Two-dimensional MoS2 Nanosheets Research Articles

Two-Dimensional MoS2 nanosheets as cocatalyst to augment the nanocatalytic tumor therapy

As an appealing modality of tumor nanocatalytic therapeutics, Fenton chemistry has been extensively employed to combat cancer through the generation of highly cytotoxic reactive oxygen species (ROS). For iron-triggered catalytic Fenton chemistry, the therapeutic consequence was largely dependent on the available catalytically active ferrous species. In this work, hydrothermally synthesized molybdenum disulfide (MoS2-PEG) nanosheets were served as Fenton cocatalyst to enhance the Fenton kinetics as contributed by ultrasmall gallic acid (GA)-coordinated Fe nanoparticles (GA-Fe NPs) in tumor destruction. The tetravalent Mo4+ species of MoS2-PEG cocatalysts could efficiently transfer Fe3+ species into Fe2+ species by the reduction process, regenerating the catalytically active Fe2+ species and restoring the catalytic activity of GA-Fe nanocatalysts during the Fenton-based tumor therapeutics. Based on systematic in vitro and in vivo investigations of cocatalyst-augmented Fenton nanotherapeutics against 4-T1 tumor cells/xenografts, we have demonstrated a proof-of-concept enhanced nanocatalytic tumor-therapeutic modality by MoS2-PEG/GA-Fe nanocatalyst/cocatalyst hybridized system, which offers an explicit cocatalytic strategy to improve the therapeutic efficacy during nanocatalytic tumor therapy.

Morphological and Optical Characterization of Hydrothermally-Synthesized Two-Dimensional MoS2 Nanosheets

Transition metal dichalcogenides (TMDs) are extensively utilized in optoelectronics, sensors, and battery storage due to their versatile properties. Among the TMDs, Molybdenum disulfide (MoS2) nanosheets possess remarkable optical, electronic, and chemical properties. This study employed a cost-effective hydrothermal method to synthesize high-quality 2D MoS2 nanosheets. Different characterization techniques such as XRD, SEM, EDS, FTIR, Raman, UV–vis, and photoluminescence (PL) spectroscopy were utilized to evaluate the structural, morphological, chemical, and optical characteristics of the nanosheets. The XRD analysis revealed that the MoS2 nanosheets have a hexagonal crystal structure, with an average crystallite size of 27.76 nm. Furthermore, SEM images confirmed the formation of thin MoS2 nanosheets, with an estimated thickness ranging from 20–30 nm. The growth mechanism of the formation of MoS2 is discussed in detail. Different functional groups present in the material were analyzed using FTIR spectra. The difference in vibration modes analysed by Raman spectroscopy indicated the presence of layered nanosheets. The optical bandgap (2.20 eV) of the material was determined by analyzing its UV–vis spectroscopy data using the Tauc plot. PL analysis indicates a direct transition between the upper valence and lower conduction bands, suggesting that the nanosheets were synthesized with high quality. These findings have opened new possibilities for the use of MoS2 nanosheets in various applications such as optoelectronics and sensing devices.

Unveiling Xanthine Presence in Rohu Fish Using Ag+-Doped MoS2 Nanosheets Through Electrochemical Analysis.

Here, we envisage the development of the rapid, reliable, and facile electrochemical sensor for the primary detection of xanthine (Xn) which is significant for the food quality measurement, based on the silver-doped molybdenum disulfide (Ag@MoS2) nanosheets. The structural and compositional properties of the prepared samples were tested through X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and X-ray photon spectroscopy (XPS). The two-dimensional (2D) MoS2 nanosheets provide the large surface area for the sensing applications and the silver ions help in the enhanced electrochemical response. The fabricated enzymatic biosensor exhibits magnificent cyclic stability with a limit of detection of 27nM. Also, the sensor was tested for rapid, reproducible, specific, and regenerable up to 10 cycles and has a shelf life of 2weeks. The outcomes of this study suggest that the proposed matrix could be employed for the fabrication of devices for early detection of xanthine.

Synergetic enhancement effect of two-dimensional MoS2 nanosheets and metal organic framework-derived porous ZnO nanorods for photodegradation performance.

