Morphology Of MoS2 Research Articles

Enhancing Organic Pollutant Degradation Efficiency through a Photocatalysis-Electro-Fenton System via MoS2 Crystal Morphology Regulation.

A photocatalysis-electro-Fenton (PEF) system was constructed via molybdenum disulfide (MoS2) to remove tetracycline (TC) without an external oxidant supply and solution pH adjustment. In the system, original graphite felt (GF) was used as a cathode, from which H2O2 was in situ generated continuously under power. MoS2 was motivated by visible light to facilitate the cycle of Fe2+/Fe3+, enhancing the Fenton process to produce •OH. The experimental results showed that the system can increase the degradation rate of pollutants by more than 5 times. Moreover, the quenching and electron paramagnetic resonance (EPR) tests demonstrated that •OH was the dominant active species. X-ray photoelectron spectroscopy (XPS) characterization, Mo concentration, and cycle experiments proved the excellent catalytic activity and chemical stability of MoS2. It is worth mentioning that the photocatalytic performances of different morphologies of MoS2 (flower, flake, and radar) were compared. As a result, flower-like MoS2 exhibited a much superior photoresponse than flake and radar, which could accelerate the Fe2+/Fe3+ cycle further effectively. These findings highlight the morphology-performance relationship of MoS2 under a PEF system and the mechanisms of contaminant degradation, which is of great significance for developing photoelectric Fenton technology.

Impact of water vapor on the 2D MoS2 growth in metal-organic chemical vapor deposition

In the presented work, the method of metal–organic chemical vapor deposition (MOCVD) using Mo(CO)6 and H2S assisted by oxidative etching with water vapor, was employed for the synthesis of MoS2. This study was aimed at detailed investigation of the films' properties obtained via this method and identifying methods for elimination of such disadvantages as the carbon impurities and the small size of crystalline domains in the films. It was found that in the temperature range from 850 °C to 950 °C, the effect of water vapor on the morphology of MoS2 is significantly different. The study of the chemical states of molybdenum and sulfur made it possible to associate the size of the crystal domains formed with the efficiency of removing the oxidized states of Mo6+ and S6+. It is assumed that the increase in the domains’ size is due to rapid lateral growth, resulting from the complete removal of the oxidized states at the edges, as well as a decrease in the density of nucleation centers due to the etching of less stable seeds on the substrate surface.

Unveiling the Influences of In Situ Carbon Content on the Structure and Electrochemical Properties of MoS2/C Composites.

In this work, a MoS2/C heterostructure was designed and prepared through an in situ composite method. The introduction of carbon during the synthesis process altered the morphology and size of MoS2, resulting in a reduction in the size of the flower-like structures. Further, by varying the carbon content, a series of characterization methods were employed to study the structure and electrochemical lithium storage performance of the composites, revealing the effect of carbon content on the morphology, structure characteristics, and electrochemical performance of MoS2/C composites. The experimental setup included three sample groups: MCS, MCM, and MCL, with glucose additions of 0.24 g, 0.48 g, and 0.96 g, respectively. With increasing carbon content, the size of MoS2 initially decreases, then increases. Among these, the MCM sample exhibits the optimal structure, characterized by smaller MoS2 dimensions with less variation. The electrochemical results showed that MCM exhibited excellent electrochemical lithium storage performance, with reversible specific capacities of 956.8, 767.4, 646.1, and 561.4 mAh/g after 10 cycles at 100, 200, 500, and 1000 mA/g, respectively.

Probing the interplay of interactions, screening and strain in monolayer MoS2 via self-intercalation

Controlling many-body interactions in two-dimensional systems remains a formidable task from the perspective of both fundamental physics and application. Here, we explore remarkable electronic structure alterations of MoS2 monolayer islands on graphene on Ir(111) induced by non-invasive self-intercalation. This introduces significant differences in morphology and strain of MoS2 as a result of the modified interaction with the substrate. Consequently, considerable changes of the band gap and non-rigid electronic shifts of valleys are detected, which are a combined effect of the screening of the many-body interactions and strain in MoS2. Furthermore, theory shows that each substrate leaves a unique stamp on the electronic structure of two-dimensional material in terms of those two parameters, restricted by their correlation.

