In vitro investigations on the effects of graphene and graphene oxide on polycaprolactone bone tissue engineering scaffolds

Polycaprolactone(PCL)scaffolds that are produced through additive manufacturing are one of the most researched bone tissue engineering structures in the field.Due to the intrinsic limitations of PCL,carbon nanomaterials are often investigated to reinforce the PCL scaffolds.Despite several studies that have been conducted on carbon nanomaterials,such as graphene(G)and graphene oxide(GO),certain challenges remain in terms of the precise design of the biological and nonbiological properties of the scaffolds.This paper addresses this limitation by investigating both the nonbiological(element composition,surface,degradation,and thermal and mechanical properties)and biological characteristics of carbon nanomaterial-reinforced PCL scaffolds for bone tissue engineering applications.Results showed that the incorporation of G and GO increased surface properties(reduced modulus and wettability),material crystallinity,crystallization temperature,and degradation rate.However,the variations in compressive modulus,strength,surface hardness,and cell metabolic activity strongly depended on the type of reinforcement.Finally,a series of phenomenological models were developed based on experimental results to describe the variations of scaffold’s weight,fiber diameter,porosity,and mechanical properties as functions of degradation time and carbon nanomaterial concentrations.The results presented in this paper enable the design of three-dimensional(3D)bone scaffolds with tuned properties by adjusting the type and concentration of different functional fillers.

结构有序的Si/void/C/graphene纳米复合结构的制备及储锂性能

采用简单的超声、冷冻干燥和热还原相结合的自组装方法,设计和构建了纳米硅核/间隙/无定形碳壳层/石墨烯(Si/void/C/graphene)三维有序纳米复合结构。在该结构中,纳米硅核与碳壳层之间的空隙有效避免了硅的巨大体积膨胀对碳层的破坏,大幅度提高了锂离子电池的循环稳定性;将Si/void/C纳米结构嵌入在石墨烯层与层之间,利用石墨烯卓越的导电性和柔韧性,进一步缓冲了硅材料的体积效应和提高了复合材料的导电性能。该复合材料在4200 m A·h·g^(-1)(1 C)电流密度下循环1000次后比容量仍高达1603 m A·h·g^(-1);在67 A·g^(-1)(16 C)的高倍率下,比容量仍有310 m A·h·g^(-1),显示出了在锂离子电池负极材料领域的巨大应用潜力。

Use of graphene-based materials as carriers of bioactive agents

Graphene possesses a large specific surface area, a high Young’s modulus, high fracture strength, high electrical conductivity, and excellent optical performance. It has been widely studied for biomedical use since its first appearance in the literature. This article offers an overview of the latest advances in the design of graphene-based materials for delivery of bioactive agents. To enhance the translation of these carriers into practical use, the toxicity involved is needed to be examined in future research in more detail. In addition, guidelines for standardizing experimental conditions during the evaluation of the performance of graphene-based materials are required to be established so that candidates showing higher practical potential can be more effectively identified for further development. This can streamline the optimization and use of graphene-based materials in delivery applications.

Utilization of Nanomaterials as Anode Modifiers for Improving Microbial Fuel Cells Performance

Microbial fuel cells(MFCs)are an attractive innovation at the nexus of energy and water security for the future.MFC utilizes electrochemically active microorganisms to oxidize biodegradable substrates and generate bioelectricity in a single step.The material of the anode plays a vital role in increasing the MFC’s power output.The anode in MFC can be upgraded using nanomaterials providing benefits of exceptional physicochemical properties.The nanomaterials in anode gives a high surface area,improved electron transfer promotes electroactive biofilm.Enhanced power output in terms of Direct current(DC)can be obtained as the consequence of improved microbe-electrode interaction.However,several limitations like complex synthesis and degeneration of property do exist in the development of nanomaterial-based anode.The present review discusses different renewable nanomaterial applied in the anode to recover bioelectricity in MFC.Carbon nanomaterials have emerged in the past decade as promising materials for anode construction.Composite materials have also demonstrated the capacity to become potential anode materials of choice.Application of a few transition metal oxides have been explored for efficient extracellular electron transport(EET)from microbes to the anode.

