Structure Of Carbon Nanotubes Research Articles

Boosting the Performance of on-Chip Vertically-Aligned Carbon Nanotube Supercapacitors Via Solvent-Free Radiofrequency Nitrogen Plasma Treatment

Supercapacitors are essential components for energy storage devices in many fields, including renewable energy systems, electric vehicles, and portable electronics [1]. Carbon nanotube arrays have shown great promise for use in supercapacitors due to their high surface area and excellent electrical conductivity. However, the specific capacitance of these arrays needs to be increased to improve the overall energy storage capacitance of the supercapacitor.This study presents an innovative approach to enhance the specific capacitance of on-chip vertically-aligned carbon nanotube (VACNT) structures for the development of high-performance supercapacitors. The proposed technique involves employing a solvent-free radiofrequency (RF) nitrogen plasma treatment to dope nitrogen onto VACNT surfaces. The plasma doping process utilizes reactive ion etching-induced coupled plasma (RIE-ICP) to optimize the parameters for nitrogen incorporation [2]. The nitrogen plasma treatment introduces nitrogen-containing functional groups, thereby improving their specific capacitance. The dry process is compatible with semiconductor fabrication and can be integrated into existing manufacturing techniques [1]. This study provides a promising avenue for tailoring the nitrogen doping process to achieve desired performance enhancements for on-chip VACNT supercapacitors.The plasma doping process involves the generation of reactive nitrogen species in the plasma, which subsequently interact with the VACNT surfaces. Under the influence of the RF electric field, nitrogen gas molecules are ionized and can react with the carbon atoms of the VACNTs, resulting in the formation of nitrogen-containing functional groups and the substitution of carbon atoms with nitrogen atoms within the carbon lattice [3].The improved capacitance can be attributed to the incorporation of nitrogen functional groups and to the modification of the electronic properties of the carbon nanotubes, including additional charge carriers, leading to an increase in electrical conductivity [4] and introduction of the pseudocapacitance effect [5]. There are various types of nitrogen species in the carbon lattice, such as pyridinic, pyrrolic, and graphitic nitrogen. Among these, pyridinic and pyrrolic nitrogen are known to be more electrochemically active [5], contributing to the enhanced specific capacitance. The increased electrical conductivity stems from the introduction of nitrogen dopants, which alter the electronic structure of the VACNTs, creating localized states near the Fermi level and thus facilitating charge transport [4].The level of nitrogen doping depends on several process factors, including the plasma power, gas pressure, and treatment duration. Higher plasma power generates a larger number of reactive nitrogen, while lower gas pressure results in a higher ionization efficiency. Furthermore, a longer treatment duration increases the chance of nitrogen incorporation into the VACNT structures [3]. By carefully controlling these parameters during the nitrogen plasma treatment, it is possible to tailor the nitrogen doping process to achieve the desired performance enhancement for on-chip VACNT supercapacitors.The treatment is performed in a chamber with a pressure of 10 Pa, a nitrogen gas flow rate of 10 sccm, an ICP power of 200W, and a bias voltage of -120 V. We report a specific capacitance of modified VACNTs of 18 mF/cm2(Figure 1), nearly twice that of pristine samples (Figure1(B)), for dense arrays of 1012 CNTs/ cm2. XPS result confirms 11.76% nitrogen content and 13% oxygen content in treated samples (N-VACNTs), aligning with previous studies on wet process nitrogen-doped carbon nanotubes [5]. Oxygen content also plays a crucial role in VACNT-based supercapacitor performance, improving surface wettability which will reduce the resistance between electrode and electrolyte [6, 7]. However, excessive oxygen content can negatively affect VACNT supercapacitor lifetime. By finding the trade-off between nitrogen and oxygen content, we optimized the doping process, enhancing specific capacitance, stability (Figure 2), and lifetime for on-chip VACNT structures.In conclusion, our study demonstrates that the solvent-free RF nitrogen plasma treatment can effectively enhance the specific capacitance of on-chip VACNT structures by up to 100%, making them suitable for integration into high-performance on-chip supercapacitor.

