Two-dimensional (2D) molybdenum disulfide (MoS₂) nanomaterials are an emerging class of biomaterials that are photoresponsive at near-infrared wavelengths (NIR). Here, we demonstrate the ability of ...2D MoS₂ to modulate cellular functions of human stem cells through photothermal mechanisms. The interaction of MoS₂ and NIR stimulation of MoS₂ with human stem cells is investigated using whole-transcriptome sequencing (RNA-seq). Global gene expression profile of stem cells reveals significant influence of MoS₂ and NIR stimulation of MoS₂ on integrins, cellular migration, and wound healing. The combination of MoS₂ and NIR light may provide new approaches to regulate and direct these cellular functions for the purposes of regenerative medicine as well as cancer therapy.
The replacement of platinum with non‐precious‐metal electrocatalysts with high efficiency and superior stability for the hydrogen‐evolution reaction (HER) remains a great challenge. Herein, we report ...the one‐step synthesis of uniform, ultrafine molybdenum carbide (Mo2C) nanoparticles (NPs) within a carbon matrix from inexpensive starting materials (dicyanamide and ammonium molybdate). The optimized catalyst consisting of Mo2C NPs with sizes lower than 3 nm encapsulated by ultrathin graphene shells (ca. 1–3 layers) showed superior HER activity in acidic media, with a very low onset potential of −6 mV, a small Tafel slope of 41 mV dec−1, and a large exchange current density of 0.179 mA cm−2, as well as good stability during operation for 12 h. These excellent properties are similar to those of state‐of‐the‐art 20 % Pt/C and make the catalyst one of the most active acid‐stable electrocatalysts ever reported for HER.
A step is all it takes: A nanocomposite of uniform, ultrafine Mo2C nanoparticles (NPs) encapsulated by ultrathin graphene shells was synthesized simply by the one‐step annealing of a mixture of low‐cost dicyanamide and ammonium molybdate (see picture). The resulting material served as a hydrogen‐evolving electrocatalyst with excellent activity and long‐term stability.
Molybdenum disulfide (MoS2) is prepared by a facile sulfidation method using molybdenum-based metal-organic framework (Mo-MOF) as sacrificial templates at different temperatures (300 °C, 400 °C, ...600 °C and 800 °C). The as-prepared MoS2 has a high reversible specific capacity for sodium-ion batteries (SIBs). Among that four samples, the anode material MoS2 synthesized at 400 °C has a stable structure and the superior electrochemical performance. The average discharge capacities of the MoS2/C-400 °C electrode are 910, 810, 670, 620 and 535 mAh g−1 at different current densities of 0.1, 0.2, 0.5, 1.0 and 2.0 A g−1, respectively. Remarkably, when the current density returns to 0.1A g−1, the reversible capacity still can maintain at 870 mAh g−1. Moreover, even at a large current density of 0.5A g−1, the specific capacity of MoS2/C-400 °C electrode also can retain at about 500 mAh g−1 after 150 cycles.
Here, two-dimensional molybdenum disulfide (2D-MoS.sub.2) nanosheets were efficiently extracted from dispersions by precipitation method and then directly applied as co-catalyst for enhancing Fenton ...reactions. The 2D-MoS.sub.2 nanosheets were completely extracted in a short time, while surfactant was left in dispersion. The average length and layer number of extracted 2D-MoS.sub.2 nanosheets are 110.41 nm and 2.6, respectively. Due to the loose structure and a small amount of adsorbed surfactant, the extracted 2D-MoS.sub.2 nanosheets exhibited excellent dispersibility in various solvents. The 2D-MoS.sub.2 nanosheets as co-catalyst promoted greatly the production rate of reactive hydroxyl radicals (·OH) and thus decreased remarkably the dosage of ferrous salts and H.sub.2O.sub.2. The co-catalytic property of 2D-MoS.sub.2 nanosheets is much better than that of commercial bulk MoS.sub.2 because 2D-MoS.sub.2 provides abundant active edge sites. This work not only demonstrated a scalable and efficient method for extracting 2D-MoS.sub.2 nanosheets from dispersions, but also widened the applications areas of 2D-MoS.sub.2 and provided an excellent co-catalyst for Fenton reactions.
Abstract
Rational design of the catalysts is impressive for sustainable energy conversion. However, there is a grand challenge to engineer active sites at the interface. Herein, hierarchical ...transition bimetal oxides/sulfides heterostructure arrays interacting two-dimensional MoO
x
/MoS
2
nanosheets attached to one-dimensional NiO
x
/Ni
3
S
2
nanorods were fabricated by oxidation/hydrogenation-induced surface reconfiguration strategy. The NiMoO
x
/NiMoS heterostructure array exhibits the overpotentials of 38 mV for hydrogen evolution and 186 mV for oxygen evolution at 10 mA cm
−2
, even surviving at a large current density of 500 mA cm
−2
with long-term stability. Due to optimized adsorption energies and accelerated water splitting kinetics by theory calculations, the assembled two-electrode cell delivers the industrially relevant current densities of 500 and 1000 mA cm
−2
at record low cell voltages of 1.60 and 1.66 V with excellent durability. This research provides a promising avenue to enhance the electrocatalytic performance of the catalysts by engineering interfacial active sites toward large-scale water splitting.