微波法制备碳纳米材料的机理及进展

微波法具有加热快速、易于控制、反应均匀等优点,是制备功能性碳纳米材料的重要技术。其制备原理是基于碳基材料优异的本征介电性能,碳基材料与微波电磁场相互作用产生介电损耗,快速形成局部高能场,实现高速制备。本文首先简要介绍了微波与物质的相互作用机理,然后分别从微波在制备过程中的作用、关键实验参数以及微波制备的碳材料的特征等方面详细介绍了微波作为能量输入制备一维碳纳米管、二维石墨烯以及三维纳米多孔碳的优势,最后对宏量快速制备多功能和高性能碳纳米材料的发展进行了展望。

石墨烯基二氧化碳还原电催化材料研究进展

通过电化学方法来减少二氧化碳(CO_(2)),同时生产燃料和高附加值化学品,是一种克服全球变暖问题的有效策略,对于缓解能源和环境的双重压力具有重要的现实意义。由于CO_(2)稳定的分子结构,设计高选择性、高能效和低成本的电催化剂是关键。石墨烯及其衍生物因其独特且优异的物理、力学和电学性能,相对较低的成本,使其在CO_(2)电还原方面具有竞争力。此外,石墨烯基材料的表面可以通过使用不同的方法进行改性,包括掺杂、缺陷工程、构建复合结构和包覆形状。首先,本文综述了电化学CO_(2)还原的基本概念、评价标准,以及催化原理和过程。其次,简要介绍了石墨烯基催化剂的制备方法,并按照催化位点的类别,总结了石墨烯基催化剂近年来的研究进展。最后,对CO_(2)电还原技术未来发展方向进行了探讨与展望。

碳纳米材料对含能材料降感研究进展

为了充分利用碳纳米材料的性能优势,本文总结了碳纳米材料对含能材料降感的研究进展。分析了典型碳纳米材料,如石墨、碳纳米管、石墨烯及其衍生物和富勒烯及其衍生物对降低含能材料撞击感度、冲击波感度和摩擦感度的作用,并探讨了不同碳纳米材料的降感机制。最后对碳纳米材料在该领域的发展前景进行了展望,认为优化碳纳米材料与含能材料的复合材料制备工艺、深入理解碳纳米材料性质并进行功能化修饰、调控碳纳米材料与含能材料的界面相互作用以及进一步探究碳纳米材料的降感机制将是今后研究的重点工作。

碳纳米材料在周围神经再生领域的研究与应用

背景:虽然神经导管为周围神经修复提供了潜在的治疗手段,但传统神经导管只能为修复过程提供机械通道支持,治疗效果仍有待提高。碳纳米材料具有良好的理化性质,在电化学及组织工程等领域有着广阔的应用前景。负载碳纳米材料的神经导管,在经过适宜的功能化修饰后,有望进一步提升神经修复质量。目的:对近年来负载碳纳米材料的神经导管/支架应用于周围神经修复的研究进展作一综述。方法:在PubMed、Web of Science、中国知网和万方数据库中检索在周围神经再生方面应用碳纳米材料导管的相关文献,英文检索词为“carbon nanomaterials,carbon-based nanomaterials,nerve conduit,nerve guidance conduit,scaffold,nerve regeneration,peripheral nerve repair,peripheral nerve injury”,中文检索词为“碳纳米材料,碳材料,石墨烯,碳纳米管,神经导管,神经支架,神经修复,神经再生,周围神经损伤”,最终纳入69篇文章进行综述。结果与结论:①碳纳米材料主要通过激活钙离子通道及诱导胞内钙活动发生的方式恢复受损神经生物电信号传导,不同神经导管设计策略的应用提高了神经修复的效果。②神经内血管化是修复周围神经损伤的前提,碳纳米材料生成的活性氧及活性氮触发了后续相关信号通路,促进神经内新生血管形成。③M1和M2型巨噬细胞的比例变化会影响周围神经损伤的修复,碳纳米材料在损伤早期通过促进巨噬细胞向M2型极化以发挥抗炎和促神经再生作用。④部分碳纳米材料在胞内诱导过量活性氧生成,可能具有不利于神经修复的细胞毒性,但合适的功能化修饰能够改善碳纳米材料产生的不良作用。⑤碳纳米材料虽然能够恢复周围神经损伤微环境,发挥促进周围神经再生的积极作用,但由于固有的细胞毒性及不明确的体内转归降解途径,碳纳米材料距离临床应用仍有距离。未来研究可以通过如功能化改性等方法提高碳纳米材料的生物相容性,而经过改良的碳纳米材料在神经组织工程领域有着较好的应用前景。

Growth of Large-Area Single- and Bi-Layer Graphene by Controlled Carbon Precipitation on Polycrystalline Ni Surfaces

We report graphene films composed mostly of one or two layers of graphene grown by controlled carbon precipitation on the surface of polycrystalline Ni thin films during atmospheric chemical vapor deposition(CVD).Controlling both the methane concentration during CVD and the substrate cooling rate during graphene growth can signifi cantly improve the thickness uniformity.As a result,one-or two-layer graphene regions occupy up to 87%of the fi lm area.Single layer coverage accounts for 5%11%of the overall fi lm.These regions expand across multiple grain boundaries of the underlying polycrystalline Ni fi lm.The number density of sites with multilayer graphene/graphite(>2 layers)is reduced as the cooling rate decreases.These fi lms can also be transferred to other substrates and their sizes are only limited by the sizes of the Ni fi lm and the CVD chamber.Here,we demonstrate the formation of fi lms as large as 1 in^(2).These fi ndings represent an important step towards the fabrication of large-scale high-quality graphene samples.

