Carbon Nanotube Nanocomposites Research Articles

Studies on sustainable CuO/ZnO@MWCNT electrodes and their supercapacitive performances in redox additive electrolyte

Supercapacitive performances of copper oxide and zinc oxide loaded multiwalled carbon nanotube (CuO/ZnO@MWCNT - CZM) nanocomposites (NCs) in redox additive electrolyte were reported. CZM NCs were hydrothermally synthesized and calcinated at 500 °C for 5 h. The structural characteristics of the prepared NCs were examined using powder X-ray diffraction analysis. Scanning electron microscopy and vibrational spectroscopy techniques were employed to analyse the surface features and molecular interactions of the prepared NCs, respectively. The working electrodes were fabricated using CZM NCs and tested in pure 3 M potassium hydroxide (KOH) and 0.2 M potassium ferrocyanide added 3 M KOH electrolytes (K4[Fe(CN)6] – RAE). Fabricated electrode exhibited the specific capacitances of 199.4 Fg−1 (at 8 Ag−1) in KOH and 1829.43 Fg−1 (at 15 Ag−1) in RAE, respectively. Furthermore, an asymmetrical-type supercapacitor was constructed using CZM NCs and activated carbon-coated Ni foil as the working and counter electrodes, respectively. Fabricated device demonstrated 18.5 W h kg−1 and 1875 W kg−1 of energy and power densities, respectively, with 83.05 Fg−1 of specific capacitance in RAE. Electrochemical studies confirmed that the prepared CZM NCs demonstrated superior performances in RAE.

Synthesis of nanosized spinel ferrites MnFe2O4 on the surface of carbon nanotubes for the creation of polymer composites with enhanced microwave absorption capacity

Currently, the creation of new protective materials able to absorb the electromagnetic (EM) radiation is an important direction strongly linked to the use of high-tech electronics which leads to EM pollution in a wide range of high frequencies. The wide-band absorption and large bandwidth are two important factors affected the absorbing performance of materials. In this research, the development of polymer nanocomposites based on the multi-walled carbon nanotubes (CNTs) as a conductive component modified by manganese ferrite (MnFe2O4) nanoparticles as a magnetic component made it possible to increase the efficiency of absorption of EM waves in the frequency range 1–41 GHz as a result of good impedance matching characteristics in comparison with pure manganese ferrite. Finally, the absorption coefficient of EM waves in the frequency range of 5–20 GHz for MnFe2O4/0.065 vol.%CNT nanocomposites about 2.5–3 times higher than for MnFe2O4. The present work shows, that the introduction of MnFe2O4/CNT composites into the both amorphous (epoxy resin) and crystalline (polychlorotrifluoroethylene) polymer matrices makes it possible to manage microwave absorbing properties as well as a shift of the region of frequencies of maximum peak values of the absorption coefficient and reflection loss. The obtained relations prove that by the change of the amount of the modifying component (MnFe2O4) on the surface of carbon nanotubes, the content of the MnFe2O4/CNT nanocomposite in the polymer matrixes, and the thickness of the polymer composites it is possible to control the absorption coefficient and reflection loss of EM waves in the high frequency range. The MnFe2O4/0.044CNT–PCTFE and MnFe2O4/0.065CNT–epoxy resin composites exhibit higher bandwidth in relation to other reported composites or structures at the same thickness.

Preparation and Characterization Techniques of High-Density Polyethylene (HDPE) Reinforced with Multi-walled Carbon Nanotube (MWCNT) Nano-composites—A Review

Preparation and Characterization Techniques of High-Density Polyethylene (HDPE) Reinforced with Multi-walled Carbon Nanotube (MWCNT) Nano-composites—A Review

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

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

Synergistic Interactions in Sequential Process Doping of Polymer/Single-Walled Carbon Nanotube Nanocomposites for Enhanced n-Type Thermoelectric Performance.

