Metal-sulfur Bond Research Articles

Sleuthing the performance of the sustainable mixed metal trichalogenide BaS:Sn2S3:LaS from single source route as an electrode material for charge storage

A novel ternary transition and lanthanide metal composite sulfide (Ba, Sn, and La) has been developed using a single-source precursor method with diethyldithiocarbamate ligand. The resulting BaS:Sn2S3:LaS chalcogenide exhibits a finely tuned band gap of 3.88 eV, reflecting its superior optical performance. This eco-friendly sulfide features an average crystalline size of 17.93 nm and displays a mix of phases. Vibrational analysis reveals distinct transmission peaks corresponding to metal-sulfur bonds. Morphologically, BaS:Sn2S3:LaS composite is characterized by irregularly shaped particles forming a randomly agglomerated mass. The electrochemical charge storage properties of the semiconducting trichalcogenide BaS:Sn2S3:LaS have been investigated using cyclic voltammetry, galvanostatic charge-discharge, and impedance spectroscopy. BaS:Sn2S3:LaS electrode demonstrated impressive performance, storing electrical charge efficiently with a specific capacity of 659.6 F g⁻1 and achieving a power density of up to 3661.65 W kg⁻1. Additionally, the electrode exhibited low resistance, with an equivalent series resistance (Rs) of just 0.43 Ω, indicating efficient ion diffusion across the interface. Given its excellent redox activity and low resistance, BaS:Sn2S3:LaS shows strong potential as an electrode material for supercapacitors and batteries.

High-Entropy Transition Metal Phosphorus Trichalcogenides for Rapid Sodium Ion Diffusion.

High-entropy strategies are regarded as a powerful means to enhance performance in energy storage fields. The improved properties are invariably ascribed to entropy stabilization or synergistic cocktail effect. Therefore, the manifested properties in such multicomponent materials are usually unpredictable. Elucidating the precise correlations between atomic structures and properties remains a challenge in high-entropy materials (HEMs). Herein, atomic-resolution scanning transmission electron microscopy annular dark field (STEM-ADF) imaging and four dimensions (4D)-STEM are combined to directly visualize atomic-scale structural and electric information in high-entropy FeMnNiVZnPS3. Aperiodic stacking is found in FeMnNiVZnPS3 accompanied by high-density strain soliton boundaries (SSBs). Theoretical calculation suggests that the formation of such structures is attributed to the imbalanced stress of distinct metal-sulfur bonds in FeMnNiVZnPS3. Interestingly, the electric field concentrates along the two sides of SSBs and gradually diminishes toward the two-dimensional (2D) plane to generate a unique electric field gradient, strongly promoting the ion-diffusion rate. Accordingly, high-entropy FeMnNiVZnPS3 demonstrates superior ion-diffusion coefficients of 10-9.7-10-8.3 cm2 s-1 and high-rate performance (311.5 mAh g-1 at 30 A g-1). This work provides an alternative way for the atomic-scale understanding and design of sophisticated HEMs, paving the way for property engineering in multi-component materials.

SILAR deposited Cu2MnSnS4 thin films for sustainable energy applications

A heavy metal-free chalcopyrite (Cu2MnSnS4) thin film has been synthesized via the SILAR method by varying the adsorption and reaction time. The fabricated thin films are characterized by structural, spectral, and optical properties that are analyzed. The X-ray diffraction studies indicated the formation of Cu2MnSnS4 with grain size ranging from (16–18 nm). The Field Emission Scanning Electron Microscopic (FESEM) analysis revealed uniform film formation. Fourier Transformed Infrared Spectral (FTIR) analysis shows that sharp peaks are observed at 552 cm−1 and 1248 cm−1, indicating the presence of metal-sulfur bonds. The peak at 810 cm−1 is due to the resonance interaction of the sulfide ion. The band gap of Cu2MnSnS4 is in the range of 1.96–2.01 eV from UV–visible absorption studies.