The use of carbon nanomaterials in membrane distillation membranes:a review

Membrane distillation(MD)is a thermal-based separation technique with the potential to treat a wide range of water types for various applications and industries.Certain challenges remain however,which prevent it from becoming commercially widespread including moderate permeate flux,decline in separation performance over time due to pore wetting and high thermal energy requirements.Nevertheless,its attractive characteristics such as high rejection(ca.100%)of nonvolatile species,its ability to treat highly saline solutions under low operating pressures(typically atmospheric)as well as its ability to operate at low temperatures,enabling waste-heat integration,continue to drive research interests globally.Of particular interest is the class of carbon-based nanomaterials which includes graphene and carbon nanotubes,whose wide range of properties have been exploited in an attempt to overcome the technical challenges that MD faces.These low dimensional materials exhibit properties such as high specific surface area,high strength,tuneable hydrophobicity,enhanced vapour transport,high thermal and electrical conductivity and others.Their use in MD has resulted in improved membrane performance characteristics like increased permeability and reduced fouling propensity.They have also enabled novel membrane capabilities such as in-situ fouling detection and localised heat generation.In this review we provide a brief introduction to MD and describe key membrane characteristics and fabrication methods.We then give an account of the various uses of carbon nanomaterials for MD applications,focussing on polymeric membrane systems.Future research directions based on the findings are also suggested.

Functionalization of nitrogen-doped graphene quantum dot:A sustainable carbon-based catalyst for the production of cyclic carbonate from epoxide and CO_(2)

A series of organic compounds were successfully immobilized on an N-doped graphene quantum dot (N-GQD) to prepare a multifunctional organocatalyst for coupling reaction between CO_(2)and propylene oxide (PO).The simultaneous presence of halide ions in conjunction with acidic-and basic-functional groups on the surface of the nanoparticles makes them highly active for the production of propylene carbonate (PC).The effects of variables such as catalyst loading,reaction temperature,and structure of substituents are discussed.The proposed catalysts were characterized by different techniques,including Fourier transform infrared spectroscopy (FTIR),field emission scanning electron microscopy/energy dispersive X-ray microanalysis (FESEM/EDX),thermogravimetric analysis (TGA),elemental analysis,atomic force microscopy (AFM),and ultraviolet–visible (UV-Vis) spectroscopy.Under optimal reaction conditions,3-bromopropionic acid (BPA) immobilized on N-GQD showed a remarkable activity,affording the highest yield of 98%at 140℃ and 106Pa without any co-catalyst or solvent.These new metal-free catalysts have the advantage of easy separation and reuse several times.Based on the experimental data,a plausible reaction mechanism is suggested,where the hydrogen bonding donors and halogen ion can activate the epoxide,and amine functional groups play a vital role in CO_(2)adsorption.

The utilization of carbon-based nanomaterials in bone tissue regeneration and engineering:Respective featured applications and future prospects

In recent years,with advancements in bone tissue regeneration and engineering technologies,carbon-based nanomaterials(CNMs)have progressively demonstrated advantages in the therapies of critical bone defects and related diseases that conventional substances fail to develop,such as excellent mechanical properties,large specific surface,tunable surface characteristics,and superior biocompatibility.More importantly,carbon-based nanomaterials with efficient cell proliferation and osteogenic differentiation could have a significant impact on bone tissue regeneration.In this paper,we have reviewed the characteristic applications of extraordinary types of carbon-based nanomaterials(fullerene,carbon dots,carbon nanotubes,as well as graphene and its derivatives)in bone tissue regeneration and engineering based on their structural properties,with a view to presenting their unique advantages,applications,and current directions of development as specifically and comprehensively as possible.

碳纳米材料在天然橡胶中的分散及补强研究

对不同碳纳米材料进行结构分析,通过机械混炼将不同用量的碳纳米材料添加到天然橡胶(NR)中,研究碳纳米材料在NR中的分散状态及对胶料硫化特性和物理性能的影响。结果表明:随着碳纳米材料用量的增大,胶料的Fmax-FL增大,t90缩短;当碳纳米材料用量小于6份时,可以在橡胶基体中均匀分散;在低应变下,4种碳纳米材料对NR的补强作用从大到小的顺序为多壁碳纳米管、物理法石墨烯、等离子体法石墨烯、炭黑N234,但在高应变下多壁碳纳米管会影响NR的结晶自补强性能。