Preparation of Transparent Conductive Films Using Carbon Nanotubes

Carbon nanotubes (CNTs), since the discovery by Iijima, have attracted tremendous interests in scientific research mainly due to their exceptional structure and physical properties. The high aspect ratio, light weight, extraordinary stiffness, and strength make CNTs a potentially very functional material to be used in polymer nanocomposites application. Carbon nanotubes are single or multilayered coaxial tubes of six-membered ring networks composed of carbon. It is an allotrope of carbon and is sometimes classified as a type of fullerene. Carbon nanotubes are expected to be applied to materials that normally do not conduct heat or electricity, such as resin, rubber, ink, and paint. In addition, it is expected to be applied to the electronics field because of its conductivity and thermal conductivity even in small quantities and high strength when made into long lengths. One of the problems of CNTs is the tendency of CNTs to aggregate with each other due to intermolecular interactions. In the aggregated state, CNTs cannot exhibit their inherently useful characteristics, and therefore, a technology to disperse CNTs at the nano-level is required. Currently, two major methods are being considered for dispersing CNTs: The first is dispersion by chemical modification. By introducing carboxylic acid into strong acid treated CNTs and introducing hydrophilic or hydrophobic substituents here, solubilization in water or organic solvents is possible. However, there is a problem that this destroys the structure of CNTs and thus greatly impairs their original properties.The other method is to physically disperse CNTs. This is a very simple method that uses ultrasonic irradiation to loosen bundled CNTs, but the dispersion is only temporary, and re-agglomeration occurs quickly. Problems have also been reported, such as excessive ultrasonic irradiation destroying the structure of the CNTs. We have succeeded in producing CNTs nano dispersion gels by adding an aromatic compound to agglomerated CNTs and applying agitation and ultrasonic irradiation. The following describes the process of preparing CNTs dispersion gels. After agglomerated CNTs are temporarily dispersed by ultrasonic irradiation, an aromatic compound (dispersant) is added and mixed and agitated. The dispersed CNTs and the aromatic compound are combined by π-π interaction, and the aromatic compound is adsorbed on the CNTs surface. When CNTs molecules adsorbed with aromatic compounds approach each other, the aromatic compounds on the surface form π-π interactions. At this point, the CNTs are in a gel-like state. Since this dispersion gel does not chemically modify the CNTs, it can be prepared without destroying the structure of the CNTs. The CNTs gel proved to be free from aggregation even after the dispersant component was removed, and the network structure was maintained. In addition, this dispersion gel shows high electrical conductivity because the CNTs are dispersed three-dimensionally and the CNTs form three-dimensional conductive paths in the gel.Next, we introduce the preparation of CNT composite resin. CNT composite resin is prepared by adding binder resin to the carbon nanotube dispersion gel prepared earlier, mixing, and stirring, and ultrasonic irradiation. A transparent conductive film is created by forming the prepared CNT composite resin on a glass slide. In recent years, transparent conductive films have been in high demand due to the development of electronics products, and the use of CNTs as the main material is expected to significantly reduce the cost of development, as they are less expensive than Metallic materials such as indium tin oxide and can be stably supplied. The challenge of this research is that the amount of black CNTs added, which imparts conductivity, significantly affects the transparency of the transparent conductive film. Therefore, it is necessary to select aromatic compounds and resin materials that achieve both high conductivity and transparency with low amounts of added CNTs from a molecular chemistry perspective. In our previous research, we focused on the chemical bonding between resin materials and CNTs for the first time and attempted to improve electrical conductivity by using hydrogen bonding for CNTs. In addition, by combining polycarbonate, which exhibits high transparency and impact resistance, with CNT dispersion gel, we attempted to fabricate a transparent conductive film with high durability. As a result, we succeeded in developing a transparent conductive film material with performance applicable to touch panels.In this study, CNTs dispersion gels prepared with aromatic compounds were evaluated using absorbance measurements and Raman spectroscopy. The Raman spectra measurements allowed us to quantitatively evaluate the interaction between SWCNTs and aromatic compounds. The possibility of charge-transfer complex formation was also suggested by the results of absorbance measurements. Figure 1

Preparation of Conductive Composite Resin Using Metallic and Semiconducting SWCNTs

