Synthesis, properties, and applications of graphene oxide/reduced graphene oxide and their nanocomposites

Thanks to their remarkable mechanical, electrical, thermal, and barrier properties, graphene-based nanocomposites have been a hot area of research in the past decade. Because of their simple top-down synthesis, graphene oxide (GO) and reduced graphene oxide (rGO) have opened new possibilities for gas barrier, membrane separation, and stimuli-response characteristics in nanocomposites. Herein, we review the synthesis techniques most commonly used to produce these graphene derivatives, discuss how synthesis affects their key material properties, and highlight some examples of nanocomposites with unique and impressive properties. We specifically highlight their performances in separation applications, stimuli-responsive materials, anti-corrosion coatings, and energy storage. Finally, we discuss the outlook and remaining challenges in the field of practical industrial-scale production and use of graphene-derivative-based polymer nanocomposites.

APPLICATION OF SUPERCRITICAL TECHNIOUE IN PREPARATION OF ULTRAFINE OXIDE PARTICLE

Ultrafine particle (UFP)alumina has been prepared by supereritical fluid drying process of inorganic salt with organic solvent system, which is reported for the first time. UFP-alumina prepared from this system is featured by its hish specific surface area, large pore volume, small perticle size and low bulk density.

Preparation of Graphene Materials and Their Applications in the Field of Electrochemistry

In the development of modern society, many new materials and technologies have been integrated into the development of various industries. As a new type of two-dimensional carbon nanomaterials, graphene has great advantages in physical and chemical properties and is widely used in various fields of development. Among them, the electrochemical method is one of the important ways to prepare graphene materials, which has the characteristics of quickness and environmental protection, and can effectively produce a large amount of high-quality graphene and its composite materials. Based on this, the paper introduces the preparation method of graphene materials and studies the application of graphene materials in the field of electrochemistry.

Reduced Graphene Oxide/Carbon Nanofiber Based Composite Fabrics with Spider Web‑like Structure for Microwave Absorbing Applications

Composite fabrics with excellent microwave absorbing performance are highly desired.Herein,reduced graphene oxide/carbon nanofiber(rGO/CNF)based composite fabrics with spider web-like structure were successfully synthesized by electrostatic spinning technique.The spider web-like structure in the composite fabrics provides a connected network for efficient conductive loss of microwave energies.Magnetic loss benefits from the deposited nickel nanoparticles(Ni NPs)anchored in the carbon nanofibers.Meanwhile,the deposited thin polypyrrole(PPy)layers on the conductive network acts as a protective layer for Ni NPs as well as provides abundant interfaces for dissipating electromagnetic energies,which endow the composite fabrics stable microwave absorbing performance.Due to the synergistic effect of microwave absorb-ing mechanism,the maximum reflection loss(RL_(max))of the composite fabric at 6.72 GHz is-46.15 dB,and the effective absorption bandwidth(EAB)is as wide as 8.63 GHz(from 9.37 to 18 GHz).What's more,favorable mechanical and heat insulation properties of the composite fabrics reveal its multifunctional advantages.This rGO/CNF based composite fabric demonstrates a new direction for multifunctional and flexible microwave absorbing materials(MAMs).

Graphene quantum dots:preparations,properties,functionalizations and applications

Zero-dimensional graphene quantum dots(GQDs)exhibit many different properties,such as strong fluorescence,nonzero bandgap and solubility in solvents,compared to two-dimensional graphene.GQDs are biocompatible and have low toxicity;hence,they are widely used in the biomedical field.The edge effect of GQDs is of particular interest because edge modification can regulate the performance of nanomaterials.In this review,various preparation methods for GQDs,which can be divided into three main categories,namely top-down,bottom-up and chemical methods,are discussed.The unique optical,electrical,thermal and magnetic properties of GQDs are reviewed.The functionalization of GQDs by doping with heteroatoms and forming composites with other materials is studied,and the characteristics of these GQDs are also discussed.The applications of these GQDs in the fields of optics,electricity,optoelectronics,biomedicine,energy,agriculture and other emerging interdisciplinary fields are reviewed to highlight the enormous potential of nanomaterials.This review reports on the recent advancement in GQD research and suggests future directions for the development of GQDs.

Structure and synthesis of graphene oxide

Graphene oxide(GO)is one typical two-dimension structured and oxygenated planar molecular material.Researchers across multiple disciplines have paid enormous attention to it due to the unique physiochemical properties.However,models used to describe the structure of GO are still in dispute and ongoing to update.And currently,synthesis methods for mass production are seemingly abundant but in fact,dominated by a few core methodologies.To update with the state-of-art opinions and progresses,herein we present a mini critical review regarding the synthesis of GO as well as its models and simulations of structure.Also,we discuss the perspectives.

