TiO2 nanorods based self-supported electrode of 1T/2H MoS2 nanosheets decorated by Ag nano-particles for efficient hydrogen evolution reaction

Molybdenum disulfide (MoS₂) has shown significant promise as an economic hydrogen evolution reaction (HER) catalyst for hydrogen generation, but its catalytic performance is still lower than noble metal-based catalysists. Herein, a silver nanoparticles (Ag NPs)-decorated 1T/2H phase layered MoS₂ electrocatalyst grown on titanium dioxide nanorod arrays (Ag NPs/1T(2H) MoS₂/TNRs) was prepared through acid-tunable ammonium ion intercalation. Taking advantage of MoS₂ layered structure and crystal phase controllability, as-prepared Ag NPs/1T(2H) MoS₂/TNRs exhibited ultrahigh HER activity. As-proposed strategy combines facile hydrogen desorption (Ag NPs) with efficient hydrogen adsorption (1T/2H MoS₂) effectively circumventes the kinetic limitation of hydrogen desorption by 1T/2H MoS₂. The as-prepared Ag NPs/1T(2H) MoS₂/TNRs electrocatalyst exhibited excellent HER activity in 0.5 mol/L H₂SO₄ with low overpotential (118 mV vs. reversible hydrogen electrode (RHE)) and small Tafel slope (38.61 mV/dec). The overpotential exhibts no obvious attenuation after 10 h of constant current flow. First-principles calculation demonstrates that as-prepared 1T/2H MoS₂ exhibit a large capacity to store protons. These protons can be subsequently transferred to Ag NPs, which significantly increases the hydrogen coverage on the surface of Ag NPs in HER process and thus change the rate-determining step of HER on Ag NPs from water dissociation to hydrogen recombination. This study provides a unique strategy to improve the catalytic activity and stability for MoS₂-based electrocatalyst.     

An ultrasensitive electrochemical immunosensor for CA72-4 based on a signal amplification strategy of MoS2 nanoflower-supported Au nanoparticles

Accurate detection of cancer antigen 72-4 (CA72-4), a tumor-associated glycoprotein, is of great significance for gastric cancer diagnosis and immunotherapy monitoring. Modification of noble metal nanoparticles on transition metal dichalcogenides can significantly enhance functions, such as electron transport. Molybdenum disulfide gold nanoparticles nanocomposites (MoS₂-Au NPs) were prepared in this study and a series of characterization studies were carried out. In addition, a label-free, highly sensitive electrochemical immunosensor molybdenum disulfide -Au nanoparticles/Glassy carbon electrode (MoS₂-Au NPs/GCE) was also prepared and used for the detection of CA72-4. The electrochemical performance of the immunosensor was characterized by electrochemical techniques, such as cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). The results indicated that better MoS₂-Au NPs nanomaterials have been synthesized, and the prepared electrochemical immunosensor, MoS₂-Au NPs/GCE, showed excellent electrochemical performance. The sensor exhibited high detection sensitivity under optimal conditions, including an incubation time of 30 min, an incubation temperature of 25 °C, and a pH of 7.0. The electrochemical immunosensor also had a low detection limit of 2.0 × 10^?5 U/mL (S/N = 3) in a concentration range of 0.001–200 U/mL, with good selectivity, stability, and repeatability. In conclusion, this study provided a theoretical basis for the highly sensitive detection of tumor markers in clinical biological samples.     

Chitosan coated molybdenum sulphide nanosheet incorporated with tantalum oxide nanomaterials for improving cancer photothermal therapy

In recent years, two-dimensional nanomaterials (2D) prominent for site specific photothermal treatment (PTT), which are one of the most interesting strategy due to their maximizing cancer cell killing efficiency without the normal cells. Several robust methods are established for 2D material synthesis and improving the photothermal conversion efficiency (PCE), biocompatibility, and photostability in cancer PTT. Such preferred mechanism like nanomaterial decoration on to their surface would enable access to tunable 2D nanomaterial properties to improve cancer PTT. Here, we first time report a robust route for deposition of tantalum (TaO₂) on to chitosan (CS) coated molybdenum sulphite (MoS₂) nanosheet surface via electrostatic interaction, which assists to improve cancer PTT efficiency. Detailed studies prove that prepared TaO₂-CS-MoS₂ nanomaterial shows lack of toxicity, photostability and PCE was calculated from 26 °C to 47.2 °C under the 808 nm irradiation/5 min. Therefore, the TaO₂ deposition particularly interest to promote the photostability, biocompatibility and PCE of bare MoS₂ nanosheets. Therefore, the possible mechanism is highly expected to improve biological features in cancer PTT.     

