Binary Metal Sulfides Research Articles

NiCo2S4 nano composite structure with high electrochemical performance in band gap

Synthesize NiCo2S4 and its application to find out electrochemical performance of anionic reaction in nano chemistry. Because of binary transition metal sulfide NiCo2S4 are prepared by using a Chemical precipitation to find out anionic movement within the compound. But the electrochemical were used as a conductive network for the NiCo2S4 hexagonal nano plates. Hence hexagonal nano plates have an average crystalline size of the particles 38.34nm and 20.06nm. Nickel and cobalt sulfides with various stoichiometries have been synthesized from Ni(CH3COO)2.2H2O, CoCl2.6H2O with different sulfur precursors using as a direct method. The morphological composite were characterized by (scanning electron microscopy) SEM, XRD (X-ray diffraction), EDX, UV-visible, FTIR spectrum and optical band-gap energy were evaluated. Optical band-gap energies in the range 4.7 eV−5.1 eV were observed.

One-step superficial electrodeposition of nickel-cobalt-sulfide for high-energy hybrid asymmetric supercapacitor

A cathodic electrodeposition (ED) technique is adopted to grow multi-component nickel–cobalt-sulfide (NCS) nanosheet arrays on highly conducting nickel foam substrate. The chronoamperometry (CA) deposited electrode has shown exceptional electrochemical activity in terms of specific capacity, rate capability and excellent redox reversibility than the cyclic voltammetry (CV) deposited electrode. Having the benefit of highly conductive nanosheet arrays and three-dimensional open framework of the nanostructure, the binary metal sulfide exhibits high specific capacity of 820 C g−1 at 2 A g−1. When the NCS electrodes were combined with boron-doped graphene oxide to form an asymmetric hybrid supercapacitor, it delivered a high energy density of 83 Wh g−1 and high-power density of 9619 W kg−1.

In-situ etching and ion exchange induced 2D-2D MXene@Co9S8/CoMo2S4 heterostructure for superior Na+ storage

2D-2D MXene@Co9S8/CoMo2S4 heterostructure has been successfully prepared by anchoring Co9S8/CoMo2S4 nanosheets on few-layered MXene through In-situ etching and ion exchange methods, as well as the subsequent sulfidation processes. MXene flakes used as substrate can effectively suppress the aggregation of Co9S8/CoMo2S4 nanosheets, which further increase reactive sites, ensure the full contact/infiltration of electrolyte, as well as promote charge transfer to improve the reversibility of redox reactions. Besides, this hierarchical structure of 2D-2D MXene@Co9S8/CoMo2S4 hybrids can provide buffer space for the volume expansion of electrode materials during the discharge/charge process. When applied as anode for SIBs, the hierarchical hybrids present superior electrochemical performances with outstanding rate capability (172 mAh/g at 5.0 A/g) and cycling stability (196 mAh/g at 1.0 A/g after 350 cycles), which were further demonstrated by the Ex-situ XRD and XPS results. This work provides an effective way to prepare heterostructure hybrid by combining MXene with binary metal sulfides with unexpected performance in SIBs and may develop hybrid electrode materials for further application in commercial SIBs.

A novel Fe-Co-S/P electrode for aqueous symmetric supercapacitors

Developing electrode materials with high specific capacitance within both positive and negative potential window is an effective way to obtain aqueous supercapacitors with high energy density. In this work, P doped Fe-Co-S binary metal sulfides (Fe-Co-S/P) was demonstrated to show high specific capacitance within a wide potential window from − 1–0.55 V. When used as cathode, it exhibited a specific capacitance of 0.8 F cm−2 (320 F g−1). After 20,000 cycles at 20 mA cm−2, it even increased to 242.3% of the initial capacitance. When used as anode, it also had a specific capacitance of 1.34 F cm−2 (536 F g−1) and satisfied cyclic performance (71.4% of the initial capacitance after 20,000 cycles). Moreover, the symmetric supercapacitors (SSCs) assembled with the Fe-Co-S/P electrodes delivered high energy density of 106.42 Wh kg−1 at a power density of 800 W kg−1 and exhibited excellent cyclic stability by preserving 93.9% of the initial capacitance after 5000 cycles. This work not only establishes Fe-Co-S/P as a high-performance supercapacitor electrode material, but also provides a new strategy to design and construct high-performance aqueous SSCs.