Low-temperature synthesis of sp^2 carbon nanomaterials

sp^2 carbon nanomaterials are mainly composed of sp^2-hybridized carbon atoms in the form of a hexagonal network. Due to the p bonds formed by unpaired electrons, sp^2 carbon nanomaterials possess excellent electronic, mechanical, and optical properties, which have attracted great attention in recent years.As the advanced sp^2 carbon nanomaterials, graphene and carbon nanotubes(CNTs) have great potential in electronics, sensors, energy storage and conversion devices, etc. The low-temperature synthesis of graphene and CNTs are indispensable to promote the practical industrial application. Furthermore, graphene and CNTs can even be expected to directly grow on the flexible plastic that cannot bear high temperature,expanding bright prospects for applications in emerging flexible nanotechnology. An in-depth understanding of the formation mechanism of sp^2 carbon nanomaterials is beneficial for reducing the growth temperature and satisfying the demands of industrial production in an economical and low-cost way. In this review, we discuss the main strategies and the related mechanisms in low-temperature synthesis of graphene and CNTs, including the selection of precursors with high reactivity, the design of catalyst, and the introduction of additional energy for the pre-decomposition of precursors. Furthermore, challenges and outlooks are highlighted for further progress in the practical industrial application.

氮掺杂石墨烯/多孔碳复合材料的制备及其氧还原催化性能

采用简单、无模板的方法制备了氮掺杂多孔石墨烯/碳复合材料(NPGC)。采用SEM、XRD、Raman、XPS等分析手段对NPGC的形貌、组成以及结构进行了表征,利用旋转圆盘电极技术测试了其电催化氧还原反应(ORR)活性。结果表明,葡萄糖在水热后生成的碳与石墨烯成功复合,并在950℃炭化、活化后形成了相互渗透、结构良好的三维片状多孔网络结构;其氮含量高达9.47%。NPGC作为一种高效的非金属ORR电催化剂,在碱性溶液中具有较高的起始电位[0.87 V(vs RHE)]和较大的极限电流密度(4.7 mA?cm?2),以及其ORR平均转移电子数为3.8。与商业Pt/C催化剂相比,NPGC具有较强的耐甲醇性和长期耐久性,且制备成本较低,具有广阔的应用前景。

新型纳米碳材料的应用新进展

近年来,富勒烯、纳米碳管和石墨烯的发现和报道使纳米碳材料受到各界广泛地重视。新型碳材料可以显著提高复合材料的机械性能和导热性能;制备出具有特殊形貌和微观结构的电极材料,应用在电化学器件中可以改善电化学性能,提高能量转化效率;在催化剂和储氢材料方面也有良好的应用前景。主要总结了这三种纳米碳材料的优异性能及其在储氢材料、超级电容器、催化材料等领域的最新研究进展,并对其未来发展趋势予以展望。

纳米碳材料在聚合物阻燃中的应用研究进展

综述了近年来纳米碳材料在聚合物阻燃应用方面所取得的研究进展,重点讨论了碳纳米管、富勒烯、石墨烯和纳米炭黑等纳米碳材料在单独用作阻燃剂、改性后用作阻燃剂以及与其他物质协同阻燃聚合物方面取得的研究成果,并指出聚合物/纳米碳材料阻燃体系的研究应侧重于阻燃机理,并将纳米碳材料与其他阻燃剂协同使用,以便发挥各自的优势。

电吸附电极制备研究进展

电吸附是一种相对新兴的水处理技术,其中电极是制约电吸附性能的关键因素,也是电吸附研究的热点。综述了近年来电吸附电极的研究情况,主要介绍了以活性炭(纤维)、石墨烯、炭气凝胶、碳纳米材料为原材料的电极制备研究进展。其中石墨烯和碳纳米材料基体电极具有良好的循环使用性能和高吸附容量,是目前最具应用前景的一类电吸附电极,是今后电吸附电极研究的主要方向。

纳米材料增强复合钎料的研究进展

综合评述了纳米材料增强复合钎料的研究与应用现状。首先介绍了纳米材料增强复合钎料的制备方法,讨论了机械混合法与原位合成法的工艺及特点,然后分别从金属颗粒、氧化物或其他化合物及碳纳米材料3个方面来介绍纳米材料对复合钎料微观组织及性能的影响。重点指出了具有优异性能的碳纳米管与石墨烯材料增强复合钎料的研究进展,并对其发展趋势进行分析和展望。

煤基纳米碳材料制备技术的研究与应用

纳米碳材料可以由化工产品、木材、煤等原料制取,在现代工业中发挥着越来越重要的作用。我国煤炭资源丰富,开发煤基纳米碳材料制备技术意义重大。文章介绍了碳纳米管和石墨烯两种具有代表性纳米碳材料的结构、特点、应用前景,阐述了以煤为原料制备两种材料的工艺流程,以为提高煤炭资源的综合利用程度提供理论参考。