High-performance supercapacitor electrode based on a nanocomposite of polyaniline and chemically exfoliated MoS<Subscript>2</Subscript> nanosheets

In this study, MoS₂ nanosheets were first prepared by exfoliating its bulk material in HCl/LiNO₃ solution with a yield of 45%, and then a facile strategy was developed to synthesize polyaniline/MoS₂ (PANI/MoS₂) nanocomposite via in situ polymerization. Structural and morphological characterizations of MoS₂ nanosheets and the nanocomposite were investigated by scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray powder diffraction. The results of SEM illustrated that orderly sawtooth polyaniline (PANI) nanoarrays were formed on the surface of MoS₂ nanosheets. The nanocomposite displayed good electrochemical performance as a supercapacitor electrode material. The specific capacitance reached 560 F/g at a current density of 1.0 A g^?1 in 1.0 M H₂SO₄ solution. Such good performance is because that the MoS₂ nanosheets provided a highly electrolytic accessible surface area for redox-active PANI and a direct path for electrons.     

Amelioration of human acute lymphoblastic leukemia (ALL) cells by ZnO-TiO2-Chitosan-Amygdalin nanocomposites

The present study aims to study the cytotoxicity of ZnO-TiO₂-Chitosan-Amygdalin nanocomposites (ZnO-TiO₂-Chitosan-Amygdalin) on T lymphoblast cancer cells (MOLT-4). In a study, nanocomposites containing 2.5 to 15 µg/ml MTT were screened for their anticancer activity. Its anticancer properties were significantly higher than those of other nanocomposites with an IC₅₀ value of 10.34 µg/ml. We studied the mechanism of action for cytotoxic cell death by fluorescence microscopy using Acridine Orange/EtBr (AO/EtBr) and Rhodamine 123 staining procedures. Using DCFH-DA, ZnO-TiO₂-Chitosan-Amygdalin nanocomposites were analyzed to determine ROS production. The change in apoptotic protein expression for the 24 h following treatment with MOLT-4 cells for Caspase-3, 8, and 9. Nanocomposites containing ZnO-TiO₂-Chitosan-Amygdalin increased the number of early and late apoptotic cells in MOLT-4 cells. ZnO-TiO₂-Chitosan-Amygdalin nanocomposites also enhanced mitochondrial apoptosis through Caspase cascade signaling. MOLT-4 cells phosphorylated Caspase cascade in response to ZnO-TiO₂-Chitosan-Amygdalin nanocomposites. Compared to the control group, the cancer cells treated with ZnO-TiO₂-Chitosan-Amygdalin nanocomposites significantly arrest the proliferation and induces cleavage of pro-apoptotic proteins which leads to apoptotic cell death. Accordingly, ZnO-TiO₂-Chitosan-Amygdalin nanocomposites might be effective against T lymphoblast cancer.     

<Emphasis Type="Italic">In-situ</Emphasis> TEM investigation of MoS<Subscript>2</Subscript> upon alkali metal intercalation

Phase transition in two dimensional molybdenum disulfide (MoS₂) can be induced by several methods and has been investigated for decades. Alkali metal insertion of MoS₂ had been proved an effective method to cause phase transition early in 1970s, and has been gaining renewed interest recently, due to the possible application of MoS₂ in energy storage. The alkali metal intercalation of MoS₂ has been studied by various techniques, among which in-situ transmission electron microscopy (TEM) provides unique capability of real time resolving the structural evolution of the materials at high spatial resolutions. Here by in-situ TEM technique we investigated the structural evolution of MoS₂ upon lithium and sodium intercalation, along with transformation of the nanosheet and variation of the electron diffraction patterns. The intercalation process is accompanied by emergence of superstructures, which exist in several forms. The ion intercalation results in phase transition of MoS₂ from 2H to 1T, and the driving mechanism of the phase transition are discussed. The work provides a more comprehensive understanding of ion intercalation induced phase transition of MoS₂.     