Controllable synthesis of hierarchical core-shell NiS2/CoS2@N,S-C nanospheres for lithium storage

Transition metal sulfides (TMSs) present high theoretical capacity as anode materials for Lithium-ion batteries, and structural design of TMSs is proved to be an effective strategy to acquire satisfactory electrochemical performances. Herein, the hierarchical NiS 2 /CoS 2 @N,S-C nanospheres consisting of NiS 2 /CoS 2 matrixes and N,S-codoped carbon outer layer (N,S-C) are fabricated. Additionally, NiS 2 /CoS 2 @N,S-C nanospheres with different core-shell structures appear in this study when the amount of nickle and cobalt is precisely controlled, which further confirms the different abilities of nickle and cobalt in tailoring and modulating structure. In particular, the NiS 2 /CoS 2 @N,S-C(Ni:Co=1:2) with yolk-shell property presents sufficient internal void space, which is conductive to the transport of Li + and electron. Moreover, the protective N,S-codoped carbon layer and the porous sheet arrays provide the enhanced structural stability and increased active sites. Benefitting from the unique structure, the NiS 2 /CoS 2 @N,S-C(Ni:Co=1:2) anode with binary metal sulfide composition presents good cycling performance (795 mAh g −1 at 0.2 A g −1 after 100 cycles) and rate capability (469 mAh g −1 at 5 A g −1 ). This study provides a reference for the design and preparation of novel TMSs-based materials with different morphologies in the field of energy storage. • NiS 2 /CoS 2 nanosphere encapsulated in the N,S-codoped carbon layer to synthesize the hierarchical NiS 2 /CoS 2 @N,S-C. • The regulation of core-shell structure of NiS 2 /CoS 2 nanospheres by changing the molar ratio of Ni/Co. • The N,S-codoped carbon layer improves the structural stability and conductivity of the final composites. • The NiS 2 /CoS 2 @N,S-C(Ni:Co=1:2) delivers the improved lithium storage performance than other vulcanized composites.

Synthesis and electrochemical mechanisms of yolk-shell ZnCo2S4 for high-performance supercapacitors

Ternary metal sulfides have excellent electrochemical energy-storage and charge-transfer capabilities, outperforming binary metal sulfides and traditional metal oxides; thus, they have great potential for application in electrochemical supercapacitors. In this study, ZnCo2S4 nanoparticles with a unique yolk-shell microstructure are synthesized through a two-stage hydrothermal method based on controlling the second sulfidation treatment period. The resulting yolk-shell nanoparticle possesses adjustable interspaces between the ZnCo2S4 core and yolk, resulting in high specific surface area and mesoporosity. The material characteristics enlarge the reaction sites and facilitate the charge-transfer pathways, and the material could accommodate volume expansion during ion and electron transport. Moreover, the ZnCo2S4 has a high Co3+ content, which benefits Faradaic redox reactions for intensifying electron transport and charge-storage capability. The desirable material physical/chemical properties are supported with rationally designed ZnCo2S4 nanoparticles, which affect the capacitor electrochemical performance, varied with the sulfidation duration. The 18 h-sulfided yolk-shell ZnCo2S4 exhibits the optimal properties, demonstrating its potential application as a supercapacitor electrode. The resulting asymmetric supercapacitor with the yolk-shell ZnCo2S4 electrode achieves excellent energy densities of 92 Wh kg−1 and 66 Wh kg−1 at power density values of 2400 W kg−1 and 18,000 W kg−1, respectively, with good electrochemical stability.

Reverse Conversion Treatment of Gaseous Sulfur Trioxide Using Metastable Sulfides from Sulfur-Rich Flue Gas.

