Showing papers on "Nanotube published in 2014"
TL;DR: The development of highly conductive NiCo2S4 single crystalline nanotube arrays grown on a flexible carbon fiber paper (CFP), which can serve not only as a good pseudocapacitive material but also as a three-dimensional conductive scaffold for loading additional electroactive materials.
Abstract: We report on the development of highly conductive NiCo2S4 single crystalline nanotube arrays grown on a flexible carbon fiber paper (CFP), which can serve not only as a good pseudocapacitive material but also as a three-dimensional (3D) conductive scaffold for loading additional electroactive materials. The resulting pseudocapacitive electrode is found to be superior to that based on the sibling NiCo2O4 nanorod arrays, which are currently used in supercapacitor research due to the much higher electrical conductivity of NiCo2S4. A series of electroactive metal oxide materials, including CoxNi1–x(OH)2, MnO2, and FeOOH, were deposited on the NiCo2S4 nanotube arrays by facile electrodeposition and their pseudocapacitive properties were explored. Remarkably, the as-formed CoxNi1–x(OH)2/NiCo2S4 nanotube array electrodes showed the highest discharge areal capacitance (2.86 F cm–2 at 4 mA cm–2), good rate capability (still 2.41 F cm–2 at 20 mA cm–2), and excellent cycling stability (∼4% loss after the repetitive ...
1,008 citations
TL;DR: A three-dimensional (3D) electrode composed of nitrogen, oxygen dualdoped graphene-carbon nanotube hydrogel film is fabricated, which shows a remarkable oxygen-evolution catalytic performance in both alkaline and acidic solutions.
Abstract: A three-dimensional (3D) electrode composed of nitrogen, oxygen dualdoped graphene-carbon nanotube hydrogel film is fabricated, which greatly favors the transport and access of gas and reaction intermediates, and shows a remarkable oxygen-evolution catalytic performance in both alkaline and acidic solutions.
576 citations
TL;DR: In this paper, the NiCo2S4 nanotube arrays hybrid electrode exhibits an ultrahigh specific capacitance of 14.39 ± 1.39 µm at 5 µm and cycling stability of 92% after 5000 cycles at a high mass loading of 6 µm.
504 citations
TL;DR: This work converts molecular precursors into ultrashort singly capped ‘armchair’ nanotube seeds using surface-catalysed cyclodehydrogenation on a platinum surface, and elongates these during a subsequent growth phase to produce single-chirality and essentially defect-free SWCNTs with lengths up to a few hundred nanometres.
Abstract: Present preparation methods fail to meet fully the demand for structurally pure single-walled carbon nanotubes; surface-catalysed cyclodehydrogenation reactions are now shown to convert precursor molecules deposited on a platinum(111) surface into ultrashort nanotube seeds that can then be grown further into defect-free and structurally pure single-walled carbon nanotubes of single chirality. The electronic properties of single-walled carbon nanotubes (SWCNTs) are extraordinarily sensitive to their precise structure. To exploit their technological potential fully, samples containing only one SWCNT type are needed. Juan Ramon Sanchez-Valencia et al. have combined synthetic chemistry with materials engineering to develop a strategy that, with further optimization, could provide a route to nanotube-based materials for use in light detectors, photovoltaics, field-effect transistors and sensors. They use a surface-catalysed cyclodehydrogenation reaction to fold rationally designed precursor molecules deposited on a Pt(111) surface to produce 'end caps' that act as seeds for the growth of defect-free and structurally pure SWCNTs. The technique requires only modest temperatures and is fully compatible with today's complementary metal oxide semiconductor technologies. Cover: Konstantin Amsharov. Over the past two decades, single-walled carbon nanotubes (SWCNTs) have received much attention because their extraordinary properties are promising for numerous applications1,2. Many of these properties depend sensitively on SWCNT structure, which is characterized by the chiral index (n,m) that denotes the length and orientation of the circumferential vector in the hexagonal carbon lattice. Electronic properties are particularly strongly affected, with subtle structural changes switching tubes from metallic to semiconducting with various bandgaps. Monodisperse ‘single-chirality’ (that is, with a single (n,m) index) SWCNTs are thus needed to fully exploit their technological potential1,2. Controlled synthesis through catalyst engineering3,4,5,6, end-cap engineering7 or cloning strategies8,9, and also tube sorting based on chromatography10,11, density-gradient centrifugation, electrophoresis and other techniques12, have delivered SWCNT samples with narrow distributions of tube diameter and a large fraction of a predetermined tube type. But an effective pathway to truly monodisperse SWCNTs remains elusive. The use of template molecules to unambiguously dictate the diameter and chirality of the resulting nanotube8,13,14,15,16 holds great promise in this regard, but has hitherto had only limited practical success7,17,18. Here we show that this bottom-up strategy can produce targeted nanotubes: we convert molecular precursors into ultrashort singly capped (6,6) ‘armchair’ nanotube seeds using surface-catalysed cyclodehydrogenation on a platinum (111) surface, and then elongate these during a subsequent growth phase to produce single-chirality and essentially defect-free SWCNTs with lengths up to a few hundred nanometres. We expect that our on-surface synthesis approach will provide a route to nanotube-based materials with highly optimized properties for applications such as light detectors, photovoltaics, field-effect transistors and sensors2.
