石墨烯的性能及应用研究

碳材料是地球上最普遍也是最奇妙的一种材料,它可以形成世界上最硬的金刚石,也可以形成最软的石墨,人类一直不断深入研究着.自2004年被Geim等人发现以来,石墨烯因其独特的结构和性质就一直是物理学和材料学领域的研究热点。它是目前世界上最薄的材料,仅有一个碳原子厚,与所有其他已知材料不同,石墨烯高度稳定,且作为热导体,石墨烯比目前任何其他材料的导热效果都好。因此,石墨烯开始成为备受瞩目的国际前沿和热点。本文首先概述了石墨烯的结构及性能,然后针对其在复合材料、光电功能材料与器件以及其他领域的应用进行重点阐述。     

功能化石墨烯改性酚醛树脂及其性能

首先通过改进的Hummer法制得氧化石墨烯(GO),然后通过表面改性和化学还原制得功能化石墨烯(FRGO),最后通过原位聚合法制得FRGO/酚醛树脂(PF)复合材料,对有关产物进行了表征和测试。结果表明：适量引入FRGO,可明显改善PF的力学性能、摩擦性能和热稳定性;当FRGO质量分数为1.0%时,复合材料的弯曲强度、弯曲模量和冲击强度均达到最大值82.34MPa、3.84GPa和13.12kJ·m^-2,分别比PF提高了81.48%、51.18%和99.39%;当FRGO质量分数为1.5%时,复合材料的摩擦系数降至0.91,比PF降低了27.7%;引入FRGO后,PF的玻璃化转变温度、分解温度和残炭率均明显提高。     

石墨烯的光电性能及其应用

石墨烯是目前发现唯一存在的二维自由态原子晶体.其独特的二维结构和优异的电学、光学、力学以及热学性能,是当前纳米材料领域的研究热点之一.本文综述了石墨烯的制备方法,介绍了其光学、电学性能及在光电应用中的研究进展.同时,对目前石墨烯在光电领域的发展趋势进行了展望.     

氧化石墨烯重力热管传热性能研究

实验研究了在氧化石墨烯纳米流体质量分数为0,0.01％,0.05％,0.1％,0.2％时,50,60,70,80,90℃加热温度和50％,60％,70％,80％充液率对重力热管启动性能和传热特性的影响.实验结果表明:氧化石墨烯纳米流体质量分数越大,重力热管热阻越小;在加热温度为90℃、充液率为60％时,质量分数为0.2...     

聚丙烯/石墨烯复合材料性能研究进展

利用石墨烯优异的导电率、断裂强度等物理性质,可使聚丙烯(PP)/石墨烯复合材料表现出更好的力学性能以及导电性能。主要概述了PP/石墨烯复合材料的合成方法及其性能改进研究进展,并对PP/石墨烯复合材料的未来发展做了展望。     

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。     

石墨烯复合材料的制备及性能研究

为研究石墨烯在复合材料中的潜在价值,以石墨烯的特有属性为依据,通过在真空密闭环境中离心分散制得目标溶液,将混合溶液在高温环境中活化氢键,制得石墨烯-聚酯丙基复合材料薄膜,根据不同复合材料的石墨烯添加量,分析了石墨烯复合材料的力学性能、疏水性和热稳定性。研究结果表明,当石墨烯添加量为92%时,有助于增强材料的弹性模量;当石墨烯添加量为3%时,降低了材料的疏水性,石墨烯使复合材料的综合性能大幅提升,为复合材料推广研究提供了科学依据。     

石墨烯纳米复合材料的制备及性能研究

以泡沫镍为模板、石墨为催化剂、酚醛树脂为碳源,采用水热法以及热处理方法制备了三维石墨烯复合材料,再利用化学沉积法制备三维氧化镍-石墨烯-泡沫镍复合材料,并对其结构和电性能进行了分析,研究结果表明,该复合材料的石墨化程度高,具备电极特性,电化学性能稳定。     

Near-UV-emitting graphene quantum dots from graphene hydrogels

We report a novel method to prepare graphene quantum dots (GQDs) from graphene hydrogels. Graphene hydrogels were prepared using a hydrothermal technique, and GQDs were released from the hydrogels on immersion of the hydrogels in low-polarity organic solvents. This method did not require additional treatments such as the centrifugation, filtration and dialysis typical of the general hydrothermal method. These GQDs were observed to fluoresce, with their strongest emission in the near-UV region, at ∼347 nm. Moreover, these GQDs, when in their pure state, formed a highly viscous liquid insoluble in water due to their lack of many oxygen-containing functional groups.     