This study focuses on the fabrication of nanocomposite thermoelectric devices by blending either a naphthalene-diimide (NDI)-based conjugated polymer (NDI-T1 or NDI-T2), or an isoindigo (IID)-based conjugated polymer (IID-T2), with single-walled carbon nanotubes (SWCNTs). This is followed by sequential process doping method with the small molecule 4-(2,3-dihydro-1,3-dimethyl-1H-benzimidazol-2-yl)-N,N-dimethylbenzenamine (N-DMBI) to provide the nanocomposite with n-type thermoelectric properties. Experiments in which the concentrations of the N-DMBI dopant are varied demonstrate the successful conversion of all three polymer/SWCNT nanocomposites from p-type to n-type behavior. Comprehensive spectroscopic, microstructural, and morphological analyses of the pristine polymers and the various N-DMBI-doped polymer/SWCNT nanocomposites are performed in order to gain insights into the effects of various interactions between the polymers and SWCNTs on the doping outcomes. Among the obtained nanocomposites, the NDI-T1/SWCNT exhibits the highest n-type Seebeck coefficient and power factor of -57.7 µV K-1 and 240.6 µW m-1 K-2 , respectively. However, because the undoped NDI-T2/SWCNT exhibits a slightly higher p-type performance, an integral p-n thermoelectric generator is fabricated using the doped and undoped NDI-T2/SWCNT nanocomposite. This device is shown to provide an output power of 27.2 nW at a temperature difference of 20 K.

Quantitative evaluation of released nanomaterials from carbon nanotube epoxy nanocomposites during environmental exposure and mechanical treatment

Carbon nanotubes (CNTs) are promising nanomaterials exhibiting high thermal and electrical conductivities, significant stiffness, and high tensile strength. As a result, CNTs have been utilized as additives to enhance properties of various polymeric materials in a broad range of fields. In this study, we investigated the release of CNTs from CNT epoxy nanocomposites exposed to environmental weathering and mechanical stresses. The presence and amount of CNTs released from degraded polymer nanocomposites is important because CNTs can impact physiological systems in humans and environmental organisms. The weathering experiments in this study included nanocomposite exposure to both UV and a water spray, to simulate sunlight and rain exposure, whereas mechanical stresses were induced by shaking and ultrasonication. CNT release from epoxy nanocomposites was quantified by a 14C-labeling method that enabled measurement of the CNT release rates after different weathering and mechanical treatments. In this study, a sample oxidizer was used prior to liquid scintillation counting, because it was shown to reduce interferences from the presence of polymeric materials and achieve a high recovery (95%). Polymer nanocomposite degradation was confirmed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), and light microscopy. A continuous release of 14C-labeled nanomaterials was observed after each UV and simulated rain exposure period, with 0.23% (mass/mass) of the total embedded mass of CNTs being released from the CNT nanocomposite during the full weathering process, suggesting that the water spray induced sufficient mechanical stress to eliminate the protective effect of the surface agglomerated CNT network. Importantly, additional mechanical stresses imposed on the weathered nanocomposites by shaking and ultrasonication resulted in further release of approximately 0.27% (mass /mass).

Investigation of microwave-absorbing properties of aligned polyaniline/multi-walled carbon nanotubes nanocomposites

A aligned polyaniline/carbon nanotubes (a-PANI/CNTs) nanocomposite was synthesized by in situ polymerization. The structural and the microwave-absorbing properties of the a-PANI/CNTs nanocomposites were studied. Transmission electron microscopy, X-ray diffraction and Raman spectra were carried out to confirm the formation of a vertically grown PANI array on the surface of the CNTs. With a matching thickness of 1.5 mm, the a-PANI/CNTs had a maximum reflection loss of about −29.49 dB. Moreover, the bandwidth corresponding to reflection loss below −10 dB was about 4.42 GHz (13.58 GHz to 18.00 GHz), which is significantly better than those of CNTs, PANI and PANI/CNTs. We ascribed the enhanced microwave-absorbing properties to the unique ordered structure of aligned PANI.

Enhanced the properties of carbon‐paste nanocomposite by carboxylation of multi‐walled carbon nanotubes

