Search Results (42)

The influence of multiwall carbon nanotube (MWCNT) reinforcements on electrochemical corrosion investigations at varying NaCl concentrations (0.4 M, 0.6 M, 0.8 M, 1 M) of Mg-Zn-Ce nanocomposites is studied in this work. The Mg-Zn-Ce/MWCNT nanocomposites were developed by using an ultrasonication-assisted hybrid stir–squeeze (UHSS) casting method with different MWCNT concentrations (0, 0.4, 0.8, 1.2 wt.%) in a Mg-Zn-Ce magnesium alloy matrix. The microstructural characterizations shown using X-ray diffraction revealed the presence of secondary phases (MgZn₂, Mg₁₂Ce), T-phase (Mg₇Zn₃RE), α-Mg, and MWCNT peaks. Optical microscopy results showed grain refinement in the case of nanocomposites. Transmission electron microscope studies revealed well-dispersed MWCNT, indicating the good selection of processing parameters. The uniform dispersion of MWCNTs was achieved due to a hybrid stirring mechanism along with transient cavitation, ultrasonic streaming, and squeeze effect. The higher E_corr value of −1.39 V, lower I_corr value (5.81 µA/cm²), and lower corrosion rate of 0.1 mm/Yr (↑77%) were obtained by 0.8% nanocomposite at 0.4 M NaCl concentration, when compared to the monolithic alloy. The Mg(OH)₂ passive film formation on 0.8 wt.% nanocomposite was denser, attributed to the refined grains. At higher NaCl concentration, the one-dimensional morphological advantage of MWCNT helped to act as a barrier for further Mg exposure to excessive Cl⁻ attack, which reduced the formation of MgCl₂. Therefore, the UHSS-casted Mg-Zn-Ce/MWCNT nanocomposites present a good potential as sacrificial anodes for use in a wide range of industrial applications. Full article

Z-scheme Zn₃In₂S₆/NiFe₂O₄ nanocomposites were prepared by electrospinning and hydrothermal methods, and their photocathodic protection performance was studied on 304 SS and Q235 CS in NaCl solution (3.5 wt.%). The two-dimensional Zn₃In₂S₆ loaded on the one-dimensional NiFe₂O₄ resulted in faster electron migration and enhanced light absorption capability. Moreover, it had been observed through electrochemical testing that the assembly of Zn₃In₂S₆/NiFe₂O₄ heterojunctions improves the efficacy of photocathodic protection. Following illumination, the self-corrosion potentials of 304 SS and Q235 CS coupled with Zn₃In₂S₆/NiFe₂O₄ nanocomposites decreased by 1040 mV and 560 mV, and the photoinduced current densities were 1.2 times and 3.9 times greater than the value of Zn₃In₂S₆. Furthermore, the mechanism of enhanced photocathodic protection performance for Zn₃In₂S₆/NiFe₂O₄ heterojunctions was systematically discussed. XPS and ESR analysis indicated that Zn₃In₂S₆/NiFe₂O₄ composites follow the Z-scheme electron migration path and retain the stronger reduction and oxidation capacity of Zn₃In₂S₆/NiFe₂O₄. Therefore, the Z-scheme heterostructures are responsible for the realization of cathodic protection for carbon steel. Full article

