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•Molecular dynamics is used to study the mechanical characterization of Gr/WSe2 vertical heterostructures.•Mechanical properties and fracture mechanisms of the Gr/WSe2 are strongly ...direction-dependent.•Fracture initiates from the graphene and WSe2 layers for armchair and zigzag loading, respectively.•The WSe2 sheet undergoes a phase transformation from h-WSe2 to t-WSe2 during zigzag loading.
Assembling layered materials in the form of vertically stacked heterostructures has emerged as a facile way to leverage the properties of each component and fabricate novel highly-tailored architectures with advanced functionalities. In this study, we employ molecular dynamics (MD) simulations to characterize the temperature-dependent tensile mechanical properties of graphene/WSe2 vertical heterostructure along both the armchair and the zigzag directions utilizing a hybrid scheme of various interatomic potentials. It is found that the tensile strength of the WSe2 monolayer can be significantly improved when supported by graphene benefiting from the synergistic effects of their individual strengths. The comparisons of the predicted tensile properties of the heterostructure with that of the mixing rule exhibit excellent conformity. We found that while the bare WSe2 is more resilient to fracture along the armchair direction, the graphene supported WSe2 layer endures larger tensile stress and strain for zigzag loading. This study further reveals fascinating chirality in mechanical properties and failure mechanism of the heterostructure. Fracture initiates from the graphene layer for armchair loading, whereas the WSe2 sheet becomes more prone to fracture under zigzag loading. Crack propagates along the zigzag direction and results in the complete tearing of the specimen for armchair loading, while the crack propagation is confined in a random small region for the zigzag loading. The WSe2 nanosheet experiences major atomic rearrangements and undergoes a phase transformation from trigonal (h-WSe2) to the distorted octahedral phase (t-WSe2) during zigzag loading. Increasing temperature is found to play a crucial role in deteriorating the mechanical properties of the heterostructure. This study offers a comprehensive characterization of the tensile properties of Gr/WSe2 vertical heterostructure and discloses important deformation mechanisms that will enable the efficient utilization of this material.
The human Y chromosome harbors genes that are responsible for testis development and also for initiation and maintenance of spermatogenesis in adulthood. The long arm of the Y chromosome (Yq) ...contains many ampliconic and palindromic sequences making it predisposed to self-recombination during spermatogenesis and hence susceptible to intra-chromosomal deletions. Such deletions lead to copy number variation in genes of the Y chromosome resulting in male infertility. Three common Yq deletions that recur in infertile males are termed as AZF (Azoospermia Factor) microdeletions viz. AZFa, AZFb and AZFc. As estimated from data of nearly 40,000 Y chromosomes, the global prevalence of Yq microdeletions is 7.5% in infertile males; however the European infertile men are less susceptible to Yq microdeletions, the highest prevalence is in Americans and East Asian infertile men. In addition, partial deletions of the AZFc locus have been associated with infertility but the effect seems to be ethnicity dependent. Analysis of > 17,000 Y chromosomes from fertile and infertile men has revealed an association of gr/gr deletion with male infertility in Caucasians and Mongolian men, while the b2/b3 deletion is associated with male infertility in African and Dravidian men. Clinically, the screening for Yq microdeletions would aid the clinician in determining the cause of male infertility and decide a rational management strategy for the patient. As these deletions are transmitted to 100% of male offspring born through assisted reproduction, testing of Yq deletions will allow the couples to make an informed choice regarding the perpetuation of male infertility in future generations. With the emerging data on association of Yq deletions with testicular cancers and neuropsychiatric conditions long term follow-up data is urgently needed for infertile men harboring Yq deletions. If found so, the information will change the current the perspective of androgenetics from infertility and might have broad implication in men health.
Nanoporous carbonaceous matrix with metal oxide heterostructure demonstrates an effective renewable approach to control dye industrial waste management.
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•Synthesis of low-cost ...MF-Gr-CNTs-Ta2O5 for remediation of toxicity of EBT dye.•Degradation efficiency of 95%@100 min under light with repeatability of 8 cycles.•MTT assay and cell imaging confirm non-cytotoxicity of photodegraded by-products.•A filter prototype setup has been performed with the as-prepared cartridge matrix.•93.45% reduction in TOC of photodegraded dye in 100 min using MF-Gr-CNTs-Ta2O5.
