MoS2

In this study, an electrochemical sensor based on MoS2 with enhanced electrochemical signals from electrochemically activated carbon cloth (EACC) electrodes and cross-linked o-aminothiophenol functionalized AuNPs (o-ATP@AuNPs) was developed for the detection of the unsaturated vegetable oil antioxidant tert-butylhydroquinone (TBHQ). In this approach, carbon cloth is activated through the implementation of electrochemical methods, thereby effectively increasing its specific surface area. The resulting EACC, serving as an electrode substrate, enables the growth of additional nanomaterials and enhances conductivity...

Molybdenum disulfide (MoS2 )-based materials for piezocatalysis are unsatisfactory due to their low actual piezoelectric coefficient and poor electrical conductivity. Herein, 1T/3R phase MoS2 grown in situ on multiwalled carbon nanotubes (MWCNTs) was proposed. MoS2 @MWCNTs exhibited the interwoven morphology of thin nanoflowers and tubes, and the piezoelectric response of MoS2 @MWCNTs was 4.07 times higher than that of MoS2 via piezoresponse force microscopy (PFM) characterization. MoS2 @MWCNTs exhibited superior activity with a 91% degradation rate of norfloxacin (NOR) after actually working 24 min (as for rhodamine B, reached 100% within 18 min) by pulse-mode ultrasonic vibration-triggered piezocatalysis...

Antibiotic abuse, particularly the excessive use of tetracycline (TC), a drug with significant environmental risk, has gravely harmed natural water bodies and even posed danger to human health. In this study, a three-dimensional self-supported MoS2 /MXene nanohybrid with an expanded layer spacing was synthesized via a facile one-step hydrothermal method and used to activate peroxydisulfate (PDS) for the complete degradation of TC. The results showed that a stronger •OH signal was detected in the aqueous solution containing MoS2 /MXene, demonstrating a superior PDS activation effect compared to MoS2 or Ti3 C2 TX MXene alone...

Valleytronics, i.e., the manipulation of the valley degree of freedom, offers a promising path for energy-efficient electronics. One of the key milestones in this field is the room-temperature manipulation of the valley information in thick-layered material. Using scanning photocurrent microscopy, we achieve this milestone by observing a geometrically dependent circular photocurrent in a few-layer molybdenum disulfide (MoS2 ) under normal incidence. Such an observation shows that the system symmetry is lower than that of bulk MoS2 material, preserving the optical chirality-valley correspondence...

Molybdenum disulfide nanoflowers (MoS2 NFs) were prepared by hydrothermal method. The prepared MoS2 NFs was characterized by SEM, TEM, XRD, specific surface areas, Raman and XPS. The characterization results show that the flower-like spherical MoS2 is composed of many ultra-thin nanosheets with an average diameter of about 300-400 nm. MoS2 NFs also exhibits excellent absorption and high fluorescence intensity. In order to explore the biological behavior of MoS2 NFs, the interaction between MoS2 NFs and bovine serum albumin (BSA) was studied by UV-Vis absorption, fluorescence, synchronous fluorescence spectra, and cyclic voltammetry...

Conventional metal sulfide (SnS2) gas-sensitive sensing materials still have insufficient surface area and slow response/recovery times. To increase its gas-sensing performance, MoS2 nanoflower was produced hydrothermally and mechanically combined with SnS2 nanoplate. Extensive characterization results show that MoS2 was effectively integrated into SnS2. Four different concentrations of SnS2-MoS2 composites were evaluated for their NO2 gas sensitization capabilities. Among them, SnS2-15% MoS2 at 170 °C demonstrated the greatest response values to NO2, 7...

This study addresses a crucial challenge in two-dimensional (2D) material-based electronic devices-inefficient heat dissipation across the van der Waals (vdW) interface connecting the 2D material to its three-dimensional (3D) substrate. The objective is to enhance the interfacial thermal conductance (ITC) of 2D/3D heterostructures without compromising the intrinsic thermal conductivities (κ) of 2D materials. Using 2D-MoS2 /3D-GaN as an example, a novel strategy to enhance both the ITC across 2D/3D interface and κ of 2D material is proposed by introducing a controlled concentration (ρ) of vacancy defects to substrate's bottom surface...

The complex interplay between local chemistry, the solvent microenvironment, and electrified interfaces frequently present in electrocatalytic reactions has motivated the development of quantum chemical methods that can accurately model these effects. Here, we predict the thermodynamics of the nitrogen reduction reaction (NRR) at sulfur vacancies in 1T'-phase MoS2 and highlight how the realistic treatment of potential within grand canonical density functional theory (GC-DFT) seamlessly captures the multiple competing effects of applied potential on a catalyst interface interacting with solvated molecules...

The practical utilization of the hydrogen evolution reaction (HER) necessitates the creation of electrocatalysts that are both efficient and abundant in earth elements, capable of operating effectively within a wide pH range. However, this objective continues to present itself as an arduous obstacle. In this research, we propose the incorporation of sulfur vacancies in a novel heterojunction formed by MoS2 @CoS2 , designed to exhibit remarkable catalytic performances. This efficacy is attributed to the advantageous combination of the low work function and space charge zone at the interface between MoS2 and CoS2 in the heterojunction...

Layer-by-layer (LbL) assembly of oppositely charged materials has been widely used as an approach to make two-dimensional (2D) nanosheet-based membranes, which often involves 2D nanosheets being alternately deposited with polymer-based polyelectrolytes to obtain an electrostabilized nanosheet-polymer structure. In this study, we hypothesized that using 2D nanosheets with matching physical properties as both polyanions and polycations may result in a more ordered nanostructure with better stability than a nanosheet-polymer structure...