Sulfur trioxide (SO3) is an unstable pollutant, and its removal from the gas phase of industrial flue gas remains a significant challenge. Herein, we propose a reverse conversion treatment (RCT) strategy to reduce S(VI) in SO3 to S(IV) by combining bench-scale experiments and theoretical studies. We first demonstrated that metastable sulfides can break the S-O bond in SO3, leading to the re-formation of sulfur dioxide (SO2). The RCT performance varied between mono- and binary-metal sulfides, and metastable CuS had a high SO3 conversion efficiency in the temperature range of 200-300 °C. Accordingly, the introduction of selenium (Se) lowered the electronegativity of the CuS host and enhanced its reducibility to SO3. Among the CuSe1-xSx composites, CuSe0.3S0.7 was the optimal RCT material and reached a SO2 yield of 6.25 mmol/g in 120 min. The low-valence state of selenium (Se2-/Se1-) exhibited a higher reduction activity for SO3 than did S2-/S1-; however, excessive Se doping degraded the SO3 conversion owing to the re-oxidation of SO2 by the generated SeO32-. The density functional theory calculations verified the stronger SO3 adsorption performance (Eads = -2.76 eV) and lower S-O bond breaking energy (Ea = 1.34 eV) over CuSe0.3S0.7 compared to those over CuS and CuSe. Thus, CuSe1-xSx can serve as a model material and the RCT strategy can make use of field temperature conditions in nonferrous smelters for SO3 emission control.

Commercial Screen-Printed Electrode Decorated with Carbonaceous Binary Sulfides for Direct Glucose Detection in Human Fluid Samples

We hereby demonstrate a highly controllable, green, and rapid synthesis strategy for the production of binary metal sulfides on carbon nano-horns (CNHs) for the fabrication of non-enzymatic glucose sensor using commercial graphite screen-printed electrodes (GSPEs). CNHs were synthesized using the submerged arc discharge method as described elsewhere. In the next step, one droplet (50 µL) of the well-dispersed CNHs was carefully cast on the surface of the GCE (and GSPE). In the final step of preparing the modified electrodes, CNH/GCEs were covered by a thin layer of nickel cobalt sulfide by a simple electrochemical deposition procedure.Following the structural examination of the prepared electrocatalyst were examined. In this regard, several microscopic methods like FE-SEM or TEM were used to know more regard the morphology of the material. The FE-SEM images confirmed the successful formation of sponge like nanosheets of NiCo-S on carbonaceous material. Since CNHs are prepared from graphene sheets with open ends in horn-like shapes, they can be considered as being formed from the origami-like or crushing contortion of a single graphene sheet. According to the FE-SEM images, the agglomeration of CNHs establishes discrete nano-sphere structures with diameters in the range of 50 to 150 nm. The TEM images also confirm this nano-sphere strictures.Following detailed structural characterization, the electrocatalytic activity of the fabricated NiCo-S/CNH electrodes toward electro-oxidation of glucose is examined in detail. The cyclic voltammetry was also used for glucose electro-oxidation mechanism investigation. In addition, parameter optimization was also done by utilizing cyclic voltammetry technique. These include medium pH, deposition cycles, and metals mole ration. Moreover, the effect of the presence and absence of CNH on the electrochemical performance of glucose oxidation were also examined. It shows that in the presence of CNH the peak current density for glucose oxidation is higher that is perfect for analytical purposes and increase the analytical sensitivity. The structural properties and electrochemical response of the fabricated electrodes were also compared to their corresponding mono-metallic counterparts.The amperometric method was utilized as one of the most prevalent and momentous techniques for the quantitative determination of glucose. The applied potential in amperometric tests was optimized to be +0.5 V (vs. Ag/AgCl). The proposed electrodes were operated within two distinct linear dynamic ranges of 0.001- 0.330 mM and 0.330 - 4.53 mM of standard glucose with sensitivities of 1842 µA.mM-1.cm-2, and 854 µA.mM-1.cm-2, respectively. On the other hand, an analytical sensitivity of 467 µA.mM-1.cm-2, within the linear dynamic range of 0.5 - 6 mM was obtained for the static chronoamperometric measurements for modified commercial screen-printed electrode (GSPE). The proposed sensor showed outstanding selectivity against iso-structures and co-existing interferences, long-term durability, rapid response (1.7 s), excellent poisoning resistance against chloride ions, good repeatability, and reproducibility. The tested interferences were 0.1 mM solutions of fructose, galactose, sucrose, lactose, ascorbic acid, uric acid, dopamine hydrochloride, and NaCl. In order to demonstrate the capability of the fabricated electrodes and to evaluate their potential for glucose measurements in real physiological specimens, the glucose level was successfully measured in human blood serum, urine, and saliva samples, without any sample pre-treatment. All in all, the encouraging results make NiCo-S/CNH electrodes immensely promising for clinical and physiological glucose-level measurements.Figure 1. (a) FE-SEM image of CNH. (b) FE-SEM image of NiCo-S/CNH. (c) TEM image of CNHs. (d) Cyclic voltammogarm of NiCo-S/CNH in the absence and presence of various concentration of glucose. (e) The amperometric responses of the NiCo-S/CNH/GCEs after addition of 1 mM glucose followed by successive injection of 0.1 mM fructose, galactose, sucrose, lactose, AA, UA, DA, and NaCl. (f) Chrono amperograms of the NiCo-S/CNH/GSPEs in the presence of the different glucose concentration ranging from 0.5 ~ 10.0 mM under applying +0.5 V. Amperogram of the NiCo-S/GCEs current response obtained from the addition of (g) 50 µL human blood serum, (h) 200 µL urine, and (i) 100 µL saliva followed by injection of 400 µM standard glucose solutions under the optimum potential of +0.5 V, the amperograms of five successive glucose addition. Figure 1

