Transition Metal Sulfides Research Articles

Catalytic chemistry inspired hollow carbon nanofibers loaded with NiS/Ni as high-performance and safe Li+ reservoir

Transition metal sulfides (TMSs) based anodes hold a very broad application prospect in lithium ion batteries (LIBs). In this work, the catalytic effect of metallic nickel at high temperature was used to generate hollow carbon nanofibers loaded with NiS and Ni (denoted as NiS/Ni@HCNF). The heteroatoms doped carbon fibers buffer the huge volumetric change of NiS during the discharge/charge process, and enhance the ion transport efficiency and electrical conductivity. In addition, the high specific surface area brought by the hollow carbon nanofibers can accelerate the electrolyte penetration and speed up the transport of ions as well as electrons. When used as anode of half cell, this electrode gives 958.5 and 612.9 mAh/g after running 1000 cycles under 1 and 2 A/g, showing the extremely-low attenuation rates of 0.0483 % per cycle and 0.0643 % per cycle, respectively. Impressively, NCM//NiS/Ni@HCNF battery shows the discharge capacity of 187.6 mAh/g at 1st cycle. Regarding the next 100 cycles, the relatively-high discharge capacities (>110 mAh/g) and coulombic efficiency (CE) values (>96 %) are discerned. It is noted that the usage of NiS/Ni@HCNF electrode improves the activation energy for thermal runaway, corroborating the elevated thermal safety of battery.

Interfacial Chemistry and Catalysis of Inorganic Materials.

Heterogeneous catalysis is essential to most industrial chemical processes. To achieve a better sustainability of these processes we need highly efficient and highly selective catalysts that are based on earth-abundant materials rather than the more conventional noble metals. Here, we discuss the potential of inorganic materials as catalysts for chemical transformations focusing in particular on the promising transition metal phosphides and sulfides. We describe our recent and current efforts to understand the interfacial chemistry of these materials that governs catalysis, and to tune catalytic reactivity by controlled chemical modification of the material surfaces and by use of interfacial electric fields.

Investigation of two dimensional‐MoS2/reduced graphene oxide electrode for applications of NOx gas sensors

AbstractIntroductionTo generate GO and rGO nanoparticles, high‐temperature thermal reduction and the Hummers' technique were both employed. A GO sample is heated and turned into rGO nanopowder. A MoS2 precursor is then added to make a MoS2/rGO composite structure.ObjectivesThe themes of this research work consist of (1) preparation of molybdenum disulfide (MoS2) powder produced by hydrothermal method and sulfurization reaction; (2) graphene oxide (GO) nanoparticles prepared by Hummers' method, compounded with MoS2 to form molybdenum disulfide/reduced graphene oxide (MoS2/rGO) powder in order to reduce the working temperature of a gas sensing process; (3) evaluation of effects of MoS2 and MoS2/rGO sensing devices for NO and NO2 (NOx) gas detection.Results and conclusionWhen tested under various gas concentration and ambient temperature conditions, the NOx gas concentration is 10 ppm, and the working temperature is 150°C, the response value obtained reaches 14.4. In this study, MoS2; a member of two‐dimensional (2D) transition metal sulfide materials, was applied as the main body of the sensing material, and rGO was used as a functional additive. For creating new gas sensing devices, significant progress has been made in creating and designing NOx gas sensing devices for MoS2/rGO composite materials.

Cu(I/II)-Co(II/III) photocatalyst with intrinsic electron transport centre for photoreduction of chromium(VI) and photodegradation of methyl violet

A redox switchable photocatalyst consisting of mixed valent copper (CuI/II) sulfide (CuxS) and cobalt (CoII/III) oxide (CoyOz) designated as CuxS-CoyOz (x=1,2, y=1,3 and z=1,4) was synthesized to execute the Z-scheme photocatalysis process for photoreduction of chromium(VI), and photodegradation of Methyl Violet (MV) dye. The synthesized photocatalyst with a band gap of 3.3 eV was found to be highly effective to reduce 99.62% Cr(VI) and 99.32% of MV dye under UV-light irradiation. The possibility of switching the oxidation state in Cu and Co centre favored the band edge electron transfer on light irradiation and supported the Z-scheme electron transport chain. The photocatalytic reduction and degradation process was dependent on various reaction conditions like catalyst amount, pH of the reaction mixture, irradiation time. The reduction of Cr(VI) occurred with high efficacy at pH=2 while the MV dye degradation proceeded at high pH=10. The catalyst could reduce maximum concentration of Cr(VI) upto 250 ppm and MV dye upto 10−3 M. The mechanism of the photocatalytic processes were well studied by different spectroscopic and electrochemical analysis. The photocatalytic activity of synthesized CuxS-CoyOz catalyst was compared with five other transition metal sulfides M-S (MnS, FeS, CoaSb, NiS and ZnS, where a=3, 4; b=3, 4) combined with cobalt oxide and it was found that CuxS-CoyOz exhibited the highest activity in both the photocatalytic process.