In-situ formation of 2H phase MoS2/cerium-zirconium oxide nanohybrid for potential electrochemical detection of an anticancer drug flutamide

The developing field of sensors is highly motivated and attracted by two-dimensional transition metal dichalcogenides (TMDs) with transition metal oxide integration. Initially, molybdenum disulfide (MoS₂), one among the TMDs with cerium-zirconium oxide (CZO), was one-pot synthesized via hydrothermal method for sensing flutamide (FLD). The as-synthesized hybrid nanocomposite was characterized to understand their physical and chemical presence. MoS₂-CZO was well assigned with crystalline nature observed from X-ray powder diffraction and X-ray photoelectron spectroscopy. High-resolution transmission electron microscopy confirms the irregularly arranged nanoparticles wrapped with MoS₂ sheets. The wide surface area with more electroactive sites has provided higher conductance of the MoS₂-CZO/glassy carbon electrode. The limit of detection was 0.005 μM with a linear range of 0.019 μM to 668.5 μM, sensitivity 0.353 μA μM?1 cm^?2. The practical feasibility was analyzed with human urine and river water samples, whereas the obtained results showed excellent FLD detection. The fabricated MoS₂-CZO with all these distinguished analyses will be an outbreak in the field of electrochemical sensors.     

Electrophoretically deposited L-cysteine functionalized MoS2@MWCNT nanocomposite platform: a smart approach toward highly sensitive and label-free detection of gentamicin

The exploitation of antibiotics has caused many side effects on the agriculture, environment, and human health. The existing methods have numerous shortcomings in determining gentamicin (GEN), a broad-spectrum antibiotic that causes nephrotoxicity and ototoxicity when found in excess. Here, an immunosensing platform to detect GEN using multiwalled carbon nanotubes (MWCNTs) and molybdenum disulfide (MoS₂) nanocomposite, deposited electrophoretically on indium tin oxide (ITO) glass has been developed. A novel 2-D graphene analog MoS₂@ MWCNTs nanocomposite was made via a facile and low-cost hydrothermal technique using l-cysteine to achieve remarkable electrochemical properties. Subsequently, a highly sensitive electrochemical immunosensor was fabricated by assembling monoclonal antibodies against gentamicin (anti-GEN) on a MoS₂@MWCNTs modified ITO electrode. The hetero-nanostructure formed on the immunosensor surface appeared relatively good conductor for accelerating the electron transfer. GEN was determined on anti-GEN modified electrodes by utilizing the differential pulse voltammetry technique by measuring the difference in current owing to the transfer of electrons directly between the redox species and immunoelectrodes. Under optimal experimental conditions, the fabricated immunosensor had a wide linear detection range of 1 × 10^?6–40 μg/mL, a high sensitivity of 13.55 μA (log μg/mL)^?1 and a low limit of detection and limit of quantification of 0.039 μg/mL and 0.130 μg/mL, respectively. The developed immunosensor also exhibits high reproducibility, repeatability, and good selectivity against various interferences. This electrochemical immunosensor having MoS₂ modified MWCNTs displays the excellent potential for the point-of-care device for GEN testing.     

Custom-made sulfonated poly (vinylidene fluoride-co-hexafluoropropylene) nanocomposite membranes for vanadium redox flow battery applications

Sulfonated poly (vinylidene fluoride-co-hexafluoropropylene) (SPVDF-co-HFP) based nanocomposite proton exchange membranes (PEM) are fabricated by simple solution casting method using polydopamine coated exfoliated molybdenum disulfide (PDA-MoS₂) nanosheets as an alternative for Nafion® in vanadium redox flow batteries (VRFBs). PDA-MoS₂ is synthesized by the etching of exfoliated MoS₂ nanosheets with dopamine molecule by self-polymerization method. Various characteristic results clearly demonstrated that the incorporated PDA-MoS₂ nanosheets homogeneously distributed into the SPVDF-co-HFP matrix and the presence of NH/NH₂ group electrostatically interacts with SPVDF-co-HFP to form a strong acid-base pair and thus enhances the proton transport via Grotthuss type mechanism. Besides, the improvement in surface hydrophilicity provides the vehicle type conduction also. As a result, SPVDF-co-HFP/PM nanocomposite membranes showed higher proton conductivity in comparison with the pristine membrane. Especially SPVDF-co-HFP/PM-1 membrane demonstrated the excellent proton conductivity of 5.24 × 10⁻³ Scm⁻¹ at 25 °C, lower vanadium-ion permeability of 1.05 × 10⁻⁸ cm²min⁻¹ and highest membrane selectivity of 49.9 × 10⁴ Scm⁻³min. On the other hand, vanadium-ion stability of the membrane increased by adding the PD-MoS₂ content is attributed to their strong electrostatic attraction towards the polymer matrix. Overall results suggested that the SPVDF-co-HFP/PM-1 nanocomposite membrane is found to be a better alternative for commercially costly Nafion in VRFB applications.     