In situ self-assembly of mesoporous Zn-Cd-Mo-S quaternary metal sulfides with double heterojunction synergistic charge transfer for boosting photocatalytic hydrogen production

The construction of semiconductor heterojunctions is regarded as an efficient strategy for promoting photogenerated carrier transfer and enhancing photocatalytic performance. [1] Moreover, the in-situ self-assembly method of the main catalyst and the cocatalyst is believed to overcome the shortcomings of the traditional surface loading method and provide a more efficient hydrogen evolution reaction capability. In this work, Zn-Cd-Mo-S quaternary metal sulfide mesoporous nanospheres were generated by in-situ self-assembly via a one-step mild hydrothermal method. A photocatalyst with a double-heterojunction synergistic structure and a large specific surface area was constructed to form a high-speed charge transfer channel as a mechanism to promote photocatalytic hydrogen production. The best quaternary catalyst ZCM5S has a hydrogen evolution yield of 23.32 mmol h−1 g−1, which is 53 times and 11 times that of the corresponding binary (CdS) and ternary (ZnCdS) metal sulfides, respectively, and still has high stability within 20 h. Furthermore, the ZCM5S gets an apparent quantum efficiency (AQE) of 6.9 % at 420 nm. Through further analysis, such as photoluminescence (PL) and photoelectrochemical, etc., the enhanced photocatalytic performance of ZCM5S can be attributed to the synergistic effect of the heterojunction between ZnS and CdS and the heterojunction between ZnCdS and MoS2. In addition, the Pt-like structure of molybdenum sulfide cocatalyst can lead to efficient photoinduced charge separation and transfer. Meanwhile, the mesoporous structure endows the material with abundant reactive sites and increases the catalytic reaction efficiency. The unique in situ construction method of this work also provides a reference for the design and synthesis of heterojunction quaternary catalysts for green energy conversion.

Spatially Confined “Edge‐to‐Edge” Strategy for Achieving Compact Na+/K+ Storage: Constructing Hetero‐Ni/Ni3S2 in Densified Carbons

