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Controllable synthesis of P-doped MoS2 nanopetals decorated N-doped hollow carbon spheres towards enhanced hydrogen evolution
摘要： In order to construct the molybdenum disulfide (MoS2) hybrid nanostructure with enhanced conductivity and more active sites towards electrocatalytic hydrogen evolution reaction (HER), hierarchical P-doped MoS2 nanopetals decorated N-doped hollow carbon spheres (N-C@P-MoS2) core-shell structures were synthesized via calcination and hydrothermal synthesis. N-C@P-MoS2 with optimized loadings exhibited favorable HER activities with low onset overpotential (117 mV), small Tafel slopes (68 mV/dec), and fine stability compared with pure MoS2 nanosheets and all undoped samples. This is largely ascribed to the synergy of MoS2 and carbon in the rational hierarchical structures, as well as the modified electronic structure with improved conductivity, increased active sites by virtue of N and P doping. Furthermore, P-doped MoS2 nanosheets were encapsulated in carbon spheres (N-C/P-MoS2 (inside)) by controlling the dropping rate of adding MoS2 precursors. As the active sites were hampered, it is found that the N-C/P-MoS2 (inside) revealed poor HER performance compared with the core-shell counterparts. The results demonstrate that the fabrication of hierarchical MoS2/carbon composites with the synergy of structural (morphology and content) and electronic (active sites and conductivity) effects induced by various nonmetal doping pave the way for enhanced electrocatalytic HER activities.
关键词： Hollow carbon sphere,structural and electronic effect,Nonmetal doping,Hydrogen evolution reaction,Molybdenum disulfide
更新于2025-09-10 09:29:36
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MoS <sub/>2</sub> Nanoflowers as a Gateway for Solar-Driven CO <sub/>2</sub> Photoreduction
摘要： The layering of transition metal dichalcogenides (TMD) has revealed unprecedented engineering opportunities for optoelectronics, field emitter and photocatalysis applications. Precise and controlled intrinsic material property combinations is the crucial demand needed for visible light photocatalysis optimization, which we demonstrate in this work with MoS2 nanoflowers containing abundant edge plane flakes for CO2 photoreduction optimization. This is the first time controlled imperfections and flake thickness through facile CVD synthesis was demonstrated on the nanoflowers, revealing the tuning ability of flake edge morphology, nanoflower size, stacked-sheet thickness, optical band gap energy (Eg) and catalytic function. These influences facilitated Eg tuning from 1.38 to 1.83 eV and the manifestation of the 3R phase prompting improvement to the catalytic behavior. The ‘sweet spot’ of higher catalytic activity during photoreduction experiments was found in those with plentiful nanoflower density and thick edge-site abundance. Ample edge-sites with dangling bonds, and crystal impurities assisted in lowering the Eg to achieve reduced recombination for improved photocatalytic reactions, including those found on what would have been a typical chemically inert basal plane. The production rates of CO improved two-fold after a calculated post-treatment reduction step. This reliable CVD technique for nanoflower synthesis paves the way for enhanced understating of synthetic parameters for defect-laden 2D TMD nanoflower structures. We also note that photocatalysis should consider Mars applications, as deep space humans exploration will be require harvesting of the CO2 rich atmosphere to generate fuel from sustainable resources, such as the sun.
关键词： molybdenum disulfide,band gap tuning,visible light catalyst,transition metal dichalcogenide
更新于2025-09-10 09:29:36
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Molybdenum Disulfid: Differentiating Polymorphs in Molybdenum Disulfide via Electron Microscopy (Adv. Mater. 47/2018)
摘要： The presence of rich polymorphs and stacking polytypes in molybdenum disulfide (MoS2) endows it with a diverse range of properties. This has stimulated a lot of interest in the unique properties associated with each polymorph. In article number 1802397, Kian Ping Loh and co-workers discuss the use of electron microscopy for identifying the atomic structures of several important polymorphs in MoS2 and establishing the correlation between structure and properties.
关键词： polymorphs,electron microscopy,stacking polytypes,molybdenum disulfide,MoS2
更新于2025-09-09 09:28:46
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Stable Mesoporous Silica Nanoparticles Incorporated with MoS2 and AIE for Targeted Fluorescence Imaging and Photothermal Therapy of Cancer Cells
摘要： Theranostics for imaging-guided cancer treatment have obtained great attention in recent years for their outstanding capability of both tumor diagnosis and treatment. Molybdenum disulfide (MoS2) nanosheets revealed excellent photothermal conversion efficiency, which could be used as photothermal agents. However, MoS2 nanosheets would often quench or decrease the emission of fluorescence dyes when they were incorporated with these dyes to construct fluorescence-imaging-guided nanotheranostic systems. In this work, MoS2 nanosheets were embedded into mesoporous silica nanoparticles (MSNs), and Aggregation Induced Emission (AIE) fluorogen PhENH2 was chemically modified on the surface of MSNs, which could demonstrate more stable fluorescence emission compared with other MSNs with physically absorbed luminescent molecules. Moreover, folic acid (FA) was also chemically decorated on the nanoparticles to facilitate their targeted bioimaging and photothermal therapy. As expected, the obtained PhENH2-MoS2-FA MSNs could be efficiently taken up by MDA-MB-231 cells than HepG2 cells, owing to the over-expressed FA receptors on MDA-MB-231 cells. Meanwhile, these MDA-MB-231 cells could be efficiently killed under an 808 nm laser irradiation. These results indicated that the achieved multifunctional MSNs chemically decorated with AIE fluorogens would demonstrate more stable fluorescence for bioimaging-targeted photothermal therapy of MDA-MB-231 cells, which made them promising nanotheranostics for further cancer treatment.
