Synergistic Effect Of MWCNTs Research Articles

Design a novel mixed-ligand Ni-MOF/MWCNT nanocomposite to enhance the electrochemical performance of supercapacitors

Metal-organic frameworks (MOFs) have garnered considerable interest for supercapacitors as electrode materials. Although MOFs possess large pore sizes and high specific surface areas, most MOFs face major challenges due to their inferior stability and low electronic conductivity. In this study, we synthesized Ni-MOF/MWCNT nanocomposite using a mixed-ligand approach through hydrothermal method to provide more redox reaction sites, facilitate ion diffusion, increase the stability, and electronic conductivity of the electrode. Benzoic acid (BA) has partially replaced Benzene-1,3,5-tricarboxylic acid (BTC). BTC has been used to shape Ni-MOF nanosheets into flower-like microspheres, which can reduce the electron/ion diffusion path. The introduction of BA and combination of MWCNT and Ni-MOF result in high electric conductivity. Furthermore, the combination of two organic ligands, and the synergistic effect of MWCNTs and Ni-based MOFs lead to excellent electrochemical performance. The prepared Ni-MOF/MWCNT nanocomposite shows an outstanding capacitance of 900 F g−1 at 0.5 A g−1 and excellent cycling stability with 82 % capacity etention over 1000 cycles. This study presents an innovative strategy for enhancing energy storage performance.

Rare earth doped bimetal hydroxide/multi-walled carbon nanotubes as composite electrodes to achieve high-energy-density asymmetric supercapacitors

A novel electrode material of Ni–Co bimetallic hydroxide composite multi-wall carbon nanotubes (La–NiCo LDH/MWCNTs/NF) doped with rare earth elements was prepared on nickel foam (NF) by a one-step hydrothermal method and doped with different concentrations of La3+ ions. The introduction of La3+ ions can increase the layer spacing of LDH materials. The acidification of MWCNTs on the surface of NF can also enhance the collection effect of NF. The synergistic effect of MWCNTs and La3+ ions further improves the specific capacitance of the material. At the current density of 1 A g−1, the maximum specific capacitance of the sample with 5 % La3+ ion concentration reaches 4396.0 F g−1, and the capacitance retention is 70.31 % after 3000 cycles of a single electrode. When assembled into a device, the device obtains a high energy density of 77.86 Wh kg−1 at a power density of 800.0 W kg−1. After assembling into an asymmetric supercapacitor, it has undergone 8000 cycles of performance testing, and the capacitance ratio is only reduced by 4.9 %. It shows good electrochemical cycle performance. This work provides a new way to study the doping of rare earth elements for supercapacitor materials.

Ultra-Wide Range, High Sensitivity Piezoresistive Sensor Based on Triple Periodic Minimum Surface Construction.

Flexible piezoresistive sensors with biological structures are widely exploited for high sensitivity and detection. However, the conventional bionic structure pressure sensors usually suffer from irreconcilable conflicts between high sensitivity and wide detection response range. Herein, a triple periodic minimum surface (TPMS) structure sensor is proposed based on parametric structural design and 3D printing techniques. Upon tailoring of the dedicated structural parameters, the resulting sensors exhibit superior compression durability, high sensitivity, and ultra-high detection range, that enabling it meets the needs of various scenes. As a model system, TPMS structure sensor with 40.5% porosity exhibits an ultra-high sensitivity (132 kPa-1 in 0-5.7 MPa), wide detection strain range (0-31.2%), high repeatability and durability (1000 cycles in 4.41 MPa, 10000 s in 1.32 MPa), and low detection limit (1% in 80 kPa). The stress/strain distributions have been identified using finite element analysis. Toward practical applications, the TPMS structural sensors can be applied to detect human activity and health monitoring (i.e., voice recognition, finger pressure, sitting, standing, walking, and falling down behaviors). The synergistic effects of MWCNTs and MXene conductive network also ensure the composite further being utilized for electromagnetic interference shielding applications.

Carbon nanotubes – PEI – Formate dehydrogenase nano-biointerface for the specific bioelectrochemical reduction of CO2 to formate

Reduction of extensive CO2 emissions is one of the key challenges that our society must overcome in order to minimize the effects of global warming and climate change. In this respect, electrochemical reduction of CO2 via redox enzymes is believed to be a promising route to minimize global CO2 concentrations, as they specifically catalyze the selective CO2 reduction in a reversible way at low potentials and mild conditions. In this work, we describe the effective anchoring of the enzyme Desulfovibrio vulgaris Hildenborough FdhAB formate dehydrogenase using electrostatic interactions favoring oriented immobilization, to the surface of MWCNTs-modified low density graphite electrodes with subsequent protection of the enzyme with polyethyleneimine (PEI) polymer. The synergistic effect of MWCNTs and PEI has been studied. High catalytic current densities, up to −230 μA cm−2, as well as a high operational stability of 11 h of continuous long-term measurements, were achieved.