AbstractTransition metal sulfides (TMS) are considered as promising anodes for sodium/potassium ion batteries (SIBs/PIBs), and compositing TMS with conductive nanocarbons is an effective mitigation for improving rate performance and cycling stability. However, such a coupling strategy often decreases the tap density and therefore the volumetric energy of electrode. To achieve fast electron/ion transport and high volumetric capacity simultaneously, herein, a compact nanostructure with hetero Ni‐Ni3S2 nanoparticles embedded in a densified S‐doped carbon matrix (Ni‐Ni3S2@SC) is constructed via a spatially confined “edge‐to‐edge” strategy. Experimental and theoretical results confirm that the carbon matrix and metallic Ni nanoparticles provide fast electron transport pathways at two scales, while the abundant heterojunctions with strong electric fields promote the ion migration and Na/K adsorption. As an anode in SIBs/PIBs, the Ni‐Ni3S2@SC exhibits superior rate capability (289/197 mA h g−1 at 2 A g−1), stable cycling performance (88.1/86.2% capacity retention after 100 cycles), and exceptional volumetric capacity (1048/850 mAh cm−3 at 0.05 A g−1). The impressive energy‐power characteristics for Ni‐Ni3S2@SC anode are further confirmed in full cell batteries and hybrid capacitors. The reported spatially confined “edge‐to‐edge” strategy might be adapted to the construction of various binary and/or ternary metal sulfide dense electrodes for advanced energy storage devices.

Formula: see text] modified AC for removing gaseous elemental mercury from flue gas.

Mercury pollution from coal-fired power plants has always been an environmental concern, and adsorption technology is an effective method for Hg0 removal. In this study, copper-iron binary metal sulfide modified activated carbon ([Formula: see text]) adsorbent was synthesized. The performance and mechanism of mercury removal were tested by adsorption experiments and characterization methods. The results showed that the mercury removal efficiency of [Formula: see text] under simulated flue gas (SFG) conditions at 150°C could reach 91%, which was higher than [Formula: see text] and [Formula: see text]. Compared with [Formula: see text], the introduction of Fe increased the proportion of [Formula: see text], which was usually linked to [Formula: see text], resulting in the generation of more [Formula: see text](CuISI) species. Meanwhile, the generation of active sulfur sites such as [Formula: see text] was generated, which had a facilitative effect on the oxidation of Hg0. Stable [Formula: see text] was the predominant product on the adsorbent surface. The 2% sulfur loadings had significantly improved the sulfur resistance of conventional AC.

Nanoconfined bimetallic sulfides (CoSn)S heterostructure in carbon microsphere as a high-performance anode for half/full sodium-ion batteries

The development of high-capacity anode materials is crucial for sodium-ion batteries. Alloy-type anode materials have attracted tremendous attention due to their high theoretical capacities. Nonetheless, the realizations of high capacity and remarkable cycling stability are actually hindered by the sluggish reaction kinetics of sodium storage. Here, we report a binary metal sulfides CoS@SnS heterostructure confined in carbon microspheres (denoted as (CoSn)S/C) through a facile hydrothermal reaction combined with annealing treatment. The (CoSn)S/C with micro/nanostructure can shorten ion diffusion length and increase mechanical strength of electrode. Besides, the heterogeneous interface between CoS and SnS can improve the inherent conductivity and favor the rapid transfer of Na+. Benefitting from these advantages, (CoSn)S/C composite exhibits a high reversible capacity of 463 mAh g−1 and superior durability (368 mAh g−1 at 2 A g−1 after 1000 cycles). Notably, the assembled Na3V2(PO4)3//(CoSn)S/C full cell delivers a reversible capacity of 386 mAh g−1 at 0.2 A g−1, proving that the (CoSn)S/C is a promising anode material for sodium-ion batteries. The density functional theory (DFT) calculations unveil the mechanism and significance of the constructed CoS@SnS heterostructure for the sodium storage at atomic level. This work provides an important reference for in-depth understanding of reaction kinetics of bimetallic sulfides heterostructure.

Non-Equilibrium Sodiation Pathway of CuSbS2.

Binary metal sulfides have been explored as sodium storage materials owing to their high theoretical capacity and high stable cyclability. Nevertheless, their relative high charge voltage and relatively low practical capacity make them less attractive as an anode material. To resolve the problem, addition of alloying elements is considerable. Copper antimony sulfide is investigated as a representative case. In this study, we do not only perform electrochemical characterization on CuSbS2, but also investigate its nonequilibrium sodiation pathway employing in-/ex situ transmission electron microscopy, in situ X-ray diffraction, and density functional theory calculations. Our finding provides valuable insights on sodium storage into ternary metal sulfide including an alloying element.