Two-dimensional transition metal dichalcogenides and semiconductor metal oxides have shown great potential in photocatalysis. However, their stability and efficiency need to be further improved. In this paper, porous ZnO nanorods with high specific surface area were prepared from metal-organic framework ZIF-8 by a simple hydrothermal method. A MoS2/ZnO composite was constructed by loading MoS2 onto the surface of porous ZnO nanorods. Compared with ZnO materials prepared by other methods, MoS2/ZnO prepared in this paper exhibits superior photocatalytic performance. The enhanced photocatalytic activity of the MoS2/ZnO composite can be attributed to the formation of heterojunctions and strong interaction between them, which greatly facilitate the separation of electrons and holes at the contact interface. In addition, due to the wide absorption region of the visible spectrum, MoS2 can greatly broaden the light absorption range of the material after the formation of the composite material, increase the utilization rate of visible light, and reduce the combination of electrons and holes. This study provides a new way to prepare cheap and efficient photocatalysts.

Phase engineering of two-dimensional MoS2 nanosheets

Phase engineering of two-dimensional MoS2 nanosheets

Enhanced Electrochemical Biosensing of the Sp17 Cancer Biomarker in Serum Samples via Engineered Two-Dimensional MoS2 Nanosheets on the Reduced Graphene Oxide Interface.

In the present investigation, we reported a label-free and highly effective immunosensor for the first time employing a nanostructured molybdenum disulfide nanosheets@reduced graphene oxide (nMoS2 NS@rGO) nanohybrid interface for the determination of sperm protein 17 (Sp17), an emerging cancer biomarker. We synthesized the nMoS2 NS@rGO nanohybrid using a one-step hydrothermal technique and then functionalized it with 3-aminopropyltriethoxysilane (APTES). Furthermore, the anti-Sp17 monoclonal antibodies were covalently attached to the APTES/nMoS2 NS@rGO/indium tin oxide (ITO) electrode utilizing 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide-N-hydroxy succinimide (EDC-NHS) coupling chemistry. Bovine serum albumin (BSA) was then used to block nonspecific binding regions on the anti-Sp17/APTES/nMoS2 NS@rGO/ITO bioelectrode. The morphological and structural features of the synthesized nanohybrid and the modified electrodes were studied using transmission electron microscopy, scanning electron microscopy with energy dispersive X-ray (EDX) composition studies, atomic force microscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy. The immunoreaction between the Sp17 antigen and anti-Sp17 antibodies on the surface of the BSA/anti-Sp17/APTES/nMoS2 NS@rGO/ITO sensing bioelectrode was applied as the basis for the detection technique, which measured the electrocatalytic current and impedimetric response change. The designed BSA/anti-Sp17/APTES/nMoS2 NS@rGO/ITO bioelectrode showed improved amperometric and impedimetric biosensing performance in the response studies, including remarkable sensitivity (23.2 μA ng-1mL cm-2 and 0.48 kΩ mL ng-1 cm-2), wider linearity (0.05-8 and 1-8 ng mL-1), an excellent lower detection limit (0.13 and 0.23 ng mL-1), and a rapid response time of 20 min. The biosensor exhibited impressive storage durability lasting 7 weeks and showed remarkable precision in identifying Sp17 in serum samples from cancer patients, as confirmed using the enzyme-linked immunosorbent assay method.

Phase-dependent growth of Pt on MoS2 for highly efficient H2 evolution.

Crystal phase is a key factor determining the properties, and hence functions, of two-dimensional transition-metal dichalcogenides (TMDs)1,2. The TMDmaterials, explored for diverse applications3-8, commonly serve as templates for constructing nanomaterials3,9 and supported metal catalysts4,6-8. However, how the TMD crystal phase affects the growth of the secondary material is poorly understood, although relevant, particularly for catalyst development. In the case of Pt nanoparticles on two-dimensional MoS2 nanosheets used as electrocatalysts for the hydrogen evolution reaction7, only about two thirds of Pt nanoparticles were epitaxially grown on the MoS2 template composed of the metallic/semimetallic 1T/1T' phase but with thermodynamically stable and poorly conducting 2H phase mixed in. Here we report the production of MoS2 nanosheets with high phase purity and show that the 2H-phase templates facilitate the epitaxial growth of Pt nanoparticles, whereas the 1T'phase supports single-atomically dispersed Pt (s-Pt)atoms with Ptloading up to 10 wt%. We find that the Pt atoms in this s-Pt/1T'-MoS2 system occupy three distinct sites, with density functional theory calculations indicating for Pt atoms located atop of Mo atoms a hydrogen adsorption free energy of close to zero. This probably contributes to efficient electrocatalyticH2 evolution in acidic media, where we measure for s-Pt/1T'-MoS2 a mass activity of 85 ± 23 A [Formula: see text] at the overpotential of -50 mV and a mass-normalized exchange current density of 127 A [Formula: see text] and we see stable performance in an H-type cell and prototype proton exchange membrane electrolyser operated at room temperature. Although phase stability limitations prevent operation at high temperatures, we anticipate that 1T'-TMDs will also be effective supports for other catalysts targeting other important reactions.

