Cobalt Disulfide Research Articles

Lithium ion battery-assisted solar-driven water splitting

Electrocatalytic water splitting is an efficient strategy to substitute traditional fossil fuels with renewable energy H2. However, its scalable implementation, especially outdoors, has been hindered due to the lack of highly efficient and stable electrocatalysts and high-cost external electricity from the power grid. Here, we develop a hybrid nanostructure comprising N-doped carbon nanotube (NCNT) covalent-linked cobalt disulfide nanoparticles (CoS2-NPs) confined in hollow carbon nanocages (h-CoS@NC). As a bifunctional electrocatalyst for overall water splitting, the multi-heterostructure exhibits superior catalytic activities towards both hydrogen and oxygen-containing intermediates. Inspiringly, a two-electrode electrolyzer combined with the multi-heterostructure realizes a current density of 10 mA cm−2 at a low cell voltage of 1.58 V. When employing an anode of lithium ion battery (LIB), the h-CoS@NC delivers a high specific capacity of 1040 mAh g−1 at 0.1 A g−1 and maintains a considerable capacity of 648 mAh g−1, especially at rate of 5 A g−1. Furthermore, a large capacity of 582 mAh g−1 is achieved at 0.1 A g−1 for sodium ion battery. Moreover, theoretical calculations interpret that the enhanced electrochemical activities of h-CoS@NC should be attributed to the interaction between the CoS2 and carbon matrix, which effectively regulates the local electronic structures and weakens water adsorption/dissociation energies. As a proof-of-concept, a self-powered water splitting system integrating solar-charged lithium-ion battery with a water splitting electrolyzer achieves a steady H2 evolution rate at 0.4 A.

Hydrazides: An Important Tool for the Synthesis of 1,3,4-Oxadiazole

Abstract: Hydrazides, derivatives of hydrazine, are widely used in pharmaceuticals, polymers, dyes, herbicides, and as chemical preservatives. A notable application is in synthesizing 1,3,4-oxadiazole, an important aromatic compound with a five-membered heterocyclic ring containing two nitrogen atoms and one oxygen atom. Among the four oxadiazole isomers, 1,3,4-oxadiazole is the most significant, used in drug discovery, pharmaceuticals, and dyes. It is synthesized from various substituted hydrazides or hydrazones using reagents like copper, cobalt, cerium, phosphorus oxychloride, mercury oxide, potassium iodide, triflic anhydride, and carbon disulfide. This study reviews the synthesis methods of 1,3,4-oxadiazole, highlighting the advantages and disadvantages of different catalysts and conditions, providing useful insights for researchers.

Rapid Synthesis of Hierarchical Cobalt Disulfide Nanostructures by Microwave-Assisted Hydrothermal Method for High Performance Supercapatteries

Rapid Synthesis of Hierarchical Cobalt Disulfide Nanostructures by Microwave-Assisted Hydrothermal Method for High Performance Supercapatteries

Bifunctional effects of nitrogen-doped carbon quantum dots on CoS2/mesoporous carbon composites for high-performance lithium-ion batteries

Cobalt disulfide (CoS2) stands as a promising candidate for anode materials in lithium-ion batteries due to its high theoretical capacity, but it faces challenges associated with the shuttle effect of lithium polysulfide during cycling. To address these issues, zeolitic imidazolate framework (ZIF)-derived composites have been extensively explored because of distinct advantages such as the formation of nano-sized particles, heteroatom doping, and highly porous structures. However, ZIF-derived carbon supports primarily consist of ultra-micropores that can impede lithium-ion diffusion. Herein, we aimed to enhance cycling stability by introducing a nitrogen-doped carbon quantum dot (NCQD) solution derived from N-methyl-2-pyrrolidone into cobalt-based ZIF-67 to modify the porosity and dope heteroatoms of CoS2 nanoparticle-embedded heteroatom-doped carbon composites (CoS2/NSC). The mildly acidic NCQD solution resulted in the partial etching of the ZIF-67 structure, along with the deposition of NCQDs as a nitrogen source. Notably, the pore sizes could be adjusted by varying the concentration of the NCQD solution, while retaining the nitrogen functional groups during carbonization. The electrode using CoS2/NSC with the 2.8 mL NCQD pre-treatment exhibited enhanced C-rate capability with the capacity of 392 mAh/g at 2.0 A/g. Moreover, the cycling stability was improved, with a capacity retention of 77 % after 100 cycles.