Ni/Co-MOFs derived NiS2/Co3S4 heterostructured microspheres for high-performance asymmetric supercapacitors

Despite the relatively mature state with respect to the technology for synthesizing transition metal sulfide structure, preparation of heterostructured transition metal sulfides with superior structure and high specific capacitance is still challenging. Herein, we prepared NiS2/Co3S4 heterostructured microspheres by the two-part hydrothermal method using bimetallic MOFs as precursors. By constructing this heterostructure, we aimed to modify the electronic structure of electrode materials to enhance the electrochemical performance. We did not need carbonization in the preparation process and showed good electrochemical properties with a great appearance. Experimental and characterization analysis demonstrated the successful synthesis of NiS2/Co3S4 heterostructured microspheres. The NiS2/Co3S4 electrode manifests a specific capacity of 252.3 mAh/g at 1 A/g. Furthermore, the hybrid asymmetric supercapacitor with NiS2/Co3S4 as the positive electrode has the energy density of 4.29 Wh kg−1 at the power density of 61.99 W kg−1 according to the stack volume. These heterostructured mixed metal sulfide electrode materials with high specific capacity and high rate provide new ideas for research.

Binary transition metal sulfides MoS2–NiS2 anchored on biomass-derived carbon for improved performance of lithium–sulfur batteries

The poor electrical conductivity of sulfur and electrochemically active solid-state products (Li2Sn, n = 1–3), and the shuttle effect have led to the low cycling stability of lithium-sulfur batteries and the low utilization of the sulfur cathode. In this work, 3D porous biomass-derived carbon material (KMC) was prepared from Miscanthus sinensis by KOH activation. The transition metal sulfide with excellent adsorption and catalytic characteristics was effectively combined with the conductive porous biomass-derived carbon material, and a KMC/MoS2−NiS2 composite material was obtained. The product was characterized by field emission scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy. Results show that MoS2−NiS2 nanoparticles can be uniformly distributed on the porous carbon material. Electrochemical measurements reveal that with an initial specific capacity of 1292 mA h g–1 at a current density of 0.1 C. After 400 cycles at 0.5 C, the specific capacity of KMC/MoS2−NiS2/S decays from 1007 to 814 mA h g–1. Thus, the capacity decay rate per cycle is about 0.054 %. This strategy provides a new idea for developing lithium−sulfur batteries with attractive performance.

Revealing the Dynamic Lithiation Process of Copper Disulfide by in Situ TEM.

Transition metal oxides, fluorides, and sulfides are extensively studied as candidate electrode materials for lithium-ion batteries driven by the urgency of developing next-generation higher energy density lithium batteries. These conversion-type electrode materials often require nanosized active materials to enable a "smooth" lithiation and de-lithiation process during charge/discharge cycles, determined by their size, structure, and phase. Herein, the structural and chemical changes of Copper Disulfide (CuS2) hollow nanoparticles during the lithiation process through an in situ transmission electron microscopy (TEM) method are investigated. The study finds the hollow structure of CuS2 facilitates the quick formation of fluidic Li2S "drops," accompanied by a de-sulfurization to the Cu7S4 phase. Meanwhile, the metallic Cu phase emerges as fine nanoparticles and grows into nano-strips, which are embedded in the Li2S/Cu7S4 matrix. These complex nanostructured phases and their spatial distribution can lead to a low de-lithiation barrier, enabling fast reaction kinetics.

A Review on Catalytic Progress of Polysulfide Redox Reactions on Transition Metal Sulfides in Li‐S Batteries from Structural Perspective

AbstractThe commercialization of Li−S batteries is seriously hindered by polysulfides with severe shuttle effect, and the inherent insulating properties and slow reaction kinetics of insoluble Li2S products. Transition metal sulfides (TMSs) have a high adsorption capacity for polysulfides and have been shown to have a strong catalytic effect on polysulfide conversion reactions. This paper reviews the research on the application of Unary TMSs, heterostructures, etc. in Li−S batteries, and gives some research methods for TMD catalysts in Li−S batteries. Finally, it points out the main focuses and direction of future Li−S battery research and development. It aims to provide some insights into the design and manufacture of advanced Li−S batteries for commercial use.