Enhancing Lubrication Performance of Calcium Sulfonate Complex Grease Dispersed with Two-Dimensional MoS2 Nanosheets

Calcium sulfonate complex greases (CSCG) have proven to be a sustainable alternative to lithium complex greases, which still require appropriate additives to deliver lubrication performance benefits under extreme working conditions such as heavy load, high speed, and high temperature. The anti-wear and friction reducing properties of CSCG enhanced by two-dimensional MoS2 nanosheets (2D MoS2) with a narrow lateral size and thickness distributions were evaluated by a four-ball tribometer. The results showed that the CSCG with 0.6 wt.% 2D MoS2 performs best, with a 56.4% decrease in average friction coefficient (AFC), 16.5% reduction in wear scar diameter (WSD), 14.3% decrease in surface roughness, and a 59.4% reduction in average wear depth. Combining SEM-EDS images, Raman, and X-ray photoelectron spectra, it is illustrated that the physical transferred film and tribo-chemical film consisting of MoS2, Fe2O3, FeSO4, CaCO3, CaO, and MoO3 were generated on the worn surface, which improves the lubrication performance of CSCG considerably.

The Effect of Sonication Parameters on the Thickness of the Produced MoS2 Nano-Flakes

Liquid Phase Exfoliation (LPE) is a common route to produce two-dimensional MoS2 nanosheets. In this research, MoS2 powder is exfoliated by an ultrasonic probe (sonicator) in a water-ethanol solution. It is reported that MoS2 as a prototype 2D Transition Metal Dichalcogenide, has a band gap that increases with a decreasing number of layers. There are some factors that affect the average band gap energy value and the thickness of the exfoliated flakes. We varied different parameters of the ultrasonic probe like power, pulse percentage and time duration of sonication to investigate the effects on the number of MoS2 layers. Our findings from the UV-Visible spectra, SEM, FESEM and TEM images indicate that the minimum thickness for these samples was acquired at 50% of the input power of the sonicator we used (65 W) and the optimum pulse percentage is 50%. The current study also found that the average amount of band gap increased with an increase in sonication time, and then remained unchanged after 60 minutes.

In-situ-grown multidimensional Cu-doped Co1-xS2@MoS2 on N-doped carbon nanofibers as anode materials for high-performance alkali metal ion batteries

Transition metal sulfides with the high theoretical capacity and low cost have been considered as advanced anode candidate for alkali metal ion batteries, but suffered from unsatisfactory electrical conductivity and huge volume expansion. Herein, a multidimensional structure Cu-doped Co1-xS2@MoS2 in-situ-grown on N-doped carbon nanofibers (denoted as Cu-Co1-xS2@MoS2 NCNFs) have been elaborately constructed for the first time. The bimetallic zeolitic imidazolate framework CuCo-ZIFs were encapsulated in the one-dimensional (1D) NCNFs through an electrospinning route and then on which the two-dimensional (2D) MoS2 nanosheets were in-situ grown via a hydrothermal process. The architecture of 1D NCNFs can effectively shorten ion diffusion path and enhance electrical conductivity. Besides, the formed heterointerface between MOF-derived binary metal sulfides and MoS2 can provide extra active centers and accelerate reaction kinetics, which guarantee a superior reversibility. As expected, the resulting Cu-Co1-xS2@MoS2 NCNFs electrode delivers excellent specific capacity of Na-ion batteries (845.6 mAh/g at 0.1 A/g), Li-ion batteries (1145.7 mAh/g at 0.1 A/g), and K-ion batteries (474.3 mAh/g at 0.1 A/g). Therefore, this innovative design strategy will bring a meaningful prospect for developing high-performance multi-component metal sulfides electrode for alkali metal ion batteries.

Photoluminescence of Two-Dimensional MoS2 Nanosheets Produced by Liquid Exfoliation

Extraordinary properties of two-dimensional materials make them attractive for applications in different fields. One of the prospective niches is optical applications, where such types of materials demonstrate extremely sensitive performance and can be used for labeling. However, the optical properties of liquid-exfoliated 2D materials need to be analyzed. The purpose of this work is to study the absorption and luminescent properties of MoS2 exfoliated in the presence of sodium cholate, which is the most often used surfactant. Ultrasound bath and mixer-assisted exfoliation in water and dimethyl sulfoxide were used. The best quality of MoS2 nanosheets was achieved using shear-assisted liquid-phase exfoliation as a production method and sodium cholate (SC) as a surfactant. The photoluminescent properties of MoS2 nanosheets varied slightly when changing the surfactant concentrations in the range C(SC) = 0.5–2.5 mg/mL. This work is of high practical importance for further enhancement of MoS2 photoluminescent properties via chemical functionalization.

