石墨烯的制备与表征

采用液相氧化法制备了氧化石墨,并通过水合肼还原氧化石墨制备了石墨烯。采用傅里叶变换红外光谱(FT-IR)、拉曼光谱(RS)、X-射线衍射(XRD)、热失重法(TG)等测试方法对石墨、氧化石墨和石墨烯的结构与耐热性进行了对比分析。研究结果表明,氧化石墨被水合肼还原成石墨烯后,氧化石墨的一部分sp3杂化碳原子被还原成石墨的sp2杂化碳原子,石墨烯sp2杂化碳层平面的平均尺寸比氧化石墨大,但结晶强度和规整度比石墨有所降低。在本实验条件下,氧化石墨的还原状态结构不可能被完全恢复到原有的石墨状态,也就是说石墨烯的结构和石墨结构还是有差别的。热分析结果表明,石墨烯具有比氧化石墨更为优异的热稳定性。     

石墨烯气凝胶的水热法制备及表征

以石墨为原料,高锰酸钾为氧化剂,通过超声制备具有不同片径的氧化石墨烯,采用一步水热还原制备石墨烯水凝胶,将石墨烯水凝胶进行冷冻干燥制备石墨烯气凝胶。分别采用X-射线衍射、拉曼光谱、扫描电镜、透射电镜对石墨烯气凝胶的结构、形貌进行了表征。结果表明,通过水热法还原氧化石墨烯可得到具有丰富多孔结构的石墨烯气凝胶。     

石墨烯气凝胶的水热法制备及表征

以石墨为原料,高锰酸钾为氧化剂,通过超声制备具有不同片径的氧化石墨烯,采用一步水热还原制备石墨烯水凝胶,将石墨烯水凝胶进行冷冻干燥制备石墨烯气凝胶。分别采用X-射线衍射、拉曼光谱、扫描电镜、透射电镜对石墨烯气凝胶的结构、形貌进行了表征。结果表明,通过水热法还原氧化石墨烯可得到具有丰富多孔结构的石墨烯气凝胶。     

石墨烯的制备及其性能表征

采用Hummers法制备了氧化石墨,并通过高频超声分散得到氧化石墨烯悬浮液,通过水合肼还原制备了石墨烯。利用傅里叶红外透射光谱(FT-IR)、X射线衍射(XRD)、扫描电子显微镜(SEM)、热重分析(TG)等测试方法对石墨、氧化石墨以及石墨烯的结构组成、微观形貌和耐热性进行了分析。结果表明:氧化石墨被还原成石墨烯后,含氧基团基本被去除,片层尺寸缩小,晶体结构的强度和完整度有所下降,热稳定性增加。     

石墨烯载钴材料的制备

本实验以150μm鳞片状石墨为原料,采用Hummers法制备氧化石墨,经超声波振荡得到氧化石墨烯,加入水合肼回流制得石墨烯材料.氧化石墨烯与CoSO4溶液混合,采用功能离子预吸附的方式,将金属离子有效地分散在氧化石墨烯载体上,原位还原金属颗粒和石墨烯,制备石墨烯载钴材料.     

神府烟煤及其煤岩组分制备氧化石墨烯的组成、结构演变

以煤为原料制备石墨烯是一种非常有前景的煤炭材料化、高值化利用途径。针对煤岩组分的组成、结构差异,探明煤岩组分在制备氧化石墨烯过程中的演变规律,是开发煤基石墨烯制备技术的理论基础。利用重选法富集低变质神府煤中镜质组和惰质组,并将富集煤岩组分通过高温石墨化得到石墨化碳,以石墨化碳为前驱体通过改良的Hummers氧化法制备煤基氧化石墨烯。利用元素分析、红外光谱、X射线衍射、拉曼光谱、扫描电镜、透射电镜以及原子力显微镜等研究煤及其煤岩组分在制备氧化石墨烯过程中的组成和结构演变规律。结果表明炭化处理使煤有机大分子结构向无定形碳结构转变,高温石墨化使煤有机大分子结构向石墨碳结构转变;惰质组呈片状结构且分子结构中芳香结构单元较多导致石墨化碳微晶尺寸较大,高温石墨化处理后其拉曼光谱的(A_D1/A_G)值为0.382,镜质组高温石墨化处理后的(A_D1/A_G)值为0.686,原煤高温石墨化处理后的(A_D1/A_G)值为0.864;利用富惰质组得到的石墨化碳制备氧化石墨烯厚度尺寸约...     