Tunable Colossal Anomalous Hall Conductivity in Half-Metallic Material Induced by d-Wave-Like Spin-Orbit Gap.

The anomalous Hall conductivity (AHC) in magnetic materials, resulting from inverted band topology, has emerged as a key adjustable function in spin-torque devices and advanced magnetic sensors. Among systems with near-half-metallicity and broken time-reversal symmetry, cobalt disulfide (CoS2) has proven to be a material capable of significantly enhancing its AHC. In this study, the AHC of CoS2 is empirically assessed by manipulating the chemical potential through Fe- (hole) and Ni- (electron) doping. The primary mechanism underlying the colossal AHC is identified through the application of density functional theory and tight-binding analyses. The main source of this substantial AHC is traced to four spin-polarized massive Dirac dispersions in the kz = 0 plane of the Brillouin zone, located slightly below the Fermi level. In Co0.95Fe0.05S2, the AHC, which is directly proportional to the momentum-space integral of the Berry curvature (BC), reached a record-breaking value of 2507 Ω-1cm-1. This is because the BCs of the four Dirac dispersions all exhibit the same sign, a consequence of the d-wave-like spin-orbit coupling among spin-polarized egorbitals.

Structural, morphological and electrical properties of hydrothermally synthesized cobalt disulfide (CoS2) nanoparticles

Cobalt disulfide (CoS2) is a highly sophisticated metal chalcogenide that has garnered significant attention due to its distinctive properties such as its electrical, optical, catalytic, and magnetic capabilities and potential for use in a range of applications. In this work, pure CoS2 nanoparticles were synthesized using the economical and facile hydrothermal method. The X-Ray diffraction (XRD) method was used to characterize the synthesized sample, confirming that it has a cubic crystal structure with space group P a −3. The Debye-Scherrer’s formula was implemented to determine the average crystallite size of nanoparticles and found to be 24.24 nm. Through the use of Field Emission Scanning Electron Microscopy (FESEM), the morphology and effective grain size of the obtained sample was determined. FTIR spectrophotometry was used to examine the vibrational stretching of the various bonds in CoS2. UV-Vis spectroscopy is employed to measure the optical property of the sample. The optical bandgap calculated from the Tauc Plot is around 1.90 eV reflecting the presence of photovoltaic properties in the sample. The change in dielectric permittivity and loss have been observed for the sample in the frequency range of 100 Hz to 10KHz at different temperatures between 303K and 423K. The frequency-dependent electrical conductivity of CoS2 is also explained. The observations revealed the presence of unique electrical and structural properties in the synthesized sample.

Chemical/Electrochemical Dual‐Driven Transition Behavior of Copper Element from Current Collector to Chalcogenide Anode in Sodium‐Ion Batteries

AbstractThe transition phenomenon involving copper replacing the transition metal elements within transition metal chalcogenides (TMCs) is a recent and unique observation in the context of sodium ion batteries (SIBs) where TMCs serve as anodes. Fundamental understanding of the driving forces and kinetics governing this transition is crucial for elucidating the sodium storage mechanism in TMCs anodes. Herein, cobalt disulfide (CoS2) has been chosen as a representative anode. It is revealed that the transition behavior of copper replacing cobalt during the cycling originates from chemical/electrochemical dual‐driving forces. The chemical driving force emanates from the interaction between Cu+ dissolved in the electrolyte and the resulting sodium polysulfide products. The reaction extent is intricately linked to the surface roughness of the copper collector. The electrochemistrical driving force is effectively elucidated through the application of the Hard‐Soft‐Acid‐Base theory. Multiple charaterization techniques, such as Solid‐state nuclear magnetic resonance (ssNMR) have been employed to confirm that cobalt exists as cation instead of metal after transition. This research offers a novel perspective understanding the transition behavior exhibited by CoS2, with potential wider implications for understanding analogous behaviors in other metal sulfide anodes.