The novel Auricularia-like MoS2 as binder-free electrodes for enhanced capacitive deionization

Molybdenum disulfide (MoS2) has been proven to be an effective and promising electrode material for capacitive deionization (CDI) due to its unique architectures and excellent electrochemical activity. However, MoS2-based electrodes still suffer from the high contact electrical resistance between MoS2 and the current collectors because of the necessity of adding binder during their fabrication. In this work, a flexible MoS2-based electrode with no binders was successfully fabricated. It was found that the frameworks of stainless-steel mesh with surface treatment could serve as an ideal substrate to provide plenty of active nucleation sites for the growth of MoS2. Consequently, a novel morphology of MoS2 with Auricularia-like architectures was produced. Based on electrochemical impedance spectroscopy (EIS), the charge transfer resistance was reduced to nearly zero after the treatment, highly increasing the transportation of charges inside the electrodes compared to the common MoS2-based electrodes. As a result, the binder-free MoS2-based electrodes demonstrated a superior desalination performance of 28.76 mg g-1 (1.2 V) for NaCl solution, which was superior to that of common MoS2-based and many other advanced materials-based electrodes. The novel MoS2-based electrode not only facilitates the utilization of MoS2 in CDI but also paves the way for its application in other electrochemical domains.

Au – MoS2 nanoflowers sensors on interdigitated electrode for monitoring human respiration

Abstract Respiratory humidity sensors are essential for monitoring breath conditions in a variety of applications such as respiratory disease diagnosis, sleep apnea screening, and personalized medicine. With the increasing prevalence of respiratory diseases, such as asthma, chronic obstructive pulmonary disease (COPD), and sleep apnea, they have become essential tools for healthcare professionals, researchers and individuals. However, existing humidity sensors often suffer from poor sensitivity, slow response, and limited flexibility. In this paper, we report a novel Au – MoS2 respiratory humidity sensor that exhibits high resistivity, fast response, and excellent flexibility. The sensor is fabricated by drop casting a thin layer of Au decorated MoS2 on copper interdigitated electrodes (fabricated using copper clad PCB). The increase in the intensity of the peak was observed in Au – MoS2 hybrids in comparison to MoS2 analyzed using micro–Raman Spectroscopy. Using scanning electron microscopy (SEM), the morphology of MoS2 was observed, confirming its flower like structure. The Au nanoparticles were detected on the edges of MoS2, confirmed by transmission electron microscope (TEM).
The interfacial electronic interaction suggests that there is the formation of Schottky barrier between Au and MoS2 as confirmed by X–Ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). The improved electronic interaction results in better sensing properties. The high dielectric constant and excellent surface-to-volume ratio of the MoS2 layer make it extremely sensitive to humidity; the Au nanoparticles offer good electrical conductivity and mechanical flexibility in its place. The study tested a respiratory sensor in a simulated environment, finding it more responsive to breathing and quick to return to rest. This suggests potential for the Au-MoS2 sensor in tracking breath states due to its sensitivity and adaptability, promising applications across various fields.

Effect of different MoS2 morphologies on the formation and performance of adsorptive-catalytic nanocomposite membranes

This study synthesized three MoS₂ morphologies—nanospheres, nanoplatelets, and nanosheets—under varied conditions and incorporated them into chitosan membranes. TEM confirmed unique morphologies and crystallinity. Clean water flux showed that the nanoplatelet (P-CM) membrane had the highest flux due to higher porosity. The P-CM membrane excelled in removing Mn²⁺ and Zn²⁺ ions, achieving 93.0 ± 0.5% and 90.4 ± 1.5% removal, outperforming membranes with nanospheres (S-CM) and nanosheets (T-CM). Its superior performance is attributed to thicker nanoplatelets forming more water channels. The MoS₂‘s tri-layered structure generated reactive oxygen species (ROS) via H₂O₂ catalysis, contributing to enhanced heavy metal removal. These adsorptive-catalytic membranes combine adsorption with catalytic decomposition of heavy metals, highlighting the work’s novelty and superior performance. The membranes demonstrated excellent flux recovery and reusability (96.0 ± 0.5% for P-CM) after chemical cleaning. The findings emphasize the impact of nanomaterial morphologies on membrane performance in water treatment and environmental remediation.

