WS2 Nanorods Research Articles

Temperature-dependent hydrothermal processing of WS2 nanorods with controlled growth morphology, crystallography and optical properties

WS2 nanorods with uniform size-distribution of width 120 nm and length 600–950 nm were successfully processed at 230 °C by reliable and cost-effective hydrothermal method. Two more temperatures (±10 °C) were employed to understand its influence on structural- and optical-properties. Consequences achieved from crystallography and spectroscopy analyses suggest that formation of hexagonal-phase of crystalline WS2 with direct allowed band-gap values in upward manner as temperature increased. In light of temperature-dependent studies achieved from experimental evidences, plausible growth-mechanism of WS2 nanorods was proposed. It will provide potential reference for future studies in both basic- and applied-WS2 research.

WS2 Nanorod as a Remarkable Acetone Sensor for Monitoring Work/Public Places.

Here, we report the synthesis of the WS2 nanorods (NRs) using an eco-friendly and facile hydrothermal method for an acetone-sensing application. This study explores the acetone gas-sensing characteristics of the WS2 nanorod sensor for 5, 10, and 15 ppm concentrations at 25 °C, 50 °C, 75 °C, and 100 °C. The WS2 nanorod sensor shows the highest sensitivity of 94.5% at 100 °C for the 15 ppm acetone concentration. The WS2 nanorod sensor also reveals the outstanding selectivity of acetone compared to other gases, such as ammonia, ethanol, acetaldehyde, methanol, and xylene at 100 °C with a 15 ppm concentration. The estimated selectivity coefficient indicates that the selectivity of the WS2 nanorod acetone sensor is 7.1, 4.5, 3.7, 2.9, and 2.0 times higher than xylene, acetaldehyde, ammonia, methanol, and ethanol, respectively. In addition, the WS2 nanorod sensor also divulges remarkable stability of 98.5% during the 20 days of study. Therefore, it is concluded that the WS2 nanorod can be an excellent nanomaterial for developing acetone sensors for monitoring work/public places.

Co‐Construction of Sulfur Vacancies and Heterojunctions in Tungsten Disulfide to Induce Fast Electronic/Ionic Diffusion Kinetics for Sodium‐Ion Batteries

Engineering novel electrode materials with unique architectures has a significant impact on tuning the structural/electrochemical properties for boosting the performance of secondary battery systems. Herein, starting from well-organized WS2 nanorods, an ingenious design of a one-step method is proposed to prepare a bimetallic sulfide composite with a coaxial carbon coating layer, simply enabled by ZIF-8 introduction. Rich sulfur vacancies and WS2 /ZnS heterojunctions can be simultaneously developed, that significantly improve ionic and electronic diffusion kinetics. In addition, a homogeneous carbon protective layer around the surface of the composite guarantees an outstanding structural stability, a reversible capacity of 170.8 mAh g-1 after 5000 cycles at a high rate of 5 A g-1 . A great potential in practical application is also exhibited, where a full cell based on the WS2- x /ZnS@C anode and the P2-Na2/3 Ni1/3 Mn1/3 O2 cathode can maintain a reversible capacity of 89.4 mAh g-1 after 500 cycles at 1 A g-1 . Moreover, the underlying electrochemical Na storage mechanisms are illustrated in detail by theoretical calculations, electrochemical kinetic analysis, and operando X-ray diffraction characterization.

Efficient Electrocatalytic Performance of WP Nanorods Propagated on WS2/C for Hydrogen Evolution Reduction

AbstractThrough a stepwise synthesis, intercalation followed by chemical vapor deposition (CVD) method, WP nanorods have been grown on the surface of WS2/C composite. Compared to WS2/C, WP nanorods@WS2/C demonstrate better hydrogen evolution reaction (HER) activity and long‐term chronopotentiometric stability as well as suitability in both acid electrolyte and alkaline electrolyte. In order to uncover the enhanced HER property reason, systematic characterizations were applied to assist analyzing. The characterizations used include X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X‐ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), electrochemical active surface area (ECSA), Raman, and BET. Based on the analysis, it points that improved ECSA, synergy between WS2 and WP nanorods, and enhanced degree of graphitization as well, leads to better HER activities of WP nanorods@WS2/C over WS2/C. This work highlights significant role of WP nanorods in WP/WS2/C three‐phase composite in electrocatalytic hydrogen evolution and may evoke new interest in related nanostructure study.