5-Fluorouracil-containing inorganic iron oxide/platinum nanozymes with dual drug delivery and enzyme-like activity for the treatment of breast cancer

Intrinsic enzyme-mimic activity of inorganic nanoparticles has been widely used for nanozymatic anticancer and antibacterial treatment. However, the relatively low peroxidase-mimic activity (PMA) and catalse-mimic activity (CMA) of nanozymes in tumor microenvironment has hampered their potential application in the cancer therapy. Therefore, in this study, we aimed to fabricate platinum (Pt) nanozymes dispersed on the surface of iron oxide (Fe₃O₄) nanosphere that, in addition to boosting the PMA and CMA, resulted in the formation of a pH-sensitive nano-platform for drug delivery in breast cancer therapy. After development of Fe₃O₄ nanospheres containing Pt nanozymes and loading 5-fluorouracil (abbreviated as: Fe₃O₄/Pt-FLU@PEG nanospheres), the physicochemical properties of the nanospheres were examined by electron microscopy, dynamic light scattering, zeta potential, X-ray diffraction, thermogravimetric, BET surface, and PMA/CMA analyses. Then, the cytotoxicity of the Fe₃O₄/Pt-FLU@PEG nanospheres against 4T1 cells was investigated by the cell counting kit-8 assay and flow cytometry. Also, the anticancer effect of fabricated nanoplatform was assessed in mouse bearing 4T1 cancer tumors, in vivo. The results showed that the Fe₃O₄/Pt-FLU@PEG nanospheres provide a platform for optimal FLU loading, continuous pH-sensitive drug release, and potential PMA and CMA to increase the level of ROS and O₂, respectively. Cytotoxicity outputs showed that the Fe₃O₄/Pt-FLU@PEG nanospheres mitigate the proliferation of 4T1 cancer cells mediated by apoptosis and intracellular generation of reactive oxygen species (ROS). Furthermore, in vivo assays indicated a significant reduction in tumor size and overcoming tumor hypoxia. Overall, we believe that the developed nanospheres with dual enzyme-mimic activity and pH-sensitive drug delivery can be used for ROS/chemotherapy double-modality antitumor therapy.     

Synthesis of keratine,silver, and flavonols nanocomposites to inhibit oxidative stress in pancreatic beta-cell (INS-1) and reduce intracellular reactive oxygen species production

Flavonols (FLA) from Vaccinium macrocarpon (V. macrocarpon) were identified using high-performance liquid chromatography coupled with mass spectrometry detection. Nanoparticles were prepared using highly crosslinked keratin (KER) from human hair and silver and entrapped with flavonols [KER + FLA + AgNPs]. Nanocomposites were characterized using UV–Vis spectroscopy, transmission electron microscopy (TEM), X-ray diffraction, zeta potential, and dynamic light scattering, and release profiles. The interactions between the capping agent and the silver core have been investigated using FTIR spectroscopy·H₂O₂ is a source of Reactive Oxygen Species (ROS) and acts as an activator of oxidative stress affecting NS-1 cells, and the protective effect of the nanocomposites were evaluated against H₂O₂-induced pancreatic β-cell damage. LC-MS/MS and HPLC analyses revealed the presence of 12 flavonols in V. macrocarpon plant extract. The cell apoptosis and proliferation, were evaluated by Hoechst 33342 staining, flow cytometry and Cell Counting Kit-8 respectively. Preincubation of the NS-1 cells with 250 µg/mL of H₂O₂ induced oxidative stress conditions that show pancreatic β-cell dysfunction, including ROS, cell death, mitochondrial function, antioxidant enzymes, and lipid peroxidation. Nevertheless, pretreatment with FLA and [KER + FLA + AgNPs] prevented mitochondria disruption, maintained cellular ATP levels, inhibited LDH release, intracellular ROS production, decreased lipid peroxidation, increased expression of antioxidant enzymes (CAT, SOD, and GPx) and GSH levels. These results indicate that nanocomposites could protect rat INS-1 pancreatic β-cell from H₂O₂-induced oxidative damage, apoptosis and proliferation by reducing the production of intracellular reactive oxygen species.     

