Chalcogenide Research Articles

Flash-induced chemical reaction: Conversion of a sulphide into oxide and its densification in

The present work shows that the rate of a chemical reaction can be enhanced by application of electric field and the reaction temperature can be lowered significantly. Roasting is a metallurgical process where metal sulphides transform into metal oxide when heated in presence of air. Conventional roasting of zinc sulphide (ZnS) requires high temperatures (>800 °C) and is a sluggish process. Field-induced roasting and densification occurred together at a furnace temperature as low as 650 °C in <10 s. Interrupted experiments in stage III of flash showed that cubic ZnS first transformed to hexagonal ZnS at ∼ 844 °C (which appears above 1020 °C) before transforming to ZnO. The hexagonal phase was retained at room temperature only if the flash was turned off in <5 s. This study introduces a new method for speeding up chemical reactions using electric fields, which is both fast and energy efficient.

High-Entropy Metal Sulfide Promises High-Performance Carbon Dioxide Reduction.

The efficient conversion of carbon dioxide (CO2) requires the development of stable catalysts with high selectivity and reactivity within a wide potential range. Here, the high-entropy metal sulfide CuAgZnSnS4 is designed for CO2 reduction with excellent performance (FEcarbonproducts ≥ 90%) in whole test potential windows (600 mV) based on the synergistic effect of the high-entropy metal sulfide. In particular, CuAgZnSnS4 exhibits better single-product selectivity with the highest FEHCOOH/FECO value (29.03) at -1.28 versus reversible hydrogen electrode (RHE). In combination with in situ measurements and theoretical calculations, it is further revealed that the synergistic effect of CuAgZnSnS4 realizes the controllable regulation of the surface electronic structure at Sn active sites, strengthening orbital interactions between *OCHO and Sn active sites. As a result, the effective adsorption and activation of *OCHO instead of *H are obtained, improving the single-product selectivity of electrocatalytic CO2 reduction and inhibiting the competitive hydrogen evolution reaction significantly. Our findings may complete the understanding of the synergistic effect for high-entropy materials in catalysis and offer new insight into the design of efficient electrocatalysts with high catalytic activity.

Recyclable biomimetic flower membranes for ofloxacin degradation by peroxymonosulfate activation under visible-light

The construction of a novel ofloxacin degradation catalyst coupled with photocatalysis and PMS activation is of great significance for the regeneration of water resources. A ternary metal (Co, Zn and Mo) sulfide heterojunction with biomimetic flower structure was synthesized using the solvent heat method. And then PVDF@CoZnMoSx membranes were synthetised by researched solvent-assisted nanoparticle embedding (SANE) method, which yielded efficient ofloxacian (OFX) degradation (97.1 %) by PMS activation. The effects of actual environment (such as co-exist ions, organic matter, and actual water matrices) on OFX degradation were observed, and PVDF@CoZnMoSx-3 (Zn:Co = 3:1, PCZM3) exhibited good tolerance for these factors and application value in practice. The pathways of OFX degradation were clarified by LC-MS analysis, and T.E.S.T software simulated the toxicity of the intermediates (P1-P20) gained from LC-MS, which substantiated the efficacy and safety of the PCZM3/PMS system in OFX degradation. The reusability and stability analysis displayed that the OFX degradation of PCZM3/PMS system was maintained in 5 consecutive cycles without additional treatment, and a small number of ions (Co, Zn and Mo) were leached during the OFX degradation. Totally, a new strategy was raised to construct multivariate metal sulfide membranes and couple the photocatalysis and PMS activation, which provided new insights for catalyst membranes to optimize performance.

Indium-free silver thiogallate nanoflake-clusters grown on carbon nitride edges for hydrogen peroxide photosynthesis with enhanced activity and stability

