MoS2 Nanospheres Research Articles

Three-Dimensional Flexible SnO2@Hard Carbon@MoS2@Soft Carbon Fiber Film Anode toward Ultrafast and Stable Sodium Storage.

Developing flexible electrodes for the application in sodium-ion batteries (SIBs) has received great attention and has been still challenging due to their merits of additive-free, lightweight, and high energy density. In this work, a free-standing 3D flexible SIB anode with the composition of SnO2@hard carbon@MoS2@soft carbon is designed and successfully synthesized. This electrode combines the energy storage advantages and hybrid sodium storage mechanisms of each material, manifested in the enhanced flexibility, specific capacity, conductivity, rate, cycling performances, etc. Based on the synergistic effects, it exhibits much higher specific capacity than SnO2 carbon nanofibers, as well as more excellent cycling performance (250 mA h g-1 after 500 cycles at 1 A g-1) than MoS2 nanospheres (32 mA h g-1). In addition, relevant kinetic mechanisms are also expounded with the aid of theoretical calculation. This work provides a feasible and advantageous strategy for constructing high-performance and flexible energy storage electrodes based on hybrid mechanisms and synergistic effects.

Borate ester hybrid photothermal nanofluid derived from C3N4/MoS2 catalyzed esterification for efficient organic-inorganic synergistic lubrication

The inferior dispersion stability and simple functionality of MoS2-based nanofluids restrict their efficient application in lubrication. Herein, a novel nanofluid composed of C3N4/MoS2, 3-isocyanatopropyltrimethoxysilane, and C3N4/MoS2-catalyzed product (polyethylene glycol-borate ester, PEG-BA) was proposed. C3N4 nanosheets could induce the formation of regular MoS2 nanospheres. The resulting C3N4/MoS2 showed excellent catalytic activity for the esterification of PEG-BA. The C3N4/MoS2 @PEG-BA nanofluid exhibited favorable dispersion stability in PEG600 with no stratification for ≥ 82 days. The addition of 3.0 wt% C3N4/MoS2 @PEG-BA nanofluid could significantly reduce friction coefficient (30.7 %) and wear scar diameter (28.9 %). The excellent lubrication properties of the nanofluid are attributed to the synergistic lubrication effect of C3N4/MoS2 and PEG-BA. Furthermore, the nanofluid exhibits remarkable photothermal conversion performance in both oil and air mediums.

TiO2 nanorod decorated with MoS2 nanospheres: An efficient dual-functional photocatalyst for antibiotic degradation and hydrogen production

The design and preparation of dual-functional photocatalysts for simultaneously realizing photocatalytic wastewater purification and hydrogen energy generation pose significant challenges. This article presents the engineering of a binary heterostructured photocatalyst by combining TiO2 (nanorods) and MoS2 nanosphere using a straightforward solvothermal method and the assessment of the phase structures, morphologies, and optical properties of the resulting nanocomposites using diverse analytical techniques. The TiO2(Rod)/MoS2 composite exhibits remarkable efficacy in degrading ciprofloxacin, achieving 93% removal rate within 1 h, which is four times higher than that of bare TiO2. Moreover, the optimized TiO2(Rod)/MoS2 presents an outstanding hydrogen production rate of 7415 μmol g−1, which is ∼24 times higher than that of pristine TiO2. Under UV–visible light irradiation, the TiO2(Rod)/MoS2 heterojunction displays an exceptional photocatalytic performance in terms of both photodegradation and hydrogen production, surpassing the performance of TiO2 particle/MoS2. The study findings demonstrate that TiO2(Rod)/MoS2 nanocomposites exhibit considerably improved photocatalytic degradation and hydrogen generation activities. Based on the experimental results, a possible mechanism is proposed for the transfer and separation of charge carriers in Z-scheme heterojunctions.

