碳纳米结构构建:十二烷基二甲基苄基氯化铵@氯化钠体系

碳纳米材料用途十分广泛,但其形貌的控制和制备方法的完善仍然是个研究热点和亟需攻克的难点。在此,基于阳离子表面活性剂十二烷基二甲基苄基氯化铵(DDBAC)@氯化钠(NaCl)体系成功制备了碳纳米结构（碳纳米管、纳米碳球、棒状和层状碳纳米结构）。以DDBAC为碳源。碳化过程中使用NaCl晶体分隔DDBAC的有序聚集体。结果表明,通过控制DDBAC浓度制备出不同形貌的碳纳米结构,在1倍临界胶束浓度（CMC）~5CMC下制备了球形、棒形碳纳米结构和碳纳米管,在10CMC下制备了矩形层状碳纳米结构。利用TEM、PL、Raman等手段对制备的碳纳米结构进行表征。通过TEM分析DDBAC @ NaCl体系结构的转变,建立了胶束结构的演变过程。表面活性剂浓度的增加最终使得碳纳米形态从球形碳纳米结构到层状碳纳米结构的变化。本实验结论表明了表面活性剂@盐体系是一种潜在的制备碳纳米结构的方法。     

Shape‐Controlled Growth of Carbon Nanostructures: Yield and Mechanism

Carbon nanostructures with precisely controlled shapes are difficult materials to synthesize. A facet‐selective‐catalytic process was thus proposed to synthesize polymer‐linked carbon nanostructures with different shapes, covering straight carbon nanofiber, carbon nano Y‐junction, carbon nano‐hexapus, and carbon nano‐octopus. A thermal chemical vapor deposition process was applied to grow these multi‐branched carbon nanostructures at temperatures lower than 350 °C. Cu nanoparticles were utilized as the catalyst and acetylene as the reaction gas. The growth of those multi‐branched nanostructures was realized through the selective growth of polymer‐like sheets on certain indexed facets of Cu catalyst. The vapor–facet–solid (VFS) mechanism, a new growth mode, has been proposed to interpret such a growth in the steps of formation, diffusion, and coupling of carbon‐containing oligomers, as well as their final precipitation to form nanostructures on the selective Cu facets.     

Construction of various nanostructures on carbon nanotube films

Construction of nanostructures on surfaces has appealed intensive attention due to its significant applications in diverse fields. Especially, engineering surface properties via surficial nanostructures is actually the creation of functional interface-based materials and slated to be the key aspect for the future of materials science. Although many efforts have been made, there are only a few reports about the construction of nanostructures on carbon nanotube film surfaces. The big challenge for constructing on carbon films is that these carbon assemblies are easy to be dispersed by immersion in a chemical solution. Here, in this paper, we have shown for the first time the fabrication of different kinds of nanostructures, i.e. nanoneedles, nanoparticles, nanospirals, on carbon nanotube films by using facile and cheap electrodeposition method and precise physical deposition method. We pretreat the films by an electrical method to strengthen the films to avoid dispersion during the electrodeposition process. These composite films are still very flexible after coating with nanostructures. Compared with those precise physical deposition methods, the facile electrodeposition method is more suitable for constructing nanostructures on carbon nanotube films, due to the low requirement for planeness of films. It is interesting to find that these nanostructures can endow superhydrophobicity or higher conductivity for these flexible composite films, which greatly broaden the potential applications for carbon nanotube films in the fields of battery, moisture self-cleaning, electrostatic energy harvesting, and enhancing condensation heat transfer for more efficiency of energy utilization, environmental, and thermal management.     

Efficient direct electron transfer with enzyme on a nanostructured carbon film fabricated with a maskless top-down UV/ozone process

We have developed a new carbon film electrode material with thornlike surface nanostructures to realize efficient direct electron transfer (DET) with enzymes, which is very important for various enzyme biosensors and for anodes or cathodes used in biofuel cells. The nanostructures were fabricated using UV/ozone treatment without a mask, and the obtained nanostructures were typically 2-3.5 nm high as confirmed by atomic force microscopy measurements. X-ray photoelectron spectroscopy and transmission electron microscopy revealed that these nanostructures could be formed by employing significantly different etching rates depending on nanometer-order differences in the local sp(3) content of the nanocarbon film, which we fabricated with the electron cyclotron resonance sputtering method. These structures could not be realized using other carbon films such as boron-doped diamond, glassy carbon, pyrolyzed polymers based on spin-coated polyimide or vacuum-deposited phthalocyanine films, or diamond-like carbon films because those carbon films have relatively homogeneous structures or micrometer-order crystalline structures. With physically adsorbed bilirubin oxidase on the nanostructured carbon surface, the DET catalytic current amplification was 30 times greater than that obtained with the original carbon film with a flat surface. This efficient DET of an enzyme could not be achieved by changing the hydrophilicity of the flat carbon surface, suggesting that DET was accelerated by the formation of nanostructures with a hydrophilic surface. Efficient DET was also observed using cytochrome c.     