The production of cost-effective novel materials for PV solar cells with long-term stability, high energy conversion efficiency, enhanced photon absorption, and easy electron transport has stimulated great interest in the research community over the last decades. In the presented work, Cu/Cu₂S-MWCNTs nanocomposites were produced and analyzed in the framework of potential applications for PV solar cells. Firstly, the surface of the produced one-dimensional Cu was covered by Cu₂S nanoflake. XRD data prove the formation of both Cu and Cu₂S structures. The length and diameter of the one-dimensional Cu wire were 5–15 µm and 80–200 nm, respectively. The thickness of the Cu₂S nanoflake layer on the surface of the Cu was up to 100 nm. In addition, the Cu/Cu₂S system was enriched with MWCNTs. MWCNs with a diameter of 50 nm interact by forming a conductive network around the Cu/Cu₂S system and facilitate quick electron transport. Raman spectra also prove good interfacial coupling between the Cu/Cu₂S system and MWCNTs, which is crucial for charge separation and electron transfer in PV solar cells. Furthermore, UV studies show that Cu/Cu₂S-MWCNTs nanocomposites have a wide absorption band. Thus, MWCNTs, Cu, and Cu₂S exhibit an intense absorption spectrum at 260 nm, 590 nm, and 972 nm, respectively. With a broad absorption band spanning the visible–infrared spectrum, the Cu/Cu₂S-MWCNTs combination can significantly boost PV solar cells’ power conversion efficiency. Furthermore, UV research demonstrates that the plasmonic character of the material is altered fundamentally when CuS covers the Cu surface. Additionally, MWCN-Cu/Cu2S nanocomposite exhibits hybrid plasmonic phenomena. The bandgap of Cu/Cu₂S NWs was found to be approximately 1.3 eV. Regarding electron transfer and electromagnetic radiation absorption, the collective oscillations in plasmonic metal-p-type semiconductor–conductor MWCNT contacts can thus greatly increase energy conversion efficiency. The Cu/Cu₂S-MWCNTs nanocomposite is therefore a promising new material for PV solar cell application. Full article

Optical absorbers based on Tamm plasmon states are known for their simple structure and high operational efficiency. However, these absorbers often have limited absorption channels, and it is challenging to continuously adjust their light absorption rates. Here, we propose a Tamm plasmon state optical absorber composed of a layered stack structure consisting of one-dimensional topological photonic crystals and graphene nano-composite materials. Using the four-by-four transfer matrix method, we investigate the structural relationship of the absorber. Our results reveal that topological interface states (TISs) effectively excite the optical Tamm state (OTS), leading to multiple absorption peaks. This expands the number of absorption channels, with the coupling number of the TIS determining the transmission quality of these channels—a value further adjustable by the period number of the photonic crystals. Tuning the filling factor, refractive index, and thickness of the graphene nano-composite material allows for a wide range of control over the device’s absorption rate, from 0 to 1. Additionally, adjusting the defect layer thickness, incident angle, and Fermi energy enables us to control the absorber’s operational bandwidth and the switching of its absorption effect. This work presents a new approach to expanding the tunability of optoelectronic devices. Full article

Terbium (III) iodide is an interesting chemical compound with unique chemical properties. The introduction of terbium iodide into single-walled carbon nanotubes (SWCNTs) is an environment-friendly process, and it leads to the development of new nanocomposites with improved properties. The embedded terbium iodide forms new one-dimensional atomic structures inside the SWCNTs. Moreover, the electronic properties of filled SWCNTs are modified. Here, the atomic structures of terbium iodide-filled SWCNTs are investigated using high-resolution transmission electron microscopy, and their microstructure, morphology, and filling degrees are studied. The electronic properties of filled SWCNTs are investigated using spectroscopy. Raman spectroscopy provides information on the charge transfer inside filled SWCNTs. The number of transferred electrons and the charge transfer density along the SWCNT axis are estimated from the Raman spectra. These data on charge transfer are required for the application of terbium iodide-filled SWCNTs in nanoelectronics, thermoelectric power generation, and sensors. The obtained quantitative data reveal the high doping efficiencies of SWCNTs with terbium iodide. This is one of the most effective dopants for SWCNTs. The data show a strong p-doping of SWCNTs with the charge transfer from SWCNTs to terbium iodide. The data from Raman spectroscopy testify to the shift of the Fermi level to the valence band of the SWCNTs. The Fermi level shifts are estimated from these data. They are in the range of 0.3–0.4 eV and are comparable to the values for SWCNTs filled with other rare earth metals using environment-friendly processes. Full article