低温氧化石墨制备技术研究

采用Hummers法、硫酸/磷酸法和反应釜法3种化学氧化法制备氧化石墨,在超声情况下,将氧化石墨分散于水中制备氧化石墨烯。采用X衍射(XRD)、扫描电镜(SEM)对所得氧化石墨、氧化石墨烯分别进行表征。并对制备氧化石墨的3种化学氧化过程进行对比分析,结果表明,Hummers法在高温阶段有红色刺激性气体放出,且发生喷溅现象。硫酸/磷酸法和反应釜法是在低温条件下进行,制备过程比Hummers法安全、环保。氧化石墨XRD结果表明,3种化学氧化法中氧化程度最好的是硫酸/磷酸法,其次是反应釜法,最后是Hummers法。氧化石墨烯SEM结果表明,氧化石墨经超声处理后剥离成为氧化石墨烯纳米片。     

低温氧化石墨制备技术研究

采用Hummers法、硫酸/磷酸法和反应釜法3种化学氧化法制备氧化石墨,在超声情况下,将氧化石墨分散于水中制备氧化石墨烯。采用X衍射(XRD)、扫描电镜(SEM)对所得氧化石墨、氧化石墨烯分别进行表征。并对制备氧化石墨的3种化学氧化过程进行对比分析,结果表明,Hummers法在高温阶段有红色刺激性气体放出,且发生喷溅现象。硫酸/磷酸法和反应釜法是在低温条件下进行,制备过程比Hummers法安全、环保。氧化石墨XRD结果表明,3种化学氧化法中氧化程度最好的是硫酸/磷酸法,其次是反应釜法,最后是Hummers法。氧化石墨烯SEM结果表明,氧化石墨经超声处理后剥离成为氧化石墨烯纳米片。     

低温热剥离制备石墨烯及其电化学性能研究

以石墨为原料,采用改进的Hummers法制备了氧化石墨,300℃下热剥离氧化石墨制备得到石墨烯.采用红外光谱、扫描电镜表征了石墨烯的还原程度及形貌结构,运用循环伏安、恒流充放电等测试方法研究了石墨烯的电容性能.结果表明:石墨烯片层之间被充分剥离开来,拥有一定的孔道结构.在1 mol·L-1的硫酸电解液中,石墨烯制备的电极比电容达411 F·g-1.电极组装的电容器,能量密度5.37 W·h·kg-1时,功率密度为604 W·kg-1,循环1000次后比电容保持率为94％.组装的超级电容器电化学性能及循环稳定性能良好.     

氧化石墨烯/聚氨酯复合材料的制备及性能研究

采用溶液共混浇注成膜法制备氧化石墨烯/热塑性聚氨酯(TPU)复合材料,并对其结构和性能进行研究。结果表明:氧化石墨烯在TPU基体材料中分散较好;随着氧化石墨烯用量(0～5份)的增大,氧化石墨烯/TPU复合材料的拉伸强度增大,拉断伸长率未明显下降;当相同用量(均为1份)的氧化石墨烯、碳纳米管、石墨和炭黑分别填充TPU时,氧化石墨烯/TPU复合材料物理性能提高幅度最大,补强性能最好。     