Modulating Electronic Structure with Copper Doping to Promote the Electrocatalytic Performance of Cobalt Disulfide in Li-O2 Batteries.

Introducing heteroatom into catalyst lattice to modulate its intrinsic electronic structure is an efficient strategy to improve the electrocatalytic performance in Li-O2 batteries. Herein, Cu-doped CoS2 (Cu-CoS2 ) nanoparticles are fabricated by a solvothermal method and evaluated as promising cathode catalysts for Li-O2 batteries. Based on physicochemical analysis as well as density functional theory calculations, it is revealed that doping Cu heteroatom in CoS2 lattice can increase the covalency of the CoS bond with more electron transfer from Co 3d to S 3p orbitals, thereby resulting in less electron transfer from Co 3d to O 2p orbitals of Li-O species, which can weaken the adsorption strength toward Li-O intermediates, decrease the reaction barrier, and thus improve the catalytic performance in Li-O2 batteries. As a result, the battery using Cu-CoS2 nanoparticles in the cathode exhibits superior kinetics, reversibility, capacity, and cycling performance, as compared to the battery based on CoS2 catalyst. This work provides an atomic-level insight into the rational design of transition-metal dichalcogenide catalysts via regulating the electronic structure for high-performance Li-O2 batteries.

Prussian blue-derived hollow carbon-wrapped Fe-doped CoS2 nanocages as durable electrocatalyst for efficient hydrogen evolution

Cobalt disulfide (CoS2) is regarded as a low cost and abundant non-noble electrocatalyst, but some drawbacks limit its application due to its sluggish intrinsic electrocatalytic kinetics and high hydrogen evolution overpotential. In this work, carbon-wrapped Fe-doped CoS2 nanocages (C/Fe–CoS2) were synthesized via gradual sulfurization of cobalt hexacyanoferrate and evaluated as electrocatalysts for hydrogen evolution reaction (HER). The nanocage architecture exposes more electrochemically active site, and carbon wrapping reduces the agglomeration of C/Fe–CoS2 and optimizes the electronic structure, while the Fe doping decreases the hydrogen adsorption free energy of CoS2. Therefore, C/Fe–CoS2 demonstrates a superior HER performance, showing a benchmark current density of 10 mA cm−2 at the low overpotential of 151 mV in acidic electrolyte and a remarkable stability (cyclic voltammetry cycling for 3000 cycles and continuous electrolysis at the overpotential of 180 mV for 25,000 s). The as-designed C/Fe–CoS2 should be one of the most promising catalysts for HER application. This strategy highlights the construction of high performance electrocatalysts via structure designing and heteroatom doping for efficient and stable hydrogen generation.

Study on the effect of carbon nanotubes loaded with cobalt disulfide modified multifunctional separator on Li-S battery

To solve the “deadliest” shuttle effect in Li-S battery, the design of appropriate separator become more and more important for better electrochemical performance. CoS2/CNTs composites were obtained by loading cobalt disulfide on the surface of CNTs through two-step pyrolysis. Through morphological analysis and physical property characterization, CoS2 was proved to be well loaded on CNT, and there was a good contact between the composite and PP separator. Inorganic metal sulfides in the modified layer of CoS2/CNTs can enhance the utilization of active sulfur materials through the enhanced chemical adsorption of LiPSs, which is further enhanced by the high electrical conductivity of CNTs. Moreover, the composite material can also accelerate the catalytic conversion of LiPSs, accelerate the ion diffusion rate, weaken the reaction polarization, effectively weaken the capacity decline caused by the shuttle effect, and enhance the electrochemical performance of the system.