Hydrogen peroxide (H2O2) is a promising solar fuel and its photocatalytic production has been regarded as a green and sustainable alternative to the conventional anthraquinone method. Ternary metal sulfide photocatalysts with unique superiorities are arousing increasing attention. However, photocorrosion still exists and the extensive use of scarce indium renders a limited prospect. Herein, silver thiogallate (AgGaS2) with latent advantages in electronic properties and higher reserves of gallium than indium is reported for the first time in H2O2 photosynthesis. Experiments have unveiled that the activity of single unmodified AgGaS2 surpasses that of many counterparts. Furthermore, a novel type-Ⅱ heterostructure with hollow AgGaS2 nanoflake-clusters grown on the edges of carbon nitride has been constructed with enhanced photocatalytic performance. In the presence of isopropanol as a sacrificial reagent, the optimum heterostructure produces H2O2 with concentration 3.4 times higher than that by AgGaS2 in a long-term reaction. Besides, it maintains 87 % of initial activity after five cycles, outperforming that of AgGaS2 (35 %). Improvement and inactivation mechanisms are carefully investigated, confirming that the internal electric fields at the heterointerfaces between AgGaS2 and carbon nitride promote the separation of photogenerated charge carriers and suppress the photoreduction of Ag+, which are main reasons for the enhanced activity and stability of the heterostructure. This work has attested to the potential of indium-free AgGaS2 in H2O2 photosynthesis with the elucidated improvement and inactivation mechanisms for follow-up optimizations.

Multifunctional Effect of Carbon Matrix with Sulfur Dopant Inspires Mixed Metal Sulfide as Freestanding Anode in Sodium-Ion Batteries.

As active materials for large-radius Na+ storage, metal sulfide (MS) anodes still face several challenges, including poor intrinsic electric conductivity, severe volume change along with the shuttle and dissolution effects of discharge-produced polysulfides. In this work, the mixed nickel-manganese sulfides (NiMnS) in the morphology of uniform 2D ultrathin nanosheets are derived from layered metal-organic frameworks (MOFs), where the NiS-MnS heterojunction are accommodated in carbon matrix with S dopant (NiMnS/SC). Through experiments and density functional theory (DFT) simulations, it is revealed that the carbon matrix with S dopant has multifunctional effects on active NiMnS during the charge/discharge process, including conductive intermediary, electrochemical active site, physical barrier, and chemical adsorption. This work may promote the design of MS-based electrodes in SIBs and extend the application of carbon material with S dopant in Na-S batteries.

Polarization squeezing in chalcogenide fibers.

We experimentally demonstrate the generation of polarization-squeezed light in a short piece of solid-core chalcogenide (ChG) (As2S3) fiber via the Kerr effect for femtosecond pulses at 1.56 µm. Directly measured squeezing of -2.8 dB is obtained in a setup without active stabilization. Numerical simulations are in good agreement with the experimental results and indicate that the measured squeezing in our setup is mainly limited by the losses in the detection system rather than by the fiber properties.

Pressure induced semiconductor-like to metal transition and linear magnetoresistance in Cr2S2.88 single crystal

The transition metal chalcogenide Cr2S3-xhas unique properties, such as a lower antiferromagnetic transition temperature, semiconducting behavior, and thermoelectric properties. We focus on the effects of high pressure on the properties of electrical transport and structure in the single crystal Cr2S2.88. It is observed that the resistance drops abruptly by approximately two orders of magnitude and the temperature derivative of the resistance changes from negative to positive after 15.7 GPa. The Cr2S2.88crystal has undergone transitions from a semiconductor-like phase to a metal I phase and then to another metal II phase. Simultaneously, a structural phase transition after 16.1 GPa is confirmed by synchrotron angle dispersive x-ray diffraction. After the structural phase transition, the negative magnetoresistance becomes positive with increasing pressure and shows a linear relationship in the metal II phase. Electron-type carriers dominate in the semiconductor-like phase, but hole-type carriers dominate after the structural phase transition. Our work provides an example of the effective modulation of semiconductor-like properties by pressure, which is meaningful for the innovation and development of semiconductor technology.

Pyrite‐Based Solid‐State Batteries: Progresses, Challenges, and Perspectives

AbstractPyrite (FeS2), as a transition metal sulfide, has a promise application in the field of secondary batteries due to its abundant reserves, high theoretical capacity, safety, and non‐toxicity. However, serious volume expansion and shuttle effect of FeS2 in liquid secondary batteries limit its further development. Solid‐state batteries offer effective solutions to these challenges. In this review, the synthesis methods of FeS2 and recent progress in FeS2‐based solid‐state lithium/sodium batteries are presented, and the effects of FeS2 size and morphology, solid electrolyte type, and battery structure design on the electrochemical performance of solid‐state batteries are discussed. By analyzing and summarizing the problems in applying FeS2 in solid‐state batteries, the remaining challenges in this field are discussed and future directions are proposed. This review aims to guide research on high‐performance solid‐state batteries based on FeS2 and promote further development of FeS2 in electrochemical energy storage.