Dielectric capacitors have garnered significant attention in recent decades for their wide range of uses in contemporary electronic and electrical power systems. The integration of a high breakdown field polymer matrix with various types of fillers in dielectric polymer nanocomposites has attracted significant attention from both academic and commercial sectors. The energy storage performance is influenced by various essential factors, such as the choice of the polymer matrix, the filler type, the filler morphologies, the interfacial engineering, and the composite structure. However, their application is limited by their large amount of filler content, low energy densities, and low-temperature tolerance. Very recently, the utilization of two-dimensional (2D) materials has become prevalent across several disciplines due to their exceptional thermal, electrical, and mechanical characteristics. Compared with zero-dimensional (0D) and one-dimensional (1D) fillers, two-dimensional fillers are more effective in enhancing the dielectric and energy storage properties of polymer-based composites. The present review provides a comprehensive overview of 2D filler-based composites, encompassing a wide range of materials such as ceramics, metal oxides, carbon compounds, MXenes, clays, boron nitride, and others. In a general sense, the incorporation of 2D fillers into polymer nanocomposite dielectrics can result in a significant enhancement in the energy storage capability, even at low filler concentrations. The current challenges and future perspectives are also discussed. Full article

Polymeric nanofibers have emerged as exclusive one-dimensional nanomaterials. Various polymeric nanofibers and nanocomposite nanofibers have been processed using the thermoplastic, conducting, and thermoset matrices. This review aims to highlight the worth of electrospinning technology for the processing of polymer/nanocarbon nanocomposite nanofibers. In this regard, the design, morphology, physical properties, and applications of the nanofibers were explored. The electrospun polymer/nanocarbon nanofibers have a large surface area and fine fiber orientation, alignment, and morphology. The fiber processing technique and parameters were found to affect the nanofiber morphology, diameter, and essential physical features such as electrical conductivity, mechanical properties, thermal stability, etc. The polymer nanocomposites with nanocarbon nanofillers (carbon nanotube, graphene, fullerene, etc.) were processed into high-performance nanofibers. Successively, the electrospun nanocomposite nanofibers were found to be useful for photovoltaics, supercapacitors, radiation shielding, and biomedical applications (tissue engineering, antimicrobials, etc.). Full article

Crystals of NaSn₂F₅ were obtained from an aqueous solution. Their morphology and habitus were studied via scanning electron microscopy and X-ray phase diffraction analysis. The crystals obtained have a long prismatic shape with a very large aspect ratio (>100). The faceting of the crystal is represented by the (110) face, while the (100) face is practically absent. A nanocomposite incorporating one-dimensional (1D) NaSn₂F₅@SWCNT crystals was synthesized from the melt by means of the capillary wetting technique. The embedded fragment is represented by two planes of Sn cations, which provide contrast in high-resolution electron microscopy images. The cation plane is represented by the (110) crystallographic plane of the NaSn₂F₅ structure. The crystallographic direction [2$\overline{2}$3] coincides with the nanotube axis. The first layer of Sn cations forms a hexagonal network with Sn atoms at its nodes. The tin atoms in the second layer are arranged according to the closest spherical packing law in a plane, but with a distance between atoms that is two times greater than that in the first layer. Sn cations’ hexagon sizes are ~0.87 nm and ~0.69 nm in size. According to the Raman spectroscopy data, the nanocomposite behaves as an electron acceptor. The SWCNT diameter of 1.54 nm revealed using NaSn₂F₅@SWCNT Raman spectroscopy corresponds to their diameter in electron microscope images and the diameter used for modeling. Full article