486 citations
TL;DR: The authors mimicking nature's bottom-up construction processes is one of the most promising directions in the development of robotic construction systems, which can be found in many applications, e.g.
Abstract: Successfully mimicking nature's bottom-up construction processes is one of the most promising directions.
410 citations
TL;DR: Self-supported Li4Ti5O12-C nanotube arrays with high conductivity architectures are designed and fabricated for application in Li-ion batteries and exhibit remarkable rate capability and cycling performance.
Abstract: Self-supported Li4Ti5O12–C nanotube arrays with high conductivity architectures are designed and fabricated for application in Li-ion batteries. The Li4Ti5O12 nanotube arrays grow directly on stainless steel foil by a facile template-based solution route, further enhancing electronic conductivity by uniform carbon-coating on the inner and outer surfaces of Li4Ti5O12 nanotubes. Owing to the shortened Li+ diffusion distance, high contact surface area, sufficient conductivity, and very good structure stability of the nanotube arrays, the self-supported Li4Ti5O12–C nanotube arrays exhibit remarkable rate capability (a reversible capability of 135 mA h g–1, 105 mA h g–1, and 80 mA h g–1 at 30C, 60C, and 100C, respectively) and cycling performance (approximate 7% capacity loss after 500 cycles at 10C with a capacity retention of 144 mA h g–1).
385 citations
TL;DR: In this paper, the authors presented the mechanism of nanotube growth in arc discharge and the factors affecting its formation, and the effect of experimental parameters such as setup modification, power supply, arc current, catalyst, pressure, grain size, electrode geometry and temperature on size and yield of the nanotubes.
370 citations
TL;DR: In this paper, the black titania nanotubes with substantial Ti3+ and oxygen vacancies exhibit an excellent photoelectrochemical water-splitting performance due to the improved charge transport and separation and the extended visible light response.
Abstract: Black titania nanotube arrays are prepared for the first time by the melted aluminium reduction of pristine anodized and air-annealed titania nanotube arrays. The black titania nanotubes with substantial Ti3+ and oxygen vacancies exhibit an excellent photoelectrochemical water-splitting performance due to the improved charge transport and separation and the extended visible light response. An impressive applied bias photon-to-current efficiency of 1.20% is achieved.
327 citations
TL;DR: In this paper, a green approach for synthesis of graphene-carbon nanotube aerogels with three dimensional (3D) interconnected networks prepared from natural graphite rocks was reported. And the proposed synthetic method is simple and economical for the scalable production of highly porous 3D graphene and carbon nanotubes aerogel, which can be successfully used for efficient and cost-effective oil spill clean-up and water purification.
322 citations
TL;DR: Twisted, aligned carbon nanotube/silicon composite fibers with remarkable mechanical and electronic properties are designed to develop novel flexible lithium-ion batteries with a high cyclic stability.
Abstract: Twisted, aligned carbon nanotube/silicon composite fibers with remarkable mechanical and electronic properties are designed to develop novel flexible lithium-ion batteries with a high cyclic stability. The core-sheath architecture and the aligned structure of the composite nanotube offer excellent combined properties.