Utilizing an electron redistribution strategy to inhibit the leaching of sulfur from CeO2/NiCo2S4 heterostructure for high-efficiency oxygen evolution

Developing highly active and robust transition metal chalcogenides (TMCs) electrocatalysts toward oxygen evolution reaction (OER) remains a challenge. Herein, we report an electron redistribution mechanism that involves the metal-sulfur (M-S) bond stabilization triggered by electron transfer from Ce to Ni and Co in CeO2/NiCo2S4 heterostructure, thereby effectively inhibiting the leaching of sulfur from CeO2/NiCo2S4 during the OER process. Moreover, the well-modulated heterogeneous interface enables optimal adsorption affinity for oxygen intermediates and reduces the energy barrier of OER. As a result, CeO2/NiCo2S4 exhibits superior OER activity with ultralow overpotentials of 146 and 271 mV at 10 and 100 mA cm−2, respectively. More importantly, CeO2/NiCo2S4 possesses excellent durability for over 200 h at 500 mA cm−2, surpassing individual NiCo2S4 and most of the reported TMCs-based electrocatalysts. This work provides new insights for achieving good compatibility of TMCs-based OER electrocatalysts in terms of high activity and stability.

Promotion of Rh-based La2Zr2O7 type catalysts with the transition metals to improve sulfur-tolerance in diesel reforming

Several Rh-based La2Zr2O7 type catalysts promoted by the transition metals (Mn, Fe, and Co respectively) were synthesized and used to reform n-hexadecane (a diesel surrogate) that contains 50 ppm dibenzothiophene for hydrogen production. Compared to Co-LaZrRh and Mn-LaZrRh, the Fe-LaZrRh catalyst exhibited the best hydrogen extraction capability and sulfur tolerance. This is probably due to the introduction of Fe, which not only enhances the Rh dispersion, but also facilitates the formation of electron-deficient Rh sites and the generation of oxygen vacancies. Additionally, electron-deficient Rh sites can hinder the formation of an irreversible sulfur-metal bond, thus resulting in better sulfur tolerance and thermal stability. Finally, the generated oxygen vacancies may also activate steam to form surface active oxygen species, which help remove the deposited carbon on the catalyst surface. In summary, the developed Fe-LaZrRh catalyst performed the best in the steam reforming of n-hexadecane containing 50 ppm sulfur, which deserves further exploration for future applications.

A general copper-catalysed enantioconvergent C(sp3)-S cross-coupling via biomimetic radical homolytic substitution.

Although α-chiral C(sp3)-S bonds are of enormous importance in organic synthesis and related areas, the transition-metal-catalysed enantioselective C(sp3)-S bond construction still represents an underdeveloped domain probably due to the difficult heterolytic metal-sulfur bond cleavage and notorious catalyst-poisoning capability of sulfur nucleophiles. Here we demonstrate the use of chiral tridentate anionic ligands in combination with Cu(I) catalysts to enable a biomimetic enantioconvergent radical C(sp3)-S cross-coupling reaction of both racemic secondary and tertiary alkyl halides with highly transformable sulfur nucleophiles. This protocol not only exhibits a broad substrate scope with high enantioselectivity but also provides universal access to a range of useful α-chiral alkyl organosulfur compounds with different sulfur oxidation states, thus providing a complementary approach to known asymmetric C(sp3)-S bond formation methods. Mechanistic results support a biomimetic radical homolytic substitution pathway for the critical C(sp3)-S bond formation step.

Systematic investigation of MoS2-metal sulfides (Metal = In, Sn, Cu, Cd) heterostructure via metal-sulfur bond for photocatalytic CO2 reduction

Heterojunctions between MoS2 and metal sulfides (Metal = In, Sn, Cu, Cd) were successfully constructed via the metal-sulfur bond, and their application of CO2 photoreduction into chemical values could address the problem of global warming effectively. Among all MoS2/metal sulfides, the same lamellar morphology between MoS2 and In2S3 could be ascribed for the high photocatalytic performance, which revealed the high specific surface area and benefitted for the generation of build-in electric field, thus leading to the outstanding separation and migration ability. In the opposite, the dissatisfactory photoreduction performance was emerged on the heterostructure between rod-like morphology of CdS and lamellar MoS2. Moreover, the feature of small gap between valence band minimum and Fermi level in In2S3 was remained in MoS2/In2S3 composite, which could promote more carriers to be excited. Hence, the optimal MoS2/In2S3 composite reached 10.09 μmol·h−1·g−1 of CO, 68.41 μmol·h−1·g−1 of CH4 and 6.66 μmol·h−1·g−1 of CH3OH, and the mix-coordination of CO2 adsorption and the carbene pathway over MoS2/In2S3 was revealed via in-situ DRIFTS.