Efficient Preparation and Characterization of Functional Graphene with Versatile Applicability

Graphene,as star versatile materials having extraordinarily high electric conductivity,electron mobility,thermal conductivity,thermal stability,optical transparency,and mechanical strength,has attracted much attention from scientists and engineers in the field of materials,chemistry,physics,energy,and environment in the last decade and achieved fruitful accomplishment.This review discusses preparation strategies,functionality,characterization,and applications for two dimensional nanosheet and quasi-onedimensional nanoribbon of graphene through direct exfoliation of graphite,chemical vapor deposition of hydrocarbon,laser-induced direct synthesis of graphene,laser etched graphene oxide in the dry state without the use of toxic reducing agent hydrazine,unzipping carbon nanotube,and polycondensation of polycyclic aromatics on the basis of 178 representative references mostly in 2015.The stabilization of graphene oxide prepared in chemical preparation in " top-down" is emphasized.Several vital classic methods of characterizing molecular structure,C/O ratio,defect,morphology,single-or few-layered( 2 to 10 layers) structure,porous and hollow structures,including Raman spectroscopy,AFM,SEM,TEM,STM,electron diffraction,X-ray diffraction,and X-ray photoelectron spectroscopy are systematically introduced.Because graphene possesses novel incomparable multifunctionalities,its versatile applications as novel conducting additives,reinforcing filler,separation membrane,sensor,anticorrosive coating,catalyst,electromagnetic shield,lubricant,and flexible electrode materials in electrochemical and electronic devices,including photovoltaic cells,supercapacitors,rechargeable batteries,sensors,field effect transistors,light emitting diodes,separation membranes,adsorbents and absorbents,catalysts,electro-optic modulator,terahertz emitter and detector,and semiconductors,have been mentioned.Especially in the aspect of both high performance and cost-effectiveness,graphene is expected to be even superior to the expensive carbon nanotubes.

Eco-friendly reduced graphene oxide for the determination of mycophenolate mofetil in pharmaceutical formulations

Graphene oxide(GO) was synthesized and characterized by scanning electron microscopy(SEM), energy dispersive X-ray spectroscopy(EDX), atomic force microscopy(AFM), X-ray diffraction(XRD), Fourier transform-infrared spectroscopy(FT-IR) and thermogravimetric analysis(TGA). GO was then electrochemically reduced and used for electrochemical study of mycophenolate mofetil(MMF). The electrochemically reduced graphene oxide(ERGO) film on glassy carbon electrode(GCE) showed enhanced peak current for electrooxidation of MMF. MMF exhibited two irreversible oxidation peaks at 0.84 V(peak a_1)and 1.1 V(peak a_2). Effects of accumulation time, pH and scan rate were studied and various electrochemical parameters were calculated. A differential pulse voltammetric method was developed for the determination of MMF in bulk samples and pharmaceutical formulations. Linear relationship was observed between the peak current and concentration of MMF in the range of 40 nM–15 μM with a limit of detection of 11.3 nM. The proposed method is simple, sensitive and inexpensive and, hence, could be readily adopted in clinical and quality control laboratories.

Efficient removal of chlorophenols from water with a magnetic reduced graphene oxide composite

A magnetic reduced graphene oxide composite(MRGO) was successfully prepared by a simple and green method. MRGO was then used as an adsorbent and found to exhibit enhanced removal efficiency for various chlorophenols(CPs) from water compared with its precursors, graphene oxide(GO) and reduced graphene oxide. The CPs were o-chlorophenol, p-chlorophenol, 2,4-dichlorophenol, and 2,4,6-trichlorophenol. Among them, 2,4,6-trichlorophenol, which exhibited the lowest water solubility and highest molecular weight, most easily bound to MRGO. The preferential interactions between MRGO and CPs were hydrophobic interactions(?-? stacking and hydrophobic effect). This result was confirmed by the equilibrium adsorption behavior in which isotherms were all well described by Freudlich model, indicating heterogeneous and multilayer adsorption. Therefore, CP adsorption was more favored under neutral and acidic conditions, and the decreased removal efficiency of MRGO at higher p H levels was due to the improved hydrophilicity of CPs for deprotonation effect. Moreover, MRGO showed fast removal of each CP, achieving adsorption equilibrium within 10.0 min, presented efficient separation from water under an external magnetic field, and was easily regenerated using dilute Na OH aqueous solution after reaching saturated adsorption. Adsorption capacity of the regenerated MRGO had almost no loss until after five cycles. In summary, MRGO was an efficient adsorbent for the removal of various CPs and had considerable application potential in water treatment.

Towards industrialization of graphene oxide

Graphene oxide(GO)has demonstrated potential applications in various fields,and attracted intensive attention in industry as well.Numerous companies worldwide have been working on the industrial applications of GO-based materials in,e.g.,thermal management,multifunctional composites,anti-corrosion paints,lubricants,energy storage,environment protection and biomedicals.This review presents a short summary on the proceedings of GO towards industrialization,including the large-scale production and some promising applications,by providing views on the processing strategies and challenges specifically for the industrial use of GO.This review would help the scientists in this area to find topics for overcoming challenges together with engineers.

