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Heteroatom Ni doping strategy was employed to tune the electronic conductivity of FeS 2 with rapid Na+ accessibility in sodium ion battery. As expected, Ni-FeS 2 @NC delivered high specific capacity and superior rate performance. [Display omitted] Iron sulfides (FeS 2) are promising anode materials for sodium ion batteries (SIBs); however, their inferior electronic conductivity, large volume swelling, and sluggish sodium ion diffusion kinetics lead to unsatisfactory rate performance and cycling durability. Heteroatom doping plays a crucial role in modifying the physicochemical properties of FeS 2 anodes to enhance its sodium storage. Herein, ultra-fine Ni-doped FeS 2 nanocrystals derived from a metal–organic framework (MOF) and in-situ anchored on a nitrogen doped carbon skeleton (Ni-FeS 2 @NC) are proposed to enhance both structural stability and reaction kinetics. Material characterization, electrochemical performance, and kinetics analysis demonstrate the critical role of Ni doping in sodium storage, particularly in accelerating Na+ diffusion efficiency. The N-doped carbon derived from the MOF can buffer the volume expansion and enhance the structural stability of electrode materials during sodiation/desodiation processes. As expected, Ni-FeS 2 @NC exhibits a high reversible capacity of 656.6 ± 65.1 mAh g−1 at 1.0 A g−1 after 200 cycles, superior rate performance (308.8 ± 6.0 mAh g−1 at 10.0 A g−1), and long-term cycling durability over 2000 cycles at 1.0 A g−1. Overall, this study presents an effective approach for enhancing the sodium storage performance and kinetics of anode materials for high efficiency SIBs. [ABSTRACT FROM AUTHOR]

The performance of lithium–sulfur (Li–S) rechargeable batteries is strongly dependent on the entrapment of the higher‐order intermediate polysulfides at the sulfur cathode. An attracting way of preventing the polysulfide shuttle is by introducing a polar host which can form a Lewis acid–base complex with polysulfides. Herein, the Li–S battery by incorporating iron sulfides (FeS2) as a polar Lewis acid to entrap higher‐order polysulfides at the cathode center is investigated. FeS2/S cathode demonstrates largely improved retention of capacity compared to C/S cathode (capacity fading per cycle of 0.12% and 0.80% for FeS2/S and C/S respectively) and good rate performance in Li–S batteries compared to conventional carbon–sulfur (C/S) cathode. This is attributed to the decrease in polysulfide dissolution and better retention of active sulfur in the cathode during battery cycling which is due to the polar FeS2 additive that well anchors polysulfides. The effect of FeS2 in preventing the shuttle mechanism is demonstrated by ex situ UV–vis spectroscopy and ex situ Raman spectroscopy studies. [ABSTRACT FROM AUTHOR]

The deep continental biosphere is supported by chemolithoautotrophy and depends on rock-derived substrates for energy. The majority of microorganisms in these crustal environments are likely attached to mineral surfaces within rock fractures, making characterization of deep life challenging. To better understand both biogeochemical cycling and mineral-hosted microbial communities in the deep subsurface, we characterized naturally occurring mineral particulate and associated biomass collected from boreholes drilled into a 2.7 Ga banded iron formation within the southern Canadian Shield. Particulate mineralogy was characterized via X-ray diffraction and Fe X-ray absorption near edge structure (XANES) spectroscopy. The particulate in one borehole was identified as a mixture of hematite and quartz, while the other borehole contained a mixture of the iron sulfides mackinawite and greigite, suggesting an active sulfur cycle mediated by microbial activity. Carbon associated with the particulate was imaged via scanning transmission X-ray microscopy and characterized via C XANES spectroscopy. In both boreholes, the particulate was colonized by microbial cells; many samples contained abundant biofilm. The cells and biofilm were chemically distinct, with the C XANES spectra for the cells consisting primarily of a protein-like signal and the biofilm resembling a mixture of protein, saccharide, and lipid. In the borehole containing the sulfidic particulate, the abundance of cells and biofilm increased with sample depth. Mineral particulate found in boreholes, whether forming in situ or as a result of drilling and weathering, are a valuable way to access the deep subsurface without the contamination and disturbance caused by drilling new cores. To better understand the microbial community composition and function associated with the particulate-biofilm aggregates and surrounding groundwater, filtered-water and particulate samples were characterized via shotgun metagenomic sequencing. Metagenomic analyses showed that while microbial communities were distinct between boreholes, all communities contained the genetic potential for the oxidation and reduction of a variety of sulfur phases. This suggests that the biogeochemical cycling of S, potentially connected to Fe cycling in this iron-rich habitat, could be fueling life in deep crustal environments. [ABSTRACT FROM AUTHOR]

