Carbon Nanotubes Research Articles

Immobilization of pullulanase from Bacillus licheniformis on magnetic multi-walled carbon nanotubes for maltooligosaccharide production

Immobilization of pullulanase from Bacillus licheniformis on magnetic multi-walled carbon nanotubes for maltooligosaccharide production

Zinc cobalt sulfide with carbon (graphene oxide and CNT) based nanocomposite as positive electrode for asymmetric coin cell supercapacitors

Abstract The world dependence on portable electronic devices has increased the demand for high-performance energy storage devices. The use of transition metal sulfides as faradaic electrode materials for electrochemical energy storage is rapidly increasing due to their high energy density. Herein Zinc Cobalt Sulfide (ZCS) with graphene oxide (GO) and carbon nanotubes (CNT) were used to create an interconnected ZCS composite network using a solvothermal technique. The materials were characterized by utilizing XRD, FT-Raman, TGA, FESEM/EDX, XPS, and BET. The electrochemical performance of the materials was examined using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS). The prepared electrodes exhibited both pseudocapacitor behavior and double-layer capacitor behavior, indicating the hybrid nature. Furthermore, All the electrode ZCS, ZCS/GO, ZCS/CNT, and ZCS/GO/CNT electrodes demonstrated higher capacitance behavior, with values of 420, 551, 585 and 811 F g−1 at 1 A/g. Among these ZCS/GO/CNT electrode exhibits outstanding electrochemical properties, with a notable retention of 81.08% at 10 Ag−1 because Combining ZCS nanoparticles with interconnected GO and CNT provides excellent electronic conductivity and stability. The assembled ZCS/GO/CNT//graphene oxide asymmetric coin cell (ACC) supercapacitor showed a high energy density of 33.3 Wh kg–1 at a power density of 624 W kg–1. The 3D nanostructure of ZCS/GO/CNT/Graphene oxide has great potential for developing foldable energy storage devices.

A novel electrochemical sensor based on ꞵ-cyclodextrin/bismuth oxybromide/multi-walled carbon nanotubes modified electrode with in situ addition of tetrabutylammonium bromide for the simultaneous detection and degradation of tebuconazole.

A novel electrochemical sensor-based glassy carbon electrode (GCE) was fabricated and appliedtosimultaneous detection and degradation of tebuconazole (TBZ) for the first time.TheGCE was consecutively modified by multi-walled carbon nanotubes (MWCNTs), bismuth oxybromide (BiOBr), ꞵ-cyclodextrin (ꞵ-CD), and in situ addition of tetrabutylammonium bromide (TBABr). The detection was based on the decreasing of Bi signal at its anodic potential (Epa) of 0.05V. Under the optimum conditions, the modified electrode exhibited a linear response to TBZ in the concentration range 1-100μg L-1 with a detection limit of 0.9μg L-1. TBZ was firstly adsorbed on the surface of the modified electrode through host-guest molecule interactions of the ꞵ-CD. The adsorption was further enhanced by the large surface area of BiOBr and MWCNTs. The adsorbed TBZ on the electrode surface hindered the electron transfer of Bi, thus decreasing the oxidation of Bi. In addition, the in situ addition of tetrabutylammonium bromide (TBABr) enriched TBZ via electrostatic interactions, increasing its detection sensitivity. The fabricated electrochemical sensor was applied to determine TBZ in water and soil samples from rice fields with recoveries of 80.5-100.5% and 87.6-112%, respectively. Furthermore, the degradation of TBZ on the modified electrode was studied under a solar light simulator. The degradation percentage (100%) of TBZ (50µg L-1) was achieved in5min owing to the excellent photocatalytic properties of BiOBr.

Characterization of thin-walled self-healing microcapsules reinforced with multi-walled carbon nanotubes

This study presents a novel approach to fabricating thinner shells and significantly enhancing the fracture strength of melamine-urea-formaldehyde (M-U-F) microcapsules reinforced with multi-walled carbon nanotubes (MWCNTs). Unlike previous studies that primarily focused on single-walled carbon nanotubes (SWCNTs) or MWCNTs in polyurea-formaldehyde (PUF) shells, this research advances microcapsule technology by exploring MWCNT reinforcement in M-U-F shells. We employed a dual experimental-numerical approach, combining the precision of micro-compression tests with the predictive capabilities of finite element analysis (FEA) to determine the elastic modulus of MWCNT-reinforced M-U-F microcapsules. This method offers new insights into the mechanical behavior of these microcapsules. Our findings indicate an 8.8% increase in fracture load and a 14.6% reduction in fracture displacement for MWCNT-reinforced microcapsules compared to conventional M-U-F microcapsules. Additionally, FEA confirmed the results of the micro-compression tests, showing that MWCNT-reinforced microcapsules had the best correlation with an elastic modulus of 4.00 GPa. Conventional M-U-F microcapsules corresponded to an elastic modulus of 2.25 GPa. These results provide a comprehensive understanding of how nano-reinforcement influences the structural properties of thin-walled microcapsules, with potential applications in composite damage repair and beyond.