Embedment of Molybdenum Disulfide in Electrospun Fibers as an Integrated Cathode for Lithium-Ion Batteries

As an important component of LIBs, the electrode material plays a crucial role in determining the lithium (Li) storage performance in LIBs. In this study, MoS2 nano-flowers were synthesized using a one-pot hydrothermal method. The resulting MoS2 nano-flower, along with PAN, were used as raw materials for electrospinning. After annealing treatment, MoS2/(carbon nanofibers) CNFs nano-composites coated with carbon fibers were formed. The CNFs coating exhibited electrical conductivity and enhanced structural stability of the MoS2 due to the stabilizing effect of the carbon fibers. Additionally, electrochemical tests, including CV and GCD, indicated that the optimal capacity and cycling stability were achieved when the MoS2 content was 10%. The results indicated that the charge/discharge capacity of MoS2/CNFs-10% at a current density of 100 mA/g was ~650 mAh/g. After the cycling current returned to 100 mA/g, the current recovery was ~600 mAh/g, thereby indicating outstanding cycling stability. Accordingly, our fabrication technique and new insight could both widen design strategy of multicomponent composite electrode materials and promote the practical applications of the latest emerging transition metal sulfides in next-generation high-performance lithium-ion batteries.

First-Principles Study of 3R-MoS2 for High-Capacity and Stable Aluminum Ion Batteries Cathode Material.

Currently, exploring high-capacity, stable cathode materials remains a major challenge for rechargeable Aluminum-ion batteries (AIBs). As an intercalator for rechargeable AIBs, Al3+ produces three times the capacity of AlCl4- when the same number of anions is inserted. However, the cathode material capable of producing Al3+ intercalation is not a graphite material with AlCl4- intercalation but a transition metal sulfide material with polar bonding. In this paper, the insertion mechanism of Al3+ in 3R-MoS2 is investigated using first-principles calculations. It is found that Al3+ tends to insert into different interlayer positions at the same time rather than occupying one layer before inserting into another, which is different from the insertion mechanism of AlCl4- in graphite. Ab initio, molecular dynamics calculations revealed that Al3+ was able to stabilize the insertion of 3R-MoS2. Diffusion barriers indicate that Al3+ preferentially migrates to nearby stabilization sites in diffusion pathway studies. According to the calculation, the theoretical maximum specific capacity of Al3+ intercalated 3R-MoS2 reached 502.30 mAg h-1, and the average voltage of the intercalation was in the range of 0.75-0.96 V. Therefore, 3R-MoS2 is a very promising cathode material for AIBs.

Advancing aluminum-ion batteries: unraveling the charge storage mechanisms of cobalt sulfide cathodes

Rechargeable aluminum-ion batteries (AIBs) stand out as a potential cornerstone for future battery technology, thanks to the widespread availability, affordability, and high charge capacity of aluminum. However, the efficacy of current AIBs on the market is significantly limited by the charge storage process within their graphite cathodes. To fully realize the capabilities of AIBs, the discovery of a new cathode material is essential. Transition metal sulfides present an attractive option for cathode materials, although there has been a variety of conflicting reports regarding the exact nature of their charge storage mechanisms. This paper investigates cobalt sulfide (CoSx) cathodes in AIBs, with a particular focus on deciphering the mechanisms of charge storage. Through synthesis, electrochemical testing, and post-cycling characterization, we illuminate the roles of AlCl4− intercalation, cobalt sulfide to Al2S3 conversion, and sulfur to Al2S3 conversion in charge storage. As cycling progresses, Al2S3 synthesis from segregated sulfur segments emerged as the predominant mechanism, showcasing its potential to fully leverage the high capacity of aluminum metal and propel AIBs towards higher energy densities. Despite these promising findings, the study also uncovered significant challenges, notably material loss, intra-cathode diffusion limitations, and irreversible reactions that precipitously diminish charge capacity over time. These issues highlight the critical need for enhanced electrode stability, improved electrolyte compatibility, and accelerated aluminum diffusion. The research paves the way for further exploration of transition metal sulfides as cathode materials in AIBs, highlighting the imperative for innovations that bolster mechanical and chemical stability while optimizing ion transport. This work not only contributes to the fundamental understanding of charge storage in AIBs but also charts a course for the development of more durable and efficient battery systems.