Bioinspired 1T-MoS2-based aerogel beads for efficient freshwater harvesting in harsh environments

Freshwater scarcity is one of the most critical issues worldwide, particularly in arid regions, stemming from population growth and climate change. Inspired by the hydrophilic bump structures of desert beetles, 1T-MoS2-based aerogel beads with porous structures and CaCl2-crystal loading (termed as MoAB-m@CaCl2-n) were prepared for freshwater harvesting. Metallic-phase MoS2 nanospheres exhibit excellent photothermal conversion abilities, facilitating solar-driven water desorption and evaporation. Owing to the synergistic effect of its localized surface features, hydrophilic groups, and dispersive CaCl2 particles, MoAB-2@CaCl2-2 efficiently harvests water from atmosphere with a superior moisture adsorption capacity (0.18–0.82 g g−1) at a wide range of relative humidity (10 %-70 %). Under one-sun illumination, MoAB-2@CaCl2-2 demonstrates an outstanding solar-driven water evaporation rate of 2.25 kg m-2h−1. The water evaporation rate from soil (water content = 20 %) is 1.19 kg m-2h−1, which is sufficient for sustainable freshwater generation from the soil in arid regions. More importantly, the multifunctional MoAB-2@CaCl2-2-based homemade freshwater generation prototype delivers a certain amount of water harvesting (0.99 g g−1 day−1) on a rainy day and provides an impressive daily freshwater yield (53.7 kg m−2) under natural sunlight. The integrated device exhibits excellent efficiency and practicality and offers a feasible method for freshwater harvesting in harsh environments.

Effect of doping the PM6:Y7 active layer with MoS2 nanospheres in organic solar cells

Herein, MoS2 nanostructures were synthetized and characterized, as well as PM6:Y7 based organic solar cells (OSCs) were fabricated, tested, and modelled through SCAPS-1D software. Devices were assembled and tested under regular atmosphere conditions including the top electrode Field's Metal (FM), which is a eutectic alloy of Bi, In and Sn easily deposited by melting it at ∼ 95 °C. The modelled binary OSCs through SCAPS-1D achieved a PCE of 14.2%. The active layer was doped with MoS2 nanoparticles at two different concentrations, 1 and 2% v/v, the reached experimental average PCE values were 9.1%, 10.2% and 9.3% for control devices, and for the two doping concentrations, respectively; it means a PCE percentage enhancement of 11.2% when doping at 1% of MoS2. The enhanced experimental PCE value could be partially explained because of the light absorption into the active layer through the localized surface plasmonic resonance (LSPR) phenomenon induced by the nanostructures, among other optical phenomena such as light reflection and interference effects.

Highly Active MoS2‐MXenes Hybrid Electrocatalysts Towards the Oxygen Reduction Reaction

AbstractIn this work, catalytic performance of MoS2 supported on Mo2TiC2 and Ti3C2 MXenes towards the oxygen reduction reaction (ORR) was studied. These materials were synthesised through an etching route of MAX phases as precursors of MXenes, followed by a hydrothermal treatment to coat them with MoS2. This procedure generated MoS2 nanospheres covering the MXenes, which were verified by SEM‐EDX mapping, Raman spectroscopy and XPS. Activity of these materials towards ORR was studied by RRDE, comparing its performance with that of individual MoS2 and MXenes. As main features, it was demonstrated that production of HOO− occurring on the composites decreases in comparison with individual materials. Long‐term stability tests performed in O2‐saturated electrolyte showed a drop in the activity of the materials due to the increase in the production of HOO−, although no morphological or compositional changes were observed. Despite this result, the improvement of the catalytic properties of the individual materials means that these composites can be considered as candidates to be used as supports of active non‐noble metal nanoparticles in the cathodes of anion exchange membrane fuel cells (AEMFCs).