Superior electrocatalyst based on mesoporous silica nanoparticles/carbon nanotubes modified by platinum-copper bimetallic nanoparticles for amperometric detection of hydrazine

Hydrazine is a volatile, water-soluble molecule with strong reducing ability that is widely used in various industrial and pharmaceutical fields. It is known as a combination of carcinogens and neurotoxins that have harmful effects on the liver, brain, nervous system and DNA and also cause blood disorders. Therefore, developing a sensitive, accurate, simple and fast way to measure hydrazine concentration is very important. Here, a novel and efficient sensor for the determination of hydrazine at trace level is introduced by modifying mesoporous silica nanoparticles (MSNPs)/multi-walled carbon nanotubes dispersed in carbon paste electrode with PtCu nanoparticles (PtCu NPs/MSNPs/CNTs/CPE). SBA-15 NPs as one of the MSNPs are stable matrix for bimetallic NPs which prevent their accumulation and provide conditions for low loading of catalyst due to its unique structure. For this purpose, MSNPs was firstly synthesized from stem sweep ash (SSA) as raw material. The suggested sensor indicated favorable analytical performance in 0.1 M phosphate buffer solution (PBS, pH = 7.4) with a low limit of detection (S/N = 3.3) of 0.09 μM in the wide linear range of 6 μM−17.24 mM, high sensitivity of 47.18 μA mM−1, rapid response time of ∼3 s and high repeatability/reproducibility. The analytical performance of PtCu NPs/MSNPs/CNTs/CPE originates from the presence of more available bimetallic active sites and the synergistic effect of MWCNTs with high electrical conductivity. In the presence of some usual interferences, the sensor indicated high selectivity for hydrazine detection. The practical application of PtCu NPs/MSNPs/CNTs/CPE in real samples was also evaluated. The results showed that the MSNPs with large porosity and high surface area are efficient substrate for catalyst formation and cause to fabrication of sensor with excellent accuracy, precision, and recovery for the determination of hydrazine.

Synergistic Effects of MWCNTs and High-Pressure Torsion-Induced Grain Refinement on Microhardness, Tribological Properties, and Corrosion Behavior of Cu and Cu/MWCNT Nanocomposites

Synergistic Effects of MWCNTs and High-Pressure Torsion-Induced Grain Refinement on Microhardness, Tribological Properties, and Corrosion Behavior of Cu and Cu/MWCNT Nanocomposites

A systematic study on the synergistic effects of MWCNTs and core\u2013shell particles on the physicomechanical properties of epoxy resin

Here, core–shell impact modifier particles (CSIMPs) and multiwalled carbon nanotubes (MWCNs) were used as reinforcing agents for improving the toughness and tensile properties of epoxy resin. For this purpose, emulsion polymerization technique was exploited to fabricate poly(butyl acrylate-allyl methacrylate) core-poly(methyl methacrylate-glycidyl methacrylate) shell impact modifier particles with an average particle size of 407 nm. It was revealed that using a combination of the prepared CSIMPs and MWCNTs could significantly enhance the toughness and tensile properties of the epoxy resin. Also, it was observed that the dominant factors for improving the fracture toughness of the ternary composites are crack deflection/arresting as well as enlarged plastic deformation around the growing crack tip induced by the combination of rigid and soft particles. The Response Surface Methodology (RSM) with central composite design (CCD) was utilized to study the effects of the amounts of CSIMPs and MWCNTs on the physicomechanical properties of the epoxy resin. The proposed quadratic models were in accordance with the experimental results with correlation coefficient more than 98%. The optimum condition for maximum toughness, elastic modulus, and tensile strength was 3 wt% MWCNT and 1.03 wt% CSIMPs. The sample fabricated in the optimal condition indicated toughness, elastic modulus, and tensile strength equal to 2.2 MPa m1/2, 3014.5 MPa, and 40.6 MPa, respectively.