Substrate-induced strain in molybdenum disulfide grown by aerosol-assisted chemical vapor deposition

Transition metal dichalcogenides have been extensively studied in recent years because of their fascinating optical, electrical, and catalytic properties. However, low-cost, scalable production remains a challenge. Aerosol-assisted chemical vapor deposition (AACVD) provides a new method for scalable thin film growth. In this study, we demonstrate the growth of molybdenum disulfide (MoS2) thin films using AACVD method. This method proves its suitability for low-temperature growth of MoS2 thin films on various substrates, such as glass, silicon dioxide, quartz, silicon, hexagonal boron nitride, and highly ordered pyrolytic graphite. The as-grown MoS2 shows evidence of substrate-induced strain. The type of strain and the morphology of the as-grown MoS2 highly depend on the growth substrate’s surface roughness, crystallinity, and chemical reactivity. Moreover, the as-grown MoS2 shows the presence of both direct and indirect band gaps, suitable for exploitation in future electronics and optoelectronics.

Function‐Oriented Design of Amorphous MoS2 with Abundant Active Sites for High‐Efficiency Hydrogen Evolution Reaction

AbstractMolybdenum disulfide (MoS2) has received great interest as a highly active and cost‐effective electrocatalyst for hydrogen evolution reaction (HER). However, a main challenge for developing high‐efficiency electrocatalysts is to tailor the factors affecting the HER performance, such as composition, structure, and morphology. Herein, amorphous MoS2 electrodes with different Mo and S contents are successfully synthesized by the chemical bath deposition method using different molar ratios of Mo/S precursors (Mo/S: 4 : 1, 1 : 1 and 1 : 4) at various growth times. Experimental results indicate that the composition and the surface morphology of MoS2 are strongly sensitive to the Mo and S contents, which can create different surface roughness at the interface induced by growth times. The as‐prepared MoS2 electrode with a molar ratio of 1 : 4 exhibits superior HER activity in 1 M KOH, only requiring low overpotentials of 220 mV at 20 mA cm−2, which is much lower than those of MoS2 with a molar ratio of 1 : 1 (253 mV), and 4 : 1 (290 mV), respectively. This outstanding electrochemical performance of MoS2 (Mo/S, 1 : 4) with excellent long‐term stability can be attributed to its unique sulfur‐rich MoS2 nanosheet array structure with exposed abundant active sites, a high electrochemical active surface area (ECSA: 955.50 cm2) and superior roughness factor (RF: 3822).

A novel method for vacuum synthesis and structural regulation of layered molybdenum disulfide

Molybdenum disulfide (MoS2) has received considerable attention due to its promising biomedical technologies, foldable displays and optoelectronic properties. In this work, the vacuum synthetic technology was employed to grow four-layer MoS2 from sulfur powder and molybdenum trioxide (MoO3), after holding in a threaded crucible for 30 min at 1273 K. One characteristic of this process is to increase the pressure of sulfur by using the threaded crucible. The composition and morphology of the products depend upon the synthetic temperature. The vacuum-prepared MoS2 was used as a precursor for mono- or few-layers materials by ultrasonic treatment in isopropanol solution (IPA). The structure, morphology, composition, band gap and photoluminescence (PL) of MoS2 with mono- and few-layers were investigated in detail. This work has a great impact on the tunable layers and bandgap of MoS2.

Hydrothermal synthesis of MoS2 with tunable band gap for future nano-electronic devices

Transition metal dichalcogenides (TMDs) have been explored in various domains of science and technology in the past few years. Among the numerous transition metal dichalcogenides, MoS2 has sparked the interest of researchers owing to its peculiar, layered structure and associated intriguing optical and electrical properties which can be utilized in diverse applications including catalysts, gas sensing, energy storage, hydrogen storage etc. In recent work, the hydrothermal approach is employed to make two distinct morphologies of MoS2, namely Nano-sheets and Nano-flowers, by utilizing ammonium molybdate as a precursor. Herein, X-Ray Diffraction (XRD), Field Emission Scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier Transform Infrared spectroscopy (FTIR), and UV–Visible techniques were utilized to validate the crystallographic structure, morphology, chemical composition, and band gap value of as-synthesized samples. The MoS2 synthesized nanostructures showed a good response for 100 ppm NO2 gas at 100 °C. The synthesized flower-based sensor showed a 24.03 % response and the sheet-based sensor showed a 15.64 % response value for 100 ppm NO2 gas at 100 °C. The versatile morphology of MoS2, coupled with its tunable band gap, open new avenues in the field of gas sensing.