Nano-sized iron sulfides have garnered great scientific interest as they possess a wide range of varieties, topologies, and physiochemical qualities. Particularly, iron sulfides (FeS) in the nanometer range size demonstrate enzyme-like activity by imitating organic enzymes that require an iron-sulfur cluster as a cofactor, increasing their potential for use in biomedicine. Here, sodium dithionite was used as the sulfur source and iron chloride (FeCl3·3H2O) as the iron source to create iron sulfide nanoparticles through the chemical precipitation method. The synthesis of the prepared FeS nanoparticles was confirmed by using various spectroscopic studies, i.e., TEM, SEM, DLS, VSM, XRD, and EDX, validating their size, shape, hydrodynamic diameter, magnetic properties, phase composition, and elemental composition respectively. The average particle size obtained from TEM was around 83 nm, and quasi-shaped morphology was observed from SEM. The presence of iron and sulfur within the synthesized nanoparticles was confirmed by EDX. Molecular docking is an effective tool to model the interactions between a protein and small molecules at the atomic level. The ability of a nanoparticle (ligand) to interact with proteins to form a protein–ligand complex plays a crucial role in the dynamics of proteins. The binding of nanoparticles with protein may inhibit or enhance (or have no effect) the biological function of the protein. Thus, it becomes necessary/important to know whether a particular nanoparticle should be used for drug delivery or not. The binding information obtained from the molecular docking of nanoparticles and proteins may be used to decide about the same. We have studied the interaction of ferrous/iron sulfide (FeS) with bovine serum albumin (BSA) and human serum albumin (HSA) proteins through molecular docking. The binding of ferrous/iron sulfide was studied separately with both the selected proteins. Findings demonstrated that four hydrogen bonds involving hydrogen atoms from four distinct amino acid residues of BSA protein (Arg194, Ser343, Asp450, and Ser453) are predicted by the preferential binding of FeS nanoparticles to BSA protein. However, binding to HSA involved only one hydrogen bond. We have further planned to extend our docking studies to study the interaction of BSA and HSA with anticancer drugs and drug-conjugated FeS nanoparticles. The constructive outcomes of the above studies could be used to perform in vitro studies. [ABSTRACT FROM AUTHOR]

Consumption of fossil fuels causes greenhouse effect and global warming, hence the need for renewable energy sources that are environmentally friendly. Hydrogen is one of the abundant elements on earth. Hydrogen refers to a clean and renewable energy source, hydrogen can be a good choice to reduce greenhouse gas emissions. One way to produce hydrogen is by electrochemical water splitting. This study aims to determine the characterization of iron-based nanomaterials (iron sulfide - iron hydroxide) as a water splitting catalyst in general. Iron sulfide synthesis was carried out using hydrothermal sulfidation method for 6 hours at 80 oC with nickel foam as substrate. Synthesis of iron sulfide varying the concentration of sodium sulfide nonahydrate (0.0125 M, 0.025 M, 0.05 M and 0.1 M) produced brownish yellow to blackish grey colored samples. Characterization results using XRD showed that iron sulfide peaks were detected at higher concentrations of sodium sulfide nonahydrate. Based on the results of analyzing iron hydroxide using SEM, it is known that the sample is in the form of nano walls and on iron sulfide, it is known that the sample is in the form of nanoscale particles. Based on electrochemical measurement results, iron hydroxide can be a good catalyst for hydrogen evolution reaction (HER) compared with commercial Pt/C. The overpotential of iron hydroxide is smaller than Pt/C, which is only 15 mV at a current density 10 mA/cm2 and iron sulfide can be a good catalyst for oxygen evolution reaction (OER) with electrocatalytic measurement results close to commercial RuO2. This is indicated by the small overpotential (260 mV at current densisty 10 mA/cm2 and small tafel slope (51 mV/dec). [ABSTRACT FROM AUTHOR]