Poly(ethylene glycol) conjugated nano-graphene oxide for photodynamic therapy

A novel methoxy-poly(ethylene glycol) modified nano-graphene oxide(NGO-mPEG) was designed and synthesized as a photosensitizer(PS) carrier for photodynamic therapy of cancer.NGO with a size below 200 nm was prepared using a modified Hummers' method.NGO was observed by AFM to exhibit a structure with single-layer graphene oxide sheets down to a few nanometers in height.Hydrophilic mPEG conjugation of NGO(NGO-mPEG) was found to enhance solubility in cell culture media.No apparent cytotoxicity of the NGO-mPEG was observed towards MCF-7 carcinoma cell line.Zinc phthalocyanine(ZnPc),a photosensitizer for photodynamic therapy,was loaded in the NGO-PEG through π-π stacking and hydrophobic interactions,with the drug loading efficiency up to 14 wt%.Hydrophobic ZnPc was internalized in MCF-7 cells,exhibiting a pronounced phototoxicity in the cells under Xe light irradiation.The results indicate a great potential of NGO-mPEG for photodynamic therapy of cancer.

Preparation of some new arylseleno compounds and application in the oxidation of olefins

Fifteen pyridine and substituted benzene diselenides,seleninic acids and seleninic anhydrides have been synthesized.Among them,4,4'-dipyridinediselenide,bis(2,4-dimethoxyphenyl)diselenide, 2,4-dimethoxyphenyl seleninic acid,2-pyridineseleninic acid,2-pyridineseleninic anhydride,4-pyridine- seleninic anhydride,2-nitrophenyl seleninic anhydride and 4-nitrophenyl seleninic anhydride were new compounds.Their regioselective oxidation or dehydrogenation of β-pinene,3β-benzoyloxycholest- 5-ene and androstan-3-one have been studied and compared.2-Pyridineseleninic anhydride is a more efficient oxidant than the others;most of the substituted benzeneseleno derivatives did not give the expected products.

石墨烯复合橡胶沥青改性制备方法及应用

沥青作为基础路面工程的重要选材,其性能的好坏直接关系到路面的使用年限以及使用性能,为解决沥青在实践应用中存在的老化以及流动性问题,研究提出了一种石墨烯复合橡胶对沥青进行改性的方式,并介绍了其制备方法。通过对石墨烯复合橡胶沥青材料性能的测定发现这一材料的微观结构更为紧密,且其流变性能测试以及老化性能测试结果都明显的高于基底沥青材料,更能够符合道路工程以及建筑防水的现实需要,具有较为广泛的应用前景。

石墨烯纤维及其改性纺织品的研究进展

石墨烯纤维是由石墨烯纳米片层在一维受限空间中组装而成的材料,具有优异的力学性能、电学性能和热学性能。石墨烯纤维的制备方法主要包括湿法纺丝、电纺丝和化学气相沉积等技术。石墨烯改性织物的制备方法多样,常用的有直接浸轧还原法、复配液整理法、涂布法、水热法和化学气相沉积法等。其中,直接浸轧还原法通过将织物浸泡在石墨烯氧化物溶液中,然后还原形成石墨烯膜;复配液整理法是将石墨烯与其他功能材料混合后处理织物;涂布法是将石墨烯涂布在织物表面;水热法利用高温高压条件下石墨烯的生长和沉积;化学气相沉积法则是在气相中通过化学反应沉积石墨烯膜。石墨烯纺织品目前在智能穿戴设备、抗菌防臭、导电导热等领域展现出广阔的应用前景。

氧化石墨烯/聚酰胺纳米复合材料研究进展

石墨烯具有优异的光学、电学和力学性质,石墨烯/聚合物纳米复合材料受到了学术界和产业界的共同关注。近年来,氧化石墨烯/聚酰胺纳米复合材料在提高材料性能、拓展下游应用方面取得了突破。文中综述了氧化石墨烯、还原氧化石墨烯和功能化氧化石墨烯与不同聚酰胺复合的研究进展,总结了原位聚合、熔融复合和溶液共混等制备方法,讨论了氧化石墨烯的功能化方法以及纳米复合材料的化学结构、热性能、力学性能、电化学性能及应用,同时对该领域的发展和面临的挑战进行了探讨。