Bulk synthesis of single-crystalline magnesium oxide nanotubes

Crystalline tubular magnesium oxide nanostructures were obtained through carbon-thermal evaporation of a MgO powder. Gallium oxide was added into the mixture of MgO and carbon. The reduction of gallium oxide by carbon resulted in gallium vapor at high temperatures. Condensed gallium droplets catalyzed the anisotropic growth of tubular MgO nanostructures in situ. The products were characterized by X-ray powder diffraction technique, scanning electron microscopy, and high-resolution microscopy. All the analyses indicated that the prepared tubular MgO nanostructures are, in fact, single crystals.     

Synthesis of nitrogen-doped carbon nanostructures by the reactions of small molecule carbon halides with sodium azide

Nitrogen-doped carbon nanostructures including particles, whiskers, square frameworks, lamellar layers, hollow spheres, and tubular structures have been successfully synthesized by designed direct chemical reactions of small molecule carbon halides (such as CCl4, C2Cl6) and nitridation reagent NaN3 in the absence of any templates and catalysts. The N/C ratios of the as-prepared CNx nanostructures (0.01 approximately 0.33) are strongly and systematically related to the reaction temperatures and the choice of carbon sources, as well as the presence or absence of the solvent. The Raman spectra indicate that the approaching graphitization process has occurred as the reaction temperature increases. The possible reaction mechanisms for the formation of the hollow structures are tentatively discussed according to the experimental results. This strategy provides an alternative route to synthesize nitrogen-doped carbon nanostructures and is expected to open up a new route for the synthesis of carbon nitrides.     

Enhancing the pyrolysis of scrap rubber for carbon nanotubes/graphene production via chemical vapor deposition

Carbon nanostructures are considered nowadays as very important materials for both fundamental research and industrial applications because of their well-defined morphologies, which leads to excellent performance in various fields. This study presents the preparation of carbon nanostructures starting from cheap source represented by scrap rubber after pursuing optimized pyrolysis of scrap rubber at 500^oC as deduced from thermal gravimetric analysis (TGA). The resulting cracked hydrocarbons from pyrolysis were collected over a well-designed Fe-Ni-Cu/MgO as catalyst via chemical vapor deposition (CVD), in which a growth temperature of 750^oC was undertaken for 60 min. A further attempt was elaborated where the scrap rubber was exposed to thermal aging at 90^oC for 14 days prior to CVD of its pyrolysis products in order to enhance the cracking process and increase the yield of the lighter hydrocarbons produced which leads to formation of well-defined carbon nanostructures. Characterizations on the produced carbon nanostructures were achieved using transmission electron microscopy (TEM) and Raman spectroscopy. The adsorption of methylene blue on the carbon nanostructures was also studied. The characterizations confirmed that the morphology of the resulting carbon nanostructures derived from scrap rubber without prior thermal aging composed of graphene sheets wrapping carbon nanotubes (CNTs-A). After thermal aging of scrap rubber prior to pyrolysis and CVD, the produced carbon nanostructures composed principally of CNTs (CNTs-B) in a well-defined form in higher yield. The Langmuir model appeared to be best-fitting the adsorption of MB on both samples. High monolayer adsorption capacity of 95 mg MB/g was accomplished in case of CNTs-A versus 60 mg MB/g in case of CNTs-B, respectively. Ultraviolet-Visible (UV-Vis.) spectroscopic study revealed that the presence of MB molecules on the surface of CNTs may enhance the electronic properties of the prepared samples.     

Nanostructure Engineering by Simple Tuning of Lipid Combinations

Structural morphology is the key parameter for efficacy of nanomedicine. To date, lipid‐based nanomaterial has been the most widely used material in nanomedicine and many other biomedical applications. However, to the best of our knowledge, there has not been an in‐depth or systematic investigation of the structure–function relationship of lipid‐based nanostructures. In this report, we investigated the formulation of novel lipid‐based nanostructures via simple tuning of lipid combinations. To prove this concept, we used a combination of various ratios of simple and common phospholipids with different chain lengths (14‐carbon chain DMPC: 6‐carbon chain DHPC) to find out whether a myriad of novel lipid nanostructures could be obtained. Interestingly, many combinations resulted in distinct lipid nanostructures. Drug encapsulation tests confirmed that they are able to load large amounts of drugs for biological application. In vivo anti‐tumor efficacy revealed that certain lipid nanostructures possessed superior tumor retardation effects.     

