过石墨烯分散液的吸光度回归得到了其吸光度系数.经6 000 r/min高速离心分离后,所得石墨烯分散液大部分为单层. 相似文献
13.
Sicheng Wu Jingxin Mo Yachao Zeng Yuan Wang Aditya Rawal Jason Scott Zhen Su Wenhao Ren Sheng Chen Kaixuan Wang Wei Chen Yongzhi Zhang Chuan Zhao Xianjue Chen 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(12)
An unprecedented microwave‐based strategy is developed to facilitate solid‐phase, instantaneous delamination and decomposition of graphite fluoride (GF) into few‐layer, partially fluorinated graphene. The shock reaction occurs (and completes in few seconds) under microwave irradiation upon exposing GF to either “microwave‐induced plasma” generated in vacuum or “catalyst effect” caused by intense sparking of graphite at ambient conditions. A detailed analysis of the structural and compositional transformations in these processes indicates that the GF experiences considerable exfoliation and defluorination, during which sp2‐bonded carbon is partially recovered despite significant structural defects being introduced. The exfoliated fluorinated graphene shows excellent electrochemical performance as anode materials in potassium ion batteries and as catalysts for the conversion of O2 to H2O2. This simple and scalable method requires minimal energy input and does not involve the use of other chemicals, which is attractive for extensive research in fluorine‐containing graphene and its derivatives in laboratories and industrial applications. 相似文献
14.
15.
Umar Khan Arlene O'Neill Mustafa Lotya Sukanta De Jonathan N. Coleman 《Small (Weinheim an der Bergstrasse, Germany)》2010,6(7):864-871
A method is demonstrated to prepare graphene dispersions at high concentrations, up to 1.2 mg mL?1, with yields of up to 4 wt% monolayers. This process relies on low‐power sonication for long times, up to 460 h. Transmission electron microscopy shows the sonication to reduce the flake size, with flake dimensions scaling as t?1/2. However, the mean flake length remains above 1 µm for all sonication times studied. Raman spectroscopy shows defects are introduced by the sonication process. However, detailed analysis suggests that predominately edge, rather than basal‐plane, defects are introduced. These dispersions are used to prepare high‐quality free‐standing graphene films. The dispersions can be heavily diluted by water without sedimentation or aggregation. This method facilitates graphene processing for a range of applications. 相似文献
16.
石墨烯的制备研究进展 总被引:2,自引:0,他引:2
近年来, 石墨烯以其独特的结构和优异的性能, 在化学、物理和材料学界引起了广泛的研究兴趣. 人们已经在石墨烯的制备方面取得了积极的进展, 为石墨烯的基础研究和应用开发提供了原料保障. 本文大量引用近三年最新参考文献, 综述了石墨烯的制备方法: 物理方法(微机械剥离法、液相或气相直接剥离法)与化学法(化学气相沉积法、晶体外延生长法、氧化?还原法), 并详细介绍了石墨烯的各种修饰方法. 分析比较了各种方法的优缺点, 指出了石墨烯制备方法的发展趋势. 相似文献
17.
Graphene has attracted much attention as a new nano-carbon for its unique structure and properties. However, production and dispersion of unfunctionalized graphene are still big challenges. Herein, we demonstrate a simple method for preparation and dispersion of such graphene with low cost and non toxicum. This approach is achieved by exfoliating graphite in an ethanol/water mixture and forming stable dispersion of mono- and few-layer graphenes. The ratio of ethanol/water in the mixture is found to be crucial to both the exfoliation and dispersion processes. Exfoliation in pure water or pure ethanol produces no graphene. This method avoids the conventional use of harsh oxidants and surfactants; therefore, the graphitic structure is well maintained without destruction. Benefiting from the use of ethanol and water, it can be easy to prepare transparent and conductive graphene films by vacuum filtering or spray method, and does not need special post-treatment to remove the impurity, which could be beneficial for potential applications in electronic, optic and energy areas. 相似文献