Performance Of Multiwalled Carbon Nanotubes Research Articles

High-sensitive electrochemical sensor based on Ni/NiCx-integrated functional carbon nanotubes for simultaneous determination of acetaminophen and dopamine

In complex environmental substance monitoring, the simultaneous detection of single and multiple substances with high sensitivity has been a research focus in the field of electrochemical sensors. Rational selection of appropriate dopants to optimize the electrode material is crucial in this regard. In this work, we employed a multi-doping strategy to effectively enhance the electrocatalytic performance of multi-walled carbon nanotubes (MWCNTs). By doping Ni/NiCx onto MWCNTs, we successfully constructed a heterojunction material (Ni/NiCx-N-MWCNTs). The successful doping of Ni/NiCx allows for the synergistic effects of multiple elements. Ni/NiCx serves as a conductive bridge, forming a three-dimensional network of nanotubes, which effectively reduces the aggregation of carbon nanotubes, exposes more active sites, and enhances electrocatalytic activity. The electrochemical sensor based on Ni/NiCx-N-MWCNTs demonstrated high sensitivity, selectivity, and simultaneous electrochemical detection for acetaminophen (1–150 μM, limit of detection (LOD)=0.56 μM) and dopamine (1–80.0 μM, LOD=0.19 μM). Its excellent reproducibility (relative standard deviation (RSD)=2.01 %) and interference resistance provide Ni/NiCx-N-MWCNTs with significant advantages over other electrode materials, indicating a promising application potential.

Enhanced lithium host performance of multi-walled carbon nanotubes through acidic functionalization for lithium–sulfur batteries

Carbon nanotubes (CNTs) have been explored as a potential cathode material for lithium-sulfur (Li–S) batteries owing to their unique structure. However, traditional CNTs exhibit poor dispersion properties when preparing electrodes. The non-uniform distribution of the conductive agents hinders the formation of enough sites for sulfur loading, which results in the aggregation of sulfur/Li2S and severe polarization. In this study, we propose the acidic functionalization of CNTs in the cathode structure as a practical solution for mitigating the poor dispersion and polysulfide shuttling in lithium-sulfur batteries. Multiwalled CNTs were functionalized by oxidation through acidic treatment using sulfuric, nitric, and mixed acids. The cathode prepared with a mixture of sulfuric and nitric acids showed a coulombic efficiency of 99 % after 100 cycles, with a discharge capacity of 743 mAh g−1. These findings demonstrate the effectiveness of the acidic functionalization of CNTs as a promising approach for enhancing the electrochemical performance and commercial viability of lithium-sulfur batteries.

Comparative analysis of machine learning techniques for predicting wear and friction properties of MWCNT reinforced PMMA nanocomposites

Polymer nanocomposites have received significant scientific and industrial attention due to the synergetic combination of features of a polymeric matrix and organic or inorganic nanofillers. While experiments have been essential for identifying and characterizing new materials, their high costs and limited trials have shifted the focus towards applying machine learning (ML) to predict nanocomposite properties. This study aims to establish a connection with the tribological performance of multi-walled carbon nanotubes (MWCNT) reinforced with polymethyl methacrylate (PMMA) nanocomposites through the comparison of ML techniques. The wear and friction characteristics of MWCNT-reinforced PMMA nanocomposites were predicted based on three input variables: material weight percentage, load weight, and track diameter. The features of nanocomposites were predicted using three different ensemble ML algorithms: random forest (RF), extra tree (ET), and gradient boosting machine (GBM). The dataset was utilized to train the proposed models in Python, followed by hyperparameter tuning to determine the best model for predicting target values. The results demonstrated that the GBM model outperformed the RF and ET models, with an R-squared of 0.99, RMSE of 0.62, and MAE of 0.18. The proposed models’ predictions of wear values were more precise than their friction values. These findings indicate that ML techniques, particularly the GBM model, can effectively predict the tribological properties of MWCNT-reinforced PMMA nanocomposites, potentially reducing the need for extensive experimental trials and contributing to advancements in nanocomposite material science.