Cu(I)-thioether coordination complexes based on a chiral cyclic β-amino acid ligand

Coordination complexes, particularly metalloproteins, highlight the significance of metal-sulfur bonds in biological processes. Their unique attributes inspire efforts to synthetically reproduce these intricate metal-sulfur motifs. Here, we investigate the synthesis and characterization of copper(I)-thioether coordination complexes derived from copper(I) halides and the chiral cyclic β-amino acid trans-4-aminotetrahydrothiophene-3-carboxylic acid (ATTC), which present distinctive structural properties and ligand-to-metal ratios. By incorporating ATTC as the ligand, we generated complexes that feature a unique chiral conformation and the capacity for hydrogen bonding, facilitating the formation of distinct geometric structures. Through spectroscopic analyses and density functional theory (DFT) calculations, we studied the complexes’ optical properties, including their emission bands and variable second-harmonic generation (SHG) efficiencies, which vary based on the halide used. Our findings underscore the potential of the ATTC ligand in creating unusual coordination complexes and pave the way for further investigations into their potential applications, particularly within materials science.

Extreme long-lifetime self-assembled monolayer for air-stable molecular junctions.

The molecular electronic devices based on self-assembled monolayer (SAM) on metal surfaces demonstrate novel electronic functions for device minimization yet are unable to realize in practical applications, due to their instability against oxidation of the sulfur-metal bond. This paper describes an alternative to the thiolate anchoring group to form stable SAMs on gold by selenides anchoring group. Because of the formation of strong selenium-gold bonds, these stable SAMs allow us to incorporate them in molecular tunnel junctions to yield extremely stable junctions for over 200 days. A detailed structural characterization supported by spectroscopy and first-principles modeling shows that the oxidation process is much slower with the selenium-gold bond than the sulfur-gold bond, and the selenium-gold bond is strong enough to avoid bond breaking even when it is eventually oxidized. This proof of concept demonstrates that the extraordinarily stable SAMs derived from selenides are useful for long-lived molecular electronic devices and can possibly become important in many air-stable applications involving SAMs.

Anode Electrolysis of Copper Matte to Produce Copper and Iron

Electrochemically splitting sulfides to metals and sulfur gas is a promising clean method to reduce energy consumption and environmental burden. Anode electrolysis has been proven to break metal-sulfur bonds at the anode in molten salts, but the electrolysis of complex sulfides has not been investigated. Herein, the selective extraction of Fe, Cu and S in copper matte (the mixture of FeS and Cu2S) by anode electrolysis was thoroughly studied by both thermodynamics and electrochemical tests. The FeS component was preferentially oxidized from copper matte on the anode while releasing sulfur gas, and the Fe powder as the main product was first collected from the cathode and then Cu was obtained. During potentiostatic electrolysis of copper matte on the anode, the content of Fe element was reduced from 49.1% to 18.6%, and the content of Cu element was enriched from 1.8% to 41.2%, showing the potential for not only achieving the clean sulfide electrochemical metallurgy but also effective separation. Thus, anode electrolysis could be applied to extract various complex sulfide ores.

