Hollow MoS2 Microspheres Research Articles

Thin-walled hollow MoS2 microspheres as sulfur hosts for high-performance lithium sulfur batteries

The thin-walled hollow MoS2 microsphere was synthesized by a facile released online NH3-blowing during the reduction of ammonium tetrathiomolybdate ((NH4)2MoS4) in N-methylpyrrolidone (NMP) solvent by hydrazine hydrate at 80℃and investigated electrochemically as sulfur host for lithium sulfur battery. The results show that the as-prepared MoS2 @S electrode delivers an initial specific capacity of as high as 1801 mAh g−1, albeit partly due to the formation of SEI membrane, indicating the modulation of MoS2 on the electrochemical reaction of sulfur when compared with bare sulfur electrode. Moreover, the as-prepared MoS2 @S electrode exhibits excellent cycling stability and good rate capability, corroborating the interaction of MoS2 with lithium polysulfides (LiPSs) due to the severe shuttling effect in lithium sulfur battery, which is further authenticated by cyclic voltammetry, Tafel plot and electrochemical impedance spectroscopy techniques. This is anticipated to be a straightforward strategy for the practical implementation of lithium sulfur battery as an alternative to the state-of -the-art lithium ion battery.

Hollow MoS2/rGO composites as high-performance anode materials for lithium-ion batteries

As a representative of transition metal sulfides, MoS2 has a graphene-like structure and has recently been widely used as an anode in lithium ion batteries. However, the disadvantages of poor electrical conductivity and cycle performance limit its application. Here, hollow MoS2/reduced graphene oxide (rGO) composites were successfully synthesized by a hydrothermal method using polystyrene microspheres as hard templates. The hollow MoS2 microspheres with a size of about 180 nm are distributed on the surface of graphene sheets. The hollow MoS2/rGO composites exhibit superior electrochemical properties as anode materials for lithium-ion batteries compared with the hollow MoS2 microspheres. They show a high reversible capacity of 752.4 mAh g−1 at 500 mA g−1 after 100 cycles with negligible decay as well as a high-rate performance (620.8 mA h g−1, 1 A g−1). The excellent lithium storage performance of the hollow MoS2/rGO composites can be attributed to the synergistic effect of the hollow MoS2 microspheres and graphene sheets. Graphene effectively suppresses the agglomeration of the MoS2 and maintain the structural stability of the material.

Template-assisted synthesized MoS2/polyaniline hollow microsphere electrode for high performance supercapacitors

Herein we report a template-assisted method to synthesize molybdenum disulfide/polyaniline (MoS2/PANI) hollow microspheres with excellent electrochemical performances for supercapacitors applications. The hollow MoS2 microspheres are assembled by layered MoS2 nanosheets, which provide substantial ion channels and large surface area for electrolyte ion transport. PANI is grown on the surface of the hollow MoS2 microspheres by oxidative polymerization with different mass. The MoS2/PANI-1:2 hollow microspheres electrode possesses the maximum specific capacitance of 364 F/g at a scan rate of 5 mV/s. In addition, the specific capacitance achieves 299 F/g with a current density of 10 A/g and 84.3% of the specific capacitance is retained after 8000 cycles at 10 A/g. The energy density can be as high as 32 Wh/kg at a power density of 320 W/kg. Even at a very high power density of 8320 W/kg, the energy density still maintains 23.1 Wh/kg, showing a large power density range for supercapacitor applications. We assemble a symmetric supercapacitor by using two identical MoS2/PANI microspheres electrodes, and it shows high specific capacitances of 231, 139 F/g at 0.2 and 0.5 A/g, respectively. Our results suggest that the MoS2/PANI hollow microspheres electrode have good cycle stability and significant potential for supercapacitor applications.

Flower-like hollow MoS2 microspheres/acrylic resin composites for enhanced oil contaminants removal from water

ABSTRACTIn this paper, novel flower-like hollow MoS2 microspheres (FHMs) were synthesized by a hydrothermal method using MF microspheres as template. The FHMs were hydrophobically modified and utilized as porous fillers to fabricate FHMs/acrylic resin composites through suspension polymerization. The oil-absorption tests revealed that the composite with 4 wt% FHMs had a high oil-absorption capacity, which might be due to the synergistic absorption effect of organic and inorganic components. Their high absorption capacity, rapid absorption rate, and excellent reusability make them attractive options as absorbents for practical oil/water separation.