关键词： Photothermal Therapy,Molybdenum Disulfide,Targeted Fluorescence Imaging,Aggregation Induction Emission,Stability
更新于2025-09-09 09:28:46
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Effects of Strategically Placed Water Droplets on Monolayer Growth of Molybdenum Disulfide
摘要： Two-dimensional (2D) molybdenum disulfide (MoS2) films with a tunable bandgap hold great promise for next-generation electronic and optoelectronic devices. Synthesis of large areas of high-quality MoS2 monolayers lacks experimental reproducibility. Moreover, the outcome of MoS2 growth by chemical vapor deposition is dependent on several interconnected growth parameters. In this study, we present results of MoS2 monolayer growth by strategically placing water droplets on the growth substrate and/or in the source prior to its loading in the growth chamber. The volume and distribution of water on the growth substrate and in the source had a direct impact on the morphology of the as-grown MoS2. Characterized by scanning electron microscopy (SEM), Raman microscopy, and atomic force microscopy (AFM), the number and size of MoS2 layers as well as its distribution on the growth substrate were found to have a strong dependence on the positioning of the water droplet. This study on MoS2 monolayer growth using water droplets as a promoter provides a simple and reproducible experimental technique enabling growth with high reliability.
关键词： molybdenum disulfide,water droplets,Raman microscopy,scanning electron microscopy,chemical vapor deposition,atomic force microscopy,monolayer growth
更新于2025-09-09 09:28:46
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Sensitivity enhancement of SPR optical biosensor based on Graphene–MoS2 structure with nanocomposite layer
摘要： The optical plasmonic biosensors are an important research item in the field of bio-photonics. The graphene-molybdenum disulfide (MoS2) based hybrid structures are very useful in designing and fabrication of the high sensitive biosensors. In this paper, we designed hetero-structured Air/MoS2/Nanocomposite/MoS2/Graphene as an optical biosensor with high sensitivity. The proposed configuration for this Surface Plasmon Resonance (SPR) biosensor is Otto configuration. Herein, the enhancement sensitivity of this proposed SPR biosensor is investigated in different arrangement of layers. The influence of the refractive index of the coupling prism, the thickness of the nanocomposite layer, the constituent components of the nanocomposite layer and the number of the MoS2 layer is investigated and the optimal values is calculated for the biosensor with maximum sensitivity. The maximum sensitivity ～200°/RIU is achieved with six layers of MoS2 layer and a nanocomposite layer containing the gold nanoparticles and TiO2 as host dielectric.
关键词： Sensitivity,Biosensor,Nanocomposite,Graphene,Surface plasmon resonance,Molybdenum disulfide
更新于2025-09-09 09:28:46
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Rubbing-Induced Site-Selective Growth (RISS) of MoS2 Device Patterns
摘要： The superior electronic and mechanical properties of 2D-layered transition metal dichalcogenides could be exploited to make a broad range of devices with attractive functionalities. However, the nanofabrication of such layered-material-based devices still needs resist-based lithography and plasma etching processes for patterning layered materials into functional device features. Such patterning processes lead to unavoidable contaminations, to which the transport characteristics of atomically-thin layered materials are very sensitive. More seriously, such lithography-introduced contaminants cannot be safely eliminated by conventional semiconductor cleaning approaches. This challenge seriously retards the manufacturing of large arrays of layered-material-based devices with consistent characteristics. Towards addressing this challenge, we introduce a rubbing-induced site-selective growth method capable of directly generating few-layer MoS2 device patterns without need of any additional patterning processes. This method consists of two critical steps: (i) a damage-free mechanical rubbing process for generating microscale triboelectric charge patterns on a dielectric surface, and (ii) site-selective deposition of MoS2 within rubbing-induced charge patterns. Our microscopy characterizations in combination with finite element analysis indicate that the field magnitude distribution within triboelectric charge patterns determines the morphologies of grown MoS2 patterns. In addition, the MoS2 line patterns produced by the presented method have been implemented for making arrays of working transistors and memristors. These devices exhibit a high yield and a good uniformity in their electronic properties over large areas. The presented method could be further developed into a cost-efficient nanomanufacturing approach for producing functional device patterns based on various layered materials.