石墨烯、3D石墨烯及其复合材料的研究进展

石墨烯是由单层碳原子紧密堆叠而成的蜂窝状材料,具有比表面积大、传热性能好、导电能力强等优点,普遍应用于各个领域。但由于石墨烯使用过程中易团聚,导致其应用领域受限。石墨烯组装而成的3D石墨烯拥有更大的活性表面积等特性,近年来引发密切关注。与此同时,石墨烯、3D石墨烯改性成为当前探究的焦点。本文在介绍石墨烯、3D石墨烯的结构、性能及石墨烯制备的基础上,总结了3种复合材料的主要制备途径,并且分析了其合成方法的利弊。重点探讨了它们在锂离子电池、燃料电池的电化学催化剂及传感器中的应用,简述了复合材料优良性能产生的机理。提出在掺杂改性中应注意各元素掺杂量、掺杂比例、掺杂位点的确定等问题。最后指出了石墨烯、3D石墨烯及其复合材料的制备还面临不稳定、无法大规模生产、导电率低的瓶颈并对其在固态金属锂电池、透明电池、吸附材料等领域的发展前景做了展望。     

Restoration of graphene from graphene oxide by defect repair

A simple and efficient method to repair defects in graphene oxide (GO) is reported, accompanied by a simultaneous reduction process by a methane plasma. The graphene after repair is of high quality. For a typical monolayer after repair and reduction, the minimum sheet resistance at the Dirac point and the Raman D/G peak intensity ratio are about 9.0 kΩ/□ and ～0.53, respectively.     

Patterning of graphene

Two-dimensional atomic sheets of carbon (graphene, graphane, etc.) are amenable to unique patterning schemes such as cutting, bending, folding and fusion that are predicted to lead to interesting properties. In this review, we present theoretical understanding and processing routes for patterning graphene and highlight potential applications. With more precise and scalable patterning, the prospects of integrating flat carbon (graphene) with curved carbon (nanotubes and half nanotubes) and programmable graphene folding are envisioned.     

Atomic layer etching of graphene for full graphene device fabrication

The possibility of fabricating a full graphene device was investigated by utilizing atomic layer etching (ALET) technology. By using O₂ ALET which functions by oxygen radical adsorption followed by the removal of the oxygen chemisorbed on carbon, the removal of exactly one graphene layer per ALET cycle was detected through the increase of the transmittance by 2.3% after one ALET cycle and by the decrease of the G peak in the Raman spectra. The Raman spectra also showed an increase of the D peak after ALET, indicating the formation of physical damage on the graphene surface layer. This damage was mostly recovered by hydrogen annealing at 1000 °C after ALET. Full graphene field effect transistors (source, drain: 3 layer, channel: 1, 2, 3 layer) were fabricated by reducing the channel layers using ALET, followed by annealing, and the electrical characteristics of the devices showed the possibility of fabricating fully functional graphene devices composed of an all graphene source/drain and graphene channel by utilizing ALET.     

Microwave syntheses of graphene and graphene decorated with metal nanoparticles

We report a simple and rapid method to synthesize pure graphene sheets and those decorated with metal nanoparticles by combining chemical foaming agents, green oxidizers, and microwave radiation. Under microwave radiation, an intercalated foaming agent between graphite oxide layers plays a key role in the rapid and large expansion of the graphene worm along the thickness direction and in the reduction process of the graphite oxide. By adding metal precursors to the reactant mixture, this technique can also be extended to a one-pot method to synthesize graphene decorated with metal nanoparticles. A variety of metal precursors was used to yield iron, platinum, and palladium decorated graphene sheets. These were tested for their electrocatalytic performance in organic glucose sensing and inorganic electro-active compounds, all of which showed a remarkable increase in electrochemical performance for all cases.