In this work, we investigate trion dynamics occurring at the heterojunction between organometallic molecules and a monolayer transition metal dichalcogenide (TMD) with transient electronic sum frequency generation (tr-ESFG) spectroscopy. By pumping at 2.4 eV with laser pulses, we have observed an ultrafast hole transfer, succeeded by the emergence of charge-transfer trions. This observation is facilitated by the cancellation of ground state bleach and stimulated emission signals due to their opposite phases, making tr-ESFG especially sensitive to the trion formation dynamics...

Composite materials can take advantages of the functional benefits of multiple pure nanomaterials to a greater degree than single nanomaterials alone. The UCNPs-MoS2 composite is a nano-application platform that combines upconversion luminescence and photothermal properties. Upconversion nanoparticles (UCNPs) are inorganic nanomaterials with long-wavelength excitation and short-wavelength tunable emission capabilities, and are able to effectively convert near-infrared (NIR) light into visible light for increased photostability...

Engineering symmetry breaking in thermoelectric materials holds promise for achieving an optimal thermoelectric efficiency. van der Waals (vdW) layered transition metal dichalcogenides (TMDCs) provide critical opportunities for manipulating the intrinsic symmetry through in-plane symmetry breaking interlayer twists and out-of-plane symmetry breaking heterostructures. Herein, the symmetry-dependent thermoelectric properties of MoS2 and MoSe2 obtained via first-principles calculations are reported, yielding an advanced ZT of 2...

The selective electrocatalytic reduction of nitrobenzene (NB) to aniline demands a desirable cathodic catalyst to overcome the challenges of the competing hydrogen evolution reaction (HER), a higher overpotential, and a lower selectivity. Here, we deposit Co-doped 1T MoS2 on Ti mesh by the solvothermal method with different doping percentages of Co as x % Co-MoS2 (where x = 3, 5, 8, 10, and 12%). Because of the lowest overpotential, lower charge-transfer resistance, strong suppression of the competing HER, and higher electrochemical surface area, 8% Co-MoS2 achieves 94% selectivity of aniline with 54% faradaic efficiency...

Two-dimensional electronic materials are a promising candidate for beyond-silicon electronics due to their favorable size scaling of electronic performance. However, a major challenge is the heterogeneous integration of 2D materials with CMOS processes while maintaining their excellent properties. In particular, there is a knowledge gap in how thin film deposition and processes interact with 2D materials to alter their strain and doping, both of which have a drastic impact on device properties. In this study, we demonstrate how to utilize process-induced strain, a common technique extensively applied in the semiconductor industry, to enhance the carrier mobility in 2D material transistors...

Magnesium-ion batteries (MIBs) and dual-salt magnesium/lithium-ion batteries (MLIBs) have emerged as promising contenders for next-generation energy storage. In contrast to lithium metal anode in lithium metal batteries, magnesium metal anode in MIBs and MLIBs presents a safer alternative due to the limited dendrite growth and higher volumetric capacity, along with higher natural abundance. This study explores a MLIB configuration with a novel cathode design by employing a 2D/2D nanocomposite of 1T/2H mixed phase MoS2 and delaminated Ti3 C2 Tx MXene (1T/2H-MoS2 @MXene) to address challenges associated with slow kinetics of magnesium ions during cathode interactions...

Transition-metal dichalcogenides (TMDCs), including MoS2 , have great potential in electronics applications. However, achieving low-resistance metal contacts is a challenge that impacts their performance in nanodevices due to strong Fermi-level pinning and the presence of a tunnelling barrier. As a solution, we explore a strategy of inserting monolayers of alkaline-earth sub-pnictide electrenes with a general formula of [M2 X]+ e- (M = Ca, Sr, Ba; X = N, P, As, Sb) between the TMDC and the metal. These electrenes possess two-dimensional sheets of charge on their surfaces that can be readily donated when interfaced with a TMDC semiconductor, thereby lowering its conduction band below the Fermi level and eliminating the Schottky and tunnelling barriers...

The intrinsic anisotropy of NbSe2 provides a favorable prerequisite of second harmonic generation (SHG) and rich possibilities for tailoring its nonlinear optical (NLO) properties. Here we report the highly efficient SHG of mechanically exfoliated NbSe2 flakes. The nonlinear optical response changes with excitation wavelengths, layer thicknesses, and polarizations of the excitation laser. The anisotropic SHG response further exhibits the intrinsic non-centrosymmetric crystal structure and could effectively assign the crystalline orientation of NbSe2 flakes...

It is well known that the bandgap of 2D transition metal dichalcogenides (TMDs) in the quantum confinement regime increases with a decrease in the number of layers. In this work, we show the effect of lattice strain on the dependence of the gap. We have designed an ideal system in the form of common-cationic alloyed-TMDs, Mo(S1- x Se x )2 , for such studies. With a large difference between the ionic radii of the two chalcogens, the nanoflakes of the alloys possessed a lattice strain and have been found to yield a lower bandgap than those of both the end-members, MoS2 and MoSe2 ...

Molybdenum disulfide is an emerging 2D material with several potential applications in medicine. Therefore, it is crucial to ascertain its biocompatibility. Mast cells are immune cells that are found in many organs and tissues in contact with the extracellular environment, and can be cultured from progenitor cells present in the bone marrow. Given the long period required for differentiation and proliferation of primary mast cells, human mast cell lines have emerged as a tractable model for biological and toxicological studies...