Carbon nanotube(CNT), which was discovered by Ijima, has been used wisely in various fields of materials due to their high-quality properties such as superior electrical conductivity, chemical stability and so on. Carbon nanotubes could be divided into two kinds, single-walled carbon nanotubes(SWCNTs) and multi-walled carbon nanotubes(MWCNTs). This classification is depending on carbon nanotubes' internal structure. Additionally, with further research, single-walled carbon nanotubes could be separate into metallic SWCNTs and semiconducting SWCNTs. One of the separation methods is using agarose gel electrophoresis, which was discovered by Tanaka. Based on the above method, researcher Kataura developed column separation of SWCNTs by using agarose gel without electricity. Although carbon nanotubes have been well-known for their properties, they can not exhibit them under normal conditions due to the agglutination that caused by intermolecular interaction. Therefore, to make carbon nanotubes exhibit their useful properties, technology of dispersing agglutinate carbon nanotubes is required. There are two major methods widely used to disperse CNTs currently. The first one is chemical dispersion. Increase carboxylic acid into strong acid-treated CNTs and use ultrasonic irradiation. However, excessive acid can cause damage to structure of CNTs which will make CNTs lose their original properties. Besides chemical dispersion, physical dispersion is a simple method which use ultrasonic irradiation to loosen agglutinate CNTs directly. However, in this method, re-agglutination is tend to occur, and excessive ultrasonic irradiation will also cause damage to the structure of CNTs. We have succeeded in developing CNTs' conductive composite resin with the method of dispersing CNTs by aromatic compounds.However, these resins developed by us have some shortages, such as lacking in conductivity. Although this degree of conductivity seems to reach the standard of touch screen, liquid crystal display's standard has not been reached yet. In our research, to increase the conductivity of risen, we tried to choose different kinds of CNTs, and consider that the metallic SWCNT would exhibit better conductivity than the CNT which was not separated.To test and verify if composite resin developed by metallic SWCNT could exhibit significant conductivity, we did a comparative experiment among metallic SWCNT, semiconducting SWCNT, and SWCNT without separation. Using these three types of SWCNT to develop composite resin, and then compared their conductivity.The result of the experiment above was unexpected, which showed semiconducting SWCNT's composite resin has the highest conductivity while metallic SWCNT has the worst conductivity. The prediction of this experiment's result was metallic SWCNT will exhibit the most significant conductivity because metal's conductivity is better than semiconductor under the normal condition. Through the inspection，we had a presumption that the effect of electron hopping lead to the highest conductivity of semiconducting SWCNT. Effect of electron hopping can occur in the field of semiconductor, the mechanism is that the electrons might leave their electron orbit because of external energy such as heat. In our experiment, phenylethyl alcohol was used as dispersion medium to disperse SWCNTs. Adding it to agglutinated SWCNTs will cause gaps between SWCNTs' molecules, electrons could change their orbits because of these gaps. During this effect, the movement of electrons will inflect the conductivity of the material. As a result, it was possible that semiconducting SWCNT exhibit high conductivity because of the effect of electron hopping which cause the movement of electron.

Reversible growth of solid electrolyte interface enhances charge capacity in cobalt sulfide-carbon nanotube anodes

The development of high-performance anode materials for lithium-ion batteries is a critical aspect of advancing energy storage technology. This study presents a novel approach to improve the charge capacity of anodes by harnessing the reversible growth of the solid electrolyte interface (SEI). This work focuses on cobalt sulfide (Co9S8) nanoparticles incorporated into a porous carbon nanotube (CNT) structure. Through a two-step pyrolysis process, Co9S8CNT composites, characterized by their conductive and mechanically robust CNT matrix are successfully synthesized. These Co9S8CNT anodes exhibit excellent initial charge capacity (560.5 mAh g−1 at 100 mA g−1) and remarkable stability, with a charge capacity of 633 mAh g−1 after 1000 cycles at 1000 mA g−1, accompanied by a Coulombic efficiency exceeding 99 %. Notably, this investigation reveals that the growth of the SEI plays a pivotal role in enhancing the charge capacity. Through in-situ Raman spectroscopy and other analytical techniques, it is suggested that the reversible reduction of organic solvent molecules within the large polymeric SEI is responsible for the increased charge capacity. This unique phenomenon is characterized by changes in the SEI's composition, driven by the charge and discharge processes. This study is a novel attempt to report a SEI's reversible growth that results in improved charge capacity, contrasting with prior research where SEI growth typically leads to capacity loss. Understanding this stable system provides valuable insights into increasing the cycle life and charge capacity of anodes, not only for transition metal sulfides but also for broader applications in energy storage.