扫描电子显微镜试样制备对石墨烯形貌观察的影响

以石墨烯、氧化石墨烯、还原石墨烯为研究对象,考察了扫描电子显微镜试样制备对石墨烯形貌观察的影响,包括喷镀金属对粉末试样的影响以及分散基底对石墨烯溶液试样的影响。实验结果表明,针对石墨烯和还原石墨烯等导电性能好的粉末试样,不需要喷镀金属以增加导电性,将粉末试样简单制备后直接进行观察即可获得良好的效果;对于导电性较差的氧化石墨烯及石墨烯衍生物,可以选用喷镀铂的方式增加粉末试样的导电性,但要注意电流不宜过大,时间不宜过长,否则将影响喷镀效果,难以还原试样的真实形貌;将石墨烯溶液试样分散在单晶硅片和单面铜胶带上,均可在不喷镀金属的条件下获得良好的表征效果,因此单晶硅片以及导电性更好的单面金属胶带均可作为石墨烯溶液试样的分散基底。

石墨烯基/半导体金属氧化物复合光催化剂制备工艺研究进展

光催化剂因其具有强氧化性、高化学稳定性、环保、无毒性等优点,广泛应用于污水处理、空气净化、疾病治疗、环境修复等领域。为改善纳米光催化剂的光响应范围,添加石墨烯基系列材料已成为国内外的研究热点。综述了石墨烯基材料与半导体金属氧化物复合光催化剂研究现状,总结了不同制备工艺对石墨烯基/半导体金属氧化物复合光催化剂形貌结构和光催化性能的影响,对各类制备工艺的优缺点进行了比较,并指出了相关工艺需要克服的关键技术问题,展望了石墨烯基/半导体金属氧化物复合光催化剂未来发展方向,以期为提高半导体金属氧化物的光催化性能和石墨烯基/半导体金属氧化物复合光催化剂制备工艺的优化提供参考。

氧化石墨烯/液晶网络复合膜的响应性能及仿生设计

液晶网络是由液晶聚合物单体适度交联得到,兼具有聚合物的弹性和液晶的各向异性,包括多刺激响应能力、可逆的驱动以及可编程的形状变形等性能,因此具有良好的外场响应性、分子协同作用和弹性。氧化石墨烯膜层具有优秀的光热转换性能,而光具有环保性、远程可控性等优异的特性,因此光致形变的氧化石墨烯/液晶网络(GO-LCNs)复合膜逐渐成为人们的研究热点。它可以制作柔性机器人、仿生光热驱动器等先进器件,具有良好的发展前景。本文在两种厚度的液晶网络膜上制作氧化石墨烯薄膜,构成氧化石墨烯/液晶网络复合膜,测量了温度或红外光作用下液晶网络膜厚度对其响应性能的影响。本文结果为复合膜的应用设计提供了实验基础,并以此为基础设计了GO-LCNs复合膜的仿生器件。

超亲油疏水石墨烯海绵的制备及工业应用

采用改进的Hummers法制备氧化石墨烯(GO),经超声浸渍和电热鼓风干燥箱170℃高温还原法成功制备出超亲油疏水的PU/r GO海绵。通过对制备的PU/r GO海绵进行了形貌、接触角和油水分离性能进行测试研究。结果表明,PU/r GO海绵对多种有机溶剂接触角0°,而水接触角则达到154.7°,经过连续油水分离器吸附挤压10次后,水接触角降低至140.2°,仍旧具有较好的亲油疏水性能。进水流量为50L·h^(-1)时,油水分离装置的平均除油率达最优。保证平均进水含油量为1807mg·L^(-1),稳定连续运行103h后PU/r GO海绵达到吸附饱和,出水平均含油量为10.0mg·L^(-1)左右,经测算PU/r GO海绵动态吸油量为8.32g·g^(-1)。自主研发生产的以PU/r GO海绵为核心单元的石墨烯基亲油疏水油水分离设备,可以实现不损失胺液的同时下,对含油贫胺液进行高效的油与胺液的分离,除油效率最高可达95%以上。

ZIF-8复合羧基化氧化石墨烯的制备及其性能研究

本实验采用热容剂法制取样品,样品的XRD图谱中2θ=7.3°,10.36°,12.7°,14.7°,16.42°,18.02°,22.1°,24.5°时,与ZIF-8复合羧基化氧化石墨烯标准的图谱具有一致的特征衍射峰,也就是(011)、(002)、(112)、(022)、(013)、(222)、(114)、(233)等晶面。没有杂质峰,说明制得到的ZIF-8复合羧基化氧化石墨烯材料的结晶度非常高。在440℃后ZIF-8复合羧基化氧化石墨烯的热稳定性比较好,石墨烯引入羧基使热稳定性增强。样品比表面积为4.67 m~2/g,ZIF-8复合羧基化氧化石墨烯N_2吸附/脱附饱和吸附量在13.52 cm~3/g,因此可知ZIF-8复合羧基化氧化石墨烯可以用来吸附分离N_2,介孔的结构使得ZIF-8复合羧基化氧化石墨烯适用于气体吸附和为离子运输提供良好的通道。