Investigation on open water adsorption performance of multi-walled carbon nanotubes modified MIL-96(Al)

An aluminum-based metal-organic framework material MIL-96(Al) was prepared by solvent-thermal synthesis method, and by adding multi-walled carbon nanotubes (MWCNTs) in the preparation process, MWCNT/MIL-96(Al) composite adsorbent was synthesized for the first time. The morphology of the adsorbents was discussed by scanning electron microscopy (SEM). In adsorption experiments under different working conditions, MIL-96(Al) exhibited a stable equilibrium adsorption capacity, while the addition of only 0.50% mass fraction of multi-walled carbon nanotubes increased equilibrium adsorption capacity by approximately 30%. The enhancement ratio of six composite adsorbents compared to MIL-96(Al) in equilibrium adsorption capacities was almost constant under different working conditions. The adsorption rate of MIL-96(Al) could reach up to 0.573 g g−1 h, while that of the composite adsorbents under the same conditions was 0.763 g g−1 h. MIL-96(Al) could be completely desorbed within 40 min at 110 °C, and the optimal desorption temperature of MWCNT/MIL-96(Al) was reduced to 100 °C. The cyclic stability of the seven adsorbents was also confirmed through cyclic regeneration experiments. The experimental results indicated that the MWCNT/MIL-96(Al) composite adsorbent was a potential adsorbent for solar-driven atmospheric water harvesting in arid regions.

High thermoelectric performance of multiwalled carbon nanotubes based ionogels

Ionogels have emerged as promising thermoelectric materials with Seebeck coefficient 2–3 orders of magnitude higher than Seebeck coefficient of their inorganic counter parts. However, they suffer from the problem of low ionic conductivity, which can be improved with the addition of inorganic nanofillers to the ionogels. In the present work, thermoelectric performance of multiwall carbon nanotubes (MWCNTs) based ionogels (IGs) has been investigated. IGs were synthesized via in situ radical polymerization of polyethylene glycol 200 dimethacrylate (PEG200DMA) difunctional monomer in the presence of 1-butyl-3-methyl imidazolium tetrafluoroborate (an ionic liquid) and MWCNTs. Three composites namely MWCNTs-0.25, MWCNTs-0.5 and MWCNTs-1 were prepared having the concentration of MWCNTs by 0.25, 0.5 and 1 wt% respectively. A remarkable 75.3% enhancement in ionic conductivity was achieved for the MWCNTs-1 wt% ionogel compared to the base IG at 40 °C. This substantial improvement can be attributed to the "breathing polymer chain model," which describes the dissociation of ion aggregates due to the interaction between the ionic liquid and polymer chains. In terms of thermoelectric performance amongst the MWCNT ionogels, 0.25 wt% MWCNT-based ionogels was the optimized concentration with very high Seebeck coefficient of 1.70 mV/K and power factor of 4.1 µW/m. K along with excellent thermal stability up to 386 °C. These high-performing ionogels hold great promise for efficient utilization of low-grade thermal energy.

Preparation and characterization of CS/PAT/ MWCNT@MgAl-LDHs nanocomposite for Cd2+ removal and 4-nitrophenol reduction.

The present study evaluated the performance of multiwalled carbon nanotube (MWCNT)@MgAl-layered double hydroxide (LDH) nanoparticles loaded on poly-2 aminothiazole (PAT)/chitosan (CS) matrix (CPML) to remove Cd2+ ions from aqueous solution. The removal efficiency of modified CS/PAT with MWCNT@MgAl-LDHs was increased significantly compared to pure CS/PAT. The influence of heavy metal ion concentration, pH, temperature, adsorbent dosage, and contact time on the adsorption was examined. The optimum conditions for the adsorption of Cd2+ ions were 25 0C with the adsorbent dosage of 0.06g and initial concentration for adsorption of the Cd2+ 100mg/L at pH = 8. The maximum adsorption capacity was measured to be 1106.19mg/g. The values of thermodynamic parameters namely Gibbs free energy (ΔG°), entropy change (ΔS°), and enthalpy change (ΔH°) indicated the feasibility, spontaneity and the endothermic nature of the adsorption process, respectively. The pseudo-second-order kinetics and the Langmuir model were selected as the best models for the adsorption process. Also, CPML nanocomposite (NC) was successfully tested for p-nitrophenol (p-NP) reduction in the presence of NaBH4. The reaction was nearly completed in 6min. The fabricated CPML-NC could be reused for three consecutive cycles.

Improved electrochemical performance of multi-walled carbon nanotube reinforced gelatin biopolymer for transient energy storage applications.