Developing sustainable chalcogenide for energy storage: Investigating the semiconducting MnS2: CuS: CoS2: Ni2S3 quaternary complexes as supercapacitor electrode material

Electrochemical energy storage is crucial in today’s urbanized world to achieve energy sustainability. Using a single source precursor technique, a unique and energy-efficient semiconducting [manganese: copper: cobalt: nickel] sulphide (MnS2: CuS: CoS2: Ni2S3) composite chalcogenide system has been synthesized for the first time. The resulting dithiocarbamate metallic sulfide exhibits a median crystallite size of 36.55 nm as well as a relatively small band gap of 2.61 eV. Many bonds, including the metal sulfide bond, were found, according to a functional group analysis. MnS2: CuS: CoS2: Ni2S3 was morphologically manifested as irregularly shaped particles that tended to form sphere-like shapes. MnS2: CuS: CoS2: Ni2S3 based electrode was measured for electrochemical charge-storing behaviour. With an excellent capacitance spanning around 956.76F g−1, the tetra-chalcogenide-decorated electrode demonstrated a favourable capacity for charge storage, according to the results of cyclic voltammetry conducted in 1 M potassium hydroxide. This suggests that there is a lot of potential for long-term energy storage using the electrode. This electrode elucidated the particular power density of 10020.12 W kg−1 in addition to a lowered series resistance of (Rs) = 1.98 Ω based on the impedance investigations.

Novel hydrothermally fabricated alkaline earth metal and transition metal sulfide (BaS/CuS) composite: An electrode for supercapacitor application

The speedy utilization and exploitation of fossil fuels lead to establishment of an ecosystem marked by pollution and the depletion of energy resources. Nevertheless, expediting the progress of alternative approaches to generate energy and fabricate energy storage devices is crucial. In such cases, supercapacitors (SC) emerged as the most auspicious energy storage device in terms of performance. Supercapacitors can have their electrochemical efficiency enhanced by employing several electrode materials, including transition metal oxides, chalcogenides, perovskites, and spinel. As an electrode for improved SC applications, a new BaS/CuS composite was created in this work using a hydrothermal method. The physical characterizations confirmed the proof of successful fabrication. BET results show that the prepared composite of the BaS/CuS has enhanced surface area (87.4 m2 g−1). BaS/CuS composite electrode was tested in alkaline media via three electrode configurations, and it demonstrated the high Cs (908.7F/g at 1 A/g), high energy density, and power density of 68.6 Wh kg−1 and 368.6 W kg−1 respectively, and good cyclic stability. According to the previously described findings, the synthesized electrode is promising for supercapacitor use.

Hollow transition metal chalcogenides derived from vanadium-based metal organic framework for hybrid supercapacitors with excellent energy-density and stability

In-situ synthesized hollow transition metal chalcogenides have gained significant attention on account of their excellent electrochemical properties. Here, Ni-doped V-MOF (V(Ni)-MOF) nanorod arrays as precursor are first grown on nickel foam (NF). Subsequently, the nanorod arrays are converted into V(NiCo)-OH hollow nanotube arrays with cross-linked nanosheets by Co2+ etching. Finally, V(NiCo)-OH/NF is converted into V(NiCo)-X/NF (X = O, S and Se) by annealing or ion exchange. Due to the unique morphology of hollow nanotube arrays with cross-linked nanosheets and synergistic effect of multi-metal components, the V(NiCo)-Se/NF achieves an outstanding specific capacity (1806.7 C g−1 at 1 A g−1), which is higher than that of V(NiCo)-O/NF (1208.3 C g−1) and V(NiCo)-S/NF (1558.4 C g−1). In addition, the capacity retention rate is 91.7 % (at 10 A g−1 after 10, 000 cycles). Utilizing V(NiCo)-Se/NF (positive) and activated carbon/NF (negative), the hybrid supercapacitor (HSC) achieves an impressive high energy density of 114.8 Wh kg−1 (at 679.5 W kg−1). Moreover, two HSCs in series can power the LED and stopwatch, and keep working for more than 60 min, displaying good practical application capabilities.