Electrochemical sensing of N-phenyl-1-naphthylamine using the MWCNT/β-CD through ‘host scavenger–guest pollutant’ mechanism

In this report, the synergistic effect of MWCNTs and β-cyclodextrin (β-CD) on glassy carbon electrode (GCE) for the electrochemical sensing of N-Phenylnaphthalen-1-amine (NPN) is demonstrated. The dual role of β-CD (i) as a modifier for MWCNTs, (ii) as scavenger host molecule for entrapping NPN guest molecule is also demoed through material characterization and sensing techniques. The functionalization of β-CD with MWCNTs is corroborated using spectral and XRD techniques. The emplacement of β-CD molecules in between the nanotube walls is affirmed through surface morphological and dispersion investigations. The physically modified β-CD/MWCNTs/GCE electrode possesses good dispersibility, acceptable stability, fast response, selectivity, the sensitivity of 10–6 M, the low detection limit of 15 × 10–9, and high recovery value of 100% in real samples.

Probing the electrical and dielectric properties of polyaniline multi-walled carbon nanotubes nanocomposites doped in different protonic acids

Polymer nanocomposites with vital reinforcements of conductive fillers have evinced as next-generation high-performance materials with multi-functional applications. Herein, we report the facile synthesis of thermally stable, highly electrically conducting polyaniline multi-walled carbon nanotubes (PANI/MWCNT) nanocomposites doped in two different protonic acids, i.e. hydrochloric acid (HCl) and sulphuric acid (H2SO4). The doping acids significantly affect the electric and dielectric properties of conducting polymer nanocomposites. The paper probes in the synergistic effects of MWCNTs and the effect of doping acid on the thermal stability, conductivity and dielectric properties of the nanocomposites based on PANI nanofibres. The structural, morphological, optical, thermal and electrical properties were evaluated through X-ray diffraction, scanning electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, UV–Vis spectroscopy, thermogravimetric analysis and two-point probe technique. Ascribed to the high interfacial interaction between PANI and MWCNT, and considering the effect of doping acids, nanocomposites with high thermal stability, enhanced conductivity and high dielectric constant that can store large electrical charges have been synthesized by surfactant-assisted, in situ oxidative polymerization of aniline, in the presence of potassium persulfate as oxidant. The micellar structure of surfactant assists the dispersion of MWCNTs as well as the formation of PANI/MWCNT tubular structures. The effect of surfactant below and above critical micelle concentration was also studied. This complete study would affirm such a nanocomposite which procures excellent electrical and dielectric properties for microelectronic applications.

Synergistic effect of MWCNTs and MA-g-PP on the thermal and viscoelastic properties of immiscible PTT/PP blends

The properties of immiscible blends of PTT and PP were modified by grafting and nanoparticle inclusion.

New insights into the photocatalytic endocrine disruptors dimethyl phathalate esters degradation by UV/MWCNTs-TiO2 nanocomposites

Dimethyl phthalate esters (DMPEs) are considered to be endocrine disruptors and environmentally hazardous materials in plastic industries wastewater because of its low solubility and accumulated persistent toxicity. In the present study, MWCNTs/TiO2 nanocomposites were fabricated by modified sol-gel technique using titanium isopropoxide as titanium oxide sources and purified MWCNTs, to degrade DMPEs through photocatalysis using UV irradiation. The effect of MWCNTs loading (3–15 wt %) on TiO2 and the photocatalytic performance of DMPEs in aqueous solution by UV/MWCNTs/TiO2 nanocomposites were investigated. For experiments conducted with the same illumination time, the photodegradration of DMPEs was enhanced with increasing the MWCNTs contents from 3 to 10 wt % and then decreased with a further enhancement to 15 wt %. Basically, the presence of MWCNTs in the nanocomposites can lead to the decrease in the relative amount of TiO2 in the photocatalyst and then to the decrease of the photogenerated carriers. This is because the same amount of photocatalyst was added for the photoreaction, and hence, the photodegradation of DMPEs decreases especially for the nanocomposites containing MWCNTs exceed than 10 wt %. The presence of functional group (COOH) on the MWCNTs surface would help the achievement of direct chemical bonding between MWCNTs and the TiO2 nanoparticles, resulting in the synergistic effect of MWCNTs and TiO2 where the flow of photogenerated electrons in the space charge region to the MWCNTs surface. A method based on high-performance liquid chromatography (HPLC) was developed to study the degraded DMPEs samples produced after exposure to UV light.

