Structure Of Nanotubes Research Articles

Investigation of Electromagnetic Wave Propagation in Triple Walled Carbon Nanotubes

This study examines the behavior of electromagnetic wave propagation in a unique and complex three-walled carbon nanotube structure. The structure is formed by nesting three distinct nanotubes, and the interactions between them are thoroughly analyzed, taking into account their varying electromagnetic, material, and nano properties. The structure is designed at a nanoscale to provide a comprehensive description of electromagnetic wave propagation, including the electromagnetic interaction between the second nanotube, located in the middle of the structure, and the other two nanotubes situated in both the inner and outer portions of the structure. This study presents novel findings that differ from existing literature on the subject, contributing to our understanding of this important area of research.

Near-atomic-resolution structure of J-aggregated helical light-harvesting nanotubes.

Cryo-electron microscopy has delivered a resolution revolution for biological self-assemblies, yet only a handful of structures have been solved for synthetic supramolecular materials. Particularly for chromophore supramolecular aggregates, high-resolution structures are necessary for understanding and modulating the long-range excitonic coupling. Here, we present a 3.3 Å structure of prototypical biomimetic light-harvesting nanotubes derived from an amphiphilic cyanine dye (C8S3-Cl). Helical 3D reconstruction directly visualizes the chromophore packing that controls the excitonic properties. Our structure clearly shows a brick layer arrangement, revising the previously hypothesized herringbone arrangement. Furthermore, we identify a new non-biological supramolecular motif-interlocking sulfonates-that may be responsible for the slip-stacked packing and J-aggregate nature of the light-harvesting nanotubes. This work shows how independently obtained native-state structures complement photophysical measurements and will enable accurate understanding of (excitonic) structure-function properties, informing materials design for light-harvesting chromophore aggregates.

Nanocomposites Based on Thermoplastic Acrylic Resin with the Addition of Chemically Modified Multi-Walled Carbon Nanotubes.

The main goal of this work was an improvement in the mechanical and electrical properties of acrylic resin-based nanocomposites filled with chemically modified carbon nanotubes. For this purpose, the surface functionalization of multi-walled carbon nanotubes (MWCNTs) was carried out by means of aryl groups grafting via the diazotization reaction with selected aniline derivatives, and then nanocomposites based on ELIUM® resin were fabricated. FT-IR analysis confirmed the effectiveness of the carried-out chemical surface modification of MWCNTs as new bands on FT-IR spectra appeared in the measurements. TEM observations showed that carbon nanotube fragmentation did not occur during the modifications. According to the results from Raman spectroscopy, the least defective carbon nanotube structure was obtained for aniline modification. Transmission light microscopy analysis showed that the neat MWCNTs agglomerate strongly, while the proposed modifications improved their dispersion significantly. Viscosity tests confirmed, that as the nanofiller concentration increases, the viscosity of the mixture increases. The mixture with the highest dispersion of nanoparticles exhibited the most viscous behaviour. Finally, an enhancement in impact resistance and electrical conductivity was obtained for nanocomposites containing modified MWCNTs.

The Effect of He:O Plasma Treatment on the Structure of Multi-Walled Carbon Nanotubes

The Effect of He:O Plasma Treatment on the Structure of Multi-Walled Carbon Nanotubes

Exploring the structure, assembly, and membrane interactions of Janus-base nanotubes (JBNts) through multiscale simulations

Exploring the structure, assembly, and membrane interactions of Janus-base nanotubes (JBNts) through multiscale simulations

Efficient flexible dye-sensitized solar cells from rear illumination based on different morphologies of titanium dioxide photoanode

The TiO2 with nanoparticles (NPs), nanowires (NWs), nanorods (NRs) and nanotubes (NTs) structures were prepared by using a in-situ hydrothermal technique, and then proposed as a photoanode for flexible dye-sensitized solar cell (FDSSC). The influences of the morphology of TiO2 on the photovoltaic performances of FDSSCs were investigated. Under rear illumination of 100 mW·cm−2, the power conversion efficiencies of FDSSCs achieved 6.96%, 7.36%, 7.65%, and 7.83% with the TiO2 photoanodes of NPs, NWs, NRs, and NTs and PEDOT counter electrode. The FDSSCs based on TiO2 NRs and NTs photoanodes have higher short circuit current densities and power conversion efficiencies than that of the others. The enhanced power conversion efficiency is responsible for their nanotubes and rod-shaped ordered structures, which are more beneficial to transmission of electron and hole in semiconductor compared to the TiO2 nanoparticles and nanowires disordered structure.