1T/2H mixed phase MoS2 in-situ grown on the surface of montmorillonite for selectively removing Pb2+

Molybdenum disulfide (MoS₂), as a kind of adsorbent, can selectively remove Pb²⁺ from water. However, agglomeration and fewer active S sites are the two factors that spoil the adsorption performance of MoS₂. In order to solve these problems, a new type of adsorbent: 1T/2H mixed-phase MoS₂ (D-MoS₂)/montmorillonite composites (D-Mt) are proposed via the one-step hydrothermal method, associated with filling cations. Among them, S defects are intentionally introduced to promote the conversion of the 2H phase in MoS₂ into 1T phase, contributing by adding an excessive amount of CH₄N₂S and using the hydrothermal method. Moreover, owing to filling with Na⁺, D-MoS₂ is uniformly dispersed driven by electrostatic force. Consequently, D-Mt has a large density of edge active sites, contributing to a greatly improved adsorption capacity with 175.57 mg/g, which can be attributed to the different growth directions of MoS₂ nanosheets and its unique defect structure as well as the inhibited masking effect on –OH that existing on the edge of montmorillonite. Additionally, the adsorption mechanism is confirmed via theoretical calculations, which suggests that there are electron transfers between O 2p, S 3p and Pb 6p, indicating that Pb²⁺ could be adsorbed via three paths, including interlayer ion exchange, –OH on the edge as well as S defects in D-Mt.     

Monolayer 1T and 1T′ MoSO as Promising Electrocatalyst for Hydrogen Evolution based on First Principle Calculations

Molybdenum disulfide (MoS₂) has been regarded as one of the most promising candidates for replacing Pt group noble metals as an efficient electrocatalyst to enhance the hydrogen evolution reaction (HER) in consideration of its relatively high earth abundance. Recent studies show that the catalytic efficiency of MoS₂ for HER can be promoted by the presence of 1T-phase MoS₂. It is hard to precisely control the formation of 1T-MoS₂, however, due to its metastability relative to 2H-MoS₂. Elevating the stability of 1T phase allotrope is therefore of great importance and could be realized by replacing divalent S with monovalent elements or groups according to crystal field theory, which has been demonstrated through our first-principles density functional theory (DFT) calculation results. Differential Gibbs free energy analysis for hydrogen adsorption (ΔG_H*) suggest that 1T and 1T′ MoSO (O doped MoS₂) might be taken as potential candidate catalysts for HER process with better performance than 1T and 1T′ MoS₂. We also propose a probable approach to synthesize 1T and 1T′ MoSO under oxidation circumstance environment of graphene oxide.     

Synthesis,growth, structure and characterization of nickel(II)-doped hexaaquacobalt(II) dipotassium tetrahydrogen tetra-o-phthalate tetrahydrate crystals

Single crystals of K₂[Co_(1−x)Ni_x(H₂O)₆] (C₈H₅O₄)₄·4H₂O (x = 0.25) (PCNHP), a semiorganic black colored transparent crystal of size ∼20 × 13 × 4 mm³, are grown from an aqueous solution of potassium hydrogen phthalate enriched with cobalt chloride and nickel chloride by slow evaporation solution growth technique at room temperature. Structural analysis by single crystal X-ray diffraction reveals that the crystal belongs to monoclinic system with space group P2₁/c and the cell parameters are a = 10.41(3) Å, b = 6.84(2) Å, c = 29.46(9) Å, Z = 4. Incorporation of both Co(II) and Ni(II) into the potassium hydrogen phthalate (KHP) crystal lattice is well confirmed by EDS and chemical tests. Powder XRD profiles indicate the crystallinity and FT-IR studies reveal the vibrational patterns. The UV–vis optical absorption spectrum of PCNHP shows the lower optical cut-off at ∼300 nm and the crystal was transparent in the entire visible region. The crystalline perfection of the grown crystal analysed by high-resolution X-ray diffraction (HRXRD) analysis reveals that the diffraction curve (DC) contains multi-peaks with low angular spread indicating the possibility of low angle structural grain boundaries. Scanning electron microscope (SEM) studies indicate the structure defect centers. The dielectric, thermal and mechanical behaviors of the specimen were also investigated.     

