Binary Metal Sulfides Research Articles

Bismuth activated succulent-like binary metal sulfide heterostructure as a binder-free electrocatalyst for enhanced oxygen evolution reaction

Oxygen evolution reaction (OER) is the key to achieve highly efficient hydrogen production during water splitting. Herein, flexible nanorods-integrated succulent-like Bi2S3/Ni3S2/NF heterostructure has been prepared by a facile solvothermal method and applied for OER. We highlight the unique nonequivalent sp3 hybridization of P-region metal based sulfides, which makes a possibility of electronic inductive effect and enhanced electrocatalytic performance. The Bi2S3/Ni3S2/NF catalyst shows low overpotential 268 mV at 10 mA cm−2 and low Tafel slope of 82 mV dec−1. Long-term stability evaluated at high current density suggests that succulent-like Bi2S3/Ni3S2 could be a promising alternative to noble-metal based electrocatalysts for water oxidation reaction in alkaline medium.

Highly Active Zinc Sulfide Composite Microspheres: A Versatile Template for Synthesis of a Family of Hollow Nanostructures of Sulfides.

Hollow nanostructures of metal sulfides have gained tremendous attention in catalysis, biomedicine, and energy storage and conversion owing to their intriguing structural features and fascinating physicochemical properties. Here, we reported a hard template-engaged cation exchange method to fabricate a family of binary or ternary metal sulfide (CuS, Ag2S, Bi2S3, CuxBi1-xS, ZnxCo1-xS, ZnxCd1-xS, ZnxNi1-xS, and ZnxMn1-xS) hollow microspheres via adjusting the reaction kinetic parameters including solvent and temperature in the presence of unique ZnS composite microspheres. Particularly, the shell layer thickness of metal sulfide hollow microspheres could be modulated by manipulating the reaction temperature during the cation exchanging procedure. Meanwhile, the desired elementary composition of ternary metal sulfide hollow microspheres could be achieved by varying the mole ratio and species of the metal source. This synthetic strategy could be extended to rationally design and construct other metal sulfide hollow nanostructures and provide a deep insight into the nucleation and growth process of the metal sulfide hollow microspheres with well-controlled composition and microstructures.

Scalable and Universal Route for the Deposition of Binary, Ternary, and Quaternary Metal Sulfide Materials from Molecular Precursors.

A range of binary, ternary (CFS), and quaternary (CZTS) metal sulfide materials have been successfully deposited onto the glass substrates by air-spray deposition of metal diethyldithiocarbamate molecular precursors followed by pyrolysis (18 examples). The as-deposited materials were characterized by powder X-ray diffraction (p-XRD), Raman spectroscopy, secondary electron microscopy (SEM), and energy-dispersive X-ray (EDX) spectroscopy, which in all cases showed that the materials were polycrystalline with the expected elemental stoichiometry. In the case of the higher sulfides, EDX spectroscopy mapping demonstrated the spatial homogeneity of the elemental distributions at the microscale. By using this simple and inexpensive method, we could potentially fabricate thin films of any given main group or transition metal chalcogenide material over large areas, theoretically on substrates with complex topologies.

Construction of nanocage-structured heterogeneous binary metal sulfides via step-by-step confined growth for boosted lithium storage properties.

Nanocage-structured materials - heterogeneous binary metal sulfides (MoS2 and Co9S8) in carbon nanocages (Co9S8/MoS2@CNCs) - obtained via step-by-step confined growth display superior Li-storage performance, profiting from the synergistic effect of the bimetallic sulfides, high filling rate of active materials and free interspace in the nanocage structure for volume expansion.

Synergistic activity of binary metal sulphide WS2–RuS2nanospheres for the electrochemical detection of the antipsychotic drug promazine

Schematic presentation for the synthesis of tungsten disulfide–ruthenium disulfide (WS2–RuS2) nanospheres and application for the electrochemical determination of antipsychotic drug promazine.