Ferromagnetism in silver-doped single-walled zinc oxide nanotubes

In this paper, the electronic and magnetic properties of single-walled ZnO:Ag nanotubes with a chirality of (6,0) were investigated. Ab initio simulations were carried out using Atomistic ToolKit computer code implementing density functional theory within the local spin density approximation. To obtain an accurate energy band gap for related systems, we used the Hubbard U semiempirical corrections. The introduction of the Ag atom into the ZnO nanotube structure changes the electronic structure, the energy gap decreases with the silver concentration. The calculated value of total magnetic moments of the Ag-doped single-walled ZnO NT system is 1.0 μB. Our results predict that Ag-doped ZnO NT can be a potential candidate for optoelectronic and spintronic devices.

Preparation and Ferroelectric Properties of Er Doped BaTiO3 Nanotubes

In this paper, erbium-doped barium titanate nanotubes with different concentrations were prepared by combining the anodic oxidation method with the low-temperature hydrothermal method. The TiO2 nanotubes produced by electrolysis using titanium flakes as substrate were put into barium hydroxide octahydrate solution for hydrothermal reaction, and different concentrations of Er-doped barium titanate nanotubes were prepared by adding different concentrations of Er(NO3)3·5H2O to the reaction solution. The samples with different doping concentrations were analyzed for their morphological structure, physical phase composition and ferroelectric properties. All samples were found to have complete barium titanate nanotube structure, and the diffraction peaks of XRD were compared with the standard Cope, and the doped samples were all tetragonal phase chalcogenide structure with no other impurities generated. From the hysteresis loop diagram of the samples measured by the TF-2000 ferroelectric analyzer, it can be found that the residual polarization intensity of the samples showed a characteristic of increasing and then decreasing with the increase of the doping concentration, and the residual polarization intensity was the largest at 0.151 uC/cm2 under the hydrothermal reaction condition of 180°C and 3 h with the Er3+ concentration of 0.0025 mol/L.

Photobleaching of face mask dyes BB and CR using novel BPPNTs-V2O5 nanotube composites: DFT studies of self-assembly and nanoclusters

Abstract Self-assembly method demonstrated the viable production of 3,5-bistrifluoromethyl benzylamine derivative of phenylalanine nanotubes (BPPNTs). Nano-V2O5 composite of these BPPNTs has been synthesized and characterized. The reported nanocomposite shows a highly flexible nanotube structure that provides easy access to electrons when used as an electrocatalyst or photocatalyst. This promising platform is successfully applied in the electrochemical reaction by cyclic voltammetry. Maximum photodegradation of Congo red and Brilliant blue dyes (mask layer dyes) has been observed above 50% at given time intervals). This phenomena can be used in remediation applications like the degradation of used masks. Theoretical descriptions of the self-assembled BPPNT monomer and BPPNTs-V3O6 nanocluster composite by DFT calculations produced the validation of the predicted structural applications. The results concluded the proposed nanocomposite-coated mask layers for use in photodegradable masks are a valuable outcome of this study.

The effect of electrochemical treatment on the structure of single-walled carbon nanotubes: Towards better filling efficiency

Filled single-walled carbon nanotubes (f-SWCNT) are regarded as prospective materials with diverse applications, owing to the superior combination of their intrinsic properties with those of the filler material. The variety of the potential filler materials makes solution filling through open SWCNT channels under capillary forces the most flexible method for f-SWCNT production. However, the technique requires the additional step of SWCNT cap removal, and remains poorly efficient. Here, we evaluated how the structure of the SWCNTs impacts the filling efficiency depending on the conditions of electrochemical opening treatment under cyclic voltammetry protocols. We revealed the optimal upper vertex potential to be 1.1 V vs. RHE, corresponding to the trade-off between end-cap removal efficiency and yield of wall defect formation. It allowed us to achieve a filling efficiency of ∼1680 m cm−2 of gold nanowires length per unit SWCNT film area, which is ∼10 times greater than the filling efficiency of the untreated material.