297 citations
TL;DR: The NT-Ag2O arrays can effectively kill Escherichia coli and Staphylococcus aureus even after immersion for 28 days, demonstrating the long lasting antibacterial ability.
TL;DR: In this article, a series of batch adsorption experiments were conducted to study the effect of pH, dose of adsorbent, metal concentration and temperature on Hg(II) uptake by the functionalized MWCNTs.
TL;DR: The conductive SACNT matrix not only avoids self-aggregation and ensures dispersive distribution of the sulfur nanocrystals but also offers three-dimensional continuous electron pathway, provides sufficient porosity in the matrix to benefit electrolyte infiltration, confines the sulfur/polysulfides, and accommodates the volume variations of sulfur during cycling.
Abstract: A binder-free nano sulfur–carbon nanotube composite material featured by clusters of sulfur nanocrystals anchored across the superaligned carbon nanotube (SACNT) matrix is fabricated via a facile solution-based method. The conductive SACNT matrix not only avoids self-aggregation and ensures dispersive distribution of the sulfur nanocrystals but also offers three-dimensional continuous electron pathway, provides sufficient porosity in the matrix to benefit electrolyte infiltration, confines the sulfur/polysulfides, and accommodates the volume variations of sulfur during cycling. The nanosized sulfur particles shorten lithium ion diffusion path, and the confinement of sulfur particles in the SACNT network guarantees the stability of structure and electrochemical performance of the composite. The nano S-SACNT composite cathode delivers an initial discharge capacity of 1071 mAh g–1, a peak capacity of 1088 mAh g–1, and capacity retention of 85% after 100 cycles with high Coulombic efficiency (∼100%) at 1 C. M...
Abstract: This paper describes a facile and generally feasible method to synthesize nanotube-type graphitic carbon nitride (g-C3N4) by directly heating melamine packed in an appropriate compact degree which plays a crucial role in the formation process of g-C3N4. This approach has several advantages: (i) no templates or extra organics are involved; (ii) high industrial feasibility; (iii) low cost; and (iv) general applicability. The as-synthesized g-C3N4 samples show intense fluorescence with a photoluminescent (PL) peak at 460 nm indicating their potential applications as a blue light fluorescence material. They also exhibit excellent visible-light photocatalytic activity compared to a reference P25 photocatalyst. The method reported may open up new opportunities for further studies as well as practical applications of g-C3N4 nanotubes in fields such as light-emitting devices, gas storage and photocatalysis.
TL;DR: The feasibility of tungsten disulfide nanotubes/graphene sandwich-type architecture as anode for lithium-ion batteries for the first time is demonstrated and the relatively high density of this hybrid is beneficial for high capacity per unit volume.
Abstract: Transition metal dichalcogenides (TMD), analogue of graphene, could form various dimensionalities. Similar to carbon, one-dimensional (1D) nanotube of TMD materials has wide application in hydrogen storage, Li-ion batteries, and supercapacitors due to their unique structure and properties. Here we demonstrate the feasibility of tungsten disulfide nanotubes (WS2-NTs)/graphene (GS) sandwich-type architecture as anode for lithium-ion batteries for the first time. The graphene-based hierarchical architecture plays vital roles in achieving fast electron/ion transfer, thus leading to good electrochemical performance. When evaluated as anode, WS2–NTs/GS hybrid could maintain a capacity of 318.6 mA/g over 500 cycles at a current density of 1A/g. Besides, the hybrid anode does not require any additional polymetric binder, conductive additives, or a separate metal current-collector. The relatively high density of this hybrid is beneficial for high capacity per unit volume. Those characteristics make it a potential ...
TL;DR: The as-prepared NiCo2 S4 nanotubes/Ni foam electrode shows a high specific capacitance, excellent rate capability, and good cycling stability, which suggests its promising application for electrochemical capacitors.
Abstract: Arrays of NiCo2 S4 nanotubes on nickel foam were prepared by means of a two-step method, and were directly applied as a binder-free supercapacitor electrode. Such a binder-free method enables intimate contact between the current collector and the active materials, and can effectively improve ion and charge transportation. As a result, the electrochemical performances of supercapacitors can be improved. The as-prepared NiCo2 S4 nanotubes/Ni foam electrode shows a high specific capacitance (738 F g-1 at 4 A g-1 ), excellent rate capability (78 % capacitance retention at 32 A g-1 ), and good cycling stability (retention capacity of 93.4 % after 4000 cycles), which suggests its promising application for electrochemical capacitors.