Integrating thermal energy storage and microwave absorption in phase change material-encapsulated core-sheath MoS2@CNTs

Developing advanced nanocomposite integrating solar-driven thermal energy storage and thermal management functional microwave absorption can facilitate the cutting-edge application of phase change materials (PCMs). To conquer this goal, herein, two-dimensional MoS2 nanosheets are grown in situ on the surface of one-dimensional CNTs to prepare core-sheath MoS2@CNTs for the encapsulation of paraffin wax (PW). Benefiting from the synergistic enhancement photothermal effect of MoS2 and CNTs, MoS2@CNTs is capable of efficiently trapping photons and quickly transporting phonons, thus yielding a high solar-thermal energy conversion and storage efficiency of 94.97%. Meanwhile, PW/MoS2@CNTs composite PCMs exhibit a high phase change enthalpy of 101.60 J/g and excellent long-term thermal storage durability after undergoing multiple heating–cooling cycles. More attractively, PW/MoS2@CNTs composite PCMs realize thermal management functional microwave absorption in heat-related electronic application scenarios, which is superior to the single microwave absorption of traditional materials. The minimum reflection loss (RL) for PW/MoS2@CNTs is −28 dB at 12.91 GHz with a 2.0 mm thickness. This functional integration design provides some insightful references on developing advanced microwave absorbing composite PCMs, holding great potential towards high-efficiency solar energy utilization and thermally managed microwave absorption fields.

A MXene/MoS2 heterostructure based biosensor for accurate sweat ascorbic acid detection

Biosensors with high sensitivity to sweat composition analysis are essential for non-invasive, real-time physiological monitoring of individual health status. However, it is challenging to construct a well-conductive and stable interface for electrochemical sensors. Here, we construct a sensitive sweat biosensor for ascorbic acid (AA) quantification built on a heterostructure with three-dimensional (3D) linked network microstructures made from two-dimensional (2D) MoS2 nanosheets and 2D Ti3C2 MXene. The as obtained 2D/2D heterostructures presented numerous active sites and avoid the issue of reduced surface areas, which was generally brought on by the accumulation of 2D nanomaterials. The electrode modified with 2D/2D heterostructure could realize efficient electron transport by abundant accesses to absorb AA molecules. Based on the inherent conductivity, extremely porous structure, and active catalytic properties of 2D/2D heterostructures, the biosensor for detecting the AA in artificial sweat had a sensitivity of 54.6nA μM−1 and a detection limit of 4.2 μM. This study provided a new promising approach for the design of high-performance sensing interfaces and facilitated the widespread use of personalized diagnostic devices.

Solvothermal temperature-control of active 1T phase in carbon cloth-supported MoS2 and Pt-Ni cluster electrodeposition for hydrogen evolution reaction

Establishing synthetic guidance that enables phase optimization with minimized by-products is an important task in modifying atomic arrangements and electronic structures of MoS2 through a solvothermal approach. Herein, a synthetic strategy to manipulate the 1 T and 2 H phases within MoS2 nanosheets on a support carbon cloth (MoS2/CC) is successfully demonstrated via a facile and efficient temperature-controlled solvothermal method. The 1 T and 2 H in MoS2/CC are well-characterized and quantified using Raman and XPS, revealing that MoS2/CC synthesized at 220 ºC (denoted as MoS2/CC(220)) has the highest 1 T phase content (∼ 60 %). The distinctive atomic arrangement of 1 T and 2 H are distinguished by HR-TEM. We also successfully electrodeposited Pt-Ni nanoclusters on the 1 T-rich MoS2 (Pt-Ni@MoS2/CC), which accounts for a substantially enhanced HER performance. This study highlights the capability of phase manipulation in two-dimensional MoS2 nanosheets via a one-pot solvothermal approach, which is essential for application-specified phase engineering.

Vertically aligned MoS2 nanosheets on monodisperse MXene as electrolyte-philic cathodes for zinc ion batteries with enhanced capacity.