N-doped carbon nanotubes and CoS@NC composites as a multifunctional separator modifier for advanced lithium-sulfur batteries

Lithium-sulfur batteries (LSBs), with their high theoretical energy density and specific capacity, are considered optimal candidates for next-generation energy storage systems. However, significant challenges remain in their cycle life and efficiency for practical applications, primarily due to the shuttle effect of lithium polysulfides (LiPSs) and the poor electrical conductivity of sulfur materials. The key to addressing these challenges lies in designing materials with excellent dispersion, good electrical conductivity, and high catalytic activity. In this work, we have designed and successfully synthesized a unique structural material consisting of in-situ grown cobalt sulfide nanoparticles embedded in zeolite imidazolate frameworks (ZIFs), which are derived from N-doped carbon wrapped around polypyrrole-derived N-doped carbon nanotubes (CoS@NC/NCNT). This design effectively mitigates the shuttle effect of lithium polysulfides (LiPSs) and enhances the conductivity of the material. As a result, batteries with CoS@NC/NCNT-modified separators achieved a high specific discharge capacity of 1518 mAh g−1 at 0.1 C. This work provides a reliable design strategy for synthesizing N-doped carbon nanotube/high-activity transition metal sulfide composite materials and opens new avenues for enhancing the modification and separation of high-performance lithium-sulfur batteries (LSBs).

Design of a High-Performance Near-Infrared Scintillator through Metal-Atom Substitution in Metal Chalcogenide.

We report the synthesis and optical characterization of a series of metal chalcogenides, A3SiS4Te (A = Sr2+, Ba2+, Eu2+), highlighting the metal-atom substitution strategy for the discovery of a high-performance metal chalcogenide-based near-infrared (NIR) scintillator of Eu3SiS4Te. Eu3SiS4Te exhibits exceptionally broad NIR emission with a full width at half-maximum of 210 nm, the largest among all known Eu2+-based NIR emitters. Eu3SiS4Te has a high light yield of 41697 photons/MeV and excellent resistance to hygroscopicity. Additionally, Eu3SiS4Te boasts a decay time of 531.3 ns, which is merely a quarter of that of the current state-of-the-art NIR scintillators. As a proof of concept, the response to the 241Am radioactive source was successfully identified, underscoring its potential for γ-photon-counting applications.

Biodegradable cobalt and tin doped chitosan nanocomposites from structure tailoring to solar-driven photocatalytic degradation of toxic organic dyes

The primary concern is the large amounts of emitted organic dyes through wastewater from numerous sectors. One of the most hazardous dyes commonly used in the industrial sector is methyl violet. It has been known to cause skin, gastric, and respiratory disorders. Therefore, a novel photocatalyst based on cobalt‑tin sulfide (Co3Sn2S2) was prepared using the solvothermal process. The photocatalyst was supplemented with Chitosan to prepare the cobalt tin sulfide-chitosan composite (Co3Sn2S2/Chi) for the photocatalytic degradation of methyl violet dye. Based on EDX analysis, a definite ratio of tin, cobalt, and sulfide was found. The FTIR of Co3Sn2S2/Chi revealed the characteristic bands of chitosan and metal sulfide bonds. SEM results showed that the particle had an irregular shape. The composite's crystalline structure was identified by XRD analysis as being 56 nm in crystalline size. The photocatalyst had a narrow band gap of 1.02 eV. At ideal conditions, the developed photocatalyst demonstrated greater degradation efficiency of methyl violet dye under solar light irradiation. The photocatalyst successfully decomposed 95 % of the methyl violet dye (40 ppm) within 70 min, operating at a pH of 9.0. This remarkable degradation was achieved by employing 0.25 g of the photocatalyst. The photocatalyst is more appealing and can be reused for up to three successive cycles. The photocatalyst is well-suited for “pseudo-first-order kinetics” to decontaminate methyl violet dye. The novel photocatalyst showed the most robust ability to decolorize methyl violet when exposed to sunlight and was a viable substitute for dye detoxification of organic dyes from wastewater.