ZIF-67 derived Co3S4 hollow microspheres and WS2 nanorods as a hybrid electrode material for flexible 2V solid-state supercapacitor

Transition metal dichalcogenides (TMDs) are gaining interest in the energy sector due to its 2D chemistry and heterogeneous characteristics however its stability for the long run and poor electrical conductivity are pushing the researchers to make their hybrid. Herein we synthesized the hybrid WS2 nanorods and Co3S4 microspheres composite material which attained a high energy density of 47.3 Wh/kg along at a high-power density of 512 W/kg. The hollow Co3S4 microspheres were synthesized using highly porous ZIF-67 as a precursor. Furthermore, these hollow Co3S4 microspheres are in-situ modified by combining with WS2 nanostructures to enhance its energy density. The electrodes with the synthesized hybrid material deliver the specific capacitance of 412.7 F/g at the current density of 1 A/g, Additionally, two equal weighted Co3S4/WS2 composite electrodes are used to fabricate an all-solid-state symmetrical supercapacitor device with PVA-1M H2SO4 polymer gel electrolyte, exhibiting a wide potential window of 2 V with 92% cyclic stability (2000 charge-discharge cycles) demonstrates its potential applicability for the supercapacitor application. The excellent electrochemical performance and splendid cyclic stability are attributed to the synergy of high surface area ZIF-67 derived Co3S4 microsphere for fast charge transfer with 2D networked WS2 material responsible to provide high energy density.

Temperature Dependent Synthesis of Inorganic WS2 Nano Rods

In this report we report a simplest way to synthesis inorganic Tungsten disulfide (WS2) nanorods. In this research work we used Tungsten trioxide (WO3) to produce tungsten disulfide with hydrogen gas and sulfur gas to synthesis WS2 nanorods at ambient temperature. This synthesis was done by two steps. The first step is oxide reduction and the second step is Sulfuration. And we have analyzed the changes in the nanorod structure when the reaction time is increased and when the temperature is changed at constant gas flow. The synthesized nanorods are analyzed by SEM, EDS and XRD. We report that we have successfully synthesized WS2 nanorods with the dimension of 100 to 300 nm in diameter and few micrometers in length. And we also report the changes in the structural morphology when the temperature was increased. When the temperature was increased to 1000oC the structure become very ranom.

Laser-Directed Assembly of Nanorods of 2D Materials.

Herein, the previously unrealized ability to grow nanorods and nanotubes of 2D materials using femtosecond laser irradiation is demonstrated. In as short as 20 min, nanorods of tungsten disulfide, molybdenum disulfide, graphene, and boron nitride are grown in solutions. The technique fragments nanoparticles of the 2D materials from bulk flakes and leverages molecular scale alignment by nonresonant intense laser pulses to direct their assembly into nanorods up to several micrometers in length. The laser treatment process is found to induce phase transformations in some of the materials, and also results in the modification of the nanorods with functional groups from the solvent atoms. Notably, the WS2 nanoparticles, which are ablated from semiconducting 2H WS2 crystallographic phase flakes, reassemble into nanorods consisting of the 1T metallic phase. Due to this transition, and the 1D nature of the fabricated nanorods, the WS2 nanorods display substantial improvements in electrical conductivity and optical transparency when employed as transparent conductors.