AbstractIn the present study, attempts were made to manufacture innovative conducting polymer nanocomposites (CPCs) with high performance, low cost, and appropriate electrical, mechanical, and thermal properties. However, one of the main challenges in creating CPCs is the tendency of nanofillers to agglomerate and accumulate, resulting in a decrease in the electrical properties and performance of CPCs. To address this issue, the study developed an efficient and eco‐friendly CPC using carboxymethyl cellulose (CMC) as a binder and carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) as nanofillers. The study employed a chemical functionalization method to modify CNTs and enhance their compatibility and dispersion properties in the CMC matrix. The prepared CPCs were characterized using various techniques, including Fourier‐transform infrared spectroscopy, x‐ray diffraction, and field emission scanning electron microscopy. The results showed an improvement in homogeneity and surface cohesion between CMC and O‐CNTs through chemical surface modification of CNTs via carboxylic acid functional groups. The study observed good dispersion of nanofillers without any aggregation of the CMC/GNP/O‐CNT compared with the nontreated CMC/GNP/CNT composite. While a decrease in the degree of crystallinity was observed, conductivity increased for the CPC containing oxidized CNTs. The study found that the highest conductivity of ~112 S/m was obtained for D‐CMC/GNP/O‐CNT with 25 wt% of O‐CNT, while the maximum conductivity of D‐CMC/GNP/CNT was ~80 S/m with 35 wt% of CNTs. Additionally, the study observed an improvement in electrochemical properties after treatment of CNTs in the form of higher cathodic current in cyclic voltammetry and lower charge transfer resistance in impedance spectroscopy of D‐CMC/GNP/O‐CNT35 compared to untreated one.Highlights Preparation of new conductive nanocomposite consisting of CMC, CNTs, and GNPs. Carboxylation of CNTs to improve O‐CNT and CMC intermolecular interaction CMC/GNP/O‐CNT is 40% more conductive than unmodified CNT nanocomposite. Higher thermal stability and mechanical properties were observed by using O‐CNT. O‐CNT caused higher current density and lower electron transfer resistance for CPCs.

Electrical and optical properties of polyamide 6 nanocomposites with multi-walled carbon nanotubes

In this work, quantum chemical modeling, electrical conductivity, Raman scattering, and photoluminescence of polyamide 6 nanocomposites with multi-walled carbon nanotubes (0–2.5 vol%) were investigated. It was shown that the concentration dependence of the electrical conductivity obeys the percolation theory and has the value of percolation threshold 1.41 vol%. The conductivity value of the composite at 2.5 vol% nanotubes is 1.1*10-3 S/cm. It was found that in PA6 nanocomposites filled with MWCNT an increase in the concentration of nanotubes from 0.001 to 0.015 vol%, namely in the pre-percolation region of electrical conductivity, due to a significant restructuring of the Raman spectra, which consists in a shift of the vibrational modes of the methylene groups CH2 and amide I, as well as in a change of their relative intensities. From the photoluminescence spectra of PA6-MWCNT, it can be seen, that the carbon nanotubes largely determine the conformational changes in the polymer matrix and have little effect on the defective structure of the polymer itself.The goal: to establish the mechanisms of electrical conductivity and the interaction of nanotubes with polyamide macromolecules and its influence on the electronic and optical properties of nanocomposites of polyamide multi-walled carbon nanotubes.

Design ofan electrochemical aptasensor in the presence of an array of gold nanostructure and a GO-MWCNTs nanocomposite: application in diagnosis of Alzheimer's disease.

Alzheimer's disease (AD) is considered one of the main progressive chronic diseases in elderly individuals. Early diagnosis using related biomarkers, specifically beta-amyloid peptide (Aβ), allows finding expected treatment routes. Here, we developed an electrochemical aptasensing platform for AD by employing a glassy carbon electrode (GCE) modified with a layer of jagged gold (JG) nanostructure (diameter: 60-185nm) and graphene oxide-carboxylic acid functionalized multiwalled carbon nanotubes (GO-c-MWCNTs) nanocomposite. These surface modifications acted as the signal amplifier and provided an optimum nano-interface substrate for immobilizing aptamer strands. The measurements of Aβ were performed via differential pulse voltammetry (DPV), and the aptasensor detected the analyte in a linear range from 0.1pgmL-1 to 1ngmL-1, with an estimated limit of detection (LOD) of about 0.088pgmL-1 (S/N = 3). The aptasensor showed sufficient stability (11days), reversibility (three times), and reproducibility (five times re-fabrication with relative standard deviation (RSD): 1.27). The potential interfering agents showed negligible impact on the sensing performance. Finally, the application of the aptasensor was evaluated in the presence of 10 serum samples, and the recovery values were from 93 to 110.1%.