氨基改性氧化石墨烯及其与环氧树脂的复合

对氧化石墨烯的氨基改性进行了研究,并探索了其在环氧树脂复合材料中的应用。以鳞片石墨为原料,采用Hummers法制备了氧化石墨,进而超声剥离制备了氧化石墨烯。采用三乙烯四胺和乙二胺,用缩合剂法对氧化石墨烯进行改性,并制备相应的环氧树脂复合材料。通过X射线衍射、热重分析、红外光谱、拉曼光谱、扫描电子显微镜等测试方法对所制备的材料进行了表征。结果表明,通过改性可将三乙烯四胺和乙二胺引入氧化石墨烯的表面,且氧化石墨烯被部分还原;氨基改性氧化石墨烯作为分散相加入环氧树脂基体中制备的复合材料的弹性模量和拉伸强度较纯环氧树脂明显提高,拉伸强度最大提高约60 %,弹性模量最大提高约100 %。     

氧化石墨烯/聚偏氟乙烯复合膜研究

采用Hummers法合成氧化石墨,通过超声分散法获得氧化石墨烯,并使用溶剂蒸发法制备了氧化石墨烯/聚偏氟乙烯复合膜。采用透射电子显微镜(TEM)、红外光谱(FTIR)以及X射线衍射(XRD)对氧化石墨烯的形貌和结构进行分析,对复合膜进行扫描电子显微镜(SEM)、机械性能以及导热系数的分析测定。结果表明,本实验中制备的氧化石墨烯含有大量的含氧基团;氧化石墨烯能够均匀的分散在复合膜中,并且会增加复合膜的机械性能和导热性能。复合膜的导热系数随w(氧化石墨烯)的增加而呈现先增大后减小的趋势,当w(氧化石墨烯)为0.4%时,导热系数达到最大值。     

石墨烯的制备及石墨烯/PVDF合材料介电性能的研究

通过Staudenmaier法制备了完全氧化的氧化石墨(GO),并通过高温热膨胀制备了单层石墨烯(graphene).用FT-IR、TG和XRD对GO的氧化程度、含氧官能团进行了表征;Graphene的XRD测试结果证明了单层石墨的存在.利用超声共混法制备了graphene/PV DF介电纳米复合材料.介电性能的测试表...     

石墨质改性混凝土高温性能的研究

通过热处理后混凝土力学性能及微观结构的变化,研究了石墨、氧化石墨烯复合玄武岩纤维对混凝土高温性能的影响。结果表明:石墨的添加会引起混凝土力学稳定性的降低,而氧化石墨烯则可以大幅度提升混凝土的高温力学稳定性,有效降低了热处理所带来的劣化影响;玄武岩纤维与石墨、氧化石墨烯的复合使用均未形成协同作用效果,反而降低了试样的力学性能。微观分析显示石墨分散在材料体系之中形成了界面缺陷,而氧化石墨烯可以在材料系统中形成紧密连续的交联结构,有效提高了混凝土的高温力学性能。     

Utilization of multiple graphene layers in fuel cells. 1. An improved technique for the exfoliation of graphene-based nanosheets from graphite

An improved, safer and mild method was proposed for the exfoliation of graphene like sheets from graphite to be used in fuel cells. The major aim in the proposed method is to reduce the number of layers in the graphite material and to produce large quantities of graphene bundles to be used as catalyst support in polymer electrolyte membrane fuel cells. Graphite oxide was prepared using potassium dichromate/sulfuric acid as oxidant and acetic anhydride as intercalating agent. The oxidation process seemed to create expanded and leafy structures of graphite oxide layers. Heat treatment of samples led to the thermal decomposition of acetic anhydride into carbondioxide and water vapor which further swelled the layered graphitic structure. Sonication of graphite oxide samples created more separated structures. Morphology of the sonicated graphite oxide samples exhibited expanded the layer structures and formed some tulle-like translucent and crumpled graphite oxide sheets. The mild procedure applied was capable of reducing the average number of graphene sheets from 86 in the raw graphite to nine in graphene-based nanosheets. Raman spectroscopy analysis showed the significant reduction in size of the in-plane sp² domains of graphene nanosheets obtained after the reduction of graphite oxide.     