Influence of platinum content (X) in the LaNi5PtX catalyst and reaction conditions on the properties of ferromagnetic Ni-filled CNTs

This research highlights the synthesis of carbon nanostructures using the catalytic chemical vapor deposition (CCVD) method, a hybrid process combining chemical vapor deposition (CVD) and Gas-Solid Heterogeneous Catalysis (GSHC). Intermetallic catalysts, LaNi5Ptx (x = 0, 0.05, 0.5, 1.0), were fabricated through an arc melting procedure to serve as templates for the catalytic conversion of carbon precursors into solid materials. These catalysts, featuring the ferromagnetic transition metal Ni, tend to aggregate into larger particles, reducing the rate of hydrocarbon cracking at the catalyst surface. Rare earth metals like Lanthanum were introduced to form an alloy with a higher melting point to prevent thermal aggregation. Additionally, Pt was incorporated to modify the catalytic properties of the alloy. The study primarily explores the impact of catalyst composition on carbon nanotube (CNT) production. The introduction of platinum content to the catalyst influences the rate at which Ni is filled. The research aimed to alter the catalyst's composition by varying platinum doping in the Pauli paramagnetic lanthanum nickel alloy (LaNi5) to understand the growth mechanism and morphological variations of Ni-filled CNTs. Platinum and lanthanum oxides significantly influence nickel filling in CNTs, resulting in an increased filling rate as the catalyst's Pt content varies from 0 to 1.0. However, higher Pt doping content disrupts the CNT structure with spontaneous nickel encapsulation.

Wrapping ZIF-67 with vine-like carbon nanotubes to enhance the capture of polysulfide and consolidation of active site

The shuttle effect of polysulfide and slow reaction kinetics has hindered the commercialization of lithium–sulfur batteries. Here, metal organic framework (MOF)-derived nitrogen-doped carbon was used as templates, and the continuous interspersed filamentary network structure of multi-walled carbon nanotubes (MWCNT) was used as a modifier to synthesize Co-NC@MWCNT. The exposure of Co-MOF with a high density of catalytic sites in the pores effectively improves the sulfur stability capacity of the composite and inhibits the shuttle effect. The outermost layer of coated MWCNTs and the intermediate layer of N-doped porous carbon effectively protected the Co2+ active site of the dodecahedral configuration from easy deactivation and agglomeration. The prepared Co-NC@MWCNT composite had an initial discharge capacity of 1240 mA h g−1 (0.1C), it maintained a low decay rate of 0.054 % after 1000 cycles (0.5C). The graphite-like layer gap and multilayer tube structure of the networked MWCNT can effectively mitigate volume expansion during charging and discharging and provide Li+ transport channels to improve electrical conductivity. Moreover, the energy storage devices developed as part of this work have excellent electrochemical properties and have a noteworthy industrial potential.

Preparation and characterization of shear thickening fluid/carbon nanotubes/Kevlar composite materials

AbstractShear thickening fluid (STF), carbon nanotubes (CNTs) are both promising in body protection and anti‐impact for the drastic viscosity change of STF and the extremely high tensile strength and elongation of CNTs. The excellent performance of the above two combined with traditional Kevlar fabrics can significantly improve the mechanical properties and reduce the number of layers used for body protection. This work reports a new method to prepare STF/CNTs/Kevlar with excellent tensile properties and anti‐impact performance by spraying method with 1 wt% polyvinyl alcohol (PVA) solution as a binder for better integration between CNTs and Kevlar. Surface morphology changes in the preparation process indicate the combined structure of PVA binder, CNTs, and STF, presenting a uniform macroscopic and nonuniform microscopic surface of STF/CNTs/Kevlar composite. The tensile strength and anti‐impact properties including punch residual velocity and energy absorbed were studied and results for STF/CNTs/Kevlar composite are 669.8 ± 18.1 MPa, 1.602 ± 0.045 m/s, and 21.683 ± 1.182 J in 12 ms, increased by 46.4%, 23.0%, and 240.2%, respectively, compared with neat Kevlar, owing to the improved tight bonding and friction between fabrics yarns caused by PVA adhesive and tangled CNTs, accompanied with the enhanced viscosity of STF under forces.Highlights Composites were made by spraying PVA, CNTs, and STF onto Kevlar fabrics; The tensile strength of the composite was 46.4% higher than Kevlar; The energy absorbed in 12 ms in anti‐impact tests was improved by 240.2%; Tight bonding and friction between yarns are reasons to improve properties; The raised viscosity of STF under forces is useful for mechanical properties.