Ternary metal sulfides MoCoNiS derived from metal organic frameworks for efficient oxygen evolution

Developing a highly active and low-cost non-precious metal electrocatalyst for oxygen evolution has been urgent for the clean energy system. Herein, the ternary metal sulfides MoCoNiS supported on nickel foam (MoCoNiS/NF) are successfully prepared using Mo doping Co-based metal-organic framework (Co-MOF) as precursor, which may be helpful for the good dispersion of different metal element. The uniform elements distribution of Mo, Co and Ni on MoCoNiS/NF is determined by all kinds of physical characterization. Mo doping may regulate the electronic environment around Co and Ni, suggesting the potential synergistic effects between different heteroatoms. Electrochemical test shows that MoCoNiS/NF exhibits the excellent OER activity than other single metal or binary metal sulfides as comparison samples, needing only 151 and 226 mV overpotential to achieve current density of 10 (η10 = 151 mV) and 100 mA cm−2 (η100 = 226 mV), respectively. The excellent stability of MoCoNiS/NF has been achieved. The remarkable OER performance of MoCoNiS/NF may due to the synergistic effects and good electrical conductivity as well as the three-dimensional structure of NF as substrate. Therefore, the rational design of MOF derived multi transition metal-based electrocatalysts will be an effective way for increasing OER performance.

A novel binary metal sulfide hybrid Li-ion battery anode: Three-dimensional ZnCo2S4/NiCo2S4 derived from metal-organic foams enables an improved electron transfer and ion diffusion performance

Many binary metal oxides possess poor conductivity and ion diffusion efficiency, even though they have a high theoretical capacity as secondary battery anodes. Herein, we present a double binary metal sulfide composing of ZnCo2S4/NiCo2S4 growing on carbon cloth, which was derived from a Zn–Co–Ni metal organic foam. Compared to the ZnCo2O4/NiCo2O4, the ZnCo2S4/NiCo2S4 anodes exhibit an obviously improved electrochemical performance including a high areal capacity of 2.4 mAh cm−2 after cycling for 100 times at 0.36 mA cm−2, and a Coulombic efficiency of 99.9%. A well-recoverable rate-performance is also presented. In addition, the enhancement mechanism is investigated by using density functional theory simulations, which show the density of states and Li ion diffusion energies of the ZnCo2S4/NiCo2S4 are improved compared to ZnCo2O4/NiCo2O4. It is expected that the high-performance hybrid and the theoretical enhancement mechanism would enable them to find important applications for developing emerging energy-storage materials.

Facile synthesis clusters of sheet-like Ni3S4/CuS nanohybrids with ultrahigh supercapacitor performance

Binary transition metal sulfides would have better electrochemical performance in supercapacitor, which can attribute to the synergistic effect, sufficient redox reaction and diversified nanostructure than single sulfides. In this work, new type clusters of sheet-like nickel sulfide and copper sulfide (Ni3S4/CuS) nanohybrids electrode was transformed from its hydroxide precursor through a facile chemical interface method, followed by an anion-exchange reaction. The Ni3S4/CuS composite electrode delivers much higher capacity of 970 ​C ​g-1 than its hydroxide precursor and those of the pristine Ni3S4 (559 ​C ​g-1) and CuS (148 ​C ​g-1), displays a good rate capability and cycling stability. When assembled an asymmetric capacitor, Ni3S4/CuS//AC (active carbon) presents high voltages up to 1.7 ​V and exhibits top energy density of 18.4 ​Wh Kg-1 even at high power density of 8500 ​W ​Kg-1. Such novel hybrids electrode and its synthesis method may provide a viable solution for energy storage materials issues.

Binary transition metal sulfides as an economical Pt-free counter electrodes for dye-sensitized solar cells

Binary CuxCoySz sulfide based Pt-free counter electrodes (CE) were prepared in one-step solvothermal synthesis process. The obtained CEs were characterized by SEM, XRD, and Raman spectroscopy methods. EDX analysis showed uniform distribution of Cu, Co and S. SEM images revealed different level of coverage of the FTO glass by the binary metal sulfide products. DSSCs were constructed using proposed CEs with N719 dye, and their photovoltaic and electrochemical performances were assessed against Pt reference cell. The efficiency of the CuxCoySz-3 CE produced an 11% improvement of its photovoltaic efficiency compared to the reference cell.

NiMoS4 nanocrystals anchored on N-doped carbon nanosheets as anode for high performance lithium ion batteries

Owing to the excellent electrical conductivity and high theoretical capacity, binary transition metal sulfides have attracted extensive attention as promising anodes for lithium ion batteries (LIBs). However, the relatively poor electrical conductivity and serious capacity fading originated from large volume change still hinder their practical applications. Herein, binary NiMoS4 nanoparticles are deposited on N doped carbon nanosheets (NC@NiMoS4) through a facile hydrothermal method. The N doped carbon nanosheets and the strong chemical bonding between NC and NiMoS4 can accommodate the volume change, keep the structural integrity and promote the ion/electron transfer during electrochemical reaction. The extra voids between NiMoS4 nanoparticles enlarge the contact area and reduce the lithium migration barriers. As anode for LIBs, the NC@NiMoS4 exhibits the excellent cycle stability with 834 mAh g−1 after 100 cycles at the current density of 100 mA g−1. Even at high rate of 2000 mA g−1, the specific capacity of 544 mAh g−1 can be achieved after 500 cycles.