Equilibrium locations for nested carbon nanocones

Potentially, carbon nanostructures are very important as ideal components to create many novel nano-devices. Such devices including nano-oscillators, ultra-fast optical filters and nano-bearings, are based on the unique mechanical and electronic properties of carbon nano-structures. Common carbon nanostructures used are usually C₆₀-fullerenes, carbon nanotubes, carbon nano-bundles and carbon nanotori. In the synthesis and production of carbon nanostructures, carbon nanocones tend to occur less frequently, and it is known that five different size cones may occur, depending on the number of pentagons in the atomic network. However, the simple geometric structure of carbon nanocones certainly facilitates calculations for their potential energy. Here, the Lennard–Jones potential energy function and the usual continuum approximation are employed to determine the energy for two such nested carbon nanocones which are located co-axially. We show graphically the energy profiles for any two carbon nanocones arising from the five possible structures. For both two distinct cones and two identical cones, we find that the equilibrium location moves further away from the vertex as the number of pentagons is increased. However, we observe that the equilibrium position occurs such that one cone is always inside the other, and therefore, we might expect that nested double-cones are formed according to these results.      

Synthesis,properties, and examples of the use of carbon nanomaterials

The results of a series of works on the synthesis and investigation of various carbon nanostructures and elaboration of functional materials of their basis are generalized and reviewed. Fullerenes and single-, double-, and multi-walled carbon nanotubes were prepared by the electric arc evaporation of graphite and metal—graphite rods. Diverse types of carbon nanofibers and nanotubes were grown by the catalytic pyrolysis of ethylene and methane. Graphene structures were synthesized by the chemical reduction of graphite oxide. Methods for isolation, purification, and functionalization of carbon nanostructures were elaborated. Chemical transformations in the fullerene—metal phase—hydrogen system were studied. Methods for metal cluster application on carbon nanostuctures and formation of metal hydride—carbon composites were developed. The possibilities were elucidated of using carbon nanostructures for the development of hydrogen accumulating and hydrogen generating composites, for forming carbon—polymer and carbon—ceramic composites, for preparing hardening additives to polymers and glue compositions, and for producing high-performance catalysts for hydrogenation and redox processes in fuel cells.     

Functionalized Carbon Nanomaterials Derived from Carbohydrates

A tremendous growth in the field of carbon nanomaterials has led to the emergence of carbon nanotubes, fullerenes, mesoporous carbon and more recently graphene. Some of these materials have found applications in electronics, sensors, catalysis, drug delivery, composites, and so forth. The high temperatures and hydrocarbon precursors involved in their synthesis usually yield highly inert graphitic surfaces. As some of the applications require functionalization of their inert graphitic surface with groups like ? COOH, ? OH, and ? NH₂, treatment of these materials in oxidizing agents and concentrated acids become inevitable. More recent works have involved using precursors like carbohydrates to produce carbon nanostructures rich in functional groups in a single‐step under hydrothermal conditions. These carbon nanostructures have already found many applications in composites, drug delivery, materials synthesis, and Li ion batteries. The review aims to highlight some of the recent developments in the application of carbohydrate derived carbon nanostructures and also provide an outlook of their future prospects.     

利用Ostwald熟化作用合成空心碳纳米材料

以淀粉等易获得的生物质为碳前驱物, 亚铁盐为添加剂, 采用水热法制备了碳材料. 实验发现, 在反应过程中, 首先生成了被无定形碳包裹的铁氧化物纳米棒, 形成碳/铁氧化物的核/壳结构. 在进一步的反应中, 铁氧化物核自发溶解, 最终得到了空心的碳纳米棒. 讨论了铁氧化物自发溶解的原因, 认为空心碳纳米棒的形成是由Ostwald熟化现象造成的. 当以葡萄糖或环糊精为碳前驱物时, 得到的是空心碳球, 这可能与各种碳前驱物不同的表面活性剂作用有关.     