Zinc ion batteries (ZIBs) have attracted extensive attention for their high safety and environmentally friendly nature, and considerable theoretical capacities. Due to its unique two-dimensional layered structure and high theoretical specific capacities, molybdenum disulfide (MoS2) presents as a promising cathode material for ZIBs. Nevertheless, the low electrical conductivity and poor hydrophilicity of MoS2 limits its wide application in ZIBs. In this work, MoS2/Ti3C2Tx composites are effectively constructed using a one-step hydrothermal method, where two-dimensional MoS2 nanosheets are vertically grown on monodisperse Ti3C2Tx MXene layers. Contributing to the high ionic conductivity and good hydrophilicity of Ti3C2Tx, MoS2/Ti3C2Tx composites possess improved electrolyte-philic and conductive properties, leading to a reduced volume expansion effect of MoS2 and accelerated Zn2+ reaction kinetics. As a result, MoS2/Ti3C2Tx composites exhibit high voltage (1.6 V) and excellent discharge specific capacity of 277.8 mA h g-1 at 0.1 A g-1, as well as cycle stability as cathode materials for ZIBs. This work provides an effective strategy for developing cathode materials with high specific capacity and stable structure.

The enhancement of performance and imbibition effect of slickwater-based fracturing fluid by using MoS2 nanosheets

Slickwater-based fracturing fluid has recently garnered significant attention as the major fluid for volumetric fracturing; however, lots of challenges and limitations such as low viscosity, poor salt tolerance, and possible formation damage hinder the application of the conventional simple slickwater-based fracturing fluid. In addition, nanomaterials have proven to be potential solutions or improvements to a number of challenges associated with the slickwater. In this paper, molybdenum disulfide (MoS2) nanosheets were chemically synthesized by hydrothermal method and applied to improve the performance of conventional slickwater-based fracturing fluid. Firstly, the microstructure characteristics and crystal type of the MoS2 nanosheets were analyzed by SEM, EDS, TEM, XPS, and Raman spectroscopy techniques. Then, a series of evaluation experiments were carried out to compare the performance of MoS2 nanosheet-modified slickwater with the conventional slickwater, including rheology, drag reduction, and sand suspension. Finally, the enhanced imbibition capacity and potential mechanism of the nanosheet-modified slickwater were systematically investigated. The results showed that the self-synthesized MoS2 nanosheets displayed a distinct ultrathin flake-like morphology and a lateral size in the range of tens of nanometers. In the nano-composites, each MoS2 nanosheet plays the role of cross-linking point, so as to make the spatial structure of the entire system more compact. Moreover, nanosheet-modified slickwater demonstrates more excellent properties in rheology, drag reduction, and sand suspension. The nanosheet-modified slickwater has a higher apparent viscosity after shearing 120 min under 90 °C and 170 s−1. The maximum drag reduction rate achieved 76.3% at 20 °C, and the sand settling time of proppants with different mesh in the nano-composites was prolonged. Spontaneous imbibition experiments showed that the gel-breaking fluid of nanosheet-modified slickwater exhibited excellent capability of oil-detaching, and increase the oil recovery to ∼35.43%. By observing and analyzing the interfacial behavior of MoS2 nanosheets under stimulated reservoir conditions, it was found that the presence of an interfacial tension gradient and the formation of a climbing film may play an essential role in the spontaneous imbibition mechanism. This work innovatively uses two-dimensional MoS2 nanosheets to modify regular slickwater and confirms the feasibility of flake-like nanomaterials to improve the performance of slickwater. The study also reveals the underlying mechanism of enhanced imbibition efficiency of the nano-composites.

Ligand Exchange on MoS2 Nanosheets: Applications in Array-Based Sensing and Drug Delivery.

Two-dimensional MoS2 nanosheets (2D-MoS2) have been widely used in many biological applications due to their distinctive physicochemical properties. Further, the development of surface modification using thiolated ligands allows us to use them for many specific applications. But the effect of possible ligand exchange on 2D-MoS2 has never been explored, which can play an important role in diverse biological applications. In this study, we have observed the ligand-exchange phenomenon on 2D-MoS2 in the presence of different thiolated ligands. The initial study proceeded with boron-dipyrromethene (BODIPY) functionalized MoS2 with different concentrations of glutathione (GSH), which is the most abundant thiol species in the cytoplasm of various cancer cells. It was found that in the presence of GSH the fluorescence of BODIPY can be regenerated, which is time and concentration dependent. We have also examined this phenomenon with different thiol ligands and transition-metal dichalcogenides (TMDs). We observed a variable rate of ligand exchange in different solvents, surface functionality, and receptor environments that helped us to construct sensor arrays. Interestingly, a ligand-exchange process was not observed in the presence of dithiols. Further, this concept was applied to a cancerous cell line for in vitro delivery. We found that BODIPY-functionalized 2D-MoS2 undergoes thiol exchange by intracellular GSH and subsequently enhanced the fluorescence in the cytoplasm of cancer cells. This strategy can be applied to the development of 2D-TMD-based materials for various biological applications related to ligand exchange.