Factors affecting the durability of dimethyl dithiocarbamate-stabilized air pollution control (APC) residues derived from municipal solid waste incineration

Sodium dimethyl dithiocarbamate (SDD) is widely used for stabilizing heavy metals to minimize pollution from air pollution control (APC) residues derived from municipal solid waste incineration. However, the effect of environmental conditions on heavy metal leaching from SDD-stabilized APC residues remains unknown. Therefore, this study aimed to evaluate the durability of SDD-stabilized APC residues and determine the relationship between heavy metal leaching and environmental factors, including pH, temperature, and oxygen. The results revealed that accelerated SDD decomposition and the decline in durability of SDD-stabilized APC residues were caused by acidic and aerated conditions and temperatures above 40 °C. A decrease in pH from 12.25 to 4.69 increased the Cd and Pb concentrations in SDD-stabilized APC residue leachate from below detection (0.002 mg/L) to 1.32 mg/L and 0.04 mg/L to 3.79 mg/L, respectively. Heating at 100 °C for 2 d increased the Cd and Pb concentrations from below detection (0.002 mg/L and 0.01 mg/L) to 2.96 mg/L and 0.47 mg/L, respectively. Aeration for 5 d increased the Cd and Pb concentrations from below detection to 0.09 mg/L and 0.49 mg/L, respectively. The decline in durability was attributed to acid hydrolysis, thermal decomposition, and oxidative damage of SDD, resulting in breakage of the chelated sulfur-metal bond, which was confirmed by the decrease in the oxidizable fraction of heavy metals and the SDD content. This study improves the understanding of the factors contributing to the decline in durability of heavy metals in SDD-stabilized APC residues, which is important for ensuring the long-term stabilization and environmental safety of these residues.

Straightforward Manufacturing of 3D-Printed Metallic Structures toward Customized Electrical Components.

Metalizing three-dimensional (3D)-printed polymers has been spotlighted in the field of manufacturing high-end and customized electrical components. Conventional metalization approaches that rely on the electroless plating (ELP) process typically require the use of noble metal-based catalysts or involve multistep processes, limiting their practical applications. Herein, we propose a straightforward yet effective approach to manufacture 3D-printed polymers with conductive metal layers through a thiol-mediated ELP process without involving an additional catalytic activation process. A photocurable ternary resin based on thiol-ene-acrylate monomers was precisely designed to induce excess thiol moieties on the surface of 3D-printed structures. These exposed thiol moieties served as active sites for metal ion complexion via strong metal-sulfur bonds, allowing the deposition of metal layers on the 3D-printed polymers through the ELP. Diverse metal layers, including Cu, Ag, and NiP, could be deposited onto virtually any 3D-printed structures with high uniformity and adhesion stability. To highlight the potential application of our approach, we fabricated fully functional glucose sensors through the deposition of the Cu layer on 3D-printed electrode models, and these sensors displayed excellent nonenzymatic glucose sensing performance. The proposed approach offers great insights for designing functional metallic structures and opens up new avenues for manufacturing lightweight, customized electrical components.

Facile aqueous synthesis of ZnCuInS/ZnS–ZnS QDs with enhanced photoluminescence lifetime for selective detection of Cu(ii) ions

Abstract Quaternary quantum dots (QDs) have recently gained more attention due to their low toxicity, tunable wavelength, reduced or no blueshift emission upon overcoating, improved photoluminescence (PL) quantum yield, and PL lifetime when compared to their binary (II–VI) and ternary (I–III–VI) counterparts. In this work, the aqueous synthesis of ZnCuInS/ZnS–ZnS multi-shell quaternary QDs as a nanosensor for the selective detection of Cu2+ ions was reported. The as-synthesized QDs were spherical, with a particle diameter of 3.66 ± 0.81 nm, and emitted in the first near-infrared window (725 nm) with an average decay PL lifetime of 43.69 ns. The X-ray diffraction analysis showed that the QDs were of the wurtzite structure, while the Fourier transform infrared spectroscopy confirmed GSH capping through the sulphur–metal bond. Furthermore, the fluorometric study shows that the developed multi-shell QDs were selective towards Cu2+ ions compared to other metal ions via fluorescence quenching with a limit of detection of 1.4 µM, which is below the acceptable limit in drinking water.