Nanocomposites based on 3D honeycomb-like carbon nitride with Cd0·5Zn0·5S quantum dots for efficient photocatalytic hydrogen evolution

Honeycomb-like graphitic carbon nitride (H–C3N4) with unique morphology has been studied as a promising polymer photocatalyst. Herein, a novel binary metal sulfide constructed with H–C3N4 (Cd0·5Zn0·5S/H–C3N4) was prepared though the facile in situ precipitation method. The characterization data suggest that Cd0·5Zn0·5S quantum dots (QDs) are well dispersed on the macroporous structure of H–C3N4 (156 m2 g−1), which can provide higher surface area, more catalytic active sites and larger interface contact area with accelerating the migration and separation of charge carriers. By taking advantage of 0D/3D heterojunction structure, the Cd0·5Zn0·5S/H–C3N4 dramatically boosts the photocatalytic H2 evolution rate with the visible-light illumination. The Cd0·5Zn0·5S/H–C3N4-3 yields the highest photocatalytic activity of 5145 μmol h−1 g−1, which is 4.3 times as high as that of pure Cd0·5Zn0.5S. Furthermore, Cd0·5Zn0·5S/H–C3N4 composite presents high stability after four recycles. The enhanced visible-light-driven photocatalytic H2 production is attributed to the construction of n-n type heterojunction as well as the large surface area, which can inhibit the agglomeration of Cd0·5Zn0·5S nanoparticles, and efficiently transfer the photoexcited electron-hole pairs in Cd0·5Zn0.5S. Therefore, this work provides a potential way for designing advanced 0D/3D heterojunction.

Platinum-free metal sulfide counter electrodes for DSSC applications: Structural, electrochemical and power conversion efficiency analyses

Micro/Nanoscale binary (CoS, NiS, and ZnS) and ternary (CoNi2S4 and Zn0.76Co0.24S) metal sulfides were directly grown on FTO substrates by a novel one step hydrothermal method for low-cost DSSC counter electrode applications. XRD study confirms phase pure formation of CoS, NiS, ZnS, CoNi2S4 and Zn0.76Co0.24S. HRSEM images of CoS, NiS and CoNi2S4 films exhibits hierarchical flower, hexagonal microcage and flake like particulates respectively. The ZnS and Zn0.76Co0.24S films show spherical micro-nanoparticles. The nanoflake morphological CoS and CoNi2S4 revealed high surface area measured by BET analysis. XPS result confirms the chemical states of CoNi2S4 and Zn0.76Co0.24S. A detailed electrochemical cyclic voltammetry, Tafel polarization and electrochemical impedance spectroscopy (EIS) analyses reveals the ternary metal sulfide (CoNi2S4) possesses an excellent electrocatalytic activity and electrical conductivity than other counter electrodes for the reduction of tri-iodide to iodide. Photovoltaic performance of the devices was studied using standard solar simulator at 1 Sun intensity (AM 1.5 G) and dark conditions. The reduced dark current obtained in CoNi2S4 and Zn0.76Co0.24S confirms the less recombination of electrons in ternary metal sulfides based DSSCs. The power conversion efficiency of ~4.03% achieved in Pt-free CoNi2S4 counter electrode is comparable to standard Pt based DSSC (~4.59%). The CoNi2S4 exhibiting good device performance and high electrocatalytic activity can serve as efficient low-cost counter electrode for Pt-free DSSCs.

Novel approach to synthesize NiCo2S4 composite for high-performance supercapacitor application with different molar ratio of Ni and Co

Here, we developed a new approach to synthesize NiCo2S4 thin films for supercapacitor application using the successive ionic layer adsorption and reaction (SILAR) method on Ni mesh with different molar ratios of Ni and Co precursors. The five different NiCo2S4 electrodes affect the electrochemical performance of the supercapacitor. The NiCo2S4 thin films demonstrate superior supercapacitance performance with a significantly higher specific capacitance of 1427 F g−1 at a scan rate of 20 mV s−1. These results indicate that ternary NiCo2S4 thin films are more effective electrodes compared to binary metal oxides and metal sulfides.