Membrane Fusion Mediated by Cationic Helical Peptide L-MMBen through Phosphatidylglycerol Recruitment.

Membrane fusion is the basis for many biological processes, which holds promise in biomedical applications including the creation of engineered hybrid cells and cell membrane functionalization. Extensive research efforts, including investigations into DNA zippers and carbon nanotubes, have been dedicated to the development of membrane fusion strategies inspired by natural SNARE proteins; nevertheless, achieving a delicate balance between membrane selectivity and high fusion efficiency through precise molecular engineering remains unclear. In our recent study, we successfully designed L-MMBen, a cationic helical antimicrobial peptide that exhibits remarkable antimicrobial efficacy while demonstrating moderate cytotoxicity. In this work, we demonstrate the effective and selective induction of fusion between phosphatidylglycerol (PG)-containing membranes by L-MMBen. By combining biophysical assays at the single-vesicle level with computer simulations at the molecular level, we discovered that L-MMBen can stably adsorb onto the surface of PG-containing membranes, leading to the formation of stalk structures between vesicles and ultimately resulting in membrane fusion. Furthermore, the occurrence of fusion is attributed to the unique ability of L-MMBen to recruit PG lipids and bridge adjacent vesicles. In contrast, its nonhelical counterpart DL-MMBen was found to lack this capability despite possessing an identical positive charge. These findings present an alternative molecule for achieving selective membrane fusion and provide insights for designing helical peptides with diverse applications.

Improvement of Mechanical and Acoustic Characteristics of Halloysite Nanotube-Reinforced Polyurethane Elastomer Composites and Their Applications

Polyurethane incorporated with nanofillers such as carbon nanotubes, basalt fibers, and clay nanoparticles has presented remarkable potential for improving the performance of the polymeric composites. In this study, the halloysite nanofiller-reinforced polyurethane elastomer composites were prepared via the semi-prepolymer method. The impact of different halloysites (halloysite nanotubes and halloysite nanoplates) in polyurethane composites was investigated. Scanning electron microscopy, X-ray diffraction, infrared spectroscopy, electronic universal tensile testing, and acoustic impedance tube testing were employed to characterize the morphology, composition, phase separation, mechanical properties, and sound insulation of the samples. The composite fabricated with 0.5 wt% of halloysite nanotubes introduced during quasi-prepolymer preparation exhibited the highest tensile strength (22.92 ± 0.84 MPa) and elongation at break (576.67 ± 17.99%) among all the prepared samples. Also, the incorporation of 2 wt% halloysite nanotubes into the polyurethane matrix resulted in the most significant overall improvements, particularly in terms of tensile strength (~44%), elongation at break (~40%), and sound insulation (~25%) within the low-frequency range of 50 to 1600 Hz. The attainment of these impressive mechanical and acoustic characteristics could be attributed to the unique lumen structure of the halloysite nanotubes, good dispersion of the halloysites in the polyurethane, and the interfacial bonding between the matrix and halloysite fillers.

Vacuum Filtration-Coated Silver Electrodes Coupled with Stacked Conductive Multi-Walled Carbon Nanotubes/Mulberry Paper Sensing Layers for a Highly Sensitive and Wide-Range Flexible Pressure Sensor

Flexible pressure sensors based on paper have attracted considerable attention owing to their good performance, low cost, and environmental friendliness. However, effectively expanding the detection range of paper-based sensors with high sensitivities is still a challenge. Herein, we present a paper-based resistive pressure sensor with a sandwich structure consisting of two electrodes and three sensing layers. The silver nanowires were dispersed deposited on a filter paper substrate using the vacuum filtration coating method to prepare the electrode. And the sensing layer was fabricated by coating carbon nanotubes onto a mulberry paper substrate. Waterborne polyurethane was introduced in the process of preparing the sensing layers to enhance the strength of the interface between the carbon nanotubes and the mulberry paper substrate. Therefore, the designed sensor exhibits a good sensing performance by virtue of the rational structure design and proper material selection. Specifically, the rough surfaces of the sensing layers, porous conductive network of silver nanowires on the electrodes, and the multilayer stacked structure of the sensor collaboratively increase the change in the surface contact area under a pressure load, which improves the sensitivity and extends the sensing range simultaneously. Consequently, the designed sensor exhibits a high sensitivity (up to 6.26 kPa−1), wide measurement range (1000 kPa), low detection limit (~1 Pa), and excellent stability (1000 cycles). All these advantages guarantee that the sensor has potential for applications in smart wearable devices and the Internet of Things.