Multi-walled carbon nanotube (MWCNT) incorporated biodegradable gelatin nanocomposites (Gel/MWCNT) have been prepared following a facile solution processing method. The Fourier-transform infrared (FTIR) spectroscopy, field emission scanning electronic microscopy (FESEM), and water contact angle (WCA) measurements revealed improved structural properties and surface morphological features of the nanocomposite films due to the incorporation of MWCNT. A four-fold decrease in the DC resistivity was obtained due to the addition of MWCNTs. The specific capacitance of the nanocomposite increased from 0.12 F/g to 12.7 F/g at a current density of 0.3 μA/cm2 due to the incorporation of 0.05 wt.% MWCNT. EIS analysis and the corresponding Nyquist plots demonstrated the contributions of the different electrical components responsible for the improved electrochemical performance were evaluated using an equivalent AC circuit. The incorporation of MWCNTs was found to reduce the charge-transfer resistance from 127 Ω to 75 Ω and increase the double-layer capacitance from 4 nF to 9 nF. The Gel/MWCNT nanocomposite demonstrated improved cyclic stability with a retention of 95% of the initial capacitance even after 5000 charging/discharging cycles. The biodegradability test showed that the nanocomposite degraded completely after 30 hours of immersion in water. This fully biocompatible nature of the nanocomposites with high specific capacitance and low charge transfer resistance may offer a promising route to fabricate a nature-friendly electrode material for energy storage applications.

Experimental thermal performance investigation of double pipe heat exchanger using MWCNT/water nanofluid

This paper presents an experimental study investigating the thermal performance of multiwall carbon nanotubes in a twin-pipe heat exchanger using a water-based fluid. The research followed a two-step method, where a concentration of 0.01 weight percent of SDS surfactant was utilized to prepare the carbon nanotubes. The heat transfer coefficient, friction coefficient, and overall heat transfer coefficient of the nanofluid were compared to those of the base fluid. The results revealed that the addition of a small amount of multiwall carbon nanotubes significantly enhanced the thermal conductivity and heat transfer coefficient of the water-based fluid. Moreover, the heat transfer coefficient exhibited an increase with higher Reynolds numbers. When the nanofluid flowed counter currently and was in the outer tube, the highest values for the overall heat transfer coefficient and the heat transfer coefficient were determined as 2864 and 7655.7 W/m2K, respectively. The findings indicate notable improvements in the thermophysical and thermal characteristics of the nanofluid.

Wear Performance of Multi-Walled Carbon Nanotubes Grafted Hybrid Fiber (Carbon–Aramid) Friction Materials

Wear Performance of Multi-Walled Carbon Nanotubes Grafted Hybrid Fiber (Carbon–Aramid) Friction Materials

Durability performance of multi-walled carbon nanotube reinforced ordinary Portland/calcium sulfoaluminate cement composites to sulfuric acid attack at early stage

Exposure of cement-based structures to sulfuric acid environments can cause significant degradation. Therefore, this study focuses on the effect of multi-walled carbon nanotubes (MWCNTs) on the sulfuric acid resistance of ordinary Portland cement (OPC)-sulfoaluminate cement (SAC) composites (as repair material) at early stage. Samples were exposed to three concentrations of acid solution for 60 days. The degradation kinetics, chemistry, and microstructures of the composites were analyzed. The results of degradation kinetics (dimensional change, mass and strength loss) showed that the MWCNTs modified composites had a lower degradation rate compared to the composites without MWCNTs. XRD, TG, X-CT and SEM analysis showed that MWCNTs promoted hydration, improved structure compactness, interrupted the generation and propagation of microcracks through the bridge effect, and formed protective barriers. The degradation rate of the composite was reduced by the double optimization of chemistry and microstructure. However, diffusion-dissolution-precipitation is still the main mode of degradation in composites subjected to sulfuric acid attack, regardless of MWCNT content mixed into the composite system.

Annealing effect on the thermoelectric properties of multiwall carbon nanotubes

In this article, it is demonstrated that transport properties and thus thermoelectric performance of multiwall carbon nanotubes (MWCNTs) can be enhanced significantly by annealing. Two different samples of MWCNTs with small and large diameters were investigated. The as-prepared MWCNT samples were treated at different conditions of annealing. The pristine and annealed MWCNTs were investigated using x-ray diffraction, Raman spectroscopy and scanning electron microscope in order to investigate the microstructure, defect content and morphology before and after the annealing process. The electrical conductivity, Seebeck coefficient and thermal conductivity were measured over the temperature range of (300–450 K) and were found to correlate with the tube diameter and the annealing conditions. The electrical conductivity and Seebeck coefficient measurements show that the conduction mechanism in MWCNTs is thermal activation as the samples have degenerate semiconductor-like behavior. Upon annealing, the Seebeck coefficient increases, followed by a reduction in the thermal conductivity. The thermoelectric power factor was enhanced by annealing to realize the highest value of 1.06 μW m −1 K −2 at 475 K for the sample with the larger diameter. The thermoelectric figure of merit ZT was calculated to determine the performance of the materials. ZT of the sample of the larger tube's diameter was enhanced by about 247% at 450 K. • Pristine and annealed MWCNTs were investigated using x-ray diffraction, Raman spectroscopy and scanning electron microscope. • Thermoelectric performance of multiwall carbon nanotubes (MWNTs) is significantly enhanced by annealing. • The thermoelectric figure of merit ZT was enhanced by about 247% at 450 K.