Facile synthesis of mesoporous WS2 nanorods decorated N-doped RGO network modified electrode as portable electrochemical sensing platform for sensitive detection of toxic antibiotic in biological and pharmaceutical samples

We report a facile and ultrasound assisted sonochemical synthesis of a Tungsten disulfide nanorods decorated nitrogen-doped reduced graphene oxide based nanocomposite. The WS2 NRs/N-rGOs nanocomposite was characterized by FESEM, HRTEM, XRD, XPS and electrochemical methods and its application towards the electrochemical detection of organo-arsenic drug (coccidiostat). The WS2 NRs/N-rGOs modified SPCE was used for the electrochemical reduction of roxarsone (ROX) and it showed superior electrocatalytic performance in terms of reduction peak current and shift in overpotential when compared to those of WS2 NRs/SPCE, N-rGOs/SPCE and based SPCE. The WS2 NRs/N-rGOs modified SPCE showed an excellent sensing ability towards ROX in nitrogen saturated phosphate buffer (PB) then the other controlled modified and unmodified electrodes. The WS2 NRs/N-rGOs/SPCE displays high sensitive response towards ROX and gives wide linearity in the range of 0.1–442.6 µM ROX in neutral phosphate buffer (pH 7.0) and the sensitivity of the sensor is calculated as 14.733 µA µM−1 cm−2. The WS2 NRs/N-rGOs nanocomposite modified sensor also exhibits valuable ability of anti-interference to electroactive analytes. Furthermore, the as-prepared WS2 NRs/N-rGOs/SPCE has been applied to the determination of ROX in biological and pharmaceutical samples.

A relative study on sonochemically synthesized mesoporous WS2 nanorods & hydrothermally synthesized WS2 nanoballs towards electrochemical sensing of psychoactive drug (Clonazepam)

In this paper, mesoporous tungsten sulfide electrocatalyst (MP-WS2) were developed through a facile sonochemical technique (SC) and utilized as an electrocatalyst for the sensitive electrochemical detection of Psychoactive drug. The as-prepared SC-MP-WS2 NRs and HT-WS2 NPs (hydrothermally synthesized) were characterized using XRD, Raman, XPS, FESEM, HRTEM, BET, EDX, and electrochemical analysis, which exposed the formation of WS2 in the form of mesoporous nanorods in shape. Further, the use of the as-developed SC-MP-WS2 NRs and HT-WS2 NPs as an electrocatalyst for the detection of clonazepam (CNP). Interestingly, the SC-MP-WS2 NRs modified screen-printed carbon electrode (SC-MP-WS2 NRs/SPCE) exhibited an excellent electrocatalytic performance, and enhanced reduction peak current when compared to HT-WS2 NPs with unmodified electrode. Moreover, as-prepared SC-MP-WS2 NRs/SPCE displayed wide linear response range (10–551 µM), lower detection limit (2.37 nM) and high sensitivity (24.32 µAµM–1cm−2). Furthermore, SC-MP-WS2 NRs/SPCE showed an excellent selectivity even in the existence of potentially co-interfering compounds. The proposed sensor was successfully applied for the determination of CNP in biological and drug samples with acceptable recovery.

Superior photocatalytic activity of tungsten disulfide nanostructures: role of morphology and defects

Tungsten disulphide (WS2) nanostructures, WS2 nanosheets (WNS) and WS2 nanorods (WNR), were synthesized by varying the surfactant, N-cetyl-N, N,N-trimethyl ammonium bromide (CTAB), concentration using facile hydrothermal technique. Samples were characterized by high-resolution transmission electron microscopy (HRTEM) and field emission scanning electron microscopy (FESEM) for morphology, X-ray diffraction (XRD) to confirm their phase and crystal structure, photoluminescence (PL) and Raman studies for the determination of defect density, Tauc plot for the determination of band gap, Fourier transform infra red (FTIR) spectroscopy for functional groups and bonds, and Brunauer–Emmett–Teller (BET) isotherms for the determination of pore size and surface area. A comparative study using WS2 nanostructures (WNS and WNR) was conducted to observe the photocatalytic degradation efficiency (ƞ) and degradation kinetics on methylene blue (MB) and 4-chlorophenol (4-CP). The superior photocatalytic performance of WNS over WNR is attributed to enhanced pore size and reduced defect density. High-performance liquid chromatography was carried out for the determination of intermediate products during photocatalytic degradation.