Dual-Confinement Effect of Nanocages@Nanotubes Suppresses Polysulfide Shuttle Effect for High-Performance Lithium-Sulfur Batteries.

The shuttle effect of lithium polysulfides (LiPSs) severely hinders the development and commercialization of lithium-sulfur batteries, and the design of high-conductive carbon fiber-host material has become a key solution to suppress the shuttle effect. In this work, a unique Co/CoN-carbon nanocages@TiO2-carbon nanotubes structure (NC@TiO2-CNTs) is constructed using an electrospinning and nitriding process. Lithium-sulfur batteries using NC@TiO2-CNTs as cathode host materials exhibit high sulfur utilization (1527 mAh g-1 at 0.2 C) and can still maintain a discharge capacity of 663 mAh g-1 at a high current density of 5 C, and the capacity loss is only 0.056% per cycle during 500 cycles at 1 C. It is worth noting that even under extreme conditions (sulfur-loading = 90%, surface-loading = 5.0mg cm-2 (S), and E/S = 6.63µL mg-1), the lithium-sulfur batteries can still provide a reversible capacity of 4 mAh cm-2. Throughdensity functional theorycalculations, it has been found that the Co/CoN heterostructures can adsorb and catalyze LiPSs conversion effectively. Simultaneously, the TiO2 can adsorb LiPSs and transfer Li+ selectively, achieving dual confinement for the shuttle effect of LiPSs (nanocages and nanotubes). The new findings provide a new performance enhancement strategy for the commercialization of lithium-sulfur batteries.

Covalent Introduction of Plasma-Treated carbon nanotubes into polyimide nanocomposites at Ultra-Low content

In this paper, the effect of plasma treatment on the structure of carbon nanotubes (CNTs) and the structure/properties of polyimide (PI) nanocomposites with CNTs at ultra-low content (0.001 wt% ∼ 0.004 wt%) were investigated. Plasma treatment of CNTs under the mixture-gas of N2 and CO2 resulted in introducing isocyanate group on the surface of CNTs. PI nanocomposites with non-treated CNTs (nCNTs) or plasma-treated CNTs (pCNTs) were synthesized by in-situ polymerization, where PI as well as polyamic acid (precursor of PI) was polymerized under the presence of fillers. The structural studies revealed that pCNTs were highly dispersed in the nanocomposites with the strong interfacial interaction of covalent bond at the interface between PI and pCNTs. As a result, the excellent reinforcement effect of CNTs was successfully exploited to the PI nanocomposites at ultra-low content. For example, the Young’s modulus, tensile strength and toughness increased by 83 %, 51 % and 41 % by the incorporation of only 0.001 wt% of pCNTs, while the nanocomposite with nCNTs showed brittle behavior caused by poor interfacial interaction. Here in, we show that the characteristics of polymer matrices can be drastically changed by the addition of ultra-low content of nanofillers where the surface chemistry is optimized.

Polyolefin-derived substrate-grown carbon nanotubes as binder-free electrode for hydrogen evolution in alkaline media

Switching from a linear mode of waste management to a circular loop by transforming plastic waste into carbon nanotubes (CNTs) is a promising approach to current plastic waste treatment. One of the many applications of CNTs is its use for electrocatalytic water splitting for hydrogen evolution. Existing methods of CNTs-based hydrogen evolution reaction (HER) electrode fabrication involve additives like polymeric binders and additional steps to improve CNT dispersion, which are detrimental to the CNT structure and properties. The in-situ fabrication approach can potentially be a one-pot solution to HER electrode synthesis. In this study, polyolefins pyrolysis gas and a Co:Ni:Mg catalyst were used to fabricate binder-free CNTs-based electrodes on different substrates for HER. The study assessed CNT quality on conductive carbon paper, semiconductive silicon, and dielectric glass substrates, evaluating their HER performance in 1 M KOH. A mixture of hollow-core, bamboo-like, and cup-stacked arrangement nanotubes were synthesized on the substrates, with CNTs on glass and carbon paper substrates possessing better graphitization than CNTs grown on silicon. This is in agreement with HER performance, whereby the as-prepared electrodes required overpotentials of 267 mV, 241 mV, and 216 mV for silicon, glass, and carbon paper, respectively, to achieve 10 mA/cm2. Despite being poorly conductive, the glass substrate electrode achieved a lower overpotential than the silicon electrode. Additionally, the as-prepared silicon electrode faced a delamination issue likely attributed to the lower surface energy of the silicon substrate surface, demonstrating the weaker adhesion between the CNTs and silicon surface. The proposed approach thus showed that the in-situ fabricated electrodes performed better than separately synthesized CNTs prepared into electrodes by 27.4% and 14.2% for carbon paper and glass substrates, respectively. The improved performance of the as-prepared, binder-free electrodes can be linked to the lower charge-transfer resistance and reduced contact resistance between the CNTs and substrate.