Fast response 2D semiconductor gas sensor for memory-type NO2 detection: Test system construction, performance evaluation, and mechanism study

Two-dimensional (2D) materials, such as those in the graphene family, tin-selenide, and transition metal sulfides (TMDs), hold great promise for various applications, including gas-sensitive devices, photodetectors, and lithium batteries. In this study, we propose a fast response gas sensor for ppb-level nitrogen dioxide (NO2) detection using two-dimensional (2D) semiconductor molybdenum disulfide (MoS2). Firstly, we have constructed a gas-sensitive test system to evaluate the performance of the device. The test results demonstrate that the constructed device responds significantly to gas concentrations as low as 40 ppb and as high as 10 ppm, with a fast response time of around 8 s. We have also analyzed and explained the relevant mechanism of the response to NO2. By providing detailed insights into the construction and performance analysis of the test system, as well as the related mechanism study, our research offers valuable information for the development of fast response memory-type gas sensors for ppb-level NO2 detection.

Selecting non-metal doped FeS2 as efficient sulfur cathode host for enhanced Li-S redox chemistry.

Lithium-sulfur batteries (LSBs) are considered as the development direction of the new generation energy storage system due to their high energy density and low cost. The slow redox kinetics of sulfur and the shuttle effect of lithium polysulfide (LiPS) are considered to be the main obstacles to the practical application of LSBs. Transition-metal sulfide as the cathode host can improve the Li-S redox chemistry. However, there has been no investigation of the application of FeS2 host in Li-S redox chemistry. Applying the first-principles calculations, we investigated the formation energy, band gap, Li+ diffusion, adsorption energy, catalytic performance and Li2 S decomposition barrier of FeAx S2-x (A=N, P, O, Se; x=0, 0.125, 0.25, 0.375) to explore the Li-S redox chemistry and finally select excellent host material. FeA0.25 S1.75 (A=P, Se) has a low Li+ diffusion barrier and superior electronic conductivity. FeO0.25 S1.75 is more favorable for LiPS adsorption, followed by FeP0.25 S1.75 . FeP0.25 S1.75 (001) shows a low overpotential for the Li-S redox chemistry. In summary, FeP0.25 S1.75 has more application potential in LSBs due to its physical and chemical properties, followed by FeSe0.25 S1.75 . This work provides theoretical guidance for the design and selection of the sulfur cathode host materials in LSBs.

Layered Transition Metal Sulfides for Supercapacitor Applications

AbstractSupercapacitor (SC) devices holds an important position between traditional capacitors and ion batteries in terms of energy density and power density values. In particular, SC′s greater power density values than Li‐ion batteries make them useful for some specific applications, such as storing energy in hybrid cars while the car slows down. Increasing energy density values is one of the key challenges for the SC community. Transition metal dichalcogenides (TMDCs), are one of the new developing important material systems to have this potential, compared to their counterparts’ transition metal oxides and conductive polymers. This review is about giving insight into the electrochemical performances of two‐dimensional (2D) layered transition metal sulfides (TMS) such as MoS2, WS2, TaS2, NbS2, VS2, TiS2 and ZrS2 materials. On the other hand, the methods mostly used in synthesizing these materials are presented.

Effective Energy Storage Performance Derived from 3D Porous Dendrimer Architecture Metal Phosphides//Metal Nitride-Sulfides.

The present work addresses the limitations by fabricating a wide range of negative electrodes, including metal nitrides/sulfides on a 3D bimetallic conductive porous network (3D-Ni and 3D-NiCo) via a dynamic hydrogen bubble template (DHBT) method followed by vapour phase growth (VPG) process. Among the prepared negative electrodes, the 3D-Fe3S4-Fe4N/NiCo nanostructure demonstrates an impressive specificcapacitance (Cs) of 1125 F g-1 (2475 mF cm-2) at 1 A g-1 with 80% capacitance retention over 5000 cycles. Similarly, a 3D-Mn3P nanostructured positive electrode fabricated via electrodeposition followed by a phosphorization process exhibits a maximum specific capacity (Cg) of 923.04 C g-1 (1846.08 mF cm-2) at 1 A g-1 with 80% stability. A 3D-Mn3P/Ni//3D-Fe3S4-Fe4N/NiCo supercapattery is also assembled, and it shows a notable CS of 151 F g-1 at 1 A g-1, as well as a high energy density (ED) of 51Wh kg-1,a power density (PD) of 782.57W kg-1 and a capacitance efficiency of 76% over 10000 cycles. This may be ascribed to the use of a bimetallic 3D porous conductive template and the attachment of transition metal sulfide and nitride. The development of negative electrodes and supercapattery devices is greatly aided by this exploration of novel synthesis techniques and material choice.