The composition of a mineral is a defining characteristic. The various compositions listed for mackinawite in current mineralogical databases and reference books, such as Fe(Ni)S and Fe1+xS, are both wrong and misleading. Statistical analyses of over 100 mackinawite compositions reported over the last 50 years show a mean composition of Me1.0S where Me = Fe + Co + Ni + Cu. Mackinawite is stoichiometric FeS. As with many sulfide minerals, Ni-, Co-, and, possibly, Cu-rich varieties occur in addition to the simple iron monosulfide. These varieties are best referred to as nickelian mackinawite, cobaltian mackinawite, and cupriferous mackinawite. The results confirm that these metals substitute for Fe in the mackinawite structure rather than being contained in the interstices between the Fe-S layers. Most compositional data on mackinawites derive from electron probe microanalyses of small grains in magmatic/hydrothermal associations. The result means that there is no dichotomy between the composition of ambient temperature synthetic mackinawite (which is supposed to be equivalent to sedimentary mackinawite) and mackinawites from higher temperature associations. The correct representation of the composition of mackinawite has implications for a wide swathe of fundamental science, including the origin of life, the genesis of magmatic ore deposits, the provenance of meteorites as well as industrial applications such as water treatment and steel corrosion. The stoichiometric formulation permits the mackinawite formula to be balanced electronically using conventional Fe and S ionic species. It also enables simple, balanced chemical equations involving mackinawite. [ABSTRACT FROM AUTHOR]

Nanoparticles have been shown to inhibit major life cycle stages of ticks, indicative of the promising application of nanomaterials against hard ticks. The study thus probed into one of the alternative options to curtail Hyalomma by employing nanocomposites consisting of pyrethroids (cypermethrin and deltamethrin) coated nanoparticles of iron oxides and iron sulfides keeping alongside the evaluation of their toxicity through plant and mammalian cell lines. The nanoparticles used in this study were roughly spherical in morphology and exhibited various size dimensions upon characterization using SEM, EDX, and FTIR. The application of nanomaterials on female ovipositioning tick showed a decline up to 15% (females ovipositioned) in deltamethrin-coated FeO NPs, whereas this decline was up to 18% in Cyp-FeS NPs and up to 5% in Cyp-FeO NPs. Similarly, the larval hatching was also impacted, leading to a hatching percentage of 5% and only 1% by application of Cyp-FeS NPs and Cyp-FeO NPs, respectively. Similarly, the larval groups had LC90 of 4.1 and 4.73 mg/L for the Cyp-FeO NPs and Cyp-FeS NPs groups. The delta-FeO NPs and delta-FeS NPs demonstrated a promising effect against adult ticks, showing LC50= 3.5 mg/L, LC90= 6.7 mg/L and LC50= 3.8 mg/L, LC90= 7.9 mg/L, respectively. MTT assay revealed that the pyrethroids coupled with iron oxide nanoparticles showed the least cytotoxicity even at the highest concentration (10–1 µL) among other nanomaterials. The study thus concluded a safer spectrum of non-target effects of pyrethroids-coated nanomaterials in addition to their significant anti-tick activity. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H2S) and carbon dioxide (CO2) present in oil and natural gas cause mild steel corrosion, potentially resulting in formation of corrosion product layers on the internal surfaces of tubulars. In field experiences relating to the research reported herein, this has led to restrictions on the flow of water produced from a three-phase horizontal separator. This paper demonstrates a specific case of chemical removal of relatively hard, dark, and adherent heterogeneous deposits on the internal surface of the pipe. The phases involved in this process are iron sulfide, iron oxides and calcium carbonate existing as scales/corrosion products. To evaluate their dissolution, laboratory tests were conducted using hydrochloric acid (HCl) with additions of chlorine in the form of calcium hypochlorite [Ca(ClO)2]. Appropriate safety measures were taken employed, considering hazards associated with chlorine and toxicity of hydrogen sulfide. The treatment regime had 87 % effectiveness for scale removal in combination with propargyl alcohol (2-propyn-1-ol) as a corrosion inhibitor. [ABSTRACT FROM AUTHOR]