Multi-walled carbon nanotubes derived graphene nanoribbons for high performance supercapacitor applications

This study delineates the supercapacitive performance of multi-walled carbon nanotubes derived nanoribbons. Acid-processed carbon nanotubes were exfoliated and reduced with microwaves to yield high quality graphene nanoribbons (GNRs). Morphological and spectroscopic investigations revealed the successful preparation of graphene nanoribbons from carbon nanotubes. The three electrode system configuration with microwave exfoliated graphene nanoribbons (MWGNRs) based working electrode and H2SO4-PVA gel electrolyte has shown high specific capacitance of 404 F/g at 2 mVs−1 scan rate. This three electrode configuration showed 97.3% of initial capacitance retention after 10,000 cycles, which proves good cycle stability and retention capability of the MWGNRs based electrode with gel electrolyte. A supercapacitive device with MWGNRs based electrodes and 1 M H2SO4 –PVA gel electrolyte was fabricated and tested, which also showed high supercapacitive performance. MWGNRs have more number of reactive edges and high specific surface area as compared to pristine carbon nanotubes and therefore exhibit high specific capacitance. The proposed method is highly scalable and can pave a way to develop high performance low cost supercapacitors.

Effects of modification groups and defects on the desalination performance of multi-walled carbon nanotube (MWNT) membranes

Like single-wall carbon nanotubes (SWNTs), multi-wall carbon nanotubes (MWNTs) have channels for selective separation of ions. Moreover, MWNTs have the advantages of simpler preparation and lower cost, potentially allowing wider applications in the desalination industry. In this study, the transport of water and ions inside two types of MWNTs, i.e., double-wall carbon nanotubes (DWNTs) and tri-wall carbon nanotubes (TWNTs) were investigated using non-equilibrium molecular dynamics simulations. Modification groups, including carbon chains of different lengths and types with hydrophilic groups like carboxylate anion (COO–), and ammonium (NH3+), were used to improve the salt rejection performance. The simulation results suggest that 100% salt rejection could be achieved by adding different modification groups to various MWNTs ranging from 13 to 20 Å. More importantly, this study demonstrates that MWNT membranes with 100% desalination have water fluxes that are 10–30% greater than that of SWNT membranes with 100% desalination, implying the greater potential of MWNTs as building blocks towards next-generation desalination membranes. Additionally, even though all real-world carbon nanotubes (CNTs) have a certain amount of defects from the production process, most previous molecular model studies of water and ions transport in CNTs assumed that CNTs were perfect and defect-free. This study shows for the first time that CNTs with defects have improved salt rejection rates than perfect carbon nanotubes, although the former have lower water fluxes than the latter.

Performance of multiwalled carbon nanotube doped fly ash based clay bricks

Performance of multiwalled carbon nanotube doped fly ash based clay bricks

Application of MnO2/MWCNT composite in supercapacitors

Supercapacitors have attracted tremendous attention due to high power density, high rate capability, long cycling life and safety. The article presents the comparison of electrochemical performance of multi-walled carbon nanotubes (MWCNTs), MnO2 and MnO2/MWCNT nanocomposite as electrode mass in supercapacitor. Materialswere characterized by X-ray diffraction, scanning electron microscopy, low temperature nitrogen adsorption and cyclic voltammetry. The specific capacitance was found to increase in the row MWCNTs < MnO2 < MnO2/MWCNT achieving 32, 90 and 140 F · g−1 at 5 mV · s−1, respectively. The outstanding improvement of specific capacitance for MnO2/MWCNT was attributed to the combination of high electrical conductivity of carbon nanotubes enhancing the charge transport and faradic redox reactions occurring on MnO2 surface.