Liquid metal-assisted hydrothermal preparation of cobalt disulfide on the polymer tape surface for flexible sensor

Liquid metal-assisted hydrothermal preparation of cobalt disulfide on the polymer tape surface for flexible sensor

CoS2/N-doped carbon nanotubes hollow polyhedron derived from core-shell ZIF-8@ZIF-67 for efficient hydrogen evolution reaction

Among various hydrogen evolution reaction (HER) catalysts, cobalt disulfide (CoS2) has attracted extensive attention due to its abundant sources, favorable electrical conductivity and electrocatalytic activity. Herein, CoS2-embedded nitrogen-doping carbon nanotubes with hollow polyhedron (CoS2/NCNHP) derived from ZIF-8@ZIF-67 was synthesized and functioned as an HER electrocatalyst. Carbon materials from the pyrolysis of ZIF-8@ZIF-67 effectively retained porous structures of the zeolitic imidazolate frameworks, resulting in a high specific surface area to provide a carrier for the loading of the CoS2 nanoparticles, while the generation of N-doped carbon nanotubes (NCNTs) further enhanced the electrical conductivity of the substrate. In addition, the favorable electrochemical properties were facilitated by the synergistic effect between CoS2 and NCNTs. Therefore, the material, CoS2/NCNHP, was electrochemically tested under acidic conditions, showing the overpotential was only 144 mV at the current density of 100 mA·cm−2, and the current density remained 89.6% after a long electrolysis period of 24 h. The synthetic strategy for the controlled design of MOF-derived materials affords a new pathway in developing commercial electrocatalysts.

A facile strategy to convert low-activity commercial iron oxides and cobalt disulfide into high-activity Fenton-like catalysts: spontaneous generation of 1O2 for aqueous decontamination

Developing highly efficient, steady, and cost-effective heterogeneous catalyst for the in situ production of singlet oxygen (1O2) is the key challenge to advanced oxidation processes. Previous studies usually involve demanding reaction conditions, cumbersome preparation processes, or hazardous chemicals. Herein, a facile ball milling procedure is adopted to design a vacancy-rich iron–cobalt bimetallic heterojunctions (b-CoS2/Fe3O4) catalyst with a core–shell structure, which can convert various inefficient commercial iron oxides and cobalt disulfide into highly active catalysts for dioxygen activation. Both experiment and DFT calculations show that the direct interfacial interaction between the CoS2 and iron oxides, which is introduced by the ball milling, regulates the bond energy of Fe–O, contributing to the excellent reactivity toward molecular oxygen activation. As a result, in the absence of electricity, light, and other oxidants, the strong interaction between CoS2 and Fe3O4 enables the degradation activity of organic pollutants to be significantly enhanced. In addition, we design an automated reactor and apply it to wastewater treatment in continuous flow mode, further revealing the huge potential of the proposed system in environmental remediation.

The importance of cobalt disulfide morphology for cellulose depolymerization: Hydrogenolysis versus acid catalysis

Acid-catalyzed hydrolysis and metal-catalyzed hydrogenolysis are two important methods for conversion of cellulose into high value-added chemicals, which preferentially use homogeneous acids and precious metals as catalysts, respectively. This paper reports that cobalt disulfide (CoS2) can be competent in both acid hydrolysis and hydrogenolysis reactions as an inexpensive heterogeneous catalyst by controlling its morphology. Two kinds of CoS2 with imperfect spherical (A-CoS2) and regular octahedral (Syn-CoS2) morphologies were tested in the conversion of 5-hydroxymethylfurfural (HMF) under a hydrogen atmosphere. Interestingly, A-CoS2 showed high activity in the hydrogenolysis of HMF to 2,5-hexanedione (2,5-HD) with a yield of 81.5 wt%, while Syn-CoS2 was responsible for the acid hydrolysis of HMF to methyl levulinate (ML) in high yield of 90.8 wt%. Characterization of the two catalysts suggested that Syn-CoS2 had higher Co2+/Co3+ ratio in comparison to A-CoS2, leading to a proportional difference in their acid site numbers. The unique activity of these two catalysts was also reflected in the conversion of cellulose. In particular, Syn-CoS2 exhibited high selectivity to ML formation from cellulose and good recyclability.