The contradiction between the supply and demand of nickel resources is intensifying, and it is urgent to develop new processing and smelting processes for laterite nickel ore. Gas based smelting with H2 and CH4 as reductants is of great significance to solve the "double carbon" problem faced by the traditional metallurgical industry. Taking low-grade laterite nickel ore as the research object, CH4 as the reductant and elemental sulfur as the additive, under the conditions of different reduction temperature, reduction time, gas concentration and additive dosage, this paper discusses the reduction behavior of CH4 and iron nickel oxide in laterite nickel ore. Combined with XRD, SEM-EDS, gas analysis and other characterization methods, the phase and morphology of laterite nickel ore and its reduction products were deeply analyzed. Results surface: under the conditions of reduction temperature 800°C, reduction time 60 min, CH4 concentration 20%, elemental sulfur dosage 4%, the metallization rate of nickel and iron in the reduction product can reach 98.01% and 8.44%, respectively. Nickel oxide is almost completely reduced to nickel, and most of iron is reduced to low-price iron oxide. In the reduction process, the amorphous silicate recrystallizes into magnesium olivine phase in the reduction process. It hinders further reduction of nickel. According to SEM-EDS analysis, some metal iron and elemental sulfur generate FeS around the iron oxide region, which hinders the contact between reducing gas and FeO. Therefore, the reduction of iron is inhibited and the iron oxide content increases. It promoted the selective reduction of nickel. [ABSTRACT FROM AUTHOR]

All‐solid‐state lithium batteries (ASSLBs) based on sulfide solid electrolytes (SEs) are one of the most promising strategies for next‐generation energy storage systems and electronic devices. However, the poor chemical/electrochemical stability of sulfide SEs with oxide cathode materials and high interfacial impedance, particularly due to physical contact failure, are the major limiting factors to the development of sulfide SEs in ASSLBs. Herein, the composite cathode of MOF‐derived Fe7S8@C and Li6PS5Br fabricated by an infiltration method (IN–Fe7S8) with dissoluble sulfide electrolyte (dissoluble SE) is reported. Dissoluble SE can easily infiltrate the porous sheet‐type Fe7S8@C cathode to homogeneously contact with Fe7S8 nanoparticles that are embedded in the surrounding carbon matrixes and form a fast ionic transport network. Benefiting from applying dissoluble SE and Fe7S8@C, the IN‐Fe7S8‐based cells displayed a reversible capacity of 510 mAh g−1 after 180 cycles at 0.045 mA cm−2 at 30 °C. This work demonstrates a novel and practical method for the development of high‐performance all‐sulfide‐based solid state batteries. [ABSTRACT FROM AUTHOR]

Fe–S compounds with hexagonal crystal structure are potential hydrogen permeation barrier during H2S corrosion. Hexagonal system Fe–S films were prepared on carbon steel through corrosion and CVD deposition, and the barrier effect of different Fe–S films on hydrogen permeation was tested using electrochemical hydrogen permeation method. After that, the electrical properties of Fe–S compound during phase transformation were measured using thermoelectric measurement system. Results show that the mackinawite has no obvious barrier effect on hydrogen penetration, as a p-type semiconductor, and pyrrhotite (including troilite) has obvious barrier effect on hydrogen penetration, as an n-type semiconductor. Hydrogen permeation tests showed peak permeation performance when the surface was deposited with a continuous film of pyrrhotite (Fe1−xS) and troilite. The FeS compounds suppressed hydrogen permeation by the promotion of the hydrogen evolution reaction, semiconducting inversion from p- to n-type, and the migration of ions at the interface. [ABSTRACT FROM AUTHOR]