Self-templating fabrication of Ti-doped SnO2 @carbon nanotubes via electrospinning for high-performance lithium-ion batteries

Tin dioxide (SnO2) has attracted extensive attention as an anode for lithium-ion batteries (LIBs) due to its high theoretical specific capacity, however, it suffers from the severe volume changes upon lithiation/delithiation cycling, thus leading to fast capacity fading. To overcome the drawbacks, we herein report a facile one-pot self-templating fabrication of Ti-doped SnO2 @carbon nanotubes (Ti-SnO2 @CNTs), via annealing the electrospun precursor nanofibers of tetrabutyl titanate (TBT), tetraethyl orthosilicate (TEOS), polyvinylidene difluoride (PVDF), polyvinylpyrrolidone (PVP), and stannous chloride (SnCl2). Interestingly, the introduction of TBT or not can lead to the controlled fabrication of the tubular or solid fibrous structure. During the annealing process, the chemical reaction between PVDF, TEOS, and TBT in-situ leads to the formation of tubular structure, while the SnCl2 converts into ultrafine SnO2 nanoparticles, embedding into the PVP-derived N-doped carbon nanotubes. When employed as anode materials for LIBs, the Ti-SnO2 @CNTs deliver high reversible capacities of 868.6/495.9 mAh g−1 at 0.2/1.0 A g−1 after 200/500 cycles, higher than those for the fibrous SnO2 @CNFs counterpart (654.9/391.08 mAh g−1). The better lithium storage performance is related to the unique carbon nanotube structure and the Ti-doping, which bring improved electrical conductivity, enhanced structural stability, and shortened ion diffusion path. More importantly, we demonstrate the facile electrospinning fabrication of tubular nanostructured hybrid electrodes for high-performance energy storage applications.

Structure Design, Surface Modification, and Application of CNT Microwave‐Absorbing Composites

AbstractElectromagnetic (EM) contamination has now become a non‐negligible problem. To solve the EM contamination problem, it is imperative to develop high‐efficiency absorption materials with thin thickness, light weight, strong absorption properties, and broad absorption bands. Carbon nanotubes (CNTs) have a special helical structure and chirality, which will lead to special EM effects and therefore can absorb EM microwaves through magnetic polarization attenuation such as hysteresis loss, domain wall resonance, and aftereffect loss. Moreover, they have the characteristics of light weight, good compatibility, wide absorption frequency band, and high electrical loss angle tangent. In this paper, the different structures of CNT microwave‐absorbing composites are reviewed and the effects of the composite structures on the microwave‐absorbing properties are systematically discussed. The methods and mechanisms of surface modification of CNT absorber composites and the effects of modification on the absorber properties are summarized in detail. The progress of two specific CNT microwave‐absorbing composites, namely flexible and high‐temperature microwave‐absorbing composites, is briefly described. The shortcomings and challenges in the application of CNT microwave‐absorbing composites are described and future research directions for CNT microwave‐absorbing composites are explored.

