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Photocatalytic activity of 3D flower-like MoS2 hemispheres
Highlights: • The ultrathin MoS{sub 2} nano-sheet assembled 3D flower-like MoS{sub 2} hemispheres were prepared via hydrothermal method. • The bandgap of as-synthesized MoS{sub 2} is about 2.05 eV, resulting in a broad absorption in the visible range. • The photocatalyst of MoS{sub 2} present the optimal catalytic property under mild acidity. - Abstract: The novel 3D flower-like MoS{sub 2} hemispheres assembled by ultrathin MoS{sub 2} nano-sheet petals have been successfully prepared via a facile hydrothermal method using CTAB as surfactant. The crystal structure and morphology of the as-synthesized MoS{sub 2} samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), Raman spectra and scanning electron microscopy (SEM). Moreover the microstructure and the optical properties of MoS{sub 2} samples were also measured by transmission electron microscopy (TEM) and the UV–vis diffuse reflectance spectra (DRS). The photocatalytic performance of the flower-like MoS{sub 2} hemispheres were evaluated through the degradation of Rhodamine (RhB) and methylene blue (MB) solutions, and the stabilities of photo-catalysts were also studied through the three cycles of experiments. The effects on photo-catalytic performance from the initial pH values (3–9) of RhB and MB solutions were also investigated, indicating the samples present the optimal catalytic property at pH = 5.
Facile synthesis and photocatalytic activity of Ag3PO4 decorated MoS2 nanoflakes on carbon fiber cloth
Highlights: • A novel CC@MoS{sub 2}-Ag{sub 3}PO{sub 4} heterostructure is fabricated by a facile method. • The growth process of CC@MoS{sub 2} is investigated. • The heterostructure displays an excellent photocatalytic property. • Cyclic Voltammetry is utilized to investigate the photocatalytic mechanism. - Abstract: A novel CC@MoS{sub 2}-Ag{sub 3}PO{sub 4} heterostructure, composed of Ag{sub 3}PO{sub 4} nanoparticles decorated MoS{sub 2} nanosheets on carbon fiber cloth (CC), is fabricated by a simple hydrothermal method and a successive ionic layer absorption reaction. The CC@MoS{sub 2}-Ag{sub 3}PO{sub 4} heterostructure displays an excellent photocatalytic activity of ∼96% degradation rate for RhB solution under simulated daylight, which is more than 10 times as much as that of pure Ag{sub 3}PO{sub 4} or MoS{sub 2}. The CC@MoS{sub 2}-Ag{sub 3}PO{sub 4} heterostructure with optimized photoactivity is investigated by optical and electrochemical measurements. The CC@MoS{sub 2}-Ag{sub 3}PO{sub 4} heterostructure can not only broaden the photoresponse range of MoS{sub 2}, but also alleviate the photodegradation of Ag{sub 3}PO{sub 4}, and the easily separated CC provides a proper conductive substrate and rapid charge transfer channels. The probable photocatalytic mechanism of CC@MoS{sub 2}-Ag{sub 3}PO{sub 4} heterostructure is discussed in detail. Therefore, the CC@MoS{sub 2}-Ag{sub 3}PO{sub 4} heterostructure with high efficient photocatalytic performance and easy separation is a promising photocatalytic material.
Hierarchically MoS2 nanospheres assembled from nanosheets for superior CO gas-sensing properties
Highlights: • Preparation of 3D Hierarchical large surface area MoS{sub 2} nanospheres from nansheets. • The efficient enhanced gas-sensing response of 92.6 at 500 ppm for CO at 230 °C. • Higher selectivity towards CO than other gases at different temperature ranges. - Abstract: Hierarchical three dimensional MoS{sub 2}nanostructures composed of small sheet-like nanostructures are successfully prepared using a simple two-step hydrothermal process with sodium dodecyl sulfate (SDS), as a surface modifier. The as-preparedMoS{sub 2}nanospheres are characterized by XRD, BET, XPS, EDS, SEM and HRTEM. The gas–sensing properties of as–prepared MoS{sub 2}nanostructures are tested at 175–230 °C temperatures for 50–500 ppm concentration range, using an efficient ceramic-tube sensor system via an intelligent gas testing system. A high response and selectivity towards carbon monoxide than other gases is observed. Comparative studies of MoS{sub 2}nanostructures for different concentration of carbon monoxide gas and definite sensor-stability for different gases are studied, as well. The sensor fabrication and sensing mechanism is discussed as well.