Exploring highly active and inexpensive electrocatalysts for oxygen evolution is vital but challenging. Herein, a serial of FeS2, FeS and FeS2/rGO electrocatalysts were obtained by simple two-step method. Benefiting from the integration of FeS2 and rGO, the FeS2-450/rGO-10% exhibited the excellent catalytic activity toward OER with an ultra-low overpotential of 140 mV, a smaller Tafel slope of 71 mV/dec and high stability. The improved catalytic performance for OER could attribute to the excellent synergistic effect of the surface reconstruction of FeS2 and the introduction of rGO in FeS2-450/rGO-10% catalyst. Meanwhile, in a two-electrode system of FeS2-450/rGO-10%/NF//Pt/C/NF toward overall water splitting, the voltage at 10 mA cm−2 is only 1.52 mV, which indicates that the FeS2-450/rGO-10% can serve as the anode in practical overall water splitting.

The removal of noxious Cr(VI) from water has gained worldwide attention. In this study, biochar derived from macadamia nut shells (MHP) was embedded with iron sulfide (FeS) nanoparticles produced through a solid‐phase reduction of pyrite. The MHP‐FeS composite was evaluated for the adsorption of Cr(VI) and its subsequent reduction to Cr(III). The scanning electron microscope images revealed that the particles were of irregular shape, while the energy dispersive spectroscopy results showed the existence of Fe, S, O, and C atoms. X‐ray diffraction peaks at 2=29.8°, 33.7°, 43.7°, and 53.1° were characteristic of the formation of FeS nanoparticles. A maximum Cr(VI) adsorption capacity of 4.95 mg/g was obtained at pH 3, 60 min, and 25 °C. The higher correlation coefficient (R2>0.873) and lower residual standard error (RSE=1.43) values pointed to the adsorption process favoring Langmuir and pseudo‐second‐order models. As per thermodynamic reaction calculations, the remediation process was spontaneous and endothermic. With further optimization, this material could be a potential adsorbent and reductant for Cr(VI) in water. [ABSTRACT FROM AUTHOR]

The significant increase in demand for molybdenum (Mo) resources has led to excessive molybdate (Mo(VI)) content in water, posing a challenge to the innovation of Mo(VI) removal technology in water bodies. Nanoscale iron sulfide (FeS) has an important effect on the environmental behavior of Mo(VI) in aquatic solutions. To address the issue of easy agglomeration and poor stability of FeS, zirconia sol-modified nanoscale iron sulfide (Zr-FeS) was synthesized, and the adsorption behavior of Zr-FeS on Mo(VI) from diverse aquatic solutions was also investigated in this study. The results showed that the removal rate of Mo(VI) was increased from 28.60% to 78.32% within pH value of 7.0 when Zr/Fe molar ratio was elevated from 0 to 0.5. Moreover, the Mo(VI) adsorption efficiency by Zr-FeS was closely related to pH values, and acid conditions were beneficial for Mo(VI) adsorption. The pseudo-second-order model demonstrated a better fit to the data compared to other models. The maximum adsorption capacity of Zr-FeS towards Mo(VI) value calculated by Langmuir isotherm model was 118.48 mg/g at 298 K. The thermodynamic analysis revealed that the adsorption process of Mo(VI) was endothermic, entropically favorable, and spontaneous in nature. Competing anions (e.g., PO4 3-, HCO3 -, and SO4 2-) partially inhibited the adsorption process of Mo(VI) by Zr-FeS. While the process was less affected by dissolved oxygen and aging. The results of Fourier-transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and density functional theory (DFT) calculations revealed that the main mechanisms for Mo(VI) removal were hydrogen bonding, electrostatic interaction and surface complexation. The high stability and fast adsorption rate indicated that Zr-FeS was a promising material to remove Mo(VI) from the aquatic solutions. [ABSTRACT FROM AUTHOR]