The balanced improvement of electrochemical performance of cobalt disulfide anode material for sodium-ion batteries by constructing reduced graphene oxide conductive network based on “bucket principle”

Recently, cobalt disulfide (CoS2) as a promising candidate of anode material for sodium ion batteries is paid much attention because of the high theoretical capacity. However, the poor rate capability and cycling stability are still the barriers to the large-scale application of CoS2 resulting from its low intrinsic electronic conductivity and severe volume change during the sodiation and desodiation process. In order to address above issues, herein, reduced graphene oxide (rGO) is introduced to define the CoS2 nanoparticles growth in the solvothermal synthesis process and construct the three-dimensional conductive network, which can tune the electronic conductivity, ionic diffusivity and inhibiting effect of volume change of CoS2/rGO composites anode material. It is found that these factors show different trends accompanying with the increase of rGO doping amount. The compact rGO network is beneficial to improve the electronic conductivity and hinder the volume change of the composites, however, it maybe does harm to the fast sodium ion diffusion. And when it becomes sparse, the opposite is true. Hence, a balanced strategy based on “bucket principle” is proposed to achieve the balanced enhancement of the rate capability and cycling performance. The optimized CoS2/rGO electrode acquires a superior performance, possessing 675.8 mAh g−1 at 0.1 A g−1 and 471.1 mAh g−1 at 2.0 A g−1 with the capacity retention of 69.7%, and it still has 272.5 mAh g−1 after 500 cycles at 1.0 A g−1 in the voltage range of 0.01–3.0 V. This can be attributed to the improvement of charge transfer process and the excellent accommodating capacity of volume change provided by rGO conductive network. This balanced strategy can also be used to synthesize high-performance composite materials in other fields.

CoS2/N,S co-doped mesoporous carbon with 3D micro-nano crosslinked structure as efficient bifunctional oxygen electrocatalysts for zinc-air batteries

This work describes a bifunctional oxygen catalyst made of cobalt disulfide encapsulated in N,S co-doped mesoporous carbon with a novel three-dimensional micro-nano crosslinking structure. The proposed composite materials exhibit promising oxygen electrocatalytic activity and stability. The composite assembled rechargeable zinc-air battery can achieve a high power density of 208.9 mW/cm2, and can be stably cycled for more than 160 h. Additionally, the all-solid zinc-air battery assembled with the electrocatalyst also performs admirably. The micro-nano crosslinking and high porosity structure, as well as the large number of active sites generated by the synergy of N,S doping and the close interface between carbon matrix and CoS2, contribute to the composite's exceptional electrochemical performance. This study's rational strategy lays the path for the development of other high-performance bifunctional electrocatalysts.

The influence of crystal growth mechanism based on various sulfur sources on the morphology, component and electrochemical performance of cobalt sulfide as anode material for sodium-ion batteries

Cobalt sulfides (CoS x ) have been paid lots of attention as promising anode candidates for sodium-ion batteries owing to their merits of high theoretical capacity, good electrochemical reversibility and superior thermal stability. However, the preparation of cobalt sulfide with the excellent rate capability and long-term cyclic stability is still a great challenge. Herein, we have prepared cobalt sulfides by one-step solvothermal method using four sulfur sources including sodium thiosulfate, thioacetamide, thiourea and L -Cysteine, respectively. And the mechanism of the bond energies and groups of sulfur source molecules influence the crystal growth process are studied. Moreover, the four cobalt sulfides with different components, morphologies and structures are tested and analyzed as the anode materials for sodium-ion batteries (SIBs). The CoS x using sodium thiosulfate as the sulfur source achieves an excellent cycling performance, which still has a capacity of 690.0 mAh g −1 after 1000 cycles at 2 A g −1 with the retention of 98.1% and an outstanding rate capability of 626.6 mAh g −1 at 5 A g −1 . This superiority may be attributed to its pure component cobalt disulfide (CoS 2 ) with abundant active sites and the unique morphology leading to the high material utilization. Our studies give a clear evidence that sulfur sources play an important role in the crystal growth and constructing high-performance sulfide-based anode materials. • Cobalt sulfides were prepared by solvothermal method with different sulfur sources. • The bond energies and amino group of sulfur sources play an important role in the cobalt sulfide crystal growth mechanism. • The phase components and micromorphologies of cobalt sulfides are influenced by the species of sulfur source. • A high-performance cobalt sulfide is obtained with 626.6 mAh g −1 at 5 A g −1 and 690.0 mAh g −1 after 1000 cycles at 2 A g −1 .