Molecular dynamics investigation for mechanical and failure behaviors of carbon nanotube-reinforced functionally graded aluminum–copper nanocomposites

In this study, molecular dynamics simulation is carried out to investigate the mechanical properties and failure behavior of a novel carbon nanotube-reinforced aluminum-copper alloy nanocomposite (Al–Cu/CNT). The study explores the influence of several key parameters, including the volume fraction of the carbon nanotubes (CNT), the diameter of CNT, the structure (zigzag, armchair, and chiral) of CNT, and the applied strain rate on the mechanical behavior of Al–Cu /CNT nanocomposite structure. The MD simulation results reveal that increasing the volume fraction of the CNT evidently increases the modulus of elasticity whereas it has no detrimental effect on the failure strain levels of the nanocomposites. The size of the CNT exhibits an inverse relationship with the elastic modulus. It is noted that increasing the size of the armchair CNTs results in lower elastic modulus levels and higher failure strain levels. The failure behavior of the Al–Cu /CNT nanocomposite is observed to vary according to the structure of the CNT. The nanostructure with zigzag CNTs experiences a gradual failure mode whilst armchair CNTs lead to a sudden failure in the nanostructures. The applied strain rate plays a minor role on the elastic modulus, but a slight increase in failure strain levels is observed at higher strain rates. The mechanical behavior of functionally graded Al–Cu alloy reinforced with CNT is also investigated (Al–Cu FGM/CNT). Minor changes are noticed in the elastic modulus and the failure strain levels of Al–Cu FGM/CNT with different material variations.

A controllable design of ZIF-67 based magnetic carbon nanotubes as efficient oxidase mimetics for sensitive detection of alkaline phosphatase in serum

The activity of alkaline phosphatase (ALP) is related to various pathological processes. Therefore, developing an ALP activity detection technology with high sensitivity and accuracy is of great significance for clinical diagnosis and cancer screening. To solve uncontrollable carbon nanotubes (CNTs) structure and lack of solubility, FeCo hollow nanocages (HNCs)@CNTs catalysts were prepared by facile pyrolysis of ZIF-67 precursor mixed with Fe-Co catalyst, displaying an oxidase-like activity. From the characterization, formation of CNTs was observed on the surface of FeCo HNCs@CNTs with the mole ratio of Fe3+ to Co2+ of 3:1. Density functional theory calculations demonstrated that the performed catalytic activity of FeCo HNCs@CNTs derived from active orbital of Co-3d band, which enabled the activation and decomposition of O2 with a feasible thermodynamic process. ·O2− and 1O2 were the main reactive oxygen species as electron acceptors. ALP catalyzed the hydrolysis of ascorbic acid 2-phosphate (AAP) to convert it into ascorbic acid (AA), which could effectively reduce the FeCo HNCs@CNTs-mediated chromogenic reaction of TMB oxidation. The performance of the FeCo HNCs@CNTs-linked biosensing assay showed a broad detection range from 0.1 U/L to 150 U/L and a relatively low limit of detection of 0.083 U/L. The ALP activity of the mouse serum sample obtained by the proposed biosensing assay was highly consistent with that via the clinical method, indicating a promising technology in biomolecule detection.

Metal-encapsulated nitrogen-doped carbon nanotube arrays electrode for enhancing sulfion oxidation reaction and hydrogen evolution reaction by regulating of intermediate adsorption

For treatment of sulfion-containing wastewater, coupling the electrochemical sulfion oxidation reaction (SOR) with hydrogen evolution reaction (HER) can be an ideal way for sulfur and H2 resources recovery. Herein, we synthesize a metal-modified carbon nanotube arrays electrode (Co@NCNTs/CC) for SOR and HER. This electrode has excellent performance for SOR and HER attributed to the unique array structure. It can achieve 99.36 mA/cm2 at 0.6 V for SOR, and 10 mA/cm2 at 0.067 V for HER. Density functional theory calculations verify that metal modification is able to regulate the electronic structure of carbon nanotube, which is able to optimize the adsorption of intermediates. Employed Co@NCNTs/CC as bifunctional electrodes to establish a hybrid electrolytic cell can reduce about 67% of energy consumption compared with the traditional water splitting electrolytic cell. Finally, the hybrid electrolytic cell is used to treat actual sulfion-containing wastewater, achieving the sulfur yield of 30 mg h−1 cm−2 and the hydrogen production of 0.64 mL/min.