TL;DR: In this paper, a simple electrochemical doping method was developed to significantly improve the electronic conductivity and the electrochemical performances of TiO 2 nanotube electrodes, which achieved a very high average specific capacitance of 20.08 mF cm −2 at a current density of 0.05
TL;DR: This work measures record-high quality factors Q as high as 5 × 10(6) in ultra-clean nanotube resonators at a cryostat temperature of 30 mK, comparable to the highest Q values reported in mechanical resonators of much larger size.
Abstract: Careful, low-noise measurement techniques allow record quality factors to be determined in ultraclean, suspended carbon nanotube resonators, which are comparable to those of much larger resonators.
TL;DR: The formation of a covalent network of porphyrins around MWNT surfaces is described, based on the adsorption of cobalt(II) meso-tetraethynylporphyrins on the nanotube sidewalls followed by the dimerization of the triple bonds via Hay-coupling; during the reaction, thenanotube acts as a template for the formation of the polymeric layer.
Abstract: The development of innovative techniques for the functionalization of carbon nanotubes that preserve their exceptional quality, while robustly enriching their properties, is a central issue for their integration in applications. In this work, we describe the formation of a covalent network of porphyrins around MWNT surfaces. The approach is based on the adsorption of cobalt(II) meso-tetraethynylporphyrins on the nanotube sidewalls followed by the dimerization of the triple bonds via Hay-coupling; during the reaction, the nanotube acts as a template for the formation of the polymeric layer. The material shows an increased stability resulting from the cooperative effect of the multiple π-stacking interactions between the porphyrins and the nanotube and by the covalent links between the porphyrins. The nanotube hybrids were fully characterized and tested as the supported catalyst for the oxygen reduction reaction (ORR) in a series of electrochemical measurements under acidic conditions. Compared to similar s...
TL;DR: In this paper, a simple method for the synthesis of NiFe2O4/Fe 2O3 nanotubes by annealing core-shell Fe2Ni MIL-88/Fe MIL88 metal organic frameworks (MOFs) has been developed.
Abstract: A simple method for the synthesis of NiFe2O4/Fe2O3 nanotubes by annealing core–shell Fe2Ni MIL-88/Fe MIL-88 metal organic frameworks (MOFs) has been developed. The crystalline phase, morphology and specific surface area (BET) of the resulting sample have been systematically characterized. The results indicate that the NiFe2O4/Fe2O3 nanotubes, which have diameters of 78 nm and lengths of around 1 μm, are composed of nano-sized primary particles. The electrochemical performance of the NiFe2O4/Fe2O3 nanotubes when used as an anode material for lithium ion batteries has also been tested. A reversible specific capacity of 936.9 mA h g−1 was achieved at a current density of 100 mA g−1 up to 100 cycles. Even at 2000 mA g−1, the discharge capacity of the composite anode could still reach 423.6 mA h g−1. The enhanced electrochemical performance of the NiFe2O4/Fe2O3 nanotube anode can be ascribed to the rational design of the hierarchical porous hollow structures and the synergetic effect of different functional components.
TL;DR: In this paper, a novel contact mode between MoS2 and graphene was successfully developed, where graphene rolls up into a hollow nanotube and thin MoS 2 nanosheets are uniformly standing on the inner surface of graphitic nanotubes, thus forming mechanically robust, free-standing, interwoven MoS1@graphene nanocable webs (MoS2@G).
Abstract: Here, we have successfully developed a novel contact mode between MoS2 and graphene, where graphene rolls up into a hollow nanotube and thin MoS2 nanosheets are uniformly standing on the inner surface of graphitic nanotubes, thus forming mechanically robust, free-standing, interwoven MoS2@graphene nanocable webs (MoS2@G). Such a hybrid structure can maximize the MoS2 loading in the electrode in which over 90% of MoS2 nanosheets with stacked layer number of less than 5 can be installed. Remarkably, when calculated on the basis of the whole electrode, this binder free electrode not only shows high specific capacity (ca. 1150 mA h g−1) and excellent cycling performance (almost 100% capacity retention even after 160 cycles at a current density of 0.5 A g−1) but exhibits a surprisingly high-rate capability of 700 mA h g−1 at the rate of 10 A g−1 despite such a high MoS2 loading content, which is one of the best results of MoS2-based electrode materials ever reported thus far.