Hybrid cathodes of fluoride-ion batteries with carbon nanotubes

Solid-state fluoride-ion galvanic cells (metallic Ce anode, La1-xBaxF3-x (x ≈ 0.05) electrolyte) with carbon components in the cathode material – carbon nanotubes and nanocomposites based on them – have been created and studied. The investigations were carried out by means of cyclic voltammetry, impedance spectroscopy and electron microscopy. Tin fluoride SnF2 was used as a basic cathode material. The basic cathode was modified with additives of carbon nanotubes, which channels were filled with SnF2, PbSnF4 and their eutectic composition. Introduction of these additives lead to the charge-discharge currents improvement. The maximum value of open-circuit voltage (OCV ∼ 1.9 V) is observed with adding into the cathode material the nanocomposite of carbon nanotubes filled with the eutectic composition. Carbon nanotubes filled with tin fluoride SnF2@SWCNT proved to be the best additive in the cathode material. The sample has the biggest current density compared with the other samples (∼1.3 A/m2 at 180 °C, which is ∼4 times higher than that when using the basic cathode). The OCV of the galvanic cell with SnF2@SWCNT additive in the cathode material is stable within the investigated temperature range from 25 to 180 °C. For other galvanic cells temperature dependencies of OCV are decreasing. Results of the direct and alternating current investigations of the solid electrolyte in Ce/electrolyte/Ce symmetric cell show good converging. Direct current internal resistance of the solid electrolyte is defined by grain boundaries resistance. The impedance of a galvanic cell is determined by the composition and structure of SnF2 cathode material as the component of the cell with the highest resistance.

Multifunctional integrated electrochemical sensing platform based on mesoporous silica nanoparticles decorated single-wall carbon nanotubes network for sensitive determination of gallic acid

An efficient ultrasonic-assisted one-pot strategy was applied to prepare the multifunctional nanocomposite of single-wall carbon nanotubes (SWCNT) and mesoporous silica nanoparticles (MSNs). To achieve the sensitive detection of gallic acid (GA), the SWCNT@MSNs/GCE sensor could be fabricated by using the above nanocomposite as electrode sensitizer. For the SWCNT@MSNs nanocomposite, SWCNT with one-dimensional hollow nanostructure could form three-dimensional reinforced carbon conductive network with excellent conductivity property, high specific area, efficient charge transport channels; MSNs with mesoporous structure and large active surface area presented obvious spherical morphology and uniform particle size dispersion, which effectively boosted the accumulation capability of GA on the SWCNT@MSNs/GCE sensor. Moreover, SWCNT with excellent conductivity property could greatly remedy the non-conductivity of MSNs. The synergistic combination of SWCNT and MSNs optimized the electrochemical property of SWCNT@MSNs/GCE sensor for the detection of GA. The SWCNT@MSNs/GCE sensor exhibited good GA electrochemical detection performance (pH = 2.0, linear GA concentration: 0.03–30 μM, limit of detection: 3.806 nM). The relatively low relative standard deviation values can be achieved for the reproducibility, reproducibility and anti-interference measurements. When applied for the detection of GA amount in real tea samples, the satisfactory recoveries of 97.14–101.2% and RSD values of 1.05–4.40 could be obtained at the SWCNT@MSNs/GCE sensor.

Highly tunable ε'-negative and ε'-near-zero response at extremely low frequency region of CaCu3Ti4O12/graphitized-MWCNT metacomposites

CaCu3Ti4O12/graphitized-multiwall carbon nanotube (CCTO/g-MWCNT) nanocomposites were designed according to classical percolation theory. It is found that the ε'-negative response correlates with free carrier density and percolative g-MWCNT networks. The ε'-near-zero response was achieved at ∼802 kHz, which could be explained by the electrical dipole resonance of interconnected g-MWCNT clusters. Once the percolative g-MWCNT networks are formed in nanocomposites, Drude-type ε'-negative response is obtained at kHz region due to the low-frequency plasma oscillation. This work provides a design paradigm of epsilon-negative property by ceramic nanocomposites which will facilitate their practical application of epsilon-negative materials on dielectric ceramics, metamaterials, and electromagnetic shielding.

Electrochemical detection of methyl parathion using zirconium dioxide@single-walled carbon nanotubes nanocomposite modified glassy carbon electrode

In this work, the multifunctional nanocomposite of zirconium dioxide (ZrO2) nanoparticles and single-walled carbon nanotubes (SCN) was prepared to modify the glassy carbon electrode (GCE) for the fabrication of ZrO2@SCN/GCE sensor. The fabricated nanocomposite electrochemical sensor was successfully used to achieve the efficient and sensitive detection of methyl parathion (MP). For the ZrO2@SCN nanocomposite, ZrO2 nanoparticles could promote the enrichment of MP molecules on the electrode surface of ZrO2@SCN/GCE sensor because of the interplay between Zr-O groups and phosphorus groups of MP molecules; SCN presented efficient one-dimensional charge transport channels, which achieved the excellent conductivity property of carbon material. Moreover, SCN could greatly compensate for the non-conductivity of ZrO2 nanoparticles. The functional combination of ZrO2 nanoparticles and SCN enhanced the electrochemical detection performance of MP. The ZrO2@SCN/GCE sensor exhibited good MP detection property with low limit of detection of 6.15 nM (pH = 7.0, MP concentration: 0.01–10 μM). The fabricated sensor also showed good practical application property for the detection of MP in real samples (Lake water and green tea).