Effects of Modification Groups and Defects on the Desalination Performance of Multi-Walled Carbon Nanotube (Mwnt) Membranes

Effects of Modification Groups and Defects on the Desalination Performance of Multi-Walled Carbon Nanotube (Mwnt) Membranes

Determination of new generation amide insecticide residues in complex matrix agricultural food by ultrahigh performance liquid chromatography tandem mass spectrometry

Eight new generation amide insecticide residues analysis by multiwalled carbon nanotubes (MWCNs) cleanup, combined with QuEChERS and ultrahigh performance liquid chromatography tandem mass spectrometry has been developed and successfully applied in complex matrix such as orange, celery, onion, litchi, mango, shallot, chives, avocado, garlic. The matric effect of MWCNs is optimized and compared with ordinary cleanup materials. The results show that the performance of MWCNs is fine and effectively reduce matrix interference. Through chemical structure skeletons analyzed, chlorantraniliprole, bromoantraniliprole, and cyantraniliprole can cause same product ions of m/z 286.0 or 177.1 in the ESI+ mode, then tetrachlorantraniliprole and cyclaniliprole can produce collective ions of m/z 146.9 in the ESI− mode. The coefficients (R2) were greater than 0.9990, the limit of quantification ranges from 0.03 to 0.80 μg/kg, the recovery rate ranges from 71.2 to 120%, and the relative standard deviation (RSD) ranges from 3.8 to 9.4%. The method is fast, simple, sensitive, and suitable for the rapid determination of amide pesticides in complex matrix agricultural food.

The effect of thickness on the multiwalled carbon nanotubes performance in glass/epoxy composite laminates under dynamic loading

AbstractThe aim of this research is to investigate the thickness influence on the efficiency of multiwalled carbon nanotubes (MWCNTs) in glass/epoxy composite laminates under the high‐velocity impact. Combining 0.25 wt% of MWCNTs in the 4‐layer and 8‐layer specimens and 0.1 wt% of MWCNTs in the 16‐layer specimen led to the maximum rise in the energy absorption and specific perforation energy compared with the unreinforced laminates. The significant growth in energy absorption in the 4‐layer, 8‐layer, and 16‐layer specimens was 5.8, 8.3, and 14.4 J, respectively. The number of agglomerations (dislocations) in the matrix was consequently increased as a function of thickness, which led to the better performance of MWCNTs with lower weight percentages in the composite laminates containing more layers. The scanning electron microscope was used to observe the dispersion and agglomeration of MWCNTs in the resin epoxy, and there was also an improvement in the fiber–resin bonding.

Research on the smart behavior of MCNT grafted CF/cement-based composites

To solve the disadvantages of weak bonding between the carbon fiber (CF) and the cement matrix, as well as the poor dispersion performance of multi-walled carbon nanotubes (MCNT) in cement paste, hydrothermal synthesis and chemical grafting methods were combined to graft MCNT on the surface of CF. Scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) were coupled used to evaluate the grafting efficiency. Four-electrode method and electrochemical impedance spectroscopy (EIS) were applied to assess the electrical property of MCNT grafted CF/cement-based composites. The smart behavior of MCNT grafted CF/cement-based composites were characterized under monotonic and cyclic loading. Results showed that the hydrothermal synthesis method can effectively graft MCNT on the surface of CF, and the grafting ratio as indicated by nitrogen element was 6.78%. The conductivity of MCNT grafted CF/cement-based composites was far superior to that of untreated CF/cement-based composites. Also, the composite with the addition of MCNT grafted CF was more sensitive to the cyclic stress. Therefore, the stress sensitive property of MCNT grafted CF/cement-based composites was significantly improved, compared to its untreated counterpart.

An in-silico layer-by-layer adsorption study of the interaction between Rebaudioside A and the T1R2 human sweet taste receptor: modelling and biosensing perspectives

The human sweet taste receptor (T1R2) monomer—a member of the G-protein coupled receptor family that detects a wide variety of chemically and structurally diverse sweet tasting molecules, is known to pose a significant threat to human health. Protein that lack crystal structure is a challenge in structure-based protein design. This study focused on the interaction of the T1R2 monomer with rebaudioside A (Reb-A), a steviol glycoside with potential use as a natural sweetener using in-silico and biosensing methods. Herein, homology modelling, docking studies, and molecular dynamics simulations were applied to elucidate the interaction between Reb-A and the T1R2 monomer. In addition, the electrochemical sensing of the immobilised T1R2-Reb-A complex with zinc oxide nanoparticles (ZnONPs) and graphene oxide (GO) were assessed by testing the performance of multiwalled carbon nanotube (MWCNT) as an adsorbent experimentally. Results indicate a strong interaction between Reb-A and the T1R2 receptor, revealing the stabilizing interaction of the amino acids with the Reb-A by hydrogen bonds with the hydroxyl groups of the glucose moieties, along with a significant amount of hydrophobic interactions. Moreover, the presence of the MWCNT as an anchor confirms the adsorption strength of the T1R2-Reb-A complex onto the GO nanocomposite and supported with electrochemical measurements. Overall, this study could serve as a cornerstone in the development of electrochemical immunosensor for the detection of Reb-A, with applications in the food industry.