Improvement of N-type carbon nanotube field effect transistor performance using the combination of yttrium diffusion layer in HfO2 dielectrics and metal contacts.

In this paper, we obtained n-type top-gate carbon nanotube thin film field effect transistors (CNTFET) with source/drain extensions structure through dielectrics optimization strategy, combining the yttrium layer with HfO2 dielectric argon annealing process and metal contacts. The mechanism for enhanced n-type conduction was explained as being due to the vertical diffusion of yttrium to the HfO2 dielectric during argon annealing. This diffusion causes abending of the energy band, which results in more positive fixed charges and a reduction in the electron injection barrier between the low work function source-drain Cr electrode and carbon nanotube. The optimized technology has great prospects for the low cost, large scale and high performance n-type CNTFET to be used in integrated electronic devices.&#xD.

Ruthenium(II) N-heterocyclic carbene polymer based sensors for detection of predatory drugs like ketamine and scopolamine.

The current demand in the field of abusive drug research is to have a highly sensitive and rapid method for detecting ketamine and scopolamine, which are frequently used in drug-facilitated sexual assaults administered via beverages and food. We report here the first electrochemical sensors of N-heterocyclic carbene (NHC) coordinated ruthenium organometallic 1-dimensional polymers and their multi-walled carbon nano tube (MWCNT)-based composite for detecting ketamine and scopolamine. The preparation of ruthenium NHC organometallics and the MWCNT composite as sensors offers significant advantages for electrochemical applications, with enhanced sensitivities of 121.979 and 3.273 μA μM-1 cm-2 for ketamine and scopolamine, respectively, and selectivity in sensing applications. The complex-carbon composite sensor has a low limit of detection i.e., 0.194 and 3.18 nM for ketamine and scopolamine identification, respectively. Alongside, the selectivity of the composite sensor was evaluated in the presence of other blood constituents, and the study evidenced remarkable discernment towards the title drugs. Furthermore, real-time analyses using the composite sensor demonstrated quantitative identification of ketamine and scopolamine. Therefore, this innovation has the potential to provide valuable tools for forensic investigations and address the urgent need for real-time detection of date rape drugs. This contribution demonstrates a robust proof-of-concept that emphasizes the importance of creating non-enzymatic, environmentally friendly, and cost-effective sensors for on-site sensing applications as point-of-care devices.

Molecularly Imprinted Electrochemical Sensor Constructed by Ferrocene‐Functionalized Carbon Nanotubes for Rapid Recognition and Determination of Tryptophan

AbstractMolecular imprinting is an advanced technology in the fabrication of novel chemical sensors recently applied, enabling rapid responses and highly selective binding to specific molecules, thereby enabling efficient detection of material constituents. In this study, a new molecularly imprinted electrochemical sensor (MIES) utilizing ferrocene‐functionalized carbon‐nanotubes (Fc‐CNTs) was developed for the determination of tryptophan (Trp). The formation of molecularly imprinted polymer (MIP) involves polymerization in dimethyl sulfoxide (DMSO) using Trp, methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) as the template molecules, functional monomers, and cross‐linking agents, respectively. Due to the modification of MIPs, the sensor achieves high performance. The sensor demonstrates a linear range from 1 to 45 μM and from 45 to 330 μM, with the limit of detection of 0.44 μM, exceeding that of the majority of sensors reported in the literature. Furthermore, the sensor can effectively detect Trp in real samples, including human serum and amino acid oral liquid. The recovery rate of Trp in human serum samples is 94.2 % to 105.30 %, and in amino acid oral liquid is 94.3 % to 101.68 %. This study provides a promising approach for the effective detection and analysis of tryptophan constituents.

AlN Nanotube Decorated with Small Tin Oxide Clusters as a Novel CH4 Sensing Material.