Fatigue behaviour of innovative multifunctional epoxy resins

AbstractMulti walled carbon nanotubes (MWCNTs) and glycidyl polyhedral oligomeric silsesquioxanes (GPOSS) are common additives to enhance electrical conductivity and flame resistance of polymer resins, respectively. Yet, these additions may appreciably influence the mechanical behaviour of the polymers. In this work, the synergistic effect of MWCNTs and GPOSS on the fatigue behaviour of the polymer RTM6‐2 was investigated. The results were discussed supported by scanning electron microscopy and energy dispersive spectroscopy analyses. By enhancing the polymer with MWCNTs, a slight decrease in the fatigue life is observed in the range of the low stress levels; however, it tends to coincide with the reference material at fatigue limit. The incorporation of the flame retardant GPOSS into the polymer enhanced with MWCNTs seems to have a significant deteriorating effect on the fatigue life. Scanning electron microscopy and energy dispersive spectroscopy investigation revealed MWCNTs and GPOSS agglomerations; they seem to act as defects leading to a degradation of the fatigue resistance.

Effect of multi-wall carbon nanotubes supported palladium addition on hydrogen storage properties of magnesium hydride

To improve the hydrogen storage performance of magnesium hydride, multi-wall carbon nanotubes supported palladium (Pd/MWCNTs) was introduced to the magnesium-based materials. Pd/MWCNTs catalysts with different amounts of Pd (20 wt.%, 40 wt.%, 60 wt.%, 80 wt.%) were synthesized by a solution chemical reduction method. Afterwards, Mg95–Pdm/MWCNTs5−m (m = 0, 1, 2, 3, 4, 5) were prepared for the first time by hydriding combustion synthesis (HCS) and mechanical milling (MM). It is determined by X-ray diffraction (XRD) analysis that Pd/MWCNTs can significantly increase the hydrogenation degree of magnesium during the HCS process. The microstructures of the composites obtained by transmission electron microscope (TEM) and field emission scanning electronic microscopy (FESEM) analyses show that Pd nanoparticles are well supported on the surface of carbon nanotubes and the Pd/MWCNTs are dispersed uniformly on the surface of MgH2 particles. Moreover, it is revealed that there is a synergistic effect of MWCNTs and Pd on the hydrogen storage properties of the composites. The Mg95–Pd3/MWCNTs2 shows the optimal hydriding/dehydriding properties, requiring only 100 s to reach its saturated hydrogen absorption capacity of 6.67 wt.% at 473 K, and desorbing 6.66 wt.% hydrogen within 1200 s at 573 K. Additionally, the dehydrogenation activation energy of MgH2 in this system is decreased to 78.6 kJ/mol H2, much lower than that of as-received MgH2.

Synergistic effect of MWCNTs and graphite powder on the properties of polymer nanocomposites

Multi-walled carbon nanotube/polystyrene (MWCNT/PS), graphite powder/polystyrene (GP/PS) and multi-walled carbon nanotube-graphite powder/polystyrene (M-G/PS) nanocomposites with different contents of carbon materials were prepared by bulk radical polymerization. The products were pressed into slices to prepare specimens for electrical conductivity testing. All of the nanocomposites demonstrated good electrical conductivity. Compared to MWCNTs/PS and GP/PS composites, the M-G/PS composites showed a good synergistic effect between the MWCNTs and GP, and the electrical conductivity of M-G/PS was higher than that of GP/PS. To investigate the structure and morphology of the grafted carbon nano-materials, samples were submitted to Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA) and transmission electron microscopy (TEM) after being extracted with toluene. The results show that some polystyrene was grafted onto the surfaces of the MWCNTs, GP and M-G, which is likely responsible for the increase in the electrical conductivity of the composites. Furthermore, the mechanical properties of the M-G/PS nanocomposites increased with the M/G ratio. (C) 2014 Elsevier B.V. All rights reserved.

Ultrasensitive Voltammetric Detection of Trace Lead(II) and Cadmium(II) Using MWCNTs‐Nafion/Bismuth Composite Electrodes

AbstractMultiwall carbon nanotubes were dispersed in Nafion (MWCNTs‐NA) solution and used in combination with bismuth (MWCNTs‐NA/Bi) for fabricating composite sensors to determine trace Pb(II) and Cd(II) by differential pulse anodic stripping voltammetry (DPASV). The electrochemical properties of the MWCNTs‐NA/Bi composites film modified glassy carbon electrode (GCE) were evaluated. The synergistic effect of MWCNTs and bismuth composite film was obtained for Pb(II) and Cd(II) detection with improved sensitivity and reproducibility. Linear calibration curves ranged from 0.05 to 100 μg/L for Pb(II) and 0.08 to 100 μg/L for Cd(II). The determination limits (S/N=3) were 25 ng/L for Pb and 40 ng/L for Cd, which compared favorably with previously reported methods in the area of electrochemical Pb(II) and Cd(II) detection. The MWCNTs‐NA/Bi composite film electrodes were successfully applied to determine Pb(II) and Cd(II) in real sample, and the results of the present method agreed well with those of atomic absorption spectroscopy.