Fractal Approach to Dielectric Properties of Single Walled Carbon Nanotubes Reinforced Polymer Composites

In this paper, the internal structure and dielectric properties of unsaturated polyester resin-based neat and single-walled carbon nanotube reinforced composites were comprehensively evaluated with the fractal analysis using the Fast Fourier Transform (FFT). The greyscale images, bitmap (BMP) images and 3D tomographic images were obtained by converting the scanning electron microscope images of the materials. It was observed that the distributions of components in the resin for both materials are irregular and their surfaces exhibit anisotropic behaviors. The surface coating rate (SCR) and fractal dimensionality (FD) of the materials were also calculated using the power spectrum. It has been observed that the fractal dimensionality of the composites can be changed by the doping process and the fractalization of the nanotube doped sample increases compared to the pure material due to nanotube agglomeration, spatial distribution and the orientation. The increase in fractalization as a result of this agglomeration and orientation in carbon nanotubes explains the high dielectric constant values observed at low frequencies by increasing the number and size of carbon nanotubes clusters that act as micro capacitors in certain regions of the matrix. It has been reported that the calculations for the surface coverage ratios for both samples also support these results.

Review on Current Applications and Future Directions in Carbon Nanotubes for Cancer Therapy using AI

Abstract: Carbon nanotubes (CNTs), which are measured in nanometers, provide an advantage over standard pharmaceuticals. As a result of this capability, they may be able to deliver smaller amounts of medication directly to the damaged cells in the body. CNTs accomplish this by lowering the probability of adverse reactions, minimizing injury to healthy cells, and boosting the targeting effectiveness for diseased cells at the same time. CNTs are effective nanocarriers for protein, DNA, and anticancer medicines during chemotherapy. This article covers the structure of carbon nanotubes and emphasizes its use in nano biosensors, cancer imaging, and drug delivery systems.

Suppressing Deformation of Silicon Anodes via Interfacial Synthesis for Fast‐Charging Lithium‐Ion Batteries

AbstractSilicon anodes with high energy density are prone to mechanical deformation during cycling, including fracture, pulverization, and delamination from conductive materials, due to their large volume expansion and contraction. Although significant attention is paid to outer interface engineering such as surface coating and electrolyte design in order to maintain a steady solid electrolyte interphase (SEI), there are currently few strategies in place for stabilizing the inner interface between Si and conductive carbon host materials. In this work, it is reported that an interfacial SiC chemical bonding enhances the interaction between Si and carbon, which in turn suppresses nano‐sized void evolution and ensues Si delamination. Through the open‐edge structure of carbon nanotube (OCNT), it is demonstrated that graphitic edge planes enable to evoke of interfacial SiC specifically at the junction without overgrowth toward the bulk. As a result, an Si‐graphite composite consisting of interfacial SiC exhibits a sF cycling life (79.5% for 300 cycles at 3C charging), as well as lower overpotential under high current density up to 5C compared to paired LiNi0.6Co0.2Mn0.2O2 (NCM) cathode in pouch full‐cell tests. This study highlights the significance of inner interface engineering for developing high‐energy density Si‐based anodes toward fast charging and long‐term stability.

A Novel Approach to Investigate Sadhana and PI Indices

A topological index is a number used in QSAR and QSPR research to assess the structural properties of a graph. The Sadhana and PI, polynomial-based topological indices, have been intensively explored in the study of chemical graph theory since a few years ago. These indices are computed using their related polynomials, however, in this study, we use an instantaneous and revolutionary approach to compute these indices for hexagonal boron nitride graphs and carbon nanotube structures.

Three-dimensional graphene cross-linked carbon nanotube doping as cathode for aqueous zinc ion batteries

Aqueous zinc ion batteries (ZIBs) are becoming increasingly popular in the field of energy storage due to their high safety and environmental friendliness. This study comparatively investigated the electrochemical performance of β-MnO2 as a cathode for ZIBs after doping with different ratios of three-dimensional graphene (3D-GPE)/carbon nanotube (CNT) cross-linked composite materials with ball milling. The results show that 3D-GPE/CNT cross-linked composite has an effect on β-MnO2 microstructure and particle morphology. The cathode made of β-MnO2/(3D-GPE/CNT) with a mass ratio of 9:1 has a very high reversible capacity of 1078.93 mAh/g at a current density of 10 mA g−1, which is about 2.24 and 1.87 times the other two ratio materials (18:1 and 12:1), respectively. After 100 cycles, the median voltage difference of the β-MnO2/(3D-GPE/CNT) mass ratio 9:1 specimen battery increased. The higher the median voltage, the higher the energy of the battery. The improvement of cathode performance is directly related to the micro-state, such as the three-dimensional frameworks and carbon nanotube structures of 3D-GPE/CNT, and the macro-state, such as particle refinement, homogenization, and layered structure.