In this study, we successfully prepared core–shell heterostructured nanocomposites (Fe NWs@SiO₂), with ferromagnetic nanowires (Fe NWs) as the core and silica (SiO₂) as the shell. The composites exhibited enhanced electromagnetic wave absorption and oxidation resistance and were synthesized using a simple liquid-phase hydrolysis reaction. We tested and analyzed the microwave absorption properties of Fe NWs@SiO₂ composites with varied filling rates (mass fractions of 10 wt%, 30 wt%, and 50 wt% after mixing with paraffin). The results showed that the sample filled with 50 wt% had the best comprehensive performance. At the matching thickness of 7.25 mm, the minimum reflection loss (RL_min) could reach −54.88 dB at 13.52 GHz and the effective absorption bandwidth (EAB, RL < −10 dB) could reach 2.88 GHz in the range of 8.96–17.12 GHz. Enhanced microwave absorption performance of the core–shell structured Fe NWs@SiO₂ composites could be attributed to the magnetic loss of the composite, the core–shell heterogeneous interface polarization effect, and the small-scale effect induced by the one-dimensional structure. Theoretically, this research provided Fe NWs@SiO₂ composites with highly absorbent and antioxidant core–shell structures for future practical applications. Full article

In this study, we report the influence of vanadium oxide (VO), as a photosensitive component, on the photoactivity of TiO₂ nanotubes (TNTs). A series of TNTs of varying tube diameter were synthesized by the anodization of titanium foils at different voltages, while vanadium oxide was deposited on TNTs by wet chemical deposition. An improvement in the optical properties of nanotubes was observed after the deposition of vanadium oxide. An improvement in the optical properties (redshift in UV-Vis spectra) of TNTs and TNT/VO was noted. The photocatalytic activity was improved with increasing tube diameter, while it was weakened after the deposition of VO. Furthermore, photoactivity was investigated in photodiodes based on TNTs or TNT/VO and single crystals of CH₃NH₃PbI₃. The photoelectric measurement revealed that different TNT diameters did not influence the I-V characteristic of the photodiodes, while the deposition of VO improved the photocurrent for smaller TNTs. Full article

Nanomaterials have been extensively used in polymer nanocomposite membranes due to the inclusion of unique features that enhance water and wastewater treatment performance. Compared to the pristine membranes, the incorporation of nanomodifiers not only improves membrane performance (water permeability, salt rejection, contaminant removal, selectivity), but also the intrinsic properties (hydrophilicity, porosity, antifouling properties, antimicrobial properties, mechanical, thermal, and chemical stability) of these membranes. This review focuses on applications of different types of nanomaterials: zero-dimensional (metal/metal oxide nanoparticles), one-dimensional (carbon nanotubes), two-dimensional (graphene and associated structures), and three-dimensional (zeolites and associated frameworks) nanomaterials combined with polymers towards novel polymeric nanocomposites for water and wastewater treatment applications. This review will show that combinations of nanomaterials and polymers impart enhanced features into the pristine membrane; however, the underlying issues associated with the modification processes and environmental impact of these membranes are less obvious. This review also highlights the utility of computational methods toward understanding the structural and functional properties of the membranes. Here, we highlight the fabrication methods, advantages, challenges, environmental impact, and future scope of these advanced polymeric nanocomposite membrane based systems for water and wastewater treatment applications. Full article

Nanocomposites with one-dimensional (1D) and two-dimensional (2D) phases can demonstrate superior hardness, fracture toughness, and flexural strength. Cubic boron nitride-hexagonal boron nitride-silicon carbide whiskers (cBN-hBN-SiC_w) nanocomposites with the simultaneous containing 1D SiC_w and 2D hBN phases were successfully fabricated via the high-pressure sintering of a mixture of SiC_w and cBN nanopowders. The hBN was generated in situ via the limited phase transition from cBN to hBN. Nanocomposites with 25 wt.% SiC_w exhibited optimal comprehensive mechanical properties with Vickers hardness of 36.5 GPa, fracture toughness of 6.2 MPa·m^1/2, and flexural strength of 687.4 MPa. Higher SiC_w contents did not significantly affect the flexural strength but clearly decreased the hardness and toughness. The main toughening mechanism is believed to be a combination of hBN inter-layer sliding, SiC_w pull-out, crack deflection, and crack bridging. Full article