绿色环保法石墨烯的制备及其电化学性质研究

提出一种绿色环保型、高效的制备氧化石墨烯的方法迫在眉睫,以天然石墨为原料,采用插层法,利用高铁酸钾为强氧化剂,制备氧化石墨烯进而有水合肼还原成石墨烯。通过扫描电镜(SEM)、透射电镜(TEM)、X射线(XRD)、红外光谱(IR)对样品形貌及结构进行表征,采用循环伏安侧试法(CV)研究石墨烯材料的电化学行为结果表明:利用8 000目合成的石墨烯电化学行为最优,比电容达到126.2 F/g。     

Vacuum-assisted microwave reduction/exfoliation of graphite oxide and the influence of precursor graphite oxide

One-step synthesis of high quality graphene at gram-scale quantities is important for industrial applications, e.g. in electrochemistry for sensing and energy storage. Currently, thermal reduction/exfoliation of graphite oxide (GO) is a typical method of choice. However, it has the drawback of requiring specialized equipment for rapid thermal shock. A recent alternative method, microwave-assisted exfoliation, usually suffers from poor reduction of graphite oxide and thus low C/O ratios. Herein we show that vacuum-assisted microwave reduction/exfoliation of graphite oxide in a closed system leads to high C/O ratios and partial hydrogenation of graphene (2.6 at.% of H). Microwave irradiation of graphite oxide in vacuum leads to outgassing from GO and the creation of plasma which aids temperature distribution and hydrogenation. This plasma is quickly extinguished by further dramatic evolution of gases from GO and consequent pressure increase. We assess the influence of precursor graphite oxide, prepared by Hummers, Staudenmaier, and Hofmann methods, upon the materials properties of microwave exfoliated graphene. We show that microwave-exfoliated graphenes prepared from different graphite oxides show very fast heterogeneous electron transfer rates, with similar electrochemical behaviour to thermally reduced graphene oxide.     

The production of smectite clay/graphene composites through delamination and co-stacking

Layers from delaminated colloidal dispersions of two structurally different layered solids-octylamine-intercalated graphite oxide and cetyltrimethylammonium-intercalated smectite - could be costacked to obtain smectite clay/graphite oxide composites. The layers of the two parent solids were randomly stacked together in these composites. On thermal decomposition the graphite oxide sheets in the composites are reduced to graphene sheets resulting in clay/graphene composites. The composition is not uniform in these composites, which have many smectite-rich and carbon-rich regions. The clay component of the clay/graphene composites could be leached out to obtain exfoliated graphite.     

Monolayer graphene from graphite oxide

Graphene, a new carbon material, is attracting presently an increasing research interest. It stems from the unique electrical and mechanical properties of graphene predicted by theory. Experimental studies of graphene are, however, severely curtailed by a lack of an appropriate technique for its preparation. Mechanical cleavage of graphite proved to be ineffective, since it yields only very small (a few microns in size) particles of monolayer graphene. The rapidly developing approach based on chemical exfoliation of graphite produces large-area coatings composed primarily of arbitrarily oriented multilayer graphene particles. We have developed a technique for preparation of monolayer graphene sheets involving liquid exfoliation of crystalline graphite, which includes synthesis of graphite oxide by deep oxidation as an intermediate stage. Electron diffraction traces, as well as the variation of diffracted intensities with local orientation of graphene sheets, AFM, and HRTEM images testify to a remarkably good monolayer structure of the graphite oxide particles obtained by our technique. These results open a way to setting up high-efficiency production of monolayer graphene sheets appropriate for electrical and optical measurements and fabrication of structures for use in the field of applications.     

微波法制多孔石墨烯及对亚甲基蓝的吸附性能

以改进的Hummers法合成的氧化石墨烯为自组装原料,通过微波加热的方式制备三维多孔石墨烯材料。并采用场发射扫描电子显微镜、傅立叶红外光谱仪、X射线衍射仪对石墨、氧化石墨烯、三维多孔石墨的微观形貌和内部结构进行表征分析。以亚甲基蓝为吸附质、三维多孔石墨烯为吸附剂,研究其吸附性能。结果表明,三维多孔石墨烯材料的最大吸附量为18.0 mg·g^(-1),去除率94.63%。通过对其动力学和热力学分析可知,三维多孔石墨烯对亚甲基蓝的吸附行为适合用Langmuir模型和二级动力学模型来描述。