Porous graphene: Properties, preparation, and potential applications

Graphene has recently emerged as an important and exciting material.Inspired by its outstanding properties,many researchers have extensively studied graphene-related materials both experimentally and theoretically.Porous graphene is a collection of graphene-related materials with nanopores in the plane.Porous graphene exhibits properties distinct from those of graphene,and it has widespread potential applications in various fields such as gas separation,hydrogen storage,DNA sequencing,and supercapacitors.In this review,we summarize recent progress in studies of the properties,preparation,and potential applications of porous graphene,and show that porous graphene is a promising material with great potential for future development.     

功能化石墨烯的性能与应用

石墨烯是一种具有独特二维晶体结构的新型碳纳米材料,具有优异的力学、电学、光学和热学性能,但是在溶剂中难以分散限制了其在很多领域的应用.功能化石墨烯提高了分散性,充分发挥了石墨烯的优良性能,在储能、生物医药、传感器和复合材料方面具有光明的应用前景.综述了石墨烯和功能化石墨烯的制备方法、优良性能及其各领域的应用.     

Preparation and supercapacitor performance of assembled graphene fiber and foam

Graphene-based materials have been full of vigor and tremendous potentiality for application in supercapacitors due to its variety of unique properties such as electronic properties, simple synthesis, etc. In developing new macroscopic nanostructured graphene materials for supercapacitors, considerable efforts have been made by the scientist including our research group. In this account, we describe our development of the construction of the assembled graphene especially fiber and foam, which have great potential in addressing the challenges in the synthesis of graphene-based electrode materials for supercapacitors. As the supercapacitors are reviewed in this article, they are accordant with the rapid development of flexible, lightweight, and wearable-electronic devices, overcoming the major some drawbacks of conventional bulk supercapacitors. We hope that this summary will benefit the further research of graphene-based materials for the applications in electrochemical energy storage devices and beyond.     

非气态原料制备垂直石墨烯

垂直石墨烯是由石墨烯片垂直于基底生长而形成的一种新型3维碳材料结构,由于其独特的生长取向,可以有效减轻石墨烯层与层之间的堆叠,使石墨烯充分发挥其优异的特性.等离子体增强化学气相沉积技术作为合成垂直石墨烯的主要手段常需引入化工合成气为碳源,原料灵活性低.该文综述了非气态碳源用于垂直石墨烯的制备,介绍了所合成的垂直石墨烯在多种领域中的应用,并讨论了其生长机理.     

Heteroatom-doped graphene for electrochemical energy storage

The increasing energy consumption and envi- ronmental concerns due to burning fossil fuel are key drivers for the development of effective energy storage systems based on innovative materials. Among these materials, graphene has emerged as one of the most promising due to its chemical, electrical, and mechanical properties. Heteroatom doping has been proven as an effective way to tailor the properties of graphene and render its potential use for energy storage devices. In this view, we review the recent developments in the synthesis and applications of heteroatom-doped graphene in supercapacitors and lithium ion batteries.     

Recent advances in graphene based photoresponsive materials

Recent scientific interests reveal that graphene, with its flexibility, chemical stability, thermal conductivity,unique electronic band structure and optical transmittance, has emerged as the novel supporting material for nanocomposites for various applications. Research interests have flourished regarding decoration of conventional materials with modified graphene for achieving better optical properties. More concern is given for achieving improved photoresponse with graphene as the supporting material. The giant electron mobility and transparency of graphene enables the photo-induced electron transfer in the hybrid material, resulting in enhanced behaviour. Graphene oxide is able to effectively convert near infrared energy into heat, potentially acting as a photo-thermal switch. They act as potential candidates for photo-catalysts, sensors, photo-current switching,photo-detectors and other optical applications. In this review, we summarized the recent developments on fabrication and properties of graphene based photoresponsive materials.     