Cerium-doped 1 T phase enriched MoS2 flower-like nanoflakes for boosting hydrogen evolution reaction

MoS2 has drawn worthwhile attention in the area of hydrogen evolution reactions (HER) owing to its exceptional catalytic performance. Nonetheless, its activity is still limited by an inert substrate. Thus, doping with rare earth heteroatoms is an effective strategy to maximize its electrocatalytic activity. Here, we utilize a facile hydrothermal approach to synthesize Ce-doped MoS2. The investigation reveals that the amount of Ce doped has an impact on the efficiency of HER. The optimal amount of Ce doped can alter the morphology, defects, and electronic structure of MoS2, and further boosting its HER performance. Ce0.1-MoS2 has a lower overpotential of 113.78 mV in H2SO4 at 10 mA cm−2, with a lower Tafel slope, and ideal electrochemical active surface area. Moreover, the electrocatalyst demonstrates excellent durability for 10 h. This work unveils a dissimilar perspective for the synthesis of excellent HER activity MoS2-based catalysts.

Systematic investigation of MoS2-metal sulfides (Metal = In, Sn, Cu, Cd) heterostructure via metal-sulfur bond for photocatalytic CO2 reduction

Heterojunctions between MoS2 and metal sulfides (Metal = In, Sn, Cu, Cd) were successfully constructed via the metal-sulfur bond, and their application of CO2 photoreduction into chemical values could address the problem of global warming effectively. Among all MoS2/metal sulfides, the same lamellar morphology between MoS2 and In2S3 could be ascribed for the high photocatalytic performance, which revealed the high specific surface area and benefitted for the generation of build-in electric field, thus leading to the outstanding separation and migration ability. In the opposite, the dissatisfactory photoreduction performance was emerged on the heterostructure between rod-like morphology of CdS and lamellar MoS2. Moreover, the feature of small gap between valence band minimum and Fermi level in In2S3 was remained in MoS2/In2S3 composite, which could promote more carriers to be excited. Hence, the optimal MoS2/In2S3 composite reached 10.09 μmol·h−1·g−1 of CO, 68.41 μmol·h−1·g−1 of CH4 and 6.66 μmol·h−1·g−1 of CH3OH, and the mix-coordination of CO2 adsorption and the carbene pathway over MoS2/In2S3 was revealed via in-situ DRIFTS.

Matched micro-geometrical configuration leading to hetero-interfacial intimate contact of MoS2@UiO-66-NH2 Z-scheme heterojunction for efficient photocatalytic CO2 reduction

Z-scheme heterojunction is an effective strategy in photocatalysis, when hetero-interfacial intimate contact is the center of high-performance Z-scheme heterojunction structure. Here, x-MoS2 [x = plate (p), flower (f), and solid sphere (s)] with extensive optical absorption and high conductivity and stable UiO-66-NH2(y) (y = 100, 300, and 500 nm) with rich Lewis's acid sites were integrated to a series of x-MoS2@UiO-66-NH2(y) Z-scheme heterojunctions, which were fully characterized and used for photocatalytic reduction of CO2 (pCO2RR) into CH4 and CO. In response to the difficult modification of MoS2 and loose contact of composite bulk materials, the micro-geometric configurations on the size of UiO-66-NH2 and the morphology of MoS2 were optimized to achieve an intimate contact. The Z-scheme heterojunction f-MoS2@UiO-66-NH2 (100 nm) with perfectly matched micro-geometric configuration exhibited an excellent electron consumption rate (Rele) of 263.78 μmol g–1 h–1 and a high CH4 yield of 27.18 μmol g–1 h–1 with a selectivity of 82.44%, being far superior to most MoS2- and MOFs-based heterojunctions. Comprehensive investigations with extensive photoelectric characterizations, control experiments, and density functional theory (DFT) calculations demonstrate that the excellent photocatalytic performance of f-MoS2@UiO-66-NH2 (100 nm) could be attributed to that (i) the low size of UiO-66-NH2 strengthens mutual alignment and increases outer surface to maximize heterointerface contact with MoS2, accelerating the interfacial charge transfer; (ii) the hierarchical structure of f-MoS2 with optimal basal plane curvature greatly reduces contact barriers to present a high charge throughput with a charge excitation rate of 1.967 mV, smooth initiating the 8-electron CO2 methanation. Additionally, the durability of f-MoS2@UiO-66-NH2 (100 nm) was also investigated.