Template-assisted synthesis of hierarchically hollow C/NiCo2S4 nanospheres electrode for high performance supercapacitors

Binary transition metal sulfides hold immense promise for use in energy storage devices thanks to their higher electronic conductivity and capacity compared to that of the mono-metal sulfides arising from the richer redox reactions. Herein, hierarchically hollow C/NiCo2S4 nanosphere composites have been synthesized through carbon coating and hydrothermal processes with SiO2 nanosphere and glucose as the hard template and carbon source, respectively. The interconnected NiCo2S4 nanosheets, void spaces in the interior of nanospheres and the conductive carbon layer enable the C/NiCo2S4 composite electrode to achieve an outstanding conductivity and good stability. Accordingly, the hollow C/NiCo2S4 nanosphere electrode exhibits an extraordinary specific capacitance of 1545 F g−1, as well as an enhanced cycling stability (90.1% after 6000 cycles) at a high current density of 10 A g−1. Satisfactory energy density (34.1 Wh kg−1 at 160 W kg−1) and high power density (8000 W kg−1 at 19.8 Wh kg−1) can be obtained by fabricating an asymmetric supercapacitor with activated carbon in the operation window of 0–1.6 V. These encouraging results further reveal the promising prospects of the as-prepared C/NiCo2S4 nanocomposite for high efficient electrochemical supercapacitor.

Smart in situ construction of NiS/MoS2 composite nanosheets with ultrahigh specific capacity for high-performance asymmetric supercapacitor

NiS/MoS2 composite nanosheets were designed and prepared via facile ion-exchange, freeze-drying, and Ostwald ripening processes. MoS2 nanosheets served as backbones to absorb Ni2+ ions and form NiS nanosheets. The electrode based on the NiS/MoS2 composite nanosheets exhibited an ultrahigh specific capacity of 343.5 mA h g−1 at 9 A g−1, which was superior to that of as-prepared MoS2 nanosheets (125.8 mA h g−1) and Ni(OH)2 nanosheets (148.9 mA h g−1). In addition, NiS/MoS2 composite nanosheets presented an enhanced rate performance and good life cycle due to their hierarchical structure, high surface area with numerous active sites, and synergistic performance. A NiS/MoS2//AC asymmetric supercapacitor device operated in a large potential window (0–1.5 V) delivered a high capacitance of 48.4 F g−1 at 0.1 A g−1, an excellent energy density of 15.1 Wh kg−1 and a very high power density of 2.25 kW kg−1. This smart in situ construction process opens a new route to synthesize binary metal sulfides for high-performance energy storage devices.

Exploring the promising potential of MoS2–RuS2 binary metal sulphide towards the electrocatalysis of antibiotic drug sulphadiazine

Benefiting from the rich redox chemistry, high electrical conductivity and synergistic effect from two metal ions, the binary metal sulphides received tremendous attention in various applications. As a result, the MoS2–RuS2 nanomaterial was synthesized through the simple one-pot hydrothermal technique. The electrocatalytic activity of the as-synthesized nanomaterial was exploited towards the electrochemical detection of antibiotic drug sulphadiazine (SDZ). The electrocatalytic oxidation of the SDZ exhibited lowest anodic peak potential and ehanced anodic peak current rather than other modified electrodes. Notably, an excellent electrochemical performance with very lowest limit of detection (LOD) of 0.004 μM, appreciable linear range from 0.01 μM to 598.7 μM and high sensitivity (2.333 μA μM−1 cm−2) was obtained at MoS2–RuS2 modified electrode. Moreover, well anti-interfering property, good operational stability, repeatability and reproducibility was achieved. Facinatingly, the practicability of the modified electrode demonstrated in milk and human serum samples.