Facile one-step electrodeposition of two-dimensional nickel-iron bimetallic sulfides for efficient electrocatalytic oxygen evolution

In this work, a series of binary metal sulfides with well-defined two-dimensional (2D) nanosheet structures are in situ achieved on nickel foams (NF) via a one-step electrodeposition strategy under ambient conditions, which directly serve as effective electrodes for oxygen evolution reactions (OER) from water splitting. These NiFeS@NF nanosheets require a low overpotential of only 243 mV to deliver a current density of 10 mA cm−2, superior to that of NiCoS@NF and FeCoS@NF synthesized under the same conditions. The mechanism by which the OER kinetics are enhanced is investigated in detail, where the unique 2D nanosheet architectures and Fe incorporation play a significant role. This hassle-free approach reported here contributes to an inexpensive and convenient access to the fabrication of effective nanocatalysts that can preclude harsh synthetic conditions such as high temperature and high pressure.

Template strategy to synthesize porous Mn-Co-S nanospheres electrode for high-performance supercapacitors

Supercapacitors, such as pseudocapacitors (PCs), are widely used because of their excellent electrochemical activity and capacitance; however, it is still challenging to fabricate PCs with high stability and good electrochemical properties. Therefore, suitable templates and transition metal composite materials should be selected for improving their performance. Binary transition metal sulfides exhibit excellent electrochemical performance owing to their rich valence, electrical conductivity, and abundant electrochemical active sites. In this study, we prepared porous Mn-Co-S nanospheres (MCSN) via the hydrothermal method using silica colloidal particles was as the template; to the best of our knowledge, this is the first study to synthesize MCSN. Results suggest that the MCSN composite exhibited excellent conductivity and enhanced stability owing to the porous structure formed by the vertical growth of MnS2-CoS2 nanosheets on silica nanoparticles. The porous MCSN electrode showed an excellent specific capacitance of 1158 F g−1 at 1 A g−1. Moreover, when coupled with an activated carbon (AC) positive electrode, the supercapacitor of MCSN//AC exhibited stability of 90.4% after 5000 cycles at 10 A g−1 (the specific energy of 34 W h kg−1 at 775 W kg−1). Given the results, we believe that the prepared MCSN material has potential application prospects for high-efficiency supercapacitors.

Microwave synthesis of Zn, Cd binary metal sulfides with superior photocatalytic H2 evolution performance

Zn, Cd bimetallic sulfide (ZnCdS) with fine nanoparticles was prepared with microwave synthesis, and its morphology and structure were analyzed by electron microscope and X-ray diffractometer (XRD). Moreover, the effect of microwave power and microwave time on the photocatalytic H2 evolution property of ZnCdS was explored. Research results show that the ZnCdS solid solution was obtained by the microwave synthesis method, which shows a good photocatalytic hydrogen evolution property. When the microwave power is 320 W and the microwave time is 20 min, the as-prepared ZnCdS solid solution products have the best photocatalytic H2 evolution performance, which its value reaches 2031 μmol/g h.

Drive towards Sonochemically Synthesized Ternary Metal Sulfide for High‐Energy Supercapattery

The present research focuses on, combining the chemistry of supercapacitors and batteries to get highly efficient hybrid energy storage devices. For projected drive, a novel battery‐grade electrode material is introduced. In this regard, binary and ternary metal sulfides with different compositions are synthesized via a facile sonochemical route. The electrode material Co(25%)Cu(75%)MnS (S4) reveals prime electrochemical performance, possessing a maximum specific capacity of 503.5 C g−1 while operating at 0.5 A g−1 in a three‐electrode assembly. The charge storage performance is further scrutinized in a two‐electrode assembly. A supercapattery device (S4//AC) is fabricated by coupling the Co(25%)Cu(75%)MnS (positive) and activated carbon (negative) electrodes. The device displays outstanding energy storage performance with an ultrahigh energy density of 88.71 Wh kg−1 along with a power density of 320 W kg−1. The maximum power density delivered by the assembled supercapattery device is 8000 W kg−1 in parallel with an energy density of 20 Wh kg−1. The supercapattery device also demonstrates an excellent cyclic stability potential of 84% after 3000 continuous charge/discharge cycles. The outstanding outcomes of the fabricated device reveals its potential applications in high‐performance energy storage technologies.