Architectural Design of Photodetector Based on 2D (MoS2 Nanosheets)/1D (WS2 Nanorods) Heterostructure Synthesized by Facile Hydrothermal Method

Hydrothermal technique is utilized to synthesize 2D/1D heterostructure based on MoS2 (nanosheets)/WS2 (nanorods) for photodetector application. The sensor was fabricated by drop cast technique. X-Ray Diffraction (XRD), Fourier Transform Infra-red (FTIR) Spectroscopy, Field-Emission Scanning Electron Microscopy (FESEM), UV-Visible (Uv-Vis), Raman and X-Ray Photoelectron spectroscopy (XPS) were performed to characterize the synthesized sample. The optical sensor based on heterostructure was studied as a function of laser wavelength (λex): 635 nm (red), 785 nm (infra-red) and 1064 nm (near infra-red) and power of illuminated laser sources. The device exhibits photoresponsivity in a broadband range from the visible to the near-infrared (600–1065 nm, yield a photoresponsivity (Rp) = 15 μA/W and high specific detectivity (D*) = 24 × 106 jones at λex = 785 nm). The photoresponsive characteristics of MoS2/WS2 heterostructure hold the principle of simple power law.

WS2 and C-TiO2 Nanorods Acting as Effective Charge Separators on g-C3 N4 to Boost Visible-Light Activated Hydrogen Production from Seawater.

Semiconductor photocatalysis is regarded as an ideal method for use in solving the energy shortage and environmental issues by converting solar energy to chemical energy. Herein, we have designed a facile synthetic methodology to obtain a ternary co-modified g-C3 N4 composite via WS2 and carbon-doped TiO2 (C-TiO2 ) nanorods with highly efficient photocatalytic activity for hydrogen production from deionized (DI) water and a natural seawater system under visible-light illumination. This composite exhibits enhanced photocatalytic activity compared to the pristine g-C3 N4 , WS2 , C-TiO2 nanorods, and the reference-modified g-C3 N4 composite with individual WS2 or C-TiO2 nanorods. Co-modified g-C3 N4 composite shows a great photostability in both DI water and seawater. Under λ=420 nm monochromatic light illumination, the apparent quantum efficiency of the co-modified g-C3 N4 composite in seawater solution is 13.08 %, which is higher than pure g-C3 N4 (5.06 %). WS2 , TiO2 , and g-C3 N4 constitute a ternary heterojunction boosting the fast separation of photoinduced electron-hole pairs, which plays a crucial role in enhancing photocatalytic activity. Therefore, the WS2 and C-TiO2 nanorod co-modified g-C3 N4 composite with high photocatalytic performance provides a promising candidate for rationally utilizing the seawater resource to produce clean chemical energy.

WO3&WS2 nanorods coupled with CdS nanoparticles for enhanced visible light driven hydrogen evolution

Ternary nanocomposites comprised of one-dimensional (1D) WO3&WS2 nanorods (NRs) and CdS nanoparticles (NPs) fabricated through a two-step process were characterized using a combination of X-ray, microscopy, and spectroscopy techniques. The amount of CdS strongly influences the properties of the nanocomposites, with 40 wt.% of CdS loading showing optimal optical properties and photoelectrochemical (PEC) as well as photocatalytic activities for hydrogen evolution reaction (HER). Compared with WO3&WS2 NRs, the optimized nanocomposite shows 11.4 times enhancement in photocurrent and 6 times increase for HER with lactic acid as a sacrificial agent. The enhanced PEC and HER activities can be attributed to CdS absorption of visible light as well as the intimate contact between WO3&WS2 and CdS that efficiently enhances charge carrier separation. This work demonstrated a promising strategy in the design and fabrication of high-performance photocatalysts for photocatalytic HER applications.