In this research, ZnO/GO nanocomposites were successfully synthesized by a simple hydrothermal method using graphene oxide (GO) and zinc acetate dihydrate (Zn(CH₃COO)₂.2H₂O) as the reactants. The effect of the hydrothermal reaction time on the structure and optical property of the ZnO/GO was systematically investigated. The structure, morphology and chemical composition of the samples were measured by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS) and Raman and Fourier transform infrared (FTIR) spectroscopy, while the optical properties were measured using photoluminescence spectroscopy. The synthesized products consisted of large quantities of one-dimensional (1D) ZnO nanorods (NRs), which were dispersed uniformly on the GO surface. The XRD and Raman results reveal that the ZnO NRs in the fabricated samples had a hexagonal wurtzite structure with high crystalline quality. The FESEM and TEM images reveal that ZnO NRs with an average diameter in the range of ~85–270 nm and length in the range of ~0.3–6 μm were covered with GO sheets. Additionally, it was found that the crystallographic orientation of ZnO NRs was dependent not only on the hydrothermal reaction time but also on the presence of GO in the nanocomposites. However, the addition of GO did not affect the stoichiometric ratio and the crystal structure of ZnO NRs. The room-temperature PL results indicated that, compared to those of pure ZnO, the luminescence of the GO/ZnO nanocomposites was suppressed and shifted towards a higher wavelength (red shift), which was attributed to the incorporation of ZnO NRs within the GO matrix and the formation of a C-O-Zn chemical bond in the nanocomposites. The hydrothermal technique is considered one of the best routes due to its low cost, high growth rates, low-temperature synthesis, controllable crystallographic orientation, particle size, as well as morphology. Full article

The film flexible sensors can convert tiny changes in size or force into electrical signals. They are key components of intelligent devices and wearable devices, and are widely used in human-computer interaction, electronic skin, health monitoring, implantable diagnosis, and other fields. This kind of sensor is generally composed of polymer matrix and conductive components, while carbon nanotubes (CNT) and graphene (GN), as typical one-dimensional and two-dimensional conductive carbon nano-materials, respectively, have been used to build film flexible sensors. In order to explore the relationship between the GN size and thickness, and the performance of film sensors, the GN-CNT/PU composite film sensors were prepared by in situ polymerization of polyurethane (PU) in the presence of GN and CNT. A highly sensitive GN-CNT/PU flexible film sensor was prepared with a high gauge factor (GF) up to 13.15 in a strain range of 0–20%; an exceptionally low percolation threshold of GN is about 0.04 vol% when the CNT content is fixed at 0.2 vol%, which is below the percolation threshold of CNT/PU nanocomposites. The size of the GN layer affects the GFs of the flexible film sensors; a GN with a smaller size can achieve a greater GF. This study paves the way for the better application of different qualities of GN in flexible sensors. Full article

CdS nanoparticles were constructed onto one-dimensional (1D) CeO₂ nanorods by a two-step hydrothermal method. The X-ray diffraction (XRD), transmission election microscopy (TEM), Raman spectra, X-ray photoelectron spectra (XPS) and UV-Vis diffuse reflection spectroscopy (DRS) techniques were used to characterize these CdS/CeO₂ nanocomposites. It was concluded that when the molar ratio of CdS and CeO₂ was 1:1, the nanocomposites exhibited the best photocatalytic desulfurization activity, reaching 92% in 3 h. Meanwhile, transient photocurrent (PT) measurement, photoluminescence (PL) spectra and electrochemical impedance spectroscopy (EIS) measurement indicated that the modification of CeO₂ nanorods by CdS nanoparticles could significantly inhibit the recombination of photogenerated electrons and holes. In addition, the possible mechanism of photocatalytic oxidation desulfurization of the nanocomposites was proposed. This study may provide an effective CeO₂-based photocatalyst for photocatalytic desulfurization applications. Full article