Enhancement of thermoelectric power factor via electron energy filtering in Cu doped MoS2 on carbon fabric for wearable thermoelectric generator applications

The design and construction of state-of-the-art wearable thermoelectric materials are important for the development of self-powered wearable thermoelectric generators (WTEGs). Molybdenum disulfide (MoS2) has been reported as a noteworthy thermoelectric (TE) material because of its large intrinsic bandgap and high carrier mobility. In this work, Cu-doped two-dimensional layered MoS2 nanosheets were grown on carbon fabric (CF) via a hydrothermal method. The electrical conductivity, Seebeck coefficient, and power factor for the Cu-doped MoS2 were found to increase with increasing temperature. The maximum Seebeck coefficient was obtained for a MoS2 sample doped with 4 at% of Cu (CM4) was ∼10 μV/K at 303 K and ∼13 μV/K at 373 K. The enhancement in the Seebeck coefficient was attributed to an energy-filtering effect caused by the interfacial barrier between MoS2 and Cu. In addition, a thermoelectric device was designed with four pairs of TE materials, where CM4 (4 at%) was used as a p-type material and Cu wire was used as an n-type material. These p- and n-type materials were connected electrically in series and thermally in parallel to generate a voltage of 190.7 μV at a temperature gradient of 8 K.

Sulfonic acid (SO3H) functionalized two-dimensional MoS2 nanosheets for electrocatalytic hydrogen generation

We report the sulfonic acid (SO3H) functionalized two-dimensional (2D) molybdenum disulfide (MoS2) nanosheet with significantly enhanced physical and electrochemical properties as an efficient electrocatalyst for hydrogen evolution reaction (HER). The functionalized 2D-nanosheet shows enhanced electrocatalytic performance than the pristine one. We obtained overpotential as low as ∼82 mV (ƞ10) along with a very low Tafel slope ∼57 mV dec-1 and excellent stability (12 h) in functionalized MoS2. We also found that, with increasing the % of functional group, -SO3Hmolecules were intercalated through the MoS2layers resulting in the increase in interlayer spacing from 6.1 Å to 9.4 Å. The intercalated 2D-MoS2nanosheets with expanded interlayer distance further enhance the surface area, charge-transfer sites, and surface adsorption–desorption by lowering the ΔGH (i.e., the energy barrier of hydrogen adsorption/desorption), thereby accelerating the Volmer step of hydrogen evolution. Finally, density functional theory (DFT) calculations show significant changes in the electronic structure of the functionalized 2D-MoS2with a considerable shift in the total density of states (DOS) as compared to its pristine counterpart. The DFT calculations reveal that hybridizations occur between the SO3Handpanddstates of the S and Mo, which propel the valence band maximum towards higher energies, thus, leading to the narrowing of the bandgap of MoS2. Such changes in electronic properties further reduce work function and facilitate redox-mediated charge-transfer, thereby, enhancing the electrocatalytic activity for HER.

Fabrication of antifouling two-dimensional MoS2 layered PVDF membrane: Experimental and density functional theory calculation

Two-dimensional MoS2 nanosheets were synthesized with the exfoliation method, and deposited on PVDF support to develop high-efficiency membranes for water treatment. A variety of analyses were performed on the nanosheets, including FESEM, FTIR, UV–Visible, XRD, and EDS. In addition, the bulk and nanosheet of MoS2 were theoretically investigated using density functional theory (DFT). The theoretical and experimental results demonstrate the successful formation of MoS2 nanosheets. Analyses related to flux and membrane fouling were carried out on MoS2/PVDF membranes with various contents of the coating layer; these analyses were supported by FESEM, EDS, water contact angle, AFM, and zeta potential measurements. The antifouling properties as well as the water flux in the modified samples have improved compared to the bare sample. This is primarily related to the increase in hydrophilic properties due to the addition of nanosheets. The modified membranes also show better performance when purifying dyes, BSA, and Na2SO4. Based on these results, we conclude that PVDF/MoS2 membranes provide excellent water purification performance.