Facile strategy for controllable synthesis of hierarchical hollow MoS2 microspheres with enhanced photocatalytic properties

Tailored design of photocatalysts with complicated hollow structures is of great importance for promoting environmental remediation. In this paper, monodispersed hierarchical hollow MoS2 microspheres have been prepared via a facile and economical hydrothermal method with the assistance of surfactant (polyethylene-polypropylene glycol (F68)). The unusual design displays three important features: large specific surface area, strong light absorption, and rich catalytic active sites. The specific surface area of the hierarchical hollow MoS2 microspheres is 21.75 m2g-1, which is higher than that of MoS2 particles (4.05 m2g-1) and commercial MoS2 (2.84 m2g-1). Meanwhile, the hierarchical hollow MoS2 microspheres possess strong light absorption around a broadband wavelength from 200 nm to 800 nm. Furthermore, the ordered MoS2 nanosheets which assemble to the outer surface of the hierarchical hollow MoS2 microspheres display rich catalytic active sites, which are beneficial in promoting the fast transport of charge carriers during the process of photocatalytic reaction. As a result, the photodegradation activity test demonstrates that the hierarchical hollow MoS2 microspheres exhibit excellent photocatalytic activity and recycling stability. The reaction rate constant of the hierarchical hollow MoS2 microspheres for the photodegradation of RhB is 25.32 and 18.18 times faster than that of MoS2 particles and commercial MoS2, respectively.

Hierarchical hollow MoS2 microspheres as materials for conductometric NO2 gas sensors

Surface structure control at the atomic scale is an efficient strategy for improving the performance of gas sensing. Herein, hierarchical hollow MoS2 microspheres with enhanced performance for NO2 gas sensing were synthesized via a facile hydrothermal method. The introduction of micro-nano hierarchical structure improved the exposure of active edge sites of MoS2, and the efficiency of gas and carriers exchange and transportation during the reaction, which synthetically contribute the sensing performance enhancement. With additional optimization of reaction conditions, the hierarchical hollow MoS2 microspheres show excellent sensing performance with 3.1 times enhancement compared with the contrast sample of smooth solid structure. The rapid and sensitive response, decreased working temperature, as well as the prominent selectivity, enable the material with attractive sensing performance for NO2 detection. This study provides new opportunities on the surface morphology control at both the micro- and nanoscale for enhancing the sensing performance of MoS2.

Preparation and adsorption property of hollow MoS2 microspheres composed of nanoflakes

The hollow molybdenum disulfide (MoS2) microspheres composed of nanoflakes were successfully synthesized via a facile hydrothermal method, in which molybdenum trioxide (MoO3) and potassium thiocyanate (KSCN) were used as Mo and S source, and hexadecyltrimethyl ammonium bromide (CTAB) was as a surfactant. The hollow MoS2 microspheres obtained at different hydrothermal temperatures significantly influence their purity, crystalline quality and thermal stability. X-ray diffraction, energy dispersive, thermal gravimetric analysis, Brunauer–Emmet–Teller, a UV–visible spectrophotometer (UV–Vis), field-emission scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy were used to characterize the samples. The weak hydrolysis of MoO3 in the solution and interaction with the surfactant CTAB plays an important role in the formation of the hollow structure of MoS2 microspheres. In addition, the final adsorption capacity of the MoS2 for the different concentrations of methylene blue (MB) solutions was studied in detail. The removal and the adsorption capacity of MoS2 sample for 200 mg L−1 of MB solution could reach 85.94% and 343.74 mg g−1 after 10 min, respectively. The result indicates that the hollow MoS2 possess a significant adsorption ability for dye in the solution, which might be anticipated to be used in wastewater treatment.

Enhanced Lubrication and Photocatalytic Degradation of Liquid Paraffin by Hollow MoS2 Microspheres.

Nowadays, with the rapid development of environmental protection awareness, the demand for the emergence of a green counterpart of lubricant additive plays a more and more important role in reducing friction and wear as the times require. In this paper, full-hollow and semihollow molybdenum disulfide (MoS2) microspheres were prepared via a hydrothermal method and were characterized and confirmed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). According to our results, both fully hollow and semihollow MoS2 microspheres possessed excellent lubrication-enhancing effects for liquid paraffin (LP), while full-hollow samples after friction provided better photocatalytic degradation properties than semihollow samples after friction. Related analysis indicated that curved layer opened structures with more rim and edge sites, bigger surface area, and narrower band gap made full-hollow MoS2 samples achieve a better photocatalytic level. Thus, it was a sustainable solution for both lubrication-enhancing and photocatalytic degradation functions during different stages of the usage of lubricating oils, which suggests a potential strategy for achieving environmentally friendly developments.