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► Biosynthesis of the pterin-based molybdenum cofactor involves four steps. ► Six proteins catalyze pyranopterin synthesis, sulfur transfer and metal insertion. ► Iron, S-adenosyl ...methionine, ATP, cysteine and probably copper are needed. ► Moco is distributed by specific carrier/binding proteins to apo-enzymes. ► Moco deficiency is a severe neurodegenerative disorder; a first therapy is available.
The transition element molybdenum (Mo) needs to be complexed by a special cofactor in order to gain catalytic activity. With the exception of bacterial Mo-nitrogenase, where Mo is a constituent of the FeMo-cofactor, Mo is bound to a pterin, thus forming the molybdenum cofactor Moco, which in different variants is the active compound at the catalytic site of all other Mo-containing enzymes. The biosynthesis of Moco involves the complex interaction of six proteins and is a process of four steps, which also requires reducing equivalents, iron, ATP and probably copper. After its synthesis, Moco is distributed to the apoproteins of Mo-enzymes by Moco–carrier/binding proteins that also participate in Moco-insertion into the cognate apoproteins. A deficiency in the biosynthesis of Moco has lethal consequences for the respective organisms. In humans, Moco deficiency is a severe inherited inborn error in metabolism resulting in severe neurodegeneration in newborns and causing early childhood death. Due to our better understanding of the chemistry of Moco synthesis, a first therapy has been brought to the clinic.
•A turn on fluorescent biosensor based on molybdenum disulfide nanosheets and aptamer was developed for CEA detection.•MoS2 nanosheets with high quenching efficiency and well discrimination ability ...afforded the biosensor easy construction and high sensitivity.•The present sensing platform exhibited rapid response and high selectivity for CEA with good reproducibility.•The fabricated biosensor showed a broad detection range of 100 pg/mL-100 ng/mL and low detection limit of 34 pg/mL.
Simple, rapid, sensitive detection of tumor biomarker carcinoembryonic antigen (CEA) is of great importance for the screening, diagnosis and prognosis evaluation of various gastroenteric tumor. This paper presents a “turn-on” fluorescent biosensor based on molybdenum disulfide (MoS2) nanosheets and fluorophore labeled protein aptamer for rapid and sensitive detection of CEA protein. CEA aptamer probe can be adsorbed on the surface of MoS2 nanosheets in close proximity via van der Waals force, triggering fluorescence resonance energy transfer, and consequently fluorescence signal of aptamer probe was quenched. While in the presence of CEA protein, the fluorescence signal was recovered because aptamer probe could detach from MoS2 nanosheets with binding-induce conformation change. MoS2 nanosheets with high quenching efficiency combined with well discrimination ability between aptamer and aptamer/protein afforded the biosensor easy construction, fast detection and high sensitivity. The sensing platform also exhibited good reproducibility, selectivity and showed high sensitivity for CEA protein in a broad range of 100 pg/mL–100 ng/mL with the detection limit of 34 pg/mL. The aptamer-MoS2 based fluorescent biosensor may be an ideal mode for protein detection in clinical sample, pesticide detection and environmental monitoring.
Moiré engineering is being intensively investigated as a method to tune the electronic, magnetic and optical properties of twisted van der Waals materials. Advances in moiré engineering stem from the ...formation of peculiar moiré superlattices at small, specific twist angles. Here we report configurable nanoscale light–matter waves—phonon polaritons—by twisting stacked α-phase molybdenum trioxide (α-MoO3) slabs over a broad range of twist angles from 0° to 90°. Our combined experimental and theoretical results reveal a variety of polariton wavefront geometries and topological transitions as a function of the twist angle. In contrast to the origin of the modified electronic band structure in moiré superlattices, the polariton twisting configuration is attributed to the electromagnetic interaction of highly anisotropic hyperbolic polaritons in stacked α-MoO3 slabs. These results indicate twisted α-MoO3 to be a promising platform for nanophotonic devices with tunable functionalities.Infrared nanoimaging of phonon polaritons in twisted α-phase molybdenum trioxide bilayers reveals tunable wavefront geometries and topological transitions over a broad range of twist angles, offering a configurable platform for nanophotonic applications.
Direct synthesis of either 2H-MoS2 or α-MoO3 is made possible by thermolysis of the same single source precursor in either argon or air at moderate temperatures.
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