Zinc/lead bimetallic sulfides as hybrid material for high-performance aqueous asymmetric supercapacitor and photocatalytic degradation of organic dye

Wastewater pollution and sustainable energy resources are the utmost crises of the present world. To address these issues, photocatalysis and supercapacitors are sustainable and effective technologies. Over the years, the spontaneous evolution of bimetallic materials has demonstrated excellent performance through their unique architecture, metallic complexes, and porosity. Towards these goals, metal sulfides offer tremendous properties due to their high conductivity, and high charge storage capability. These studies introduce a novel bimetallic sulfide material (Zinc Sulfide/lead Sulfide) (ZnS/PbS) with a unique architecture derived from pristine zinc sulfide and lead sulfide. The Figure of merits for supercapacitors like specific capacity, high electronic conductivity, and highly redox active for ZnS/PbS (30:70) is achieved due to high surface area and unique 2D-sheet like morphology as compared with the pristine zinc and lead sulfide. The highest specific capacity achieved by ZnS/PbS (30:70) is 1083 C/g at 5 mV/s. The specific capacity may be attributed to the highly mesoporous nature of the material with well-defined 2D-sheet-like morphology. The hybrid device depicts a remarkable energy density (18 Wh/kg) and power density (7200 W/kg) with 90.42 % capacitive retention and 81.77 % coulombic efficiency after 5000 cycles. The high retention rate is due to the non-destructive 2D-sheet-like morphology which is sustained even after 5000 cycles. Additionally, the assembled hybrid coin cell can power the commercially available calculator for 86 minutes which shows its potential for real-world application. The photodegradation studies show that ZnS/PbS (30:70) decolor the methyl orange dye solution in 270 mins at pH 10 with good stability for 5 consecutive cycles. The mentioned studies indicate ZnS/PbS (30:70) is a potentially viable candidate as electrode material in asymmetric supercapacitors and environmental remediation.

Pressure-induced structural stability, metallization and optoelectronic properties of transition metal chalcogenide BaTiS3

The pressure effects on the structural stability, metallization and optoelectronic properties of transition metal chalcogenide BaTiS3 are investigated by performing ab-initio calculations. Our calculations show that BaTiS3 has a hexagonal structure at ambient pressure, which matches well with the available experimental values. As pressure increases, a transition from hexagonal to orthorhombic phase occurs at around 10.8 GPa. The band structure and density of states of hexagonal BaTiS3 have been calculated and analysed. Moreover, the effect of pressure on the optical properties has been studied in terms of dielectric function as well as absorption coefficient, reflectivity and extinction coefficient. The application of hydrostatic pressure has shifted the maximum absorption toward the visible range, revealing that hexagonal BaTiS3 can be used for high pressure optoelectronic applications.

Carbonaceous catalyst boosting conversion kinetics of Na2S in Na-ion batteries

Conversion-type metal sulfide anode with high theoretical capacity has received increasing attention in Na-ion batteries (SIBs), but the irreversible conversion of Na2S intermediate in charging process usually engenders low rate capability and poor cycling stability. Herein, guided by DFT calculation, a new-type carbonaceous graphitic carbon nitride (g-CN) catalyst is first reported to boost conversion kinetics of Na2S intermediate to pristine MoS2 in SIBs. Notably, the large chemisorbed energy, high selectivity and low catalytic energy barrier of g-CN catalyst can ensure its affluent charge transfers to Na2S intermediate, which chemically anchor and decompose Na2S intermediate for catalyzing its reversible conversion. Moreover, the microfluidic strategy is developed to enhance the mass diffusion of g-CN catalyst precursors into MoS2 skeleton for facilitating their subsequently covalent bonding process. The covalent bonding of g-CN catalyst on 1T-MoS2 (1T-MoS2/g-CN) superlattice with strong interfacial interaction via C-Mo bond can greatly promote Na+-storage kinetics of MoS2 in discharging process and reversible conversion reaction of Na2S intermediate to pristine MoS2 in following charging process, which is further evidenced by DFT calculation and in-situ characterizations. Consequently, the 1T-MoS2/g-CN superlattice reveals superb rate capacity and excellent cycling stability.