Dye waste management via renewable stratagem as well as understanding the nature of degraded products are highly essential for controlling the water purification process. Decoration of the photoactive heterostructure on top of a porous, chemically stable, nontoxic and rigid template is a real challenge for practical designing of low-cost cartridge for industrial waste management. Herein, the porous, high surface carbon-based Melamine Foam-Graphene-Carbon Nanotubes decorated Tantalum oxide (MF-Gr-CNTs-Ta2O5) heterostructure is successfully synthesized. The oxygen vacancies in Ta2O5lattice evident in X-ray Photoelectron Spectroscopy (XPS) analysis and facile interface in CNTs-Ta2O5observed in Transmission Electron Microscopy (TEM) imaging, promote the effective way of photogenerated charge carrier separation. The excellent photocatalytic performance is observed against Eriochrome Black T (EBT) with 95% of degradation efficiency within 100 min of photo exposure. The rate constant increases from 0.00624 to 0.03059 min-1for bare Ta2O5 to heterostructure, owing to faster kinetics involved in the generation of reactive oxygen species (ROS) for rapid photodegradation of dye. The effect of scavenger shows that superoxide radical participation is dominant in reaction kinetics with respect to other reactive species. The Total Organic Carbon (TOC) removal efficiency is achieved to be ∼ 93.45% which is remarkably high in photocatalytic degradation process. Liquid Chromatography-Mass Spectroscopy (LCMS) are performed to elucidate the non-toxic end-products evaluated via Toxicological analysis on glial cell line (C6) which shows cellular viability of 72% as compared to that of 38% for bare EBT (800 μg/ml).The photocatalyst has shown reusability till 8 cycles at a loss of ∼ 8% efficiency revealing the potential applicability towards developing cartridge technology. Knowing the porous and stable carbon-based heterostructure, a smart strategy has been adopted to demonstrate a filter-prototype setup. This study paves the way to design a cost-effective, reusable, cartridge material adopting an environmentally benign technique for waste-water purgation.
Graphene (GR)-wrapped WO3 nanosphere composite was synthesized by using a facile sol–gel method. The morphology and structural properties of the GR-WO3 nanocomposites were characterized by ...field-emission scanning electron microscopy (FESEM), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and Raman spectroscopy. The GR-wrapped WO3 nanospheres composite exhibits p-type gas sensing behavior and the response of GR-WO3 sensor toward NO2 shows a linear increase with an increase in the concentration from 7 to 56ppm at room temperature. Upon exposure to 56ppm NO2, its response value becomes 40.8%, but there is no responsiveness for the sensors based on pure WO3 and graphene sensors. The effective charge transfer through chemically bonded interfacial contact between graphene and WO3 nanospheres is proposed to be responsible for the room temperature sensing performance. This work may provide a new insight into the structural design of GR-base nanocomposites and has a potential prospect in the environment monitoring or disease detection of NO2 at room temperature.
Long-range magnetic order in graphene has been the subject of study for many researches due to its fundamental and technological prospects. Many theoretical researches have predicted the long-range ...ferromagnetic exchange in porphyrin-like graphene due to doping the transition metals centers in their structures. However, the experimental observations for such structures, have been rarely reported. In the present work the ferromagnetic properties of iron doped porphyrin-like graphene (Fe–N-Gr) are experimentally considered and the results are reported. At first, the Fe–N-Gr sample is synthesized by mechanochemical mixing of Fe, N, and C sources followed by high temperature pyrolysis treatment. The sample shows the high saturation magnetization of 140 emu/gr at room temperature. Raman, XRD, and XPS results as well as microscopic images revealed that the observed ferromagnetic behavior is induced by doped Fe–N sites in graphene, however the exact microscopic origin cannot be explained and further investigation is needed.
These results pave the way for the synthesis of magnetic porphyrin-like graphene with structurally deformed structure.
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•The magnetic properties of Fe/N doped graphene lattice was investigated.•Fe/N doped graphene shows the high saturation magnetization of 140 emu/gr at RT.•The long-range ferromagnetic order in graphene creates ferromagnetic behavior.
This review summarizes the advancement on sintered composites based on tungsten–copper (W–Cu) reinforced with graphene (Gr) or its derivative such as reduced Gr oxide (rGO) for use as electrical ...contacts applied in switching devices. Main synthesis approaches for preparing Gr or rGO reinforced W–Cu composite powders and their consolidations by using various powder metallurgy techniques are presented. The nature of the initial materials, synthesis conditions, processing parameters, and the relevant findings are disclosed and discussed. The improvement in microstructure and technical characteristics like density, electrical conductivity, hardness, coefficient of friction, wear rate, and arc ablation behavior of W–Cu–Gr/rGO composites are highlighted comparatively with that of unreinforced composites. This review reveals an insight into a novel class of composites as candidates for electrical contact applications.
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By conducting first-principles calculations with van der Waals correction, we investigate the structural, electronic, and magnetic properties of Gr/MnF3(4)/Gr sandwiched structures. ...The calculated binding energies were within 54–79meV per carbon atom for the four Gr/MnF3(4)/Gr sandwiched structures tested in our study. This result implies that the MnF3(4) clusters stabilize the AA and AB stacking in the Gr/MnF3(4)/Gr sandwich structures because of the high electronegativity of the clusters. Charge transfer from bilayer graphene to the MnF3(4) clusters is noted to induce effective hole doping in graphene. Spin polarization in the graphene layer is approximately 100% along the majority direction on the position of the Fermi level in the MnF3-doped structures. The band gaps of the spin-up and spin-down branches and the magnetic moments of the C atoms are increased by compression interlayer spacing. The MnF3 clusters affect the electronic and magnetic properties of graphene in the vicinity of the Fermi level; thus, the clusters are highly suitable for use as a dopant in spintronic applications.
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