Molecular Precursor Routes for Ag-Based Metallic, Intermetallic, and Metal Sulfide Nanoparticles: Their Comparative ORR Activity Trend at Solid|Liquid and Liquid|Liquid Interfaces

The electrochemical conversion of oxygen to water is a crucial process required for renewable energy production, whereas its first two-electron step produces a versatile chemical and oxidant─hydrogen peroxide. Improving performance and widening the limited selection of the potential catalysts for this reaction is a step toward the implementation of clean-energy technologies. As silver is known as one of the most effective catalysts of oxygen reduction reaction (ORR), we have designed a suitable molecular precursor pathway for the selective synthesis of metallic (Ag), intermetallic (Ag3Sb), and binary or ternary metal sulfide (Ag2S and AgSbS2) nanomaterials by judicious control of reaction conditions. The decomposition of xanthate precursors under different reaction conditions in colloidal synthesis indicates that carbon-sulfur bond cleavage yields the respective metal sulfide nanomaterials. This is not the case in the presence of trioctylphosphine when the metal-sulfur bond is broken. The synthesized nanomaterials were applied as catalysts of oxygen reduction at the liquid-liquid and solid-liquid interfaces. Ag exhibits the best performance for electrochemical oxygen reduction, whereas the electrocatalytic performance of Ag and Ag3Sb is comparable for peroxide reduction in an alkaline medium. Scanning electrochemical microscopy (SECM) analysis indicates that a flexible 2-electron to 4-electron ORR pathway has been achieved by transforming metallic Ag into intermetallic Ag3Sb.

Carbothermal reduction synthesis of sulfide-modified biochar for heavy metal removal

Although sulfide is effective for heavy metal immobilization, it rarely exists in pristine pyrogenic biochar and easily undergoes intensive hydrolysis. In this work, carbothermal reduction of sulfate for on-site sulfide formation and simultaneous carbon layer encapsulation was developed to synthesize sulfide (CaS) modified biochar for enhancing heavy metal immobilization capacity. The initial reaction temperature for this carbothermal reduction was 700 °C. Increasing the pyrolysis temperature, modifier electron accepting ability and loading content could facilitate carbothermal reduction as further partly confirmed by on-site MS of pyrolysis gas and S 2p XPS of biochar analysis. The formed CaS on biochar could be greatly inhibited from hydrolysis due to the encapsulation effect of carbon layer and reached nearly 100% utilization efficiency in Cd2+ fast immobilization. TEM line scan and XRD of post-adsorbed biochar indicated that high heavy metal immobilization capacity was mainly attributed to the coprecipitation reaction governed by the formation of metal-sulfur bond. Compared with reported absorbents, CaS-modified biochar via carbothermal reduction with on-site encapsulation exhibited an excellent stability and outstanding immobilization capacity for various heavy metal ions (such as Cd2+, Pb2+, Cu2+, Zn2+, Ag+).Graphical

Improving anti-coking and sulfur-resisting performance of Rh-based lanthanum zirconate pyrochlore catalysts for diesel reforming through partial substitution with alkali earth metals

This work studied the effect of partial substitution of La by alkali earth metals (Mg, Ca, and Ba) on the catalytic performance of steam reforming of diesel over pyrochlore type catalysts with n-hexadecane as surrogate fuel. The experimental results indicated that LaBaZrRh catalyst exhibited a superb catalytic activity and sulfur tolerance with ∼100% fuel conversion and ∼65.8% H2 concentration in the reformate for a runtime over 30 h in the presence of 50 ppm sulfur. The introduction of Ba was found to greatly inhibit the coke formation and sulfur poisoning to catalysts. The H2-TPR and H2 pulse chemisorption tests further revealed that it is the partial substitution of La by Ba that enhances the interaction between the active metal Rh and La2Zr2O7 support, thus significantly improving the dispersion of Rh active component and decreasing the size of Rh particles. The XPS results showed that the electron-deficient Rh was formed in LaBaZrRh catalyst. The weaker interaction between sulfur and electron-deficient metals led to the easy breaking of the sulfur-metal bond in LaBaZrRh catalyst, thus resulting in good sulfur tolerance. Additionally, the La substitution by Ba also enhanced the concentration of oxygen vacancies, which improved the coking resistance.

Intracluster ligand rearrangement: an NMR-based thermodynamic study.