Relation between Fluorescence Spectroscopy and Dynamic Light Scattering Revealed by Interaction of Transition Metal Sulfide Nanoparticles and Graphene Oxide

Relation between Fluorescence Spectroscopy and Dynamic Light Scattering Revealed by Interaction of Transition Metal Sulfide Nanoparticles and Graphene Oxide

Controllable Synthesis of Flower-like Hierarchical CuCo2S4 Nanostructure Arrays for High-Performance Hybrid Supercapacitors

Transition metal sulfides (TMSs) are considered as attractive materials in the areas of energy storage because of their unique redox properties, excellent electronic conductivity, as well as environmental friendliness. However, poor cyclic stability and limited electrochemical active sites hinder their further application. To address this issue, a flower-like hierarchical CuCo2S4 structure is constructed by a two-step hydrothermal method. In this nanostructure, CuCo2S4 grows outward to form a tightly bound hierarchical structure on the nickel foams (NFs). This oriented structure can provide more laminar gaps for electrolyte ion diffusion, exposing more reaction sites to increase the ion transport efficiency between the layers, reducing the ion transport resistance and improving the reaction kinetics. Thus, the CuCo2S4 electrode exhibits excellent energy storage performance, exhibiting a high specific capacity of 1415.6 F g−1 at 1 A g−1. After 10,000 cycles of 10 A g−1, it still has 91.9% of the initial performance. In addition, an asymmetrical supercapacitor (ASC) was constructed by choosing CuCo2S4 as the anode and RGO as the cathode, which has the maximum energy density (61.8 Wh Kg−1) at 812.1 W Kg−1 and significant cycling endurance (92.05% retention) at 10,000 turns. Briefly, the researchers successfully constructed an array of CuCo2S4 flower-like hierarchical nanostructures and confirmed their potential application in supercapacitors.

Fabrication NiCo2S4/Co9S8 composites as a promising electrode material for supercapacitors

The series of the nonstoichiometry transition metal sulfides (TMSs) composites were fabricated by hydrothermal route. NiCo2S4/Co9S8-3h shows a superior specific capacity (2532.5 F g−1 at 1 A g−1) and 81.9 % capacitance retention at 10 A g−1. Moreover, the assembled NiCo2S4/Co9S8-3h//active carbon (AC) device exhibits a high energy density of 32.9 Wh kg−1 at 750.6 W kg−1 and outstanding capacitance retention of 94.7 % after 10000 cycles.

Structural, Magnetic, and Electrical Investigations of PVA/Ni Ferrite/(MoS2)x Nanocomposites.

Transition metal sulfides (TMDs) possess exceptional dielectric properties and a narrow band gap, rendering them highly efficient as electromagnetic absorbing materials. Among these TMDs, the two-dimensional MoS2 nanosheet has received significant attention in research. However, the quest for new absorbers no longer finds satisfaction in solitary absorption mechanisms. This article introduces a successful method for creating PVA/NiFe2O4/(MoS2)x nanocomposites via a straightforward sol-gel technique, wherein porous amorphous NiFe2O4 microspheres are integrated into MoS2 nanosheets. The investigation uncovers that the incorporation of MoS2 results in an enhanced complex permittivity, facilitating the attainment of a desirable permittivity level. The PVA/NiFe2O4/(MoS2)x nanocomposite absorber exhibits an incredibly low reflection loss (RL) of -16.75 dB at a mere thickness of 1 mm, achieved through the cooperative interaction of dielectric and magnetic loss, along with the advantages of the structure and composition. Consequently, the PVA/NiFe2O4/(MoS2)x nanocomposites effectively absorb electromagnetic waves. Therefore, it is posited that MoS2-based composites hold great promise as highly effective microwave absorbers, boasting strong absorption intensity and a wide absorption frequency range, given the exceptional performance of the as-fabricated PVA/NiFe2O4/(MoS2)x nanocomposites.

Optimization of transition metal sulfide through sputtered transition metal nitride thin film for hybrid supercapacitors

Energy storage devices are an immediate requisite to reduce our reliance on fossil fuels and mitigate the environmental impact of traditional energy sources. Hybrid supercapacitors (HSCs) sprung up as the most promising solution while catering to the battery's low power density and SC's low energy density. In this regard, transition metal dichalcogenides (TMDCs) based 2D layered materials are widely explored. Here we see how the performance of the WS2 is affected by introducing a conductive interfacial layer through sputtering entitled titanium nitride (TiN), with a thickness of 100 nm between the substrate and active electrode material. WS2 and TiN-WS2 electrodes were tested for electrochemical performance by employing cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) in half and full cell respectively. The specific capacity (Qs) of a TiN-WS2 hybrid device is 329 C/g (465 F/g), with energy density (Es) and power density (Ps) of 77 Wh/kg and 4250 W/kg, respectively. The device's 91.40 % capacity retention vindicates the enhancement of the WS2 characteristics and its stability via interfacial properties. The linear model is also used to elucidate the capacitive and diffusive charge storage in comparison to the Quadratic model for device at different scan rates.