Study of prostate specific antibody-antigen binding on gold functionalized MoS2 nanospheres

Study of prostate specific antibody-antigen binding on gold functionalized MoS2 nanospheres

Synthesis of metallic-phase MoS2 nanospheres with high microwave absorbing performance

Metallic phase of MoS2 (M−MoS2) is a metastable state that does not occur naturally. To the best of our knowledge, there has been no prior preparation of pure and stable M−MoS2 nanospheres. The high purity, uniform, and stable two-dimensional M−MoS2 nanospheres were synthesized in ethyl alcohol through a hydrothermal reaction in this study. The as-prepared M−MoS2 demonstrates excellent microwave absorbing performance (MAP), with a minimum reflection loss (RL) of −39.88 dB at a thickness of 1.3 mm and an effective attenuation bandwidth (RL < -10 dB) up to 8.31 GHz (9.6875–18.0 GHz). These results suggest that M−MoS2 is a promising and cost-effective option for microwave absorption applications.

MoS2-based nanocomposites with high photothermal conversion efficiency for combinational photothermal/photodynamic tumor therapy

Photothermal conversion efficiency (PCE) plays a crucial role in tumor photothermal therapy (PTT). In this work, we developed a MoS2-based antitumor agent with enhanced photothermal conversion efficiency by size/morphology tailoring and IR820 loading for combinational photothermal/photodynamic therapy (PTT/PDT) of breast cancer. Among three MoS2-based nanomaterials, namely MoS2 nanospheres (NSs), MoS2 nanoflowers (NFs) and MoS2 quantum dots (QDs), MoS2 NSs possessed the highest PCE at 37.48%. In order to further improve the PCE, polyethyleneimine (PEI)-assisted photosensitizer IR820 decoration was carried out to prepare the MoS2@PEI@IR820 (MPI) nanocomposite. The introduced IR820 not only improves PCE of the MoS2 nanomaterials to 47.08% by increasing the light absorption for enhancing PTT, but produces cytotoxic ROS for PDT, resulting in a combinational PTT/PDT with the multifunctional MPI. In addition, in vivo fluorescence (FL) bioimaging and infrared thermographic imaging have been achieved by the designed MPI nanoplatform, which has proven to be good biocompatibility, low toxicity and high PCE. This study provides a novel way for the design and construction of prominent theragnostic nanoagents for combinational PTT/PDT.

Hybrid of carbon quantum dots modified g-C3N4 nanosheets and MoS2 nanospheres: Indirectly promote hydroxyl group production for efficient degradation of methyl orange

Azo dye molecules represented by methyl orange (MO), widely exist in industrial wastewater, and their efficient degradation requires hydroxyl groups with high oxidation activity. g-C3N4/MoS2 heterojunctions are widely used in many photocatalytic applications. However, typical type-II narrow bandgap heterojunctions have holes that cannot be directly oxidized to hydroxyl groups, which is an important barrier to MO degradation. In this work, g-C3N4 nanosheets were modified with carbon quantum dots (CQDs) and combined with spherical MoS2 nanoparticles to form CCN/MS composite photocatalysts. CQDs can be used as electronic reservoir to efficiently separate photogenerated carriers and facilitate the indirect generation of hydroxyl radicals. The results showed that the CCN/MS (10:1) sample had the most excellent degradation performance, with 93 % MO degradation in 120 min, while the control sample of CN/MS (10:1) without introducing CQDs had a degradation rate of only 24 % within the same time interval. In the mixed MO/MB degradation experiments, the degradation of MO was preferred to that of MB, suggesting the existence of a competitive mechanism between the two molecules. Our work proposes a possible pathway for the generation of hydroxyl groups using narrow bandgap semiconductor heterojunction catalysts, which provides a new perspective for understanding the degradation mechanism of pollutant molecules in real industrial wastewater.

A quadruplet 3-D laser scribed graphene/MoS2, functionalised N2-doped graphene quantum dots and lignin-based Ag-nanoparticles for biosensing