Progress of graphene growth on copper by chemical vapor deposition: Growth behavior and controlled synthesis

Recently,chemical vapor deposition (CVD) on copper has been becoming a main method for preparing large-area and highquality monolayer graphene.In this paper,we first briefly introduce the preliminary understanding of the microstructure and growth behavior of graphene on copper,and then focus on the recent progress on the quality improvement,number of layers control and transfer-free growth of graphene.In the end,we attempt to analyze the possible development of CVD growth of graphene in future,including the controlled growth of large-size single-crystal graphene and bilayer graphene with different stacking orders.     

Direct evidence for atomic defects in graphene layers

Atomic-scale defects in graphene layers alter the physical and chemical properties of carbon nanostructures. Theoretical predictions have recently shown that energetic particles such as electrons and ions can induce polymorphic atomic defects in graphene layers as a result of knock-on atom displacements. However, the number of experimental reports on these defects is limited. The graphite network in single-walled carbon nanotubes has been visualized by transmission electron microscopy (TEM) and their chiral indices have been determined. But the methods used require a long image acquisition time and intensive numerical treatments after observations to find an 'average' image, which prevents the accurate detection and investigation of defect structures. Here we report observations in situ of defect formation in single graphene layers by high-resolution TEM. The observed structures are expected to be of use when engineering the properties of carbon nanostructures for specific device applications.     

Functionalization of graphene materials by heteroatom-doping for energy conversion and storage

Recent development in nanoscience and nanotechnology has opened up new frontiers in materials science and engineering to create new materials for energy generation and storage. Owing to their earth abundance, low-cost, structural tunability, large-surface area, and unique physicochemical properties, graphitic carbon materials have attracted a great deal of attention for energy-related applications. However, the pristine graphene materials without functionalization is intractable (insoluble and infusible), which has hindered their practical applications. Therefore, considerable research effort has been devoted to the development of functionalized graphene materials with desirable properties for specific applications, including energy conversion and storage. It was demonstrated that functionalized graphene materials with tunable work functions were useful as charge-extraction materials to effectively improve solar cell performance while those with high electrocatalytic activities could be used as metal-free catalysts in fuel cells, metal-air batteries, water splitting and integrated energy systems. This article provides a timely focused review on the development of heteroatom-doped graphene materials for low-cost, but efficient, energy generation and storage.     

Preparation and characterization of graphene oxide paper

Free-standing paper-like or foil-like materials are an integral part of our technological society. Their uses include protective layers, chemical filters, components of electrical batteries or supercapacitors, adhesive layers, electronic or optoelectronic components, and molecular storage. Inorganic 'paper-like' materials based on nanoscale components such as exfoliated vermiculite or mica platelets have been intensively studied and commercialized as protective coatings, high-temperature binders, dielectric barriers and gas-impermeable membranes. Carbon-based flexible graphite foils composed of stacked platelets of expanded graphite have long been used in packing and gasketing applications because of their chemical resistivity against most media, superior sealability over a wide temperature range, and impermeability to fluids. The discovery of carbon nanotubes brought about bucky paper, which displays excellent mechanical and electrical properties that make it potentially suitable for fuel cell and structural composite applications. Here we report the preparation and characterization of graphene oxide paper, a free-standing carbon-based membrane material made by flow-directed assembly of individual graphene oxide sheets. This new material outperforms many other paper-like materials in stiffness and strength. Its combination of macroscopic flexibility and stiffness is a result of a unique interlocking-tile arrangement of the nanoscale graphene oxide sheets.     

Graphene-based hybrid materials and their applications in energy storage and conversion

Graphene attracts more and more scientists and researchers owing to its superior electronic,thermal,and mechanical properties.For material scientists,graphene is a kind of versatile building blocks,and considerable progress has been made in recent years.Graphene-based hybrid materials have been prepared by incorporating inorganic species and/or cross-linking of organic species through covalent and/or noncovalent interactions.The graphene-based hybrid materials show improved or excellent performance in various fields.In this review,we summarize the synthesis of graphene and graphene-based hybrid materials,and their applications in energy storage and conversion.     