The success of carbon nanotubes has triggered a great deal of research interest in other one-dimensional nanomaterials with the aim of designing innovative nanostructures with attractive and distinctive attributes for applications in sensing gas molecules and toxic substances. In the present study, first-principles density functional theory calculations were exploited to assess the capability of the small tin oxide cluster (SnxOy)-decorated (6,0)aluminum nitride (AlN) nanotube for detecting methane(CH4) in terms of energetic, structural, and electronic properties. We found that SnxOy clusters were chemisorbed on the surface of the AlN nanotube due to the considerable adsorption energy and the notable charge transfer from the former to the latter. Further calculations demonstrate that the energy band gap and work function of the AlN nanotube were reduced in the presence of additives. Benefiting from the higher affinity of SnxOy toward the CH4 molecule, the Sn3O3-decorated AlN nanotube exhibited the greatest CH4 adsorption energy. The electrical conductivity increased as the energy band gap and effective mass decreased dramatically. Additionally, the type of Sn3O3-decorated AlN nanotube changed from a p-type semiconductor to an n-type one after adsorbing the CH4 molecule. Therefore, the Sn3O3-decorated AlN nanotube endows great promise as a thermopower-based, resistance-based, and Seebeck-effect-based CH4 sensing material.

Carbon nanomaterials for efficient oxygen and hydrogen evolution reactions in water splitting: A review

Water splitting has gained significant attention as a means to produce clean and sustainable hydrogen fuel through the electrochemical or photoelectrochemical decomposition of water. Efficient and cost-effective water splitting requires the development of highly active and stable catalysts for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Carbon nanomaterials, including carbon nanotubes, graphene, and carbon nanofibers, etc., have emerged as promising candidates for catalyzing these reactions due to their unique properties, such as high surface area, excellent electrical conductivity, and chemical stability. This review article provides an overview of recent advancements in the utilization of carbon nanomaterials as catalysts or catalyst supports for the OER and HER in water splitting. It discusses various strategies employed to enhance the catalytic activity and stability of carbon nanomaterials, such as surface functionalization, hybridization with other active materials, and optimization of nanostructure and morphology. The influence of carbon nanomaterial properties, such as defect density, doping, and surface chemistry, on electrochemical performance is also explored. Furthermore, the article highlights the challenges and opportunities in the field, including scalability, long-term stability, and integration of carbon nanomaterials into practical water splitting devices. Overall, carbon nanomaterials show great potential for advancing the field of water splitting and enabling the realization of efficient and sustainable hydrogen production.

A Bamboo-structured N-Doped Carbon Nanotubes Encapsulated PdCo Nanoparticles: Synthesis and Catalytic Performance for Furfural Hydrogenation to Furfural Alcohol

A Bamboo-structured N-Doped Carbon Nanotubes Encapsulated PdCo Nanoparticles: Synthesis and Catalytic Performance for Furfural Hydrogenation to Furfural Alcohol

Diffraction features of single-walled carbon nanotubes

Diffraction features of single-walled carbon nanotubes

Development of modular extrusion bioprinter prototype

Introduction: The aim of this work was to develop a prototype of a modular extrusion bioprinter capable of performing 2D and 3D printing with hydrogels based on sodium alginate and gelatin. Materials and methods: The bioprinter uses Cartesian coordinate system, the print head is movable in Y and Z axes, the printing platform is in X axis and equipped with cooling system. Constructs were printed with 3 types of gels: based on gelatin with the addition various concentrations of xanthan gum; based on combination of gelatin and sodium alginate; based on gelatin and xanthan gum with the addition of carbon nanotubes. Results: The constructs from various gels corresponded to the structure determined by their digital models. Conclusions: The developed system allows performing 2D and 3D printing with gels based on gelatin, sodium alginate, including those containing carbon nanotubes and/or xanthan gum for a wide range of experimental tasks.

Effect of Nanostructure and Crosslinks on Impact Resistance of Carbon Nanotube Films Under Micro-Ballistic Impact.

Carbon nanotube (CNT) films show great promise as an advanced bulletproof materials due to their excellent energy dissipation ability under impact loadings. However, it is challenging to determine the optimized architecture structure of CNTs to enhance the impact resistance of CNT films. In this study, the impact behavior of CNT films with various architecture structures werestudied by micro-ballistic impact experiments and coarse-grained molecular dynamics (CGMD) simulations. The micro-ballistic impact experimental results showed that the cross-ply laminated (CPL) structure enhances significantly the specific energy absorption (SEA) of CNT films compared to that with disordered structure due to the synergistic interactions between covalent bonds in CNT chains. On this basis, four CPL-CNT (CCNT) films with the same areal density (ρ2D) but different single-layer areal density ( ) and one disordered CNT (DCNT) film with the same ρ2D as the CCNT films wereconstructed in CGMD models. The simulation results showed that the SEAs of all the four CCNT films are higher than DCNT film, which is consistent with experiments. In addition, the SEAs of CCNT films increase with decreasing . However, too small can lead to local plugging failure of the CNT film and therefore decrease SEA of the CNT film. Moreover, adding crosslinks could further increase the SEAs of both the DCNT and the CCNT films due to the strengthened interactions of adjacent CNTs. The crosslinked CCNT films with appropriate ρ2D is still much higher than the crosslinked DCNT films. Furthermore, it wasfurther found that when the strength of the crosslinks aligns with that of the CNT beads, the CNT film achieves preeminent impact resistance. This study provides a pathway for enhancing the impact resistance of CNT films by optimizing the microstructure and introducing crosslinks betweenCNTs.