Troponin I is a protein released into the human blood circulation and a commonly used biomarker due to its sensitivity and specificity in diagnosing myocardial injury. When heart injury occurs, elevated troponin Troponin I levels are released into the bloodstream. The biomarker is a strong and reliable indicator of myocardial injury in a person, with immediate treatment required. For electrochemical sensing of Troponin I, a quadruplet 3D laser-scribed graphene/molybdenum disulphide functionalised N2-doped graphene quantum dots hybrid with lignin-based Ag-nanoparticles (3D LSG/MoS2/N-GQDs/L-Ag NPs) was fabricated using a hydrothermal process as an enhanced quadruplet substrate. Hybrid MoS2 nanoflower (H3 NF) and nanosphere (H3 NS) were formed independently by varying MoS2 precursors and were grown on 3D LSG uniformly without severe stacking and restacking issues, and characterized by morphological, physical, and structural analyses with the N-GQDs and Ag NPs evenly distributed on 3D LSG/MoS2 surface by covalent bonding. The selective capture of and specific interaction with Troponin I by the biotinylated aptamer probe on the bio-electrode, resulted in an increment in the charge transfer resistance. The limit of detection, based on impedance spectroscopy, is 100 aM for both H3 NF and H3 NS hybrids, with the H3 NF hybrid biosensor having better analytical performance in terms of linearity, selectivity, repeatability, and stability.

Preparation of MoS2 Nanospheres using a Hydrothermal Method and Their Application as Ammonia Gas Sensors Based on Delay Line Surface Acoustic Wave Devices.

An ammonia sensor based on a delay-line surface acoustic wave (SAW) device is developed in this study by coating the delay line area of the device with a nano-structured molybdenum disulfide (MoS2) sensitive material. A SAW device of 122 MHz was designed and fabricated with a pair of interdigital transducers (IDTs) defined on a 128° y-cut LiNbO3 substrate using photolithography technologies, and the aluminum IDT electrodes were deposited by a DC magnetron sputtering system. By adjusting the pH values of precursor solutions, molybdenum disulfide (MoS2) nanospheres were prepared with various structures using a hydrothermal method. Finally, an NH3 gas sensor with high sensitivity of 4878 Hz/ppm, operating at room temperature, was successfully obtained. The excellent sensitivity performance may be due to the efficient adsorption of NH3 gas molecules on the surfaces of the nanoflower-like MoS2, which has a larger specific surface area and provides more active sites, and results in a larger change in the resonant frequency of the device due to the mass loading effect.

Preparation and mechanical properties of natural rubber composites reinforced by modified molybdenum disulfide

AbstractThe filler‐rubber interaction and filler dispersion in natural rubber (NR) composites are important factors in determining mechanical properties. Herein, Molybdenum disulfide (MoS2) and Al2O3‐coated MoS2 nanospheres are incorporated in NR/carbon black composites. The effects of MoS2 and Al2O3‐coated MoS2 on the morphology, thermal and mechanical properties of the NR composites are investigated. The morphology analysis indicates that Al2O3‐coated MoS2 could greatly improve the dispersion of carbon black in NR composites. MoS2 filler and carbon black show a synergetic effect on improving the properties of NR composites, leading to high abrasion resistance, tensile strength, elongation at break and expected dynamic mechanical properties. The thermal conductivity of NR composites increases with increasing the content of MoS2 and Al2O3‐coated MoS2. The thermal stability of the NR composites is also effectively improved by filling MoS2 and Al2O3‐coated MoS2. Furthermore, a small amount of Al2O3‐coated MoS2 significantly improves the abrasion resistance, wet grip and decreases rolling resistance of the composites. Al2O3‐coated MoS2 exhibits its potential application in green tires with good performance.

Rapid hydrogen adsorption-desorption at sulfur sites via an interstitial carbon strategy for efficient HER on MoS2

Molybdenum disulfide (MoS2), a noble-free material with plentiful unsaturated active edge sites, is expected to replace platinum catalysts for commercial electrocatalytic hydrogen production. However, efficient hydrogen adsorption-desorption processes on sulfur sites with full electron configuration still remain a challenge. Here, vertically oriented self-assembled metallic MoS2 nanospheres anchored by interstitial atomic carbon (Cia-MoS2) are proposed to achieve a rapid hydrogen adsorption-desorption process. In 0.5 M H2SO4 solution, Cia-MoS2 exhibits fast kinetics (Tafel slope of 45 mV dec−1 and overpotential of 87 mV at 10 mA cm−2), as well as a long-term durability over 72 h. As confirmed from X-ray absorption fine spectroscopy and density functional calculations, Cia significantly optimizes the overall HER performance by reconfiguring the charge landscape and re-splitting the energy level of surface S moiety, which provides a universal strategy for fabricating stable unsaturated 2D catalysts toward HER.