Tuning Pseudocapacitance via C-S Bonding in WS2 Nanorods Anchored on N,S Codoped Graphene for High-Power Lithium Batteries.

Pseudocapacitance plays an important role in high-power lithium-ion batteries (LIBs). However, it is still lack of effective methods to tailor the pseudocapacitance contribution in electrode materials for LIBs. Herein, pseudocapacitance tuned by the strength of C-S bonding has been rendered in WS2 nanorods anchored on the N,S codoped three-dimensional graphene hybrid (WS2@N,S-3DG) for the first time. The pseudocapacitive contributions in the charge storage can be enhanced effectively with the increased strength of C-S bonding. As expected, the enhanced extrinsic pseudocapacitance makes WS2@N,S-3DG a fascinating electrode material for high-power LIBs, with a high reversible capacity of 509 mA h g-1 over 500 cycles at a current density as high as 2 A g-1. These encouraging results of pseudocapacitance tailored by chemical bonding provide new opportunities for designing advanced electrode materials.

Bifunctional Carbon-Dot-WS2 Nanorods for Photothermal Therapy and Cell Imaging.

Multifunctional nanoparticles have attracted significant interest as biomedical vehicles, combining diagnostic, imaging, and therapeutic properties. We describe herein the construction of new nanoparticle conjugates comprising WS2 nanorods (NRs) coupled to fluorescent carbon dots (C-dots). We show that the WS2 -C-dot hybrids integrate the unique physical properties of the two species, specifically the photothermal activity of the WS2 NRs upon irradiation with near-infrared (NIR) light and the excitation-dependent luminescence emission of the C-dots. The WS2 -C-dot NRs have been shown to be non-cytotoxic and have been successfully employed for multicolour cell imaging and targeted cell killing under NIR irradiation, pointing to their potential utilization as effective therapeutic vehicles.

Hydrothermal fabrication of hyacinth flower-like WS2 nanorods and their photocatalytic properties

Hyacinth flower-like WS2 nanorods were successfully synthesized via a facile hydrothermal method. Sodium tungstate and L-cysteine were employed as source materials. The final products were characterized by XRD, XPS, EDS, SEM and TEM. A possible formation mechanism of these novel WS2 nanorods has been proposed. In addition, the photocatalytic activity of WS2 nanorods toward the rhodamine B was also investigated.

Synthesis and Characterization of Cobalt-Doped WS2 Nanorods for Lithium Battery Applications

Cobalt-doped tungsten disulfide nanorods were synthesized by an approach involving exfoliation, intercalation, and the hydrothermal process, using commercial WS2 powder as the precursor and n-butyllithium as the exfoliating reagent. XRD results indicate that the crystal phase of the sample is 2H-WS2. TEM images show that the sample consists of bamboo-like nanorods with a diameter of around 20 nm and a length of about 200 nm. The Co-doped WS2 nanorods exhibit the reversible capacity of 568 mAh g−1 in a voltage range of 0.01–3.0 V versus Li/Li+. As an electrode material for the lithium battery, the Co-doped WS2 nanorods show enhanced charge capacity and cycling stability compared with the raw WS2 powder.

Sonochemical synthesis of tungsten sulfide nanorodsElectronic supplementary information (ESI) available: TGA curve for the as-prepared product; AFM image of WS2 packs of nanorods. See http://www.rsc.org/suppdata/jm/b1/b110867k/

Amorphous WS2 has been prepared by ultrasound irradiation of W(CO)6 solution in diphenylmethane (DPhM) in the presence of a slight excess of sulfur at 90 °C under argon. Heating the amorphous powder at 800 °C under argon yields WS2 nanorods and their packings. The average size of WS2 nanorods was found to be 3–10 nm and 1–5 µm in thickness and length, respectively. The prepared WS2 has been characterized by elemental analysis, X-ray powder diffraction measurements, FTIR spectroscopy, differential scanning calorimetry, thermogravimetric analysis, transmission electron microscopy, scanning electron microscopy, atomic force microscopy and energy dispersive X-ray analysis.