Enhanced photoelectrochemical water splitting in ternary layered chalcogenide ZnIn2S4 coupled with MWCNT

Layered hexagonal zinc indium sulfide coupled with multiwalled carbon nanotubes (MWCNT/H-ZnIn2S4) nanocomposites were prepared via using the hydrothermal method and investigated its photoelectrochemical (PEC) water-splitting properties. A series of MWCNT/H-ZnIn2S4 nanocomposites with different concentrations of MWCNT have been synthesized. The effects of the addition of different concentrations of MWCNT on the PEC performance of H-ZnIn2S4 material are studied. The outcomes showed that the maximum value of photocurrent density is obtained for 20 wt% MWCNT/H-ZnIn2S4, which is ∼3.8 times higher as compared to the H-ZnIn2S4 photoanode under visible light illumination. The enhancement in the current density is because of the electron-accepting behavior of MWCNT that helps in the effective separation and transfer of charges at the interface. The ability of MWCNT to accept and transport electrons offers a better path to regulate the movement of photogenerated charge carriers, extending the lifetime of the photogenerated charges produced in the semiconductors. A plausible mechanism for observed enhanced PEC activity of MWCNT/H-ZnIn2S4 nanocomposites is provided, which is supported by impedance spectroscopy and Mott-Schottky results.

CARBON NANOPAPER PRODUCED FROM CARBON NANOTUBES/RESORCINOL-FORMALDEHYDE XEROGEL NANOCOMPOSITE FOR ELECTROCHEMICAL SUPERCAPASITORS

The nanocomposite of resorcinol-formaldehyde xerogel (RF-xerogel) and carbon nanotubes after carbonation at 800 °С was obtained in the form of composite carbon nanopaper (CCNP) with a thickness of 100-300 microns, a density from 0.1 g/cm2 to 0.5 g/cm2 and an electronic conductivity of more than 10 S/cm. According to the low temperature nitrogen adsorption data, the microporous structure of the nanopaper is formed by carbonized RF-xerogel, and the mesoporous structure is formed by the nanotube framework. The specific surface area of the nanopaper calculated by the method of nonlocal density function theory (NLDFT) exceeds 600 m2/g. The main contribution to the specific surface area of CCNP is made by pores with a width of ~ 0.7 nm, therefore, electrodes for a supercapacitor made of such paper are quite effective only in aqueous solutions of H2SO4 and KOH with small sizes of solvated ions. A technique for nanopaper activation with potassium hydroxide has been developed for the use of CCNP with organic electrolytes. The maximum specific surface area (NLDFT method) of activated CCNP reaches 1182 m2/g with a loss of carbon xerogel mass of ~ 25%. At the same time, the pore surface area of more than 1 nm width increases from 350 m2/g in CCNP to 685 m2/g in activated CCNP. Nanopaper has mechanical strength, pretty cheap and convenient for use in supercapacitors.

The comparative study on microstructure and magnetic properties of cobalt ferrite/MWCNTs nanocomposite prepared using mechanical mixing and hydrothermal routs

The mechanical mixing (MM) and hydrothermal are known as prevalent and facile synthesis methods of the nanocomposite. In this research, the cobalt ferrite/ multi-wall carbon nanotubes (CF/MWCNTs) nanocomposites synthesized by these methods and microstructure and magnetic properties were investigated. The nanocomposites were characterized using X-ray diffraction (XRD), Field emission electron microscope (FESEM), Raman spectroscopy, thermal gravimetric analysis (TGA), differential thermal analysis (DTA), and vibration sample magnetometer (VSM). Furthermore, the specific surface area of prepared nanocomposite was measured by the Brunauer-Emmett-Teller (BET) method. The single-phase cobalt ferrite without any impurities was observed in XRD patterns. The samples’ mean crystallite size was calculated by the Williamson –Hall and Rietveld methods which show that samples prepared by hydrothermal procedure has a larger crystallite size. Also, the obtained nanocomposites by both methods have a suitable phase distribution of CF nanoparticles and MWCNTs according to the FE-SEM micrographs. Moreover, the maximum magnetization (Mmax) for samples prepared by MM and hydrothermal methods were 35.6 and 49.5 emu/g, respectively. It is noteworthy that the Mmax values increase by 13.5 emu/g for sample synthesized by hydrothermal method compare to MM preparation. The results revealed that the presence of MWCNTs in the synthesis medium leads to cobalt ferrite nanoparticle growth and thus improves the magnetic properties.