One-step method to control the temperature of S and Mo source and its effect on the size and morphology of MoS2

Molybdenum disulfide (MoS2) is a typical two-dimensional material, which is widely used in many fields because of its excellent electrical and optical properties. In recent years, the high-quality growth of MoS2 has attracted more and more attention from researchers. Many studies have reported a two-step method for the production of MoS2 by pre-deposition of molybdenum (Mo) source and then vulcanization, which is cumbersome and time-consuming, and the preparation temperature is mostly above 800 °C, increasing energy consumption and experimental risk. In this paper, S source and Mo source can be distinguished by double temperature zone tube furnace to prepare MoS2 material in one-step method. The temperatures of S and Mo sources were designed separately, and the effect of each temperature on the quality of MoS2 was investigated. And the monolayer MoS2 with high crystalline quality was obtained at a S source temperature of 165 °C and a Mo source temperature of 680 °C. We produce MoS2 in one-step method at low temperature, which provides a reference for the synthesis of high-quality monolayer MoS2.

Liquid Shear Exfoliation of MoS2: Preparation, Characterization, and NO2-Sensing Properties.

2D materials possess great potential to serve as gas-sensing materials due to their large, specific surface areas and strong surface activities. Among this family, transition metal chalcogenide materials exhibit different properties and are promising candidates for a wide range of applications, including sensors, photodetectors, energy conversion, and energy storage. Herein, a high-shear mixing method has been used to produce multilayered MoS2 nanosheet dispersions. MoS2 thin films were manufactured by vacuum-assisted filtration. The structural morphology of MoS2 was studied using ς-potential, UV-visible, scanning electron microscopy (SEM), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy (RS). The spectroscopic and microscopic analyses confirm the formation of a high-crystalline MoS2 thin film with good inter-sheet connectivity and relative thickness uniformity. The thickness of the MoS2 layer is measured to be approximately 250 nm, with a nanosheet size of 120 nm ± 40 nm and a number of layers between 6 and 9 layers. Moreover, the electrical characteristics clearly showed that the MoS2 thin film exhibits good conductivity and a linear I-V curve response, indicating good ohmic contact between the MoS2 film and the electrodes. As an example of applicability, we fabricated chemiresistive sensor devices with a MoS2 film as a sensing layer. The performance of the MoS2-chemiresistive sensor for NO2 was assessed by being exposed to different concentrations of NO2 (1 ppm to 10 ppm). This sensor shows a sensibility to low concentrations of 1 ppm, with a response time of 114 s and a recovery time of 420 s. The effect of thin-film thickness and operating temperatures on sensor response was studied. The results show that thinner film exhibits a higher response to NO2; the response decreases as the working temperature increases.

Large area synthesis of mono/few-layer MoS2 thin films on thermal oxide silicon substrate by pulsed laser deposition technique

Two-dimensional molybdenum disulphide (2D MoS2) has emerged as an auspicious material in the development of optoelectronic devices owing to its remarkable similarities with graphene while possessing a definite bandgap. However, the production of these devices is restricted due to the difficulties in producing high-quality 2D MoS2 films on a large scale. Here we report the growth of mono/few layers of MoS2 - on thermal oxide silicon (Si/SiO2) substrate using pulsed laser deposition (PLD). The presence of Raman peaks corresponding to A1g and E12g modes of vibration confirmed the formation of 2D MoS2. The difference in Raman shift of A1g and E12g modes was used to find out the number of layers of the PLD-grown MoS2 thin films, which was found to be increasing with deposition time. Photoluminescence spectra also revealed the formation of mono/few-layered MoS2 thin films, and the thickness of the films was determined using atomic force microscopy. The MoS2 thin films were then deposited on a quartz substrate to record the absorption spectra of MoS2, and the existence of four excitonic peaks A, B and C, D further confirmed the formation of 2H MoS2. The calculation of the bandgap was done using Tauc plot studies, and a bandgap value of 1.77 eV was obtained for monolayer MoS2. The stoichiometry of Mo and S in the PLD-grown samples was determined using X-ray photoelectron spectroscopy analysis. The morphology and crystallinity of the monolayer MoS2 were studied by performing transmission electron microscopy analysis.