A brief review of graphene-based material synthesis and its application in environmental pollution management

Graphene is an interesting two-dimensional carbon allotrope that has attracted considerable research interest because of its unique structure and physicochemical properties. Studies have been conducted on graphene-based nanomaterials including modified graphene, graphene/semiconductor hybrids, graphene/metal nanoparticle composites, and graphene-complex oxide composites. These nanomaterials inherit the unique properties of graphene, and the addition of functional groups or the nanoparticle composites on their surfaces improves their performance. Applications of these materials in pollutant removal and environmental remediation have been explored. From the viewpoint of environmental chemistry and materials, this paper reviews recent important advances in synthesis of graphene-related materials and their application in treatment of environmental pollution. The roles of graphene-based materials in pollutant removal and potential research are discussed.     

晶圆级二维单晶材料生长的研究进展

低维材料因其原子级的物理尺寸而拥有独特的物理化学性质. 以石墨烯为代表的二维材料具有优越的光学、电学、力学及热学性能,在电子、光电、能源、催化等领域具有巨大的应用潜力. 大尺寸、高质量的单晶材料是大规模高端器件的应用基础. 为此,研究者们致力于实现晶圆级二维单晶材料的制造研究. 利用化学气相沉积法(CVD)制备二维材料具有薄膜质量高、可控性强、均匀性好等优点,因此,CVD成为制备高质量二维单晶材料的首选. 文章从二维导电石墨烯、绝缘氮化硼和半导体过渡金属硫族化合物入手,总结了近年来利用CVD技术外延制造二维单晶薄膜的研究进展,讨论了大面积二维单晶材料的制备策略与生长机理,指出了目前存在的问题,对未来高质量二维单晶薄膜的制备方法进行了展望. 该综述为进一步推动二维单晶材料的规模化应用提供借鉴.     

功能化石墨烯在生物医学研究中的应用

石墨烯以其独特的二维结构和优良的电学、光学、热学和机械性能,自2004年来倍受研究人员的高度关注,迅速成为材料、化学、物理和医学领域的热点研究课题.在简要介绍石墨烯基本情况的基础上,重点阐述了石墨烯在生物传感器、靶向给药中的应用.     

基于石墨烯的多维度材料构筑及性能研究进展

 石墨烯是碳原子以六角形密堆积形成的二维原子晶体,具有独特的物理化学性质,在电子器件、能源环境和生物医学等领域有着广阔的应用前景。石墨烯的可控制备和组装是其实现实际应用的前提条件。近年来,相继开发出一系列石墨烯自组装与结构调控的技术方法,得到了多种结构特异、组成丰富和性能独特的石墨烯基多维度结构。本文从水溶性的氧化石墨烯出发,综述从零维到三维一系列不同维度和尺度石墨烯的自组装行为和材料构筑策略。对石墨烯的不同组装结构进行系统分类,提出其多维度组装体系的概念。石墨烯的多维度组装体系,在微纳米尺度上包括零维度的石墨烯基纳米颗粒和一维的石墨烯纳米线,在宏观尺度上包括二维石墨烯薄膜和三维的宏观体结构,最后对相关研究领域的发展趋势进行了总结和展望,结合计算化学的相关结果,预测了一系列未开发的石墨烯自组装结构。     

DNA sequencing technology based on nanopore sensors by theoretical calculations and simulations

DNA sequencing based on nanopore sensors is a promising tool for third-generation sequencing technol- ogy because of its special properties, such as revolutionized speed and low cost. With about two decades of nanopore technology development, the pioneering work has dem- onstrated the ability of nanopores to perform single-mole- cule detection and DNA sequencing. However, the microscopic mechanisms of DNA transport dynamics through nanopores remain largely unknown. Currently, DNA microscopic transport in a nanopore is difficult to characterize and several unexpected experimental obser- vations are equivocal. This limitation can be resolved using theoretical calculations and simulations. These computa- tional methods can monitor the entire dynamic process that DNA undergoes in solution at a single-atom resolution that can accurately unveil the mystery of DNA transport dynamics and predict certain unexpected phenomena. This paper mainly reports the recent applications of computa- tional and simulation methods applied to the study of DNA transport through both biological and synthetic nanopores. We hope the theoretical calculations and simulations of DNA transport through nanopores can benefit the design of DNA sequencing devices.     