Transition metal doped into defective boron nitride nanotubes for CO2RR: Regulation of catalytic activity and mechanism by curvature effect

Utilizing electrochemical CO2 reduction reaction (CO2RR) to synthesize chemical fuels is an effective strategy to alleviate environmental pollution and energy crisis. In this work, a series of single transition metal atoms (TM = Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd) are doped into boron nitride nanotubes (BNNTs) of BN divacancy defect with different curvature parameters, which are named as TM-DVBNNT(n, n), and their CO2RR catalytic performance is systematically studied by density functional theory (DFT) methods. To begin with, the calculation results of formation energy and dissolution potential show that all TM-DVBNNT(n, n) have good thermodynamic and electrochemical stability. Secondly, after calculation of Gibbs free energy, Mn-, Fe-, Ru-, and Rh-DVBNNT(5, 5) have good catalytic performance with the corresponding limiting potential (UL) values of −0.43, −0.40, −0.27, and −0.50 V, respectively. Based on this, we further investigate the influence of curvature on the stability, activity, and mechanism of Ru-DVBNNT(n, n) with the highest activity. It is worth noting that as the diameter of Ru-DVBNNT(n, n) continues to increase, their stability and activity also continue to enhance, and Ru-DVBNNT(8, 8) with the largest diameter is expected to become the best performing CO2RR electrocatalyst with the UL value of −0.16 V. Besides, for Ru-DVBNNT(3, 3) and Ru-DVBNNT(4, 4), their final product is HCOOH. In contrast, the CH4 product is more inclined to form on Ru-DVBNNTs with chiral indexes of (5, 5), (6, 6), (7, 7), and (8, 8). In summary, this work has laid a solid theoretical foundation for future experimental design of nanotube structures.

Enhancing Sodium-Ion Transport by Hollow Nanotube Structure Design of a V5S8@C Anode for Sodium-Ion Batteries.

V5S8 has received extensive attention in the field of sodium-ion batteries (SIBs) due to its two-dimensional (2D) layered structure, and weak van der Waals forces between V-S accelerate the transport of sodium ions. However, the long-term cycling of V5S8 still suffers from volume expansion and low conductivity. Herein, a hollow nanotube V5S8@C (H-V5S8@C) with improved conductivity was synthesized by a solvothermal method to alleviate cracking caused by volume expansion. Benefiting from the large specific surface area of the hollow nanotube structure and uniform carbon coating, H-V5S8@C exhibits a more active site and enhanced conductivity. Meanwhile, the heterojunction formed by a few residual MoS2 and the outer layer of V5S8 stabilizes the structure and reduces the ion migration barrier with fast Na+ transport. Specifically, the H-V5S8@C anode provides an enhanced rate performance of 270.1 mAh g-1 at 15 A g-1 and high cycling stability of 291.7 mAh g-1 with a retention rate of 90.98% after 300 cycles at 5 A g-1. This work provides a feasible approach for the structural design of 2D layered materials, which can promote the practical application of fast-charging sodium-ion batteries.

Atomic-Scale Time-Resolved Imaging of Krypton Dimers, Chains and Transition to a One-Dimensional Gas.

Single-atom dynamics of noble-gas elements have been investigated using time-resolved transmission electron microscopy (TEM), with direct observation providing for a deeper understanding of chemical bonding, reactivity, and states of matter at the nanoscale. We report on a nanoscale system consisting of endohedral fullerenes encapsulated within single-walled carbon nanotubes ((Kr@C60)@SWCNT), capable of the delivery and release of krypton atoms on-demand, via coalescence of host fullerene cages under the action of the electron beam (in situ) or heat (ex situ). The state and dynamics of Kr atoms were investigated by energy dispersive X-ray spectroscopy (EDS), electron energy loss spectroscopy (EELS), and X-ray photoelectron spectroscopy (XPS). Kr atom positions were measured precisely using aberration-corrected high-resolution TEM (AC-HRTEM), aberration-corrected scanning TEM (AC-STEM), and single-atom spectroscopic imaging (STEM-EELS). The electron beam drove the formation of 2Kr@C120 capsules, in which van der Waals Kr2 and transient covalent [Kr2]+ bonding states were identified. Thermal coalescence led to the formation of longer coalesced nested nanotubes containing more loosely bound Krn chains (n = 3-6). In some instances, delocalization of Kr atomic positions was confirmed by STEM analysis as the transition to a one-dimensional (1D) gas, as Kr atoms were constrained to only one degree of translational freedom within long, well-annealed, nested nanotubes. Such nested nanotube structures were investigated by Raman spectroscopy. This material represents a highly compressed and dimensionally constrained 1D gas stable under ambient conditions. Direct atomic-scale imaging has revealed elusive bonding states and a previously unseen 1D gaseous state of matter of this noble gas element, demonstrating TEM to be a powerful tool in the discovery of chemistry at the single-atom level.