Controllable constructing of hollow MoS2/PANI core/shell microsphere for energy storage

Using hierarchical hollow MoS2 microspheres constructed by ultrathin nanosheets as a framework to provide large active surface area, polyaniline (PANI) nanofibers are controllably assembled on their surfaces by in-situ oxidative polymerization of different amounts of aniline monomers. The morphology and structure of these resulting composites are characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) spectroscopy analyses. In order to assess the electrochemical performances of the composites, cyclic voltammograms (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charging-discharging (GCD) tests are employed. The as-prepared MoS2/PANI-5 composite electrode delivers an enhanced specific capacitance about 633Fg−1 at the current density of 0.5Ag−1, as well as shows a remarkable capacitance retention of 86.0% at 10Ag−1 after 1000 cycles. In addition, the energy density reaches to 31.7Whkg−1 when the power density is 0.3kWkg−1. All the electrochemical tests indicate this composite has an application prospect as an electrode material for supercapacitors.

Porous hollow MoS2 microspheres derived from core–shell sulfonated polystyrene microspheres@MoS2 nanosheets for efficient electrocatalytic hydrogen evolution

Hollow MoS2 microspheres were constructed using monodisperse sulfonated polystyrene (SPS) as the template, and exhibited excellent HER performance.

Template Synthesis of Hollow MoS2 Microspheres with Enhanced Electrocatalytic Activity for Hydrogen Evolution

Template Synthesis of Hollow MoS2 Microspheres with Enhanced Electrocatalytic Activity for Hydrogen Evolution

Hollow Structured Micro/Nano MoS2 Spheres for High Electrocatalytic Activity Hydrogen Evolution Reaction

Molybdenum disulfide (MoS2) has attracted extensive attention as a non-noble metal electrocatalyst for hydrogen evolution reaction (HER). Controlling the skeleton structure at the nanoscale is paramount to increase the number of active sites at the surface. However, hydrothermal synthesis favors the presence of the basal plane, limiting the efficiency of catalytic reaction. In this work, perfect hollow MoS2 microspheres capped by hollow MoS2 nanospheres (hH-MoS2) were obtained for the first time, which creates an opportunity for improving the HER electrocatalytic performance. Benefiting from the controllable hollow skeleton structure and large exposed edge sites, high-efficiency HER activity was obtained for stacked MoS2 thin shells with a mild degree of disorder, proving the presence of rich active sites and the validity of the combined structure. In general, the obtained hollow micro/nano MoS2 nanomaterial exhibits optimized electrocatalytic activity for HER with onset overpotential as low as 112 mV, low Tafel slope of 74 mV decade(-1), high current density of 10 mA cm(-2) at η = 214 mV, and high TOF of 0.11 H2 s(-1) per active site at η = 200 mV.

Template Synthesis of Hollow MoS2Microspheres with Enhanced Electrocatalytic Activity for Hydrogen Evolution

Template Synthesis of Hollow MoS2Microspheres with Enhanced Electrocatalytic Activity for Hydrogen Evolution

Facile Synthesis of Hollow MoS2 Microspheres/Amorphous Carbon Composites and Their Lithium Storage Properties

In this paper, we report a facile process to synthesize hollow MoS2 microspheres/amorphous carbon composites (MACCs) by hydrothermal method and their improved electrochemical performance in Lithium ion batteries (LIBs). The composites prepared are characterized by XRD, SEM, HRTEM and EDS. MoS2 nanosheets are uniformly grow on the surface of amorphous carbon. The interlayer-distance of the adjacent MoS2 nanosheets in the composites is about 0.64nm. As an electrode material for the LIBs, hollow MoS2 MACCs exhibit excellent cyclic stability with 1147mAhg−1 at 100mAg−1 after 100 cycles, which displays more prominent performance than that of the hollow MoS2 microspheres. Moreover, the reversible capacity for the hollow MoS2 MACCs can be still maintain at 876mAhg−1 at 1000mAg−1. The enhanced electrochemical performance of hollow MoS2 MACCs could be attributed to their unique hollow structure, large specific surface area, the increased interlayer-distance and the synergistic effects between hollow MoS2 microspheres and amorphous carbon.

Sonochemical Preparation of MoS2 in Aqueous Solution: Replication of the Cavitation Bubbles in an Inorganic Material Morphology

Sonochemical reaction between (NH4)6Mo7O24 and CH3COSH in aqueous solution leads to the formation of hollow MoS2 microspheres, replicating the shape of cavitation bubbles. The walls of these hollow spheres consist of short and low-stacked MoS2 fringes providing to the material very high intrinsic catalytic activity in the thiophene hydrodesulfurization reaction.