Self-Assembly Preparation of Al2O3/MoS2 Bifunctional Catalyst for Highly Efficient Reduction of SO2 to Elemental Sulfur

MoS2 has been widely applied in SO2 desulfurization and hydrodesulfurization due to its special two-dimensional sheet structure and high-performance of reduction properties. MoS2 nanospheres assembled by the sheet structure of MoS2 were synthesized through a facile hydrothermal synthesis method with the assistance of a surfactant [polyvinylpyrrolidone (PVP)]. The structure of MoS2 was related to the amount of PVP addition during preparation, where the nanosheets were formed into nanospheres, and the nanospheres were generated into hollow spheres further increasing the amount of PVP addition. Meanwhile, the nanosphere size tended to decline, which was beneficial to the improvement of SO2 conversion. Research indicated that porous Al2O3 grown on the nanospheres exposed a larger amount of Lewis acid on the surfaces than that grown on the nanoflower-like structures. The SO2 conversion and sulfur selectivity were 97.05% and 98.21% under the optimized conditions. The modulation of the MoS2 morphology has been proved to be an available method to enhance the reduction of SO2 to elemental sulfur.

MoS2/MnO2 Nanoparticles Loaded with 2,2′-Azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride for Chemodynamic/Photothermal Antibacterial Applications

Drug-resistant bacterial infections pose a significant threat to global public health. Furthermore, the formation of biofilms makes traditional antibiotic treatments significantly less effective in killing multidrug-resistant (MDR) bacteria. In this work, we prepared a molybdenum disulfide (MoS2) nanosphere-based nanocomposite that utilized both photothermal therapy (PTT) and chemodynamic therapy (CDT) for effectively eradicating biofilms. A layer of manganese dioxide (MnO2) was adsorbed onto the surface of the MoS2 nanospheres by redox and electrostatic adsorption methods, and the resulting MoS2/MnO2 were loaded with 2,2′-azobis[2-(2-imidazolin-2-yl)propane]-dihydrochloride (AIPH) to form the MoS2/MnO2-AIPH nanocomposite (MMA). The microenvironment of biofilms is slightly acidic, lacks oxygen, and has a high concentration of glutathione (GSH). The MnO2 was capable of reacting with GSH to deplete it while also generating •OH radicals for CDT. In the presence of NIR light (808 nm), the temperature increase brought about by PTT further enhanced the CDT efficacy synergistically. The results showed that the photothermal conversion efficiency of the MMA was 40.5% at a concentration of 100 μg/mL, and the biofilm eradication rate of both MDR Escherichia coli and MDR Staphylococcus aureus was above 90%. The high bacterial inhibition rate (above 96%), as well as the excellent biosafety and biocompatibility of the MMA nanocomposite enabled it to effectively promote wound healing, which has significant implications in treating bacterial infections and promoting wound healing in clinical settings.

Peptide functionalized actively targeted MoS2 nanospheres for fluorescence imaging-guided controllable pH-responsive drug delivery and collaborative chemo/photodynamic therapy