Green synthesis of platinum nanoparticles by Nymphaea tetragona flower extract and their skin lightening,antiaging effects

Platinum nanoparticles (PtNPs) were green synthesized by using chloroplatinic acid (H₂PtCl₆) as raw material and Nymphaea tetragona (N. tetragona) flower extract as the capping and reducing agents to improve skin health. Size-tunable PtNPs were obtained by volume ratios of the initial H₂PtCl₆/N. tetragona of 1:1 and 1:4, in which PtNPs prepared by the ratio of 1:1 and 1:4 was defined as L1-PtNPs and L4-PtNPs. Their characterizations were investigated by UV–visible spectroscopy, TEM, XRD and FTIR spectroscopy. TEM image analysis showed the particles were well dispersed with the average particle diameters of L1 and L4-PtNPs were 4.04 ± 1.31 nm and 2.01 ± 0.80 nm, respectively. The synthesized PtNPs showed effective antioxidant property and anti-tyrosinase activity in vitro. And further experiments exclaimed that PtNPs can significantly inhibit tyrosinase activity and UVB-induced melanin biosynthesis in A375 cells. This study also revealed PtNPs can promote collagen I biosynthesis in HFF-1 cells by activating the TGF-β/Smad pathway. This research showed the potential efficacy of PtNPs in the skin field and provided evidence for people to consider applying PtNPs to skin protection.     

Hierarchical MoS2/polyaniline binary hybrids with high performance for improving fire safety of epoxy resin

Here we report a facile strategy to fabricate phosphoric acid doped polyaniline/molybdenum disulfide (PANI/MoS₂) hybrids as high-performance nanofillers in epoxy (EP) resin for the first time. In situ growth of PANI on the surface of two-dimensional MoS₂ template resulted in the uniform dispersion and strong interfacial adhesion of PANI/MoS₂ hybrids within EP matrix, which can be confirmed by the obvious increase (13.5°C) in glass transition temperature (T_g) of EP composites. The MoS₂ nanosheets also acted as a critical component to generate synergistic effect with PANI on reducing the fire hazards of EP resin. It resulted in a remarkable removal of flammable decomposed products and a considerable reduction of toxic CO yield. The dramatical decreases in real-time smoke density and total smoke production, and high-graphitized char layer in condensed phase were obtained for EP composite with 5 wt% PANI/MoS₂ hybrids. The multiple synergistic effects (synergistic dispersion and synergistic char formation) are believed to be the primary source for these obvious enhancements of properties of EP composites. This facile strategy may achieve the potential application of functionalized MoS₂ in polymeric nanocomposites.     

Neodymium YAG laser chemical vapor deposition growth of luminescent Mo2S3 nanocrystals using bulk MoS2 and its structural,optical properties and caspase-mediated apoptosis in THP-1 monocytic cells

Metal-sulphur phase-based semiconductor materials are often investigated in the field of nanotechnology. Herein, we describe the synthetic route to obtain Mo₂S₃ nanocrystals from MoS₂ via a laser-furnace technique. These nanocrystals have been tested for cytotoxicity against the monocytic leukemic THP-1 cell line. The synthetic process caused a phase change from MoS₂ to Mo₂S₃ at a temperature of 1100 °C and a pressure of 400 Torr. Powder X-ray diffraction analysis confirmed the crystallinity and structure and X-ray photoelectron spectroscopy confirmed the chemical composition and oxidation states of the Mo₂S₃ nanocrystals. The morphology of the Mo₂S₃ has been observed by using field emission scanning electron microscopy and high-resolution transmission electron microscopy. The in vitro cytotoxicity evaluation of the Mo₂S₃ nanocrystals was determined in the THP-1 cell line. The cytotoxic potential of the Mo₂S₃ against THP-1 cells was assessed by the WST-1 assay and intracellular caspase activities. The caspase activities were significantly elevated indicating the initiation of both the intrinsic and extrinsic apoptotic pathways when compared to untreated cells. Field emission scanning electron microscopy revealed that the Mo₂S₃ NCs compromised the cell membrane integrity resulting in a loss of THP-1 cell viability and apoptosis. Thus, Mo₂S₃ is an aqueous nanocrystal which shows promising cytotoxicity effect against THP-1 with good photoluminescent properties.     