Ligand and metal exchange reactions are powerful methods to tailor the properties of atomically precise metal nanoclusters. Hence, a deep understanding of the mechanisms behind the dynamics that rule the ligand monolayer is crucial for its specific functionalization. Combining variable-temperature NMR experiments and dynamic-NMR simulations, we extract the thermodynamic activation parameters of a new exchange reaction: the intracluster ligand rearrangement between the two symmetry-unique positions in [Ag25(DMBT)18]- and [Ag24Au(DMBT)18]- clusters. We report for the first time that this peculiar intracluster modification does not seem to proceed via metal-sulphur bond breaking and follows a first-order rate law, being therefore a process independent from the well-described collisional ligand exchange.

The adjacent Fe oxidation greatly enhancing OER activity on the Ni active site: S plays the role in optimizing local coordination and electronic structure

Oxygen evolution reaction (OER) is the bottleneck process of water splitting, and finding efficient, durable, low-cost, and earth-abundant electrocatalysts remains a major challenge. Here, FeNi2-400-S is to be a promising OER electrocatalyst which exhibits a low overpotential of 214 mV at a current density of 10 mA/cm2. X-ray analysis indicates that the introduction of S leads to a mismatch in bond distance between the metal-sulfur bond and the metal-metal bond, which can change the local electronic structure and favorably control the electronic oxidation. The active site position of FeNi2-400-S has been further confirmed by DFT, which the ∗OOH can stably adsorb on the Ni site of the oxidized Fe-Ni-S benefitting from the synergetic effect of the Ni site and the adjacent oxidized O on the Fe atom. Our findings demonstrate that the internal reconstruction of catalyst can make the optimization of local coordination and electronic structure, in which the in-situ generated vacancy can enable the outstanding OER performance.

A DFT study of site-dependent energetics of hexagonal MoS[formula omitted] nanoparticles under varying reaction conditions

A plane wave periodic density functional theory study of a representative hexagonal shaped MoS2 nanoparticle is conducted to compute the site-dependent energetics of the catalyst under different operating conditions. It is shown that the (1) energy for vacancy formation and the associated free energy profile of the reaction steps involved in creating the vacancy and (2) the binding energy of hydrogen and other probe atoms such as CO and lutidine, are all dependent on the location of the associated sulfur or molybdenum atom and the edge type (i.e. metal or sulfur edge). In particular, sulfur atoms near the corner are more strongly bound than those in the interior of the metal edge. Further, a larger metal-sulfur bond strength results in lower binding energy of hydrogen on that sulfur atom which in turn implies that this hydrogen is more Brønsted acidic in nature. These results indicate that the nature and the location of active sites on MoS2 is heavily dependent on the nature of the reaction that is being catalyzed and the corresponding operating conditions.

Tumor microenvironment responsive-multifunctional nanocomposites knotted injectable hydrogels for enhanced synergistic chemodynamic and chemo-photothermal therapies

Multifunctional nanomedicine has offered a promising strategy for effective anticancer therapy owing to its versatile capabilities. However, the systematic precise delivery still remains intractable challenge because of the existence of multi-staged biological barriers after intravenous administration. Herein, to address this issue, injectable and TME-responsive nanocomposite hydrogels were developed for localized and synergistic cancer therapy. The nanocomposite hydrogels (Au NBPs&Pt NCs@DOX gel) were synthesized via the formation of metal-sulfur bonds between 4arm-PEG-thiol and Au nanobipyramids or Pt nanoclusters with the DOX encapsulation. The hydrogel exhibited rapid gelation and excellent injectability. Attributed to the high absorbance of Au NBPs, the nanocomposite hydrogels revealed superior photothermal effect under NIR irradiation, which the DOX release was also regulated by NIR laser. In addition, the catalase- and peroxidase-like activities of Pt NCs were validated to convert endogenous H2O2 into ROS and O2 in situ to achieve chemodynamic therapy (CDT) and alleviate the hypoxic microenvironment. Simultaneously, catalytic therapy combined with NIR irradiation exhibited strongest inhibition to the growth of 4T1 tumor in vitro and in vivo. Thus, this study provided a new strategy for TME remodeling and local combination therapies of different therapeutic agents.