The combination of imaging and different therapeutic strategies into one single nanoplatform often demonstrates improved efficacy over monotherapy in cancer treatments. Herein, a multifunctional nanoplatform (labelled as MPRD) based on molybdenum disulfide quantum dots (MoS2 QDs) is developed to achieve enhanced antitumor efficiency by integrating fluorescence imaging, tumor-targeting and synergistic chemo/photodynamic therapy (PDT) into one system. First, polyethylene glycol (PEG)ylated MoS2 QDs (MP) with desirable stability are synthesized via a hydrothermal process using MoS2 QDs and carboxyamino-terminated oligomeric PEG as raw materials. Then, MP were conjugated with arginine-glycine-aspartic acid (RGD) peptide via amidation to form a novel nanocarrier (MPR), which possesses strong blue fluorescence, good biocompatibility and ανβ3 receptor-mediated targeting ability. More importantly, MPR generated reactive oxygen species under 808 nm laser activation to realize targeted antitumor PDT. Further doxorubicin (DOX) was loaded onto MPR, which endows MPRD with localized chemotherapy and pH-responsive drug release. The MPRD exhibits improved chemotherapy performance on HepG2 cells (overexpressing integrin ανβ3) owing to enhanced cellular uptake mediated by ανβ3 receptor and effective drug release triggered by intracellular pH. Notably, MPRD with efficient tumor targeting ability and high chemo/PDT efficacy under NIR laser irradiation is capable of inhibiting HepG2 tumor cell growth both in vitro and in vivo, which is significantly superior to each individual therapy. These findings demonstrate that MPRD holds great potential in effective cancer therapy.

Ionic Liquid‐Assisted Electrocatalytic NO Reduction to NH3 by P‐Doped MoS2

AbstractAmbient NH3 electrosynthesis from NO reduction reaction (NORR) is attractive in replacing the industrial Haber‐Bosch route; however, the competitive hydrogen evolution reaction (HER) in aqueous electrolyte typically induces a limited selectivity and activity toward NH3 production. Herein, hierarchical P‐doped MoS2 nanospheres are developed as the NORR electrocatalyst in an ionic liquid (IL) electrolyte for catalyzing the reduction of NO to NH3 with a maximal Faradaic efficiency of 69 % (−0.6 V vs RHE) and a peak yield rate of 388.3 μg h−1 mgcat.−1 (−0.7 V vs RHE), both of which are comparable to the best‐reported results. Moreover, the catalyst also shows stable NORR activity over 30 h and 6 cycles. Theoretical analyses further reveal that the P dopants in MoS2 facilitate the activation and hydrogenation of NO. Besides, the employment of hydrophobic IL electrolyte also slows down the HER kinetics effectively.

Enhanced electrochemical performance of the MoS2/Bi2S3 nanocomposite-based electrode material prepared by a hydrothermal method for supercapacitor applications.

Supercapacitors are widely used energy storage systems in the modern world due to their excellent electrochemical performance, fast charging capability, easy handling, and high power density. In the present work, pure MoS2 and MoS2/Bi2S3 nanocomposites with different compositions of bismuth were synthesized by the hydrothermal method. The structural properties of the electrode materials were studied using the XRD technique, which confirmed the formation of MoS2 and the secondary phase of Bi2S3 while increasing Bi substitution. The morphological studies of the synthesized electrode materials were performed using SEM, TEM, and HRTEM techniques, which indicated the 3D layered hierarchical structure of MoS2 nanospheres and the nanosheet-like structure of Bi2S3. The electrochemical properties of pristine MoS2 and MoS2/Bi2S3 nanocomposites were analysed by CV, CP, and EIS techniques using a 2 M KOH electrolyte in a three-electrode system. The CV curves show evidence of significant improvement in the electrochemical performance of MoS2/Bi2S3 composites compared to that of pure MoS2. The calculated specific capacitances of MoS2/Bi2S3 nanocomposites were relatively higher than those of pristine MoS2. The 20 mol% Bi added sample showed a maximum specific capacitance of 371 F g-1, compared to pristine MoS2 and other samples at a current density of 1 A g-1. The kinetics of the electrochemical process was studied. The Nyquist plots indicated that the Bi-added nanocomposites had lower Resr and RCT values, which resulted in high electrochemical performance. The experimental results revealed that Bi-substitution can further enhance the electrochemical energy storage performance of MoS2 for supercapacitor applications.

Electrochemical and Optical Properties of Microwave Assisted MoS2 Nanospheres for Solar Cell Application

Electrochemical and Optical Properties of Microwave Assisted MoS2 Nanospheres for Solar Cell Application