Ligand Modulation of Active Sites to Promote Cobalt-Doped 1T-MoS2 Electrocatalytic Hydrogen Evolution in Alkaline Media

Highly efficient hydrogen evolution reaction (HER) electrocatalyst will determine the mass distributions of hydrogen-powered clean technologies, while still faces grand challenges. In this work, a synergistic ligand modulation plus Co doping strategy is applied to 1T−MoS₂ catalyst via CoMo-metal-organic frameworks precursors, boosting the HER catalytic activity and durability of 1T−MoS₂. Confirmed by Cs corrected transmission electron microscope and X-ray absorption spectroscopy, the polydentate 1,2-bis(4-pyridyl)ethane ligand can stably link with two-dimensional 1T−MoS₂ layers through cobalt sites to expand interlayer spacing of MoS₂ (Co−1T−MoS₂-bpe), which promotes active site exposure, accelerates water dissociation, and optimizes the adsorption and desorption of H in alkaline HER processes. Theoretical calculations indicate the promotions in the electronic structure of 1T−MoS₂ originate in the formation of three-dimensional metal-organic constructs by linking π-conjugated ligand, which weakens the hybridization between Mo-3d and S-2p orbitals, and in turn makes S-2p orbital more suitable for hybridization with H-1s orbital. Therefore, Co−1T−MoS₂-bpe exhibits excellent stability and exceedingly low overpotential for alkaline HER (118 mV at 10 mA cm⁻²). In addition, integrated into an anion-exchange membrane water electrolyzer, Co−1T−MoS₂-bpe is much superior to the Pt/C catalyst at the large current densities. This study provides a feasible ligand modulation strategy for designs of two-dimensional catalysts.     

Probing the interfacial interaction between monolayer molybdenum disulfide and Au nanoclusters

Coupling of plasmonic metal nanostructures on two‐dimensional materials represents one promising approach to improve their optoelectronic device performance. In this article, we systematically investigated the interfacial interactions between Au nanoclusters and monolayer molybdenum disulfide (MoS₂) and the effect of Au decoration on the electrical transport and optical properties of MoS₂, through the combination of in situ MoS₂ field‐effect transistor device evaluation and in situ ultraviolet photoelectron spectroscopy and X‐ray photoelectron spectroscopy measurements. The in situ X‐ray photoelectron spectroscopy/ultraviolet photoelectron spectroscopy experiments revealed a weak interfacial coupling between Au nanoclusters and monolayer MoS₂. The absence of strong charge transfer between Au nanoclusters and MoS₂ was further confirmed by the photoluminescence and Raman measurements. It was also found that the electron charge‐carrier concentration in monolayer MoS₂ weakly depended on the coverage of Au nanoclusters. Copyright © 2017 John Wiley & Sons, Ltd.     

An insight to catalytic synergic effect of Pd-MoS2 nanorods for highly efficient hydrogen evolution reaction

The electrocatalytic hydrogen evolution reaction (HER) is a sustainable energy production route using green chemistry. Transition metal dichalcogenides' application in catalytic hydrogen production is limited due to a lack of solutions that simultaneously address intrinsic activity, increased surface area, electrical conductivity, and stability problems. Herein we address these issues simultaneously by modifying the electronic structure of molybdenum disulfide (MoS₂) nanorods using a low content of Pd (1 wt% and 2 wt%) dopant via a facile colloidal solvothermal route. The resulting MoS₂ nanorods doped with (1 and 2 wt%) palladium demonstrate current density of 100 mA/cm² at quit lower over-potentials of 137 mV and 119 mV than 273 mV for pure MoS₂ nanorods, accompanied by high stability. This research proposes a strategy for designing high-performance HER electrocatalysts that work in acidic medium. In addition, the Tafel slop calculated for MoS₂ is 112 mV/dec whereas for 1 and 2 wt% Pd-MoS₂, the Tafel slopes are 70 mV/dec and 46 mV/dec.