Cu and Zn metal particles modified nanocathode based electrocatalytic nitrate reduction: Effective, selective and mechanism

Nitrate contamination of water resources not only endangers ecological environment, but also poses a threat to human health. Electrochemical removal of nitrate is limited by poor electrode efficiency and high levels of by-products. Herein, Cu and Zn nanoparticles were loaded onto the surface of TiO2 nanoelectrodes by electrodeposition to improve the electrochemical activity of the electrodes. The fabricated Cu/TiO2 and Cu/Zn/TiO2 nanoelectrodes achieved nitrate removal efficiencies of 83.5 % and 93.6 %, respectively, indicating a significant improvement in nitrate removal efficiency. The physicochemical and electrochemical characteristics of the Cu/TiO2 and Cu/Zn/TiO2 electrode revealed that the TiO2 nanotube structure formed on the electrode surface increased the specific surface area of the electrode, while the uniformly attached Cu and Zn nanoparticles augmented the active sites on the electrode surface. Additionally, the loaded Zn nanoparticles enhanced the conversion of NO2−-N to N2, effectively suppressing byproducts production. The synergistic effect of TiO2 nanotubes with Cu and Zn nanoparticles made it possible to completely electrochemical remove nitrate. Under the condition of 0.5 g/L NaCl as the electrolyte, these two electrochemical systems can achieve cathodic reduction of NO3−-N and effectively inhibit the formation of NH4+-N and NO2−-N, thereby achieving the goal of harmless removal of NO3−-N. This work provides theoretical and technical support for efficient and clean removal of nitrate from environmental water bodies by electrochemistry.

Eco-friendly bamboo pulp foam enabled by chitosan and phytic acid interfacial assembly of halloysite nanotubes: Toward flame retardancy, thermal insulation, and sound absorption

Lightweight, porous cellulose foam is an attractive alternative to traditional petroleum-based products, but the intrinsic flammability impedes its use in construction. Herein, an environmentally friendly strategy for scalable fabrication of flame-retardant bamboo pulp foam (BPF) using a foam-forming technique followed by low-cost ambient drying is reported. In the process, a hierarchical structure of halloysite nanotubes (HNT) was decorated onto bamboo pulp fibers through layer-by-layer assembling of chitosan (CS) and phytic acid (PA). This modification retained the highly porous microcellular structure of the resultant BPF (92 %–98 %). It improved its compressive strength by 228.01 % at 50 % strain, endowing this foam with desired thermal insulation properties and sound absorption coefficient comparable to commercial products. More importantly, this foam possessed exceptional flame retardancy (47.05 % reduction in the total heat release and 95.24 % reduction in the total smoke production) in cone calorimetry, and it showed excellent extinguishing performance, indicating considerably enhanced fire safety. These encouraging results suggest that the flame retardant BPF has the potential to serve as a renewable and cost-effective alternative to traditional foam for applications in acoustic and thermal insulation.

Application and structure of carbon nanotube and graphene-based flexible electrode materials and assembly modes of flexible lithium-ion batteries toward different functions

Application and structure of carbon nanotube and graphene-based flexible electrode materials and assembly modes of flexible lithium-ion batteries toward different functions

Enhanced dielectric properties of poly(vinylidene fluoride) matrix nanocomposites incorporated with one–dimensional structure of titanate nanotubes

The dielectric properties of polymer nanocomposites based on a poly(vinylidene fluoride) (PVDF) matrix, filled with a one–dimensional nanostructure of titanate nanotubes (TNTs), were investigated. These studies demonstrated significant improvements in the energy storage capability of the application. The TNTs were synthesized through an alkali hydrothermal treatment method at 130 °C for 24 h, using a 10 M NaOH solution. The TNTs exhibited a large dielectric permittivity of approximately 1.2 × 104 with a low loss tangent of approximately 0.12 at 1 kHz and 25 °C. TNTs/PVDF polymer nanocomposites were studied and fabricated using liquid phase–assisted dispersion and hot–pressing methods. By introducing TNTs into the PVDF polymer, both the dielectric permittivity and loss tangent increased. Notably, the polymer nanocomposite containing 50 wt. % TNTs exhibited a dielectric permittivity of 5.3 × 103 at 1 kHz, which is ∼530 times greater than that of pure PVDF (10.78), while the loss tangent remained at 0.572. The low–frequency dielectric permittivity increased with an increase in relative humidity from 50 to 95 % due to enhanced interfacial polarization at the surface and electrode interface. However, at frequencies greater than 1 kHz, the dielectric permittivity was independent of relative humidity. The improvement in the enhanced dielectric permittivity of polymer–based nanocomposites with incorporated TNTs was ascribed to these factors.

Utility of structural engineering on the monitoring of acrolein by aluminum nitride nano tube.