Journal Article•
TL;DR: Aqueous two-phase extraction is demonstrated to enable isolation of single semiconducting and metallic single-wall carbon nanotube species from a synthetic mixture with remarkable tunability via modification of the surfactant environment set for the separation.
Abstract: Aqueous two-phase extraction is demonstrated to enable isolation of single semiconducting and metallic single-wall carbon nanotube species from a synthetic mixture. The separation is rapid and robust, with remarkable tunability via modification of the surfactant environment set for the separation.
TL;DR: This study suggests that the electrode performance can be significantly improved by optimizing the electrode geometry, and develops nanoelectrodes made up of nanotubes of iridium oxide that afford much longer intracellular access and are minimally invasive.
Abstract: Intracellular recording of action potentials is important to understand electrically-excitable cells. Recently, vertical nanoelectrodes have been developed to achieve highly sensitive, minimally invasive and large-scale intracellular recording. It has been demonstrated that the vertical geometry is crucial for the enhanced signal detection. Here we develop nanoelectrodes of a new geometry, namely nanotubes of iridium oxide. When cardiomyocytes are cultured upon those nanotubes, the cell membrane not only wraps around the vertical tubes but also protrudes deep into the hollow centre. We show that this nanotube geometry enhances cell-electrode coupling and results in larger signals than solid nanoelectrodes. The nanotube electrodes also afford much longer intracellular access and are minimally invasive, making it possible to achieve stable recording up to an hour in a single session and more than 8 days of consecutive daily recording. This study suggests that the nanoelectrode performance can be significantly improved by optimizing the electrode geometry.
TL;DR: Halloysite nanotubes (pristine or drug-loaded) are well mixable with polar and low-polar polymers allowing for functional biocomposites with enhanced mechanical strength, adhesivity and slow release of drugs or other chemical agents.
TL;DR: It is reported that screen printing, which is a simple, scalable, and cost-effective technique, can be used to produce both rigid and flexible thin-film transistors using separated single-wall carbon nanotubes.
Abstract: Semiconducting single-wall carbon nanotubes are very promising materials in printed electronics due to their excellent mechanical and electrical property, outstanding printability, and great potential for flexible electronics. Nonetheless, developing scalable and low-cost approaches for manufacturing fully printed high-performance single-wall carbon nanotube thin-film transistors remains a major challenge. Here we report that screen printing, which is a simple, scalable, and cost-effective technique, can be used to produce both rigid and flexible thin-film transistors using separated single-wall carbon nanotubes. Our fully printed top-gated nanotube thin-film transistors on rigid and flexible substrates exhibit decent performance, with mobility up to 7.67 cm2 V–1 s–1, on/off ratio of 104 ∼ 105, minimal hysteresis, and low operation voltage (<10 V). In addition, outstanding mechanical flexibility of printed nanotube thin-film transistors (bent with radius of curvature down to 3 mm) and driving capability f...
TL;DR: In this article, the authors presented unique graphene-carbon nanotube composites (GC) doped sequentially with both nitrogen and sulfur (GC-NLS) and subject them to extensive physicochemical characterization and electrochemical evaluation toward the electrochemical oxygen reduction reaction (ORR) in an alkaline electrolyte.
Abstract: The development of unique, reliable, and scalable synthesis strategies for producing heteroatom-doped nanostructured carbon materials with improved activity toward the electrochemical oxygen reduction reaction (ORR) occurring in metal–air batteries and fuel cells presents an intriguing technological challenge in the field of catalysis. Herein, we prepare unique graphene–carbon nanotube composites (GC) doped sequentially with both nitrogen and sulfur (GC-NLS) and subject them to extensive physicochemical characterization and electrochemical evaluation toward the ORR in an alkaline electrolyte. GC-NLS provides ORR onset potential increases of 50 and 70 mV in comparison to those of dual-doped individual graphene and carbon nanotubes, respectively. This highlights the significant synergistic effects that arise because of the nanocomposite arrangement, consisting of highly graphitized carbon nanotubes assembled on the surface of graphene sheets. The addition of sulfur as a co-dopant is also highly beneficial, ...