关键词： field effect transistor,molybdenum disulfide,nanofabrication,nanomanufacturing,memristor,chemical vapor deposition
更新于2025-09-09 09:28:46
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A Highly Efficient Au-MoS2 Nanocatalyst for Tunable Piezocatalytic and Photocatalytic Water Disinfection
摘要： Clean water is essential in our daily life. However, nearly one billion people are forced to drink water contaminated with bacteria, leading to diarrhea, dehydration, and even death. Previously, various photocatalysts have been applied to replace high-cost and highly toxic methods for sewage treatment. Nevertheless, the requirement of external light sources limits their application. Herein, we develop a new type of nanocatalyst based on single- and few-layered molybdenum disulfide (MoS2) nanosheets (NSs) that can catalyze the generation of reactive oxygen species (ROS) to inactivate bacteria either through a piezoelectric effect (mechanical vibration) or photocatalytic effect (light irradiation). After 60 minutes of mechanical vibration or visible-light irradiation, the MoS2 NSs can reduce Escherichia coli (E. Coli) by 99.999%. In addition, the ROS generation efficiency and bacterial disinfection performance of the catalyst can be enhanced by depositing Au nanoparticles (NPs) on MoS2 NSs. The period of mechanical vibration or visible-light irradiation that achieves the same 99.999% reduction in E. coli is shortened to 45 minutes. Moreover, a hybridization of the piezoelectric and photocatalytic effects results in a performance superior to that obtained with the individual effects. A 99.999% reduction in E. coli is also accomplished within 15 minutes through a combination of mechanical vibration and near-infrared (NIR)-light irradiation. This MoS2 nanocatalyst is a promising candidate for nextgeneration water purification systems because of its ability to be triggered by diverse environmental stimuli.
关键词： photocatalytic effect,nanosheets,Molybdenum disulfide,piezocatalytic effect,reactive oxygen species,bacterial disinfection
更新于2025-09-09 09:28:46
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Low-Temperature Process for Direct Formation of MoS2 Thin Films on Soda-Lime Glass Substrates
摘要： To obtain molybdenum disulfide (MoS2) patterns without any mechanical problems caused by the transfer process, direct current (DC) sputtering and rapid thermal processing (RTP) were used to form MoS2 instead of the conventional chemical vapor deposition (CVD) process. To form MoS2 on a soda-lime glass substrate at temperatures below 600 °C, MoS2 films were deposited at various DC sputtering powers and annealed at various temperatures from 400 °C to 550 °C. From the scanning electron microscope (SEM) and atomic force microscope (AFM) results, the surface morphologies of the MoS2 films can be observed, depending on the sputtering power and the film thickness. The Raman spectrum results showed that the E1 2g and A1 g mode peaks appeared at approximately 372 cm?1 and 400 cm?1, respectively, and the MoS2 surface was crystallized in the in-plane direction. The X-ray photoelectron spectroscopy (XPS) results showed noticeable S 2p (2p 1/2, 2p 3/2) peaks and Mo 3d (3d 3/2, 3d 5/2) peaks at stable binding energies after RTP at temperatures below 600 °C. The high mobilities and carrier densities of all the MoS2 films can be investigated from the Hall measurements.
关键词： DC Sputtering,Low Temperature,Molybdenum Disulfide (MoS2),Rapid Thermal Processing (RTP),Soda-Lime Glass
更新于2025-09-04 15:30:14
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Centimeter-Scale Nanoporous 2D Membranes and Ion Transport: Porous MoS2 Monolayers in a Few-Layer Matrix
摘要： Two-dimensional nanoporous membranes have received attention as catalysts for energy generation and membranes for liquid and gas purification but controlling their porosity and facilitating large-scale production is challenging. We show the growth and fabrication of cm-scale molybdenum disulfide (MoS2) membranes with tunable porous areas up to ~ 10% of the membrane and average nanopore diameters as large as ~ 30 nm, controlled by the etch time. We also measure ionic conductance between 0.1 and 16 μS per μm2 through variably-etched nanoporous membranes. Ensuring the mechanical robustness and large-area of the membrane, bilayer and few-layer regions form a strong supporting matrix around monolayer regions, observed by aberration-corrected scanning transmission electron microscopy. During etching, nanopores form in thin, primarily monolayer areas while thicker multi-layer regions remain essentially intact. Atomic-resolution imaging reveals that after exposure to the etchant, the number of V1Mo vacancies increases and nanopores form along grain boundaries in monolayers, suggesting that etching starts at intrinsic defect sites. This work provides an avenue for scalable production of nanoporous atomically thin membranes.
关键词： Transition metal dichalcogenides,molybdenum disulfide,nanoporous atomically thin membranes,defects,PAN etchant,nanopore
更新于2025-09-04 15:30:14