Excitons in semiconducting carbon nanotubes: diameter-dependent photoluminescence spectra

Semiconducting single-walled carbon nanotubes are one-dimensional (1D) quantum nanostructures and their unique optical responses arise from stable 1D excitons with huge binding energies. Here we review recent studies on optical properties of semiconducting carbon nanotubes. The diameter dependence of luminescence spectra and dynamics are revealed by single-nanotube spectroscopy and time-resolved optical spectroscopy. Short-range Coulomb interactions play a crucial role in energy structures of dark, triplet, and charged excitons. Enhanced exciton-exciton interactions in 1D semiconductor nanostructures determine nonlinear optical responses. We present generic configurations of neutral and charged excitons and discuss exciton optics of single-walled carbon nanotubes.     

Graphitic carbon nanostructures via a facile microwave-induced solid-state process

A novel approach to fabricate highly graphitic carbon nanostructures such as carbon nanotubes (CNTs), metal/graphitic-shell nanocrystals and hollow carbon nanospheres (HCNSs) in a very short time is demonstrated.     

Generating suspended single-walled carbon nanotubes across a large surface area via patterning self-assembled catalyst-containing block copolymer thin films

Using self-assembled block copolymers as templates, catalytically active nanostructures with controlled size and space have been produced. A self-assembled polystyrene-b-polyferrocenylsilane thin film and monolayer of surface micelles of cobalt-complexed polystyrene-b-poly(2-vinylpyridine) are fully compatible with novolac-based conventional photoresists. Combining bottom-up self-assembly of catalyst-containing block copolymers with top-down microfabrication processing, plateaus covered with arrays of catalytically active nanostructures have been generated. Spatially selective growth of suspended single-walled carbon nanotubes over a large surface area has been achieved. Greatly enhanced Raman signals have been detected from the suspended tubes. This facile method of creating highly ordered catalyst nanostructures on top of posts enables the rational synthesis of suspended carbon nanotubes, thus facilitating the study of CNT properties by optical methods and enabling the fabrication of devices based on suspended CNTs.     

Hydrothermal synthesis of carbon nanotube/cobalt oxide core-shell one-dimensional nanocomposite and application as an anode material for lithium-ion batteries

Carbon nanotube/cobalt oxide core-shell one-dimensional nanostructures were prepared via a hydrothermal synthesis method, in which nanosize cobalt oxide crystals were homogeneously coated on the surface of carbon nanotubes. The morphologies and crystal structures of the as-prepared core-shell nanocomposites were analysed by X-ray diffraction, field emission gun scanning electron microscopy, and transmission electron microscopy. When applied as anodes in lithium-ion cells, carbon nanotube/cobalt oxide core-shell nanostructures exhibited an initial lithium storage capacity of 1250 mAh/g and a stable capacity of 530 mAh/g over 100 cycles. The good electrochemical performance could be attributed to the nanocrystalline cobalt oxide and the unique core-shell one-dimensional nanostructures.     

Numerical and Experimental Study of the Multichannel Nature of the Synthesis of Carbon Nanostructures in DC Plasma Jets

Plasma Chemistry and Plasma Processing - Wide spectrum of carbon nanostructures was synthesized by means of simple plasma chemistry using DC plasma torch: carbon nanotubes, nanowalls, graphene,...     

磷纳米材料的光学、光电子和光催化应用

碳纳米结构的研究和发现鼓励科学家们寻找下一代多功能材料.过去几年中磷纳米材料吸引了人们的广泛注意.尽管对磷纳米材料的结构和性质的研究仍处于起步阶段,但预期磷纳米材料有许多独特的性质.在这篇综述中,我们总结了黑磷和红磷纳米材料的一些光学和光电子应用,以及磷在光催化剂材料方面的作用.     

Biomimetic assemblies of carbon nanostructures for photochemical energy conversion

This feature article summarizes our recent accomplishments in the field of carbon nanostructures, fullerenes and carbon nanotubes, as integrative components in multifunctional hybrid cells that bear large promise for applications as photochemical energy conversion systems.     

Carbon Nanostructures Doped with Transition Metals for Pollutant Gas Adsorption Systems

The adsorption of molecules usually increases capacity and/or strength with the doping of surfaces with transition metals; furthermore, carbon nanostructures, i.e., graphene, carbon nanotubes, fullerenes, graphdiyne, etc., have a large specific area for gas adsorption. This review focuses on the reports (experimental or theoretical) of systems using these structures decorated with transition metals for mainly pollutant molecules’ adsorption. Furthermore, we aim to present the expanding application of nanomaterials on environmental problems, mainly over the last 10 years. We found a wide range of pollutant molecules investigated for adsorption in carbon nanostructures, including greenhouse gases, anticancer drugs, and chemical warfare agents, among many more.