Graphene-based composite materials

Graphene sheets--one-atom-thick two-dimensional layers of sp2-bonded carbon--are predicted to have a range of unusual properties. Their thermal conductivity and mechanical stiffness may rival the remarkable in-plane values for graphite (approximately 3,000 W m(-1) K(-1) and 1,060 GPa, respectively); their fracture strength should be comparable to that of carbon nanotubes for similar types of defects; and recent studies have shown that individual graphene sheets have extraordinary electronic transport properties. One possible route to harnessing these properties for applications would be to incorporate graphene sheets in a composite material. The manufacturing of such composites requires not only that graphene sheets be produced on a sufficient scale but that they also be incorporated, and homogeneously distributed, into various matrices. Graphite, inexpensive and available in large quantity, unfortunately does not readily exfoliate to yield individual graphene sheets. Here we present a general approach for the preparation of graphene-polymer composites via complete exfoliation of graphite and molecular-level dispersion of individual, chemically modified graphene sheets within polymer hosts. A polystyrene-graphene composite formed by this route exhibits a percolation threshold of approximately 0.1 volume per cent for room-temperature electrical conductivity, the lowest reported value for any carbon-based composite except for those involving carbon nanotubes; at only 1 volume per cent, this composite has a conductivity of approximately 0.1 S m(-1), sufficient for many electrical applications. Our bottom-up chemical approach of tuning the graphene sheet properties provides a path to a broad new class of graphene-based materials and their use in a variety of applications.     

MXene材料储能应用研究进展

MXene是一种新型的二维过渡金属碳化物或碳氮化物,具有类似石墨烯的二维结构.MXene因其独特的物理和化学特性,以及在储能、催化、电子与光电子等领域中的良好应用前景而受到广泛关注.介绍了MXene材料的制备、表征以及在锂离子电池、钠离子电池、锂硫电池和超级电容器等储能器件上的最新研究成果.最后,对MXene材料的未来发展和挑战进行了介绍.     

纳米石墨烯的减摩抗磨研究进展

近年来,纳米石墨烯在摩擦学领域引起了一番新的热潮,纳米石墨烯因具有独特的物化性能、超薄层间结构和优良的自润滑性能,将其作为润滑添加剂能够显著提高机体的摩擦学性能。文中综述了纳米石墨烯作为固体润滑剂、水基润滑添加剂和油基润滑添加剂以及与其他纳米粒子的复合材料作为润滑添加剂的研究进展,归纳总结了石墨烯的保护层薄膜、低表面能、自润滑性能、复合材料共同作用等减摩抗磨机理;指出了纳米石墨烯存在的问题,如不同添加量的石墨烯对溶液的抗磨减摩影响较大,石墨烯的层数和结构都是影响机体抗磨减摩的重要因素,并对今后石墨烯的研究方向进行了展望。     

石墨烯吸附材料的制备与应用研究进展

石墨烯具有独特的结构、优异的性能,在诸多领域有广泛的应用.石墨烯层的原子均为表面原子,其表面积非常大,是天然的吸附材料.其易于制备、成本低廉等优势使得石墨烯吸附材料成为水处理研究中的热点.石墨烯及其复合材料已经在重金属、染料、杀虫剂、抗生素、石油等污染物的治理方面得到应用.综述了石墨烯吸附材料的制备方法以及其在污水处理方面的应用.分析了污染物在石墨烯吸附材料上的吸附行为,并讨论了石墨烯与污染物的相互作用.着重关注官能团对石墨烯吸附材料性能的影响,从化学视角提出了设计高效石墨烯吸附剂的思路.