The study delves into the adsorption process of acrolein (AC) onto both an untainted and a titanium-doped aluminum nitride nanotube (AlNNT) using computations based on density functional theory. As AC approaches the pure AlNNT, it exhibits a calculated adsorption energy (Ead) of -5.3kcal/mol, underscoring the feeble nature of the adsorption. Furthermore, there has been very little change to the AlNNT's natural electrical characteristics. On the contrary, the introduction of titanium (Ti) enhances the performance of AlNNT, rendering it more susceptible and reactive to AC signals. Analyzing the conventional Gibbs free energy of formation computationally, we ascertain that replacing a nitrogen (N) atom with a titanium (Ti) atom within the aluminum nitride nanotube (AlNNT) structure presents a more advantageous prospect. Notably, there is a substantial alteration in the energy of adsorption (Ead) for AC as a Ti atom is incorporated onto the AlNNT surface, resulting in a shift from -5.3 to -24.6kcal/mol. Energy calculations and geometric optimizations were conducted utilizing the dispersion-augmented B3LYP method, known as B3LYP-D. In this approach, Grimme's dispersion term, referred to as the "D" term, was employed to account for dispersion forces. The basis set adopted was 6-31 + + G** (d), and all computational procedures were executed using the GAMESS software program. Following the incorporation of titanium (Ti), this adjustment leads to a substantial enhancement in sensing capability, reaching a value of 93.7. This indicates an improved electrical conductivity of the aluminum nitride nanotube (AlNNT). Remarkably, the Ti-doped AlNNT demonstrates the ability to detect AC distinctly, even in the presence of HCN, formaldehyde, ethanol, toluene, and acetone. The swift recovery process becomes evident as AC desorbs from the surface of Ti-doped AlNNT, with a calculated recovery time of 14.0s.

Inactivation of influenza virus as representative of enveloped RNA viruses on photocatalytically active nanoparticle and nanotubular TiO2 surfaces

The recent pandemic showed us that there is a strong demand for standardized methods to evaluate the antiviral activity of different materials using enveloped RNA viruses (e.g. SARS-CoV-2, influenza virus). Virucidal activity can be achieved as a result of photoexcitation of a TiO2 photocatalyst under UV illumination. All standardized methods evaluating the virucidal activity of photocatalytic surfaces use bacteriophage Q-beta, a representative of small non-enveloped viruses. This work was thus devoted to the evaluation of the virucidal efficiency of photocatalytically active nanostructured TiO2 surfaces (nanotubular and nanoparticle) to inactivate the influenza virus with particular interest paid to the methodology of virucidal testing and the influence of the surface nanostructure (porosity). Two different TiO2 nanostructures were used in this study, namely nanoparticle and nanotubular structures. A significant decrease in the amount of viral RNA and titre was obtained after rinsing, because the virus was retained on the surface of the nanostructured TiO2 during exposure in the dark. The decrease can be understood as an additional effect of the surface porosity on the TiO2 virucidal activity after UV illumination. However, this fact was taken into account in the calculation of virucidal activity due to UV light. Both nanostructured TiO2 coatings have comparable porosity and thickness, but the photocatalytic activity (to oxidatively degrade aqueous pollutants) is higher for the nanoparticle than for the nanotubular surface. On the other hand, the virucidal activity is much higher for the nanotubular surface. This can be explained by the uniform and open structure of nanotubes resulting in a lower amount of virus being retained on the surface under dark conditions and the high surface area of the nanotubes.

Structure and electrical properties of double-walled silicon nanotubes depending on 585 defects and applied electric fields by SCC-DFTB method

The geometric structural and electronic properties of 585 defective double-walled silicon nanotubes (DWSiNTs) by using the self-consistent charge density functional tight-binding (SCC-DFTB) method. Furthermore, we investigated the impact of external electric field and intensity on the electronic properties. After the relaxation of perfect tubes, the structure of the tube changes significantly, and the winding direction of the tube wall changes. The buckling value of the tube wall is most closely related to the geometric shape and atomic arrangement order of tubes. The overall stability of zigzag tubes is higher than armchair tubes, and (6,6)@(10,10) stability is significantly affected by defects. The partially defected zigzag tubes change from direct band gap semiconductor properties to indirect band gap semi-metal properties. A transformation of the semiconductor-semimetal properties, direct-indirect band gap of DWSiNTs is realized. The charge transfer amplitude of the defect tubes is greater than the perfect tube. The applied electric field makes the stability of all tubes decrease linearly, and the stability of the defect tubes is higher than the perfect tube. Part of the electric field strength changes the defect tubes from semiconductor properties to semi-metal properties, and semi-metal properties to metal properties. These theoretical studies provide a reference for the preparation and future application of DWSiNTs.