Fabrication of visible light active Mn-doped Bi2WO6-GO/MoS2 heterostructure for enhanced photocatalytic degradation of methylene blue.

The increase in environmental pollution has led to an increased investigation in the development of novel ternary photocatalytic systems for remediation. These photocatalytic systems exhibit superior photocatalytic action for the removal of pollutants because of their visible light active bandgaps. A highly effective visible light active ternary heterojunction was fabricated using a hydrothermal method assisted by ultrasonication. Herein, we report the in situ hydrothermal synthesis of Mn-doped Bi2WO6-GO/ MoS2 photocatalyst, efficiently exhibiting greater photocatalytic activity for the wastewater treatment under solar light. The binary metal sulphide (MoS2) used as a co-catalyst, acted as an electron collector and graphene oxide (GO) as a support material for interfacial electron transfer to and from bismuth tungstate and MoS2. The as-prepared samples were characterized using SEM-EDX, FT-IR, XRD, XPS, BET, PL, and UV-Vis techniques. The bandgap of the novel photocatalyst was found in the visible region (2.2 eV) which helped in suppressing photoinduced electron-hole pairs recombination. The ternary Mn-doped Bi2WO6-GO/MoS2 showed 99% methylene blue removal after 60 minutes of sunlight irradiation at the optimum conditions of pH 8, catalyst dose 50 mg/100ml, and initial MB concentration of 10ppm under sunlight irradiation. The doped ternary heterostructure has proved to be an effective sunlight-active photocatalyst that can be reused without substantial loss in photocatalytic efficiency.

A Competitive Reaction Strategy toward Binary Metal Sulfides for Tailoring Electromagnetic Wave Absorption

AbstractThe development of multicomponent dielectric composites has become a mainstream approach for obtaining excellent electromagnetic wave (EMW) absorbers. However, conventional component introduction is often performed blindly and based only on semiempirical rules, lacking precise modulation of components, interfaces, and defects during the reaction process. Herein, a competitive reaction mechanism is proposed for the first time, in which not only the metal ion concentration but also its characteristic are two feasible parameters to control the components, interfaces, and defects to tailor the EMW absorption performances of Cu‐based binary metal sulfides. The appropriate heterogeneous interfaces and components and the abundant defects can synergistically benefit the EMW absorption capacity by forming perfect impedance matching and multiple dielectric polarizations. As a result, combined with these advantages, an effective absorption band) of 6.80 GHz (6.3–13.1 GHz) is achieved at 2.80 mm for Cu–Co binary metal sulfide, showing the sole middle‐frequency broadband absorption of reported sulfide‐based absorbers to date. Other Cu‐based binary metal sulfides deliver different EMW absorption behaviors. This work breaks through the limitation of traditional component design, opening up a novel methodology for designing multicomponent composites beyond sulfides with broadband absorption.

Miniaturization of binary metal sulfides electrode materials in water-ethanol solvent medium: Remarkable improvement in specific capacitance and cyclic stability

Binary metal sulfides have synthesized at ambient temperature as a positive electrode using ethanol-water as a solvent in the co-precipitation process. The incorporation of sulfur (S) into transition metals could have controlled by changing the solvents, including ethanol and water. The average particle size was measured around 15 nm using electron microscope. The specific surface area calculated around 145 m2 g-1 through NMR based relaxation method. Moreover, it has been found that the particular composition of CNS 1:1:0.15 has drawn immense electrochemical properties based on their discrete morphology. The binary sulfide electrode exhibits excellent pseudocapacitance performance, and delivered specific capacitance (SC) of 2910 F g-1 at 1 A g-1, and simultaneously depicted adequate cyclic retention ~91.5 % up to 10,000 cycles. The energy density (ED), and power density (PD) were evaluated for active electrode about ~123 Whkg−1 and ~285 W kg-1 respectively. Meanwhile, the influence of cation species (Na+, K+& Li+) in electrolyte concentrations illustrates the outstanding supercapacitive performance by decreasing internal resistance. An asymmetric solid-state (ASC) supercapacitor device was assembled which brighten the ~1.8 V of commercial LED for the validation of electrode.