Phase transition in bilayer MoS2 under tensile loading: a molecular dynamics study

Molybdenum disulfide (MoS2), especially single-layer MoS2, has been experimentally and computationally discovered to exist in several different polymorphs exhibiting various electronic and mechanical properties. The morphology of MoS2 can be tuned through strain engineering. Molecular dynamics simulations are conducted to systematically study the phase transition of single-layer MoS2 and bilayer MoS2 under the uniaxial tensile condition at room temperature. The roles of edge and S-line vacancy are investigated. Phase transitions are always triggered near the edge and vacancy sites. The initiation of the metastable T″ phase can release the tensile stress in the lattice, followed by I4/mmm phase initiation, regardless of the edge conditions. The growth of the I4/mmm phase can cause the local buckling of the MoS2 plane. With a tilted S-line vacancy, I4/mmm phase is first initiated to reduce the local shear stress accumulated near the vacancy line. Overall, the phase transition mechanism of single layer and bilayer MoS2 under the uniaxial tensile loading is provided, which guides the future strain engineering of MoS2 in nanoelectronics applications.

Revolutionizing water treatment: Exploring the efficacy of MoS2/BN/rGO ternary nanocomposite in organic dye treated water for OER and HER applications

The novelty of the present work is synthesis of 2D layered molybdenum disulfide/boron nitrate/reduced graphene oxide (MoS2/BN/rGO) ternary nanocomposites for the first time through sonication assisted hydrothermal method and explore its suitability for HER/OER applications. Also the performance evaluation was carried out against normal Distilled water as well as MB dye treated water. Flower, disk and layered morphology of MoS2, BN and rGO, respectively was confirmed from field emission scanning electron microscopy (FESEM) images. Microstructural analysis was carried out using high resolution transmission electron microscopy (HRTEM) analysis. The ternary nanocomposite revealed better degradation efficiency about 98 % of degradation against methylene blue (MB) within 45 min and the recycle analysis revealed better stability for 7 cycles. For distilled water, during the oxygen evolution reaction (OER) analysis of ternary nanocomposite showed a less over potential at 0.61 V vs. RHE @ 10 mA/cm2 and Tafel slop was calculated to be 99 mV/dec. In the case of hydrogen evolution reaction (HER), over potential @ 10 mA/cm2 was about −0.044 V vs. RHE and the Tafel slop was observed to be 115 mV/dec. The photocatalytic treated waste water was examined for both HER and OER analysis where the potential at 10 mA was about −0.422 V and 1.96 V vs. RHE, for HER and OER, respectively. Further, the Tafel slop of both HER and OER was calculated to be 290 mV/dec and 121 mV/dec, respectively. The chronoamperometry analysis confirmed better stability of the ternary nanocomposite of MoS2/BN/rGO for a period of 12 h.

Time-dependent synthesis of molybdenum disulfide for efficient electrocatalysts

Molybdenum disulfide (MoS2) is synthesized by the easy hydrothermal method for bifunctional electrocatalysts. The synthesis time from 6 to 72 h was under controlled, and then the time dependently synthesized MoS2 samples were investigated. The morphology of MoS2 changed from flakes to flower shapes with the time. Electrochemical properties as well as catalytic activities of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are studied. The synthesized MoS2 sample at 200 °C for 48 h exhibits the best performance for HER and OER among the other samples. Low Tafel slope of 98 mV/dec with overpotential of −213 mV at the current density of −10 mA/cm2 for HER is obtained, and improved Tafel slope of 114 mV/dec with overpotential of 275 mV at the current density of +10 mA/cm2 for OER is also achieved.