High performance MnNbS@MXene hybrid electrode for battery-supercapacitor hybrid device and biomedical applications

Hybrid energy storage devices have obtained a lot of interest because of their remarkable capacitance, high stability and multiple applications. The energy-storage capabilities of transition metal sulfides, such as MnNbS, have expanded beyond the domain of oxide-based materials. Transition metal sulfides and the MXene-based nano-architecture materials have been praised because of their synergistically enhanced conductivity and redox flexibility. Manganese niobium sulfide (MnNbS) binary electrode material was synthesized using the hydrothermal method. The MnNbS-MXene nanocomposite electrode was designed to improve the electrochemical characteristics. It exhibited a superior specific capacity (Qs) of 1094 C/g or 1562.85F/g at 1.5 A/g. The hybrid material (MnNbS-MXene) and activated carbon (AC) were used to make the asymmetric hybrid supercapacitors (MNS-MXene//AC). The hybrid device delivered extraordinary Qs of 153.23 C/g, energy density of 35.77 Wh/kg, and power density of 2800 W/kg. To estimate the capacity retention (CR), the device was measured up to 6000 cycles. It also revealed an astonishing CR of 91 %, which is much greater than that of pure MXene//AC and MnNbS//AC. Besides, the MnNbS-MXene//AC nanocomposite electrode is used as a chemical sensor to detect hydrogen peroxide (H2O2). The MnNbS-MXene showed high sensitivity against the H2O2. The device showed the response up to a wide range of H2O2 (1 mM-5mM). Our research presents a perspective and practical application for producing high-performance electrode material based on transition metal sulfide composites and chemical sensors to detect cancerous cells in the body.

Encapsulation of CoS2 nanoparticles in bamboo-like carbon nanotubes as advanced potassium-ion batteries anodes

Transition metal sulfides (TMSs) have been widely investigated as anode materials for potassium ion batteries (PIBs) due to their high theoretical capacity. However, the intense volume change of TMSs in the process of charge/discharge will lead to the destruction of material structure and the decrease of potassium storage performance. Herein, CoS2/CNTs composites are prepared by carbonization and in-situ vulcanization, and the CoS2 nanoparticles are encapsulated in bamboo-like carbon nanotubes. The unique structure can buffer the volume change during charge/discharge, which is responsible for the strong structural stability and remarkable electrochemical storage performance of the composite. When assembled as PIBs half-cell, the CoS2/CNT-600 composite exhibits excellent rate performance (303.7 mAh g−1 at 2000 mA g−1) and favorable cycling stability (325.7mAh g−1 at 100 mA g−1 after 500 cycles). In addition, the successful assembly of the full cell validates the practical application prospects of CoS2/CNT-600 electrodes.

NixSy/N, S-codoped carbon (NSC) hollow microspheres derived from a novel metal organic porous polymer for high performance lithium ion batteries

Addressing the challenges of volume expansion and polysulfide dissolution in transition metal sulfide (MxSy) anodes during the cycling process of lithium-ion batteries (LIBs) is crucial for their practical application. This work utilizes a novel organic ligand containing a thiol group, 5-mercapto-1-phenyl-1H-tetrazole (PTA), to design a series of metal-organic porous polymers, which are then derivatized into N, S co-doped MxSy@carbon encapsing materials. The PTA organic ligand not only serves as a dopants source of N and S but also undergoes in-situ sulfurization with metal to form MxSy nanoparticles coated with carbon. Particularly, the derived NixSy@carbon hollow microspheres feature a unique hollow spherical carbon structure that not only mitigates the volume expansion of nickel sulfide but also shortens the ion diffusion distance while providing a significant number of active sites in LIBs. The research also revealed that variations in crystal structures caused by temperature have a profound influence on the Li+ storage capabilities of the LIBs. When evaluated as anode materials for LIBs, the NiS1.03@NSC600 demonstrates excellent reversible specific capacity and good long-life cycling stability. After 700 charge/discharge cycles, the NiS1.03@NSC600 anode maintains a reversible specific capacity of 480.4 mAh g−1 at 1 A g−1. In addition, we also evaluated CuxSy@NSC and CoxSy@NSC as anode materials, both of which demonstrated excellent electrochemical performance.