Skepticism regarding the use of carbon nanotubes as reinforcing agent in ceramics for biomedical applications: A critical review

Recent advancements in composite materials, including ceramics, metals, and polymers, have shown significant promise for biomedical applications. In particular, the use of carbon nanotubes (CNTs) as reinforcement in alumina and zirconia ceramics has garnered attention due to their potential to greatly enhance mechanical properties. CNTs, with their high aspect ratio, mechanical strength, and electrical conductivity, offer unique advantages for improving traditional ceramics used in biomedical applications, such as hip and knee replacements, where alumina and zirconia have been employed since the 1970s for their superior wear resistance and biocompatibility. This review critically examines the mechanical benefits of CNT-reinforced ceramics, focusing on factors such as CNT distribution, reinforcement mechanisms, fracture toughness, and long-term durability. Additionally, it explores the significant challenge of CNT toxicity, cytocompatibility, and potential long-term health risks, particularly their non-biodegradable and carcinogenic nature, which could limit their use in medical implants. While promising, inconsistencies in reported improvements, largely due to dispersion issues and ceramic-CNT interactions, along with unresolved toxicity concerns, indicate the need for further research. This review aims to provide a comprehensive understanding of both the mechanical potential and the biological risks of CNT-reinforced ceramics in biomedical applications.

A facile method for carbon nanotube/carbon fiber‐reinforced polylactic acid composites

AbstractThe mechanical strength of polylactic acid (PLA) can be improved by carbon fiber (CF) compositing to expand its application in tissue engineering scaffolds. However, the mechanical strength of CF‐reinforced polylactic acid (CFRPLA) composites is compromised due to weak interfacial interaction resulting from the chemically inert surface of CF. In the article, carbon nanotube (CNT) with poly(diallyldimethylammonium chloride) (PDDA) as a coupling agent was covered on CF to improve the chemical activity and roughness of the surface of CF, and then the as‐prepared CF‐PCNT were further incorporated into PLA via melt compounding. The yield strength, modulus, and thermal conductivity of PLA/CF‐PCNT were 14.09%, 7.65%, and 5.24% higher than those of PLA/CF, respectively, and the volume resistivity was 99.74% lower at a 10 wt% loading. The enhancement for the mechanical properties of PLA/CF‐PCNT composites could be ascribed to the mechanical locking, hydrogen bonds and covalent bonds between CF and matrix through the interface modulation of CNT and PDDA. This facile and non‐destructive method offers a novel strategy for the modification of CF fillers.Highlights CF was modified by PDDA and CNT through a facile and non‐destructive method. The active functional groups and roughness on the surface of CF were increased. The surfaces of CFs were characterized by FT‐IR, Raman spectra, XPS and SEM. The interface was improved by mechanical locking, covalent, and hydrogen bonds. The mechanical strength, electrical and thermal conductivity of composites were improved.

Advanced synthesis techniques and tailored properties of carbon nanotube reinforced polymer composites for high-performance applications

Advanced synthesis techniques and tailored properties of carbon nanotube reinforced polymer composites for high-performance applications

The Effect of Doping Zinc Oxide Thin Films With (0.5 wt. %) Carbon Nanotubes by Vacuum Evaporation

The study included the production of nano-thin films made of zinc oxide doped with carbon nanotubes (ZnO:CNTs) at a doping ratio of 0.5 wt%. The materials are applied onto glass substrates using the vacuum evaporation process. The structural characteristics of the thin films of undiluted and doped ZnO were assessed using X-ray diffraction (XRD). Additionally, the surface properties of the films were examined using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The optical characteristics of the thin films were analyzed and described using UV-Vis spectroscopy. The ZnO thin films exhibited crystalline formations. The thin films exhibited significant orientations along the (100), (002), and (101) crystallographic planes, indicating their hexagonal phase structures. The crystal size of ZnO thin films exhibited a range of 30.87 nm to 19.96 nm after the process of doping. The study findings demonstrate that the addition of carbon nanotubes leads to an increase in the absorption ratio. Zinc-doped carbon nanotube thin films has features that make them suitable for many applications, such as gas detectors and UV detectors.