TL;DR: In this article, a stack-integrated photo-supercapacitor (PSC) thin-film device is presented, composed of a DSSC and a SC built on bi-polar ATO nanotube arrays, where an improved SC performance is achieved through selective plasma-assisted hydrogenation treatment.
Abstract: One-dimensional anodic titanium oxide (ATO) nanotube arrays hold great potential as electrode materials for both dye-sensitized solar cells (DSSCs) and electrochemical supercapacitors (SCs). In this work, a novel stack-integrated photo-supercapacitor (PSC) thin-film device is presented, composed of a DSSC and a SC built on bi-polar ATO nanotube arrays, where an improved SC performance is achieved through selective plasma-assisted hydrogenation treatment. At a high current density of 1 mA/cm2 in charge/discharge measurements, the areal capacitance of selective hydrogenated ATO two-electrode sub-device is substantially increased ∼5.1 times, with the value as high as 1.100 mF/cm2. The optimized PSC exhibits a remarkable overall photoelectric conversion and storage efficiency up to 1.64%, with fast response and superior cycling capability for more than 100 photocharge/galvanostatic discharge cycles without any decay. To meet applicable demands with a larger output voltage, a tandem PSC system is constructed, serving as the self-driven power source for an LED.
TL;DR: In this paper, an overview of the highlights of more than 10 years of research on synthesis and applications of ordered oxide structures (nanotube layers, hexagonal pore arrangements) that are formed by self-organizing anodization of metals.
TL;DR: The pseudobrookite Fe2TiO5 ultrathin layers grown on vertically aligned TiO2 nanotube arrays that can enhance the conduction and utilization of photogenerated charge carriers can open up more opportunities in the design of efficient and low-cost photoanodes working in visible light for photoelectrochemical applications.
Abstract: There remains a pressing challenge in the efficient utilization of visible light in the photoelectrochemical applications of water splitting. Here, we design and fabricate pseudobrookite Fe2TiO5 ultrathin layers grown on vertically aligned TiO2 nanotube arrays that can enhance the conduction and utilization of photogenerated charge carriers. Our photoanodes are characterized by low onset potentials of ~0.2 V, high photon-to-current efficiencies of 40–50% under 400–600 nm irradiation and total energy conversion efficiencies of ~2.7%. The high performance of Fe2TiO5 nanotube arrays can be attributed to the anisotropic charge carrier transportation and elongated charge carrier diffusion length (compared with those of conventional TiO2 or Fe2O3 photoanodes) based on electrochemical impedance analysis and first-principles calculations. The Fe2TiO5 nanotube arrays may open up more opportunities in the design of efficient and low-cost photoanodes working in visible light for photoelectrochemical applications. Metal oxides are desirable photoanode materials due to their low cost and chemical stability, but they only work in the ultraviolet range. Here, Liu et al. design anode architecture that can absorb the visible light, while maintaining photon-to-current efficiency of 40% at an onset potential of 0.2 V.
TL;DR: It is demonstrated here the similar catalytic performance of as-synthesized CuS nanostructures for the degradation of methylene blue in the dark, suggesting that light does not play a role in its catalytic behavior.
Abstract: A simple, template-free and mild solution chemistry route was employed to synthesize diverse copper sulfide (CuS) nanostructured assemblies at 70 °C by varying the solvent (water or ethylene glycol, or their ratios (3:1, 1:1 and 1:3)). The CuS structures in the shape of spheres and nanotubes were found to be assemblies of either nanoplates or nanoparticles. The nanotube formation was elaborately studied by varying the synthesis parameters such as temperature, reaction duration, precursor’s ratio, and counterions. Counterions such as NO3– and SO42– were found to be suitable for nanotube formation whereas in the presence of Cl– and OAc– ions, CuS flake-like and nanoparticle assemblies are obtained, respectively. The optical bandgaps for the CuS with different morphologies were measured to be in the range of 1.88–2.16 eV. The bandgap of CuS in the visible region of electromagnetic radiation prompted it to be used as photocatalyst in the past under natural light. However, we demonstrate here the similar catal...