Dosimetry characteristics of Epoxy/MWCNT nanocomposite in the field of gamma-rays: Effect of thickness

Polymer-carbon nanostructures have been used as gamma-ray dosimeters. The thickness of the sensitive volume material plays an important role in the determination of the dosimetry response. In this work, the thickness effect of a real-time dosimeter based on the Epoxy/Multi-walled carbon nanotube (MWCNT) nanocomposite was investigated. The amount of electrical percolation threshold (EPT) for Epoxy/MWCNT nanocomposite was initially simulated using the finite element method. Then, the 0.1 MWCNT wt% nanocomposite was fabricated using a solution method with three thicknesses of 1, 2, and 3 mm. FESEM images demonstrated a good dispersion state of the inclusions into the Epoxy matrix. The samples were irradiated by gamma-rays of Co-60 source over the dose rates of 25–166 mGy/min. In addition, dosimetric characteristics were performed, including linearity, bias-polarity, angular dependence, energy dependence, field size, and repeatability. Results revealed that with increasing the thickness, the dosimetry response was enhanced remarkably.

Ultrasonic-assisted of TiO2-MWCNT nanocomposite with advanced photocatalytic efficiency for elimination of dye pollutions

Nanocomposites of titanium dioxide (TiO2) and multi-wall carbon nanotubes (MWCNTs) were successfully synthesized (TiO2-MWCNTs) from MWCNTs and titanium tetrachloride (TiCl4) as starting precursors using ultrasonic-assisted technique. The impact of the different weight percentages of MWCNTs (1, 3, 5, and 7 wt%) on TiO2 optical, structural, and morphological properties were investigated. Subsequently, the photocatalytic activity was assessed by organic dyes degradation such as methylene Blue (MB) and rhodamine B (RhB) under ultraviolet (UV) light exposure. The characterization of synthesized materials demonstrated the anatase phase formation in both pure TiO2 and the TiO2-MWCNTs nanocomposite, according to X-ray diffraction analysis. The morphology analysis of TiO2-MWCNTs nanocomposites using FESEM and TEM confirmed the uniform dispersion of MWCNTs with an exterior diameter of 12–16 nm within the TiO2 matrix. The BET measurement of the sample's specific surface areas identified that the MWCNTs addition resulted in the increase of surface area from 76.34 to 194.35 m2 g−1 for pure TiO2 and TiO2/7 wt% MWCNTs, respectively. Furthermore, TiO2/7 wt% MWCNTs nanocomposite had lower optical bandgap energy and higher photocatalytic performance as compared to the pure TiO2. The photodegradation efficiency of TiO2/7 wt% MWCNTs nanocomposite increased from 63.63 % to 92.36 % for MB and 71.56 % to 94.13 % for RhB compared to pure TiO2, after 60 min UV light exposure.

Vibrational characteristics of attached hemispherical-cylindrical ocean shell-structure reinforced by CNT nanocomposite with graded pores on two-parameter elastic foundations applicable in offshore components

One of the essential simulations of offshore components of ocean and marine structures can be counted as a modeling of the interaction between the systems and soil's behavior on the dynamic of the offshore systems. Based on this, for the first time, the fundamental frequencies of the porous nanocomposite attached hemisphere-cylinder shell system (AHCSS), counted as ocean and marine offshore structures, reinforced by carbon nanotube (CNT) rested on the Winkler-Pasternak elastic foundations, added up as soil's behavior simulation, are investigated in this paper. In detail, to expand the effectiveness of the CNT along the matrix, eight distinct functionally graded (FG) forms besides uniform distributions are prepared. Also, two forms of porosity which are FG distributed along the FG-CNT nanocomposite, are realized to add the effect of the porosity on the nanocomposite. Addedly, the first shear deformation theory and Donnell's scheme are coupled to arrange the affiliations of the AHCSS. In addition, Hamilton's principle gets the central motion equations (CMEs) of the AHCSS. Then, the half-analytical procedure, named the generalized differential quadrature method, discretizes the CMEs. Finally, the eigenvalue method finds the frequencies of the porous nanocomposite AHCSS. Remarkably, various numerical samples are prepared and solved to indicate the effects of the Winkler-Pasternak foundations, boundary cases, porosity forms, FG-CNT models, and physical values on the frequencies of the porous nanocomposite AHCSS.