One‐Pot Synthesis of CoS2Merged in Polymeric Carbon Nitride Films for Photoelectrochemical Water Splitting

Polymeric carbon nitride (PCN) has attracted intensive interest as sustainable, metal-free semiconductor for photoelectrochemical (PEC) water splitting. Charge transfer along the films acts as the main concern to restrict the performance due to the amorphous nature of polymer. Herein, gradient concentration of cobalt disulfide (CoS2 ) merged in PCN films was realized as CSCN photoanode by a one-pot synthesis. Owing to the unique properties of CoS2 , namely high conductivity, the charge transfer of the CSCN photoanode was promoted, and thus the performance for PEC water oxidation was improved. The optimal photoanode exhibited a photoanodic current of 200 μA cm-2 at 1.23 V versus reversible hydrogen electrode under air mass 1.5 global (AM 1.5G) illumination, which was approximately 4 times that of the pristine PCN photoanode. This work provides a new design of metal-free photoanodes to improve the performance of water splitting.

Cobalt(II)-disulfide compounds with the unusual PF2O2– anion. ligand-dependent redox conversion to a cobalt(III)-thiolate complex

Herein we describe the synthesis of the cobalt(II) disulfide compounds [CoII2(LxSSLx)(μ–PO2F2)2](PF6)2 and [CoII2(LxSSLx)(NO3)4] (x = 1: di-2-(bis(2-pyridylmethyl)amino)-ethyl disulfide; x = 2: di-2-((6-methyl-2-pyridylmethyl)(2-pyridylmethyl)amino)-ethyl disulfide). The crystal structures show the cobalt(II) centers in [CoII2(LxSSLx)(μ-PO2F2)2](PF6)2 to be in distorted octahedral geometries, whereas in [CoII2(L1SSL1)(NO3)4] the geometries are distorted trigonal bipyramidal. The cobalt(II) centers in [CoII2(LxSSLx)(PO2F2)2](PF6)2 are coordinated by three nitrogen and one sulfur donor atom of the disulfide ligand, and two oxygen atoms of two bridging difluoridophosphate anions. The cobalt(II) centers in [CoII2(L1SSL1)(NO3)4] are coordinated by three nitrogen donors of the ligand and three oxygen atoms of one monodentate and one bidentate nitrate anion, the latter two oxygen atoms together occupying one of the equatorial sites of the trigonal bipyramid. It was found that the dinuclear compound [CoII2(L1SSL1)(PO2F2)2](PF6)2 is stable as such in methanol and dichloromethane solution, but in acetonitrile redox conversion occurs forming the cobalt(III) thiolate compound [CoIII(L1S)(MeCN)2]2+. The compound [CoII2(L1SSL1)(NO3)4] and the disulfide compounds of the ligand L2SSL2 do not show this redox conversion and remain in the disulfide form in all investigated solvents.

Production of methyl levulinate from cellulose over cobalt disulfide: The importance of the crystal facet (111)

The conversion of cellulose to platform chemicals has attracted much attention because of its renewability. This work proposed an earth-abundant cobalt disulfide as a heterogeneous catalyst for methyl levulinate production from cellulose. The highest yield of methyl levulinate reached 61 mol% under the tested conditions of 200 °C, 2 MPa initial pressure, 0.45 catalyst/cellulose mass ratio, and 3 h reaction time. The XRD and TEM analyses demonstrated the crystal facet (111) of cobalt disulfide as a robust active site, which was in good agreement with the highest acidity of the crystal facet (111) calculated by the work functions. The XPS characterization showed that the main chemical valence of cobalt disulfide responsible for the methyl levulinate production was the surface Co2+ species. This study is valuable for the development of a recoverable catalyst for the cellulose to methyl levulinate process.