Rational synthesis of Cu7S4/CoS2 hybrid nanorods arrays grown on Cu foam from metal-organic framework templates for high-performance supercapacitors

Nanostructured copper sulfides with well-controlled morphologies, sizes, crystalline phases and compositions have been the subject of extensive research as the promising candidates in energy-related applications due to their excellent semiconducting properties and environmental compatibility. In this work, Cu7S4/CoS2 hybrid nanorods arrays on copper foam with different Co/Cu molar ratios (denoted as Cu-Co-S/CF-x, x = 0.12, 0.25 and 0.5) were firstly fabricated by a facile metal-organic framework templated synthetic strategy with three-step procedures of in situ interface growth, cation exchange and sulfurization. The optimized Cu-Co-S/CF-0.25 binder-free electrode displays the highest specific capacitance of 2132.7 mF cm−2 at a current density of 3 mA cm−2 (762.2 F g−1 at 1 A g−1) and outstanding cycling stability (92.3% capacitance retention over 10000 cycles). What's more, the assembled asymmetric supercapacitor (Cu-Co-S/CF-0.25//AC ASC) device based on Cu-Co-S/CF-0.25 as positive electrode and activated carbon (AC) as negative electrode offers a high energy density of 82.8 μWh cm−2 at the power density of 1.1 mW cm−2 (27.6 Wh kg−1 at 1125 W kg−1), which also demonstrates long-term cycling stability. These impressive results reveal that a rational and effective strategy has been explored to prepare binary transition metal sulfide nanorods arrays from metal-organic framework template for high-performance energy storage and conversion devices.

Yolk-shell-structured zinc-cobalt binary metal sulfide @ N-doped carbon for enhanced lithium-ion storage

Owing to high capacity, low cost, and environmental benignity, transition-metal sulfides have attracted increasing attention as potential anode materials for lithium-ion batteries (LIBs). However, their practical application is impeded by poor cycling stability and rate capability due to large volume change and sluggish kinetics. Here, a yolk-shell structured zinc-cobalt binary metal sulfide @ N-doped carbon composite (Zn-Co-S@N-C) with enhanced lithium storage is reported. In this composite, unique porous yolk-shell structure provides short Li+/e− diffusion distance and offers sufficient void space to accommodate volume variation during the Li+ insertion/extraction process. The presence of N-doped carbon matrix not only enhances electron transfer kinetics, but also improves structural stability. Moreover, bimetallic sulfides enhance electrochemical reactivity for superior lithium storage and mitigate the formation of by-products. The resulting Zn-Co-S@N-C anode exhibits significantly enhanced cycling stability (667.7 mAh g−1 after 300 cycles at 1000 mA g−1) and rate capability (332.2 mAh g−1 at 5000 mA g−1).

Ni-Bi-S nanosheets/Ni foam as a binder-free high-performance electrode for asymmetric supercapacitors

Supercapacitors are attracting tremendous interests in electrochemical energy storage and binary metal sulfides are attracting increasing attention due to higher electrochemical activities over their monometal counterparts. In this report, we show a novel Ni-Bi-S nanosheets/Ni foam electrode with superior performance for supercapacitors. In the synthetic process, Ni foam is utilized as current collector as well as Ni source for the Ni-Bi-S. Bi source plays a crucial role to achieve desired morphology for the Ni-Bi-S and uniform nanosheets network can be obtained by controlling the amount of the Bi (NO3)2. The Ni-Bi-S nanosheets/Ni electrode demonstrates a high specific capacitance of 4.81 F/cm2 at 5 mA/cm2 and an outstanding cycling performance. After 3000 cycles, 97.6% of the initial capacitance can be retained at 20 mA/cm2 and the retention is still as high as 83.4% even after 6500 cycles. An asymmetric supercapacitor constructed with Ni-Bi-S cathode and commercial conductive cloth (CC) anode demonstrates with a high energy density of 2.96 mWh/cm3 and a good retention rate after 2000 cycles.

Hierarchical nanosheets-anchored-on-microsheets FeCo2S4 arrays as binder-free electrode for high-performance hybrid supercapacitor

The binary transition metal sulfides are highly desirable electrode materials for high-performance supercapacitors, thanks for their excellent electrochemical activity and electrical conductivity. Herein, the hierarchical FeCo2S4 arrays are designed and constructed on Ni foam, which consists of microsheets anchored nanosheets. The FeCo2S4 hierarchical structure provides high conductivity and abundant electroactive sites as well as facial and short ion transport paths. Therefore, the FeCo2S4 electrode achieves an excellent specific capacitance of 2488.50 F g−1 (7.66 F cm−2) at 5 mA cm−2, and a high level of cycle stability of 95.67% retention after 5000 cycles. The FeCo2S4//activated carbon (AC) device delivers the maximal energy density of 44.89 W h kg−1 and the maximal power density of 4015.56 W kg−1. The impressive electrochemical properties of hierarchical FeCo2S4 arrays make it a promising high-performance electrode for hybrid supercapacitors.