The band structure and photocatalytic mechanism of MoS2-modified C3N4 photocatalysts with improved visible photocatalytic activity
Highlights: • A series of MoS{sub 2}/g-C{sub 3}N{sub 4} photocatalyst were prepared by water exfoliation method. • The heterojunction enhanced the visible response and separated charge carriers. • The MoS{sub 2}/g-C{sub 3}N{sub 4} exhibits enhanced visible photocatalytic activity. - Abstract: A series of MoS{sub 2}/g-C{sub 3}N{sub 4} photocatalysts were prepared by modifying g-C{sub 3}N{sub 4} with different concentration of MoS{sub 2} via a water exfoliation method. The crystal structure, morphology, band structure of heterojunction, behaviors of charge carries and the redox ability were characterized by XRD, HR-TEM, absorption spectra, XPS, PL, cyclic voltammetry curves and transient photocurrent spectra. It is revealed that the introduction of MoS{sub 2} on the surface of g-C{sub 3}N{sub 4} nanosheets to form micro-heterojunction could enhance the visible response and separate photogenerated charge carriers effectively. Moreover, the ability of the photocatalyst for generating reactive oxygen species (ROS, such as O{sub 2}{sup −} and OH) was also investigated. Therefore, MoS{sub 2}/g-C{sub 3}N{sub 4} samples exhibit better photocatalytic performance for the photodegradation of HCHO than g-C{sub 3}N{sub 4} and MoS{sub 2} under visible irradiation.
Anomalous Raman and photoluminescence blue shift in mono- and a few layered pulsed laser deposited MoS2 thin films
Highlights: • Mono- and a few layered MoS{sub 2} films deposited using pulsed laser deposition technique by varying the deposition time. • The films experienced an epitaxial compression due to its adhesion with the substrate. • Lattice strain of the films led to a significant Raman frequency shift. • An anomalous PL peak was observed which is attributed to quantum confinement. - Abstract: We report on the Raman blue shift of layered MoS{sub 2} films as well as an anomalous blue shift of the photoluminescence spectra of nanocrystallite MoS{sub 2} films grown by pulsed laser deposition. Monolayer, bilayer and trilayer MoS{sub 2} films were fabricated by ablating MoS{sub 2} target for a deposition time of around 14, 24 and 30 s at a laser fluence of 2.2 Jcm{sup −2}. The two Raman active modes showed lattice strain-induced blue shift of 1–3 cm{sup −1}. The layered films showed an out-of-plane compressive strain as well as an in-plane tensile strain confirmed by Riet-Veld refinement of the X-ray diffraction pattern. TEM image of the MoS{sub 2} film for 14 s demonstrated the presence of nanocrystallites of an average size of 13 nm along with the layered film of MoS{sub 2}. An anomalous photoluminescence peak was observed corresponding to the MoS{sub 2} nanocrystallites at 2.18 eV, attributed to quantum confinement effect.
Fabrication of MoS2@SnO2-SnS2 composites and their applications as anodes for lithium ion batteries
Highlights: • The MoS{sub 2}@SnO{sub 2}-SnS{sub 2} composites were successfully fabricated. • The composites show long-term cycling performance used as anode for LIBs. • The superior performance ascribes to the synergistic effect between MoS{sub 2} and SnO{sub 2}. - Abstract: Sn-based anode for lithium-ion batteries (LIBs) has been received extensive concern, due to its high theoretical specific capacity. However, its poor stability induced by serious volume changes during charge/discharge process limits its application. MoS{sub 2} possesses a 2-dimisional (2D) graphene-like layered structure facilitates lithium ions insertion and extraction and can be served as the buffer to alleviate the volume variation. Unfortunately, 2D MoS{sub 2} nanosheets are highly susceptible to stacking/restacking during cycles, which is fatal to their capacity retention. Herein, a novel MoS{sub 2}@SnO{sub 2}-SnS{sub 2} composite has been designed and fabricated via a two-step simple hydrothermal route. Due to the synergistic effect between the ultrathin MoS{sub 2} nanosheets and the SnO{sub 2}-SnS{sub 2} nanosheets, the MoS{sub 2}@SnO{sub 2}-SnS{sub 2} composite exhibits excellent electrochemical performance as anode for LIBs.
Heterogeneous MoS2-GO membranes with enhanced resistance to swelling and restacking
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Optical and electronic property tailoring by MoS2-polymer hybrid solar cell
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