2‐dimensional FeSx nanosheets of different sizes are synthesized by applying different numbers of atomic layer deposition (ALD) cycles on TiO2 nanotube layers and graphite sheets as supporting materials and used as an electrocatalyst for the hydrogen evolution reaction (HER). The electrochemical results confirm electrocatalytic activity in alkaline media with outstanding long‐term stability (>65 h) and enhanced catalytic activity, reflected by a notable drop in the initial HER overpotential value (up to 26 %). By using a range of characterization techniques, the origin of the enhanced catalytic activity was found to be caused by the synergistic interplay between in situ morphological and compositional changes in the 2D FeSx nanosheets during HER. Under the application of a cathodic potential in alkaline media, the as‐synthesized 2D FeSx nanosheets transformed into iron oxyhydroxide‐iron oxysulfide core‐shell nanoparticles, which exhibited a higher active catalytic surface and newly created Fe‐based HER catalytic sites. [ABSTRACT FROM AUTHOR]

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Rapid industrial development has led to excessive levels of various contaminants in natural water, which poses a challenge to the innovation of environmental remediation technology. In recent years, iron sulfide and its modified materials have attracted extensive attention in environmental remediation due to their high activity in advanced oxidation processes and widespread existence in anoxic environment. This paper reviewed the latest advances of the synthesis methods for iron sulfide and modified FeS. In addition, the application of persulfate activation by iron sulfide materials (FeS, FeSx, S−ZVI, FeS@Carbon materials and MFexSy) for contaminants remediation is also reviewed, and the enhancement of this system by photo irradiation, ultrasound, and microwave have also been concluded. Additionally, the interaction mechanism of iron sulfide and persulfate with contaminants was reviewed. Based on the above contents, we concluded that the long−term stability of iron sulfide, the toxicity to organisms of iron sulfide materials in the treated water, and the combination of FeS/PS with other assisted technologies should be focused in future.

Oxidation of aggregates containing iron sulfide minerals has recently been linked to severe degradation in housing foundations in the northeast United States and the Trois-Rivières area of Quebec, Canada. Existing performance-based approaches mainly rely on the use of oxidizing solutions, which may create harsh environments and lead to unexpected results. This work evaluated the effectiveness of a mortar test by using atmospheric oxygen (a more realistic exposure condition) as an oxidizing agent and employed a design of experiments approach to investigate the effects of relative humidity (50% and 95%), oxygen content (20.9% and 35%), temperature (5°C and 60°C), and water-to-cement ratio (0.45 and 0.65) on the oxidation potential of iron sulfide-bearing aggregates. Results show that length changes of the mortar samples are mainly attributed to drying shrinkage within the experimental duration (more than 400 days), which is highly dependent on the relative humidity levels, whereas minimal to no expansion was observed under laboratory conditions. Recent efforts to simulate iron sulfide deterioration in laboratories by performance-based tests are then reviewed. Their advances and challenges as well as comparison with the proposed test are summarized, leading to a call for further development of experimental methods.

The kinetics of solid-state oxidation by air of iron, copper and zinc sulfide natural mixture, which is typical of the pyritic copper ores, is investigated. Using the high-temperature X-ray powder diffraction, thermogravimetry and differential scanning calorimetry, it was found that the process can be represented by five exothermic elementary reactions, corresponding to intensive burning of iron, copper and zinc sulfides, and two endothermic ones, associated with decomposition of copper and iron sulfates. Kinetic analysis is performed by Kissinger and Augis–Bennett methods, the model-free function mechanism was determined from y(α) master plots and iterative optimization of the kinetic parameters. The limiting steps of these reactions are nucleation and crystal growth, and the values of activation energy, pre-exponential factor and Avrami exponent are in the ranges of 140–459 kJ·mol–1, 1.41·104–3.49·1031 s–1, and 1.0–1.7, respectively. Crystallization is followed by an increase in the number of nuclei, which may be formed both at the interface and in the bulk of the ore particles, and crystal growth is one-dimensional and controlled by a chemical reaction at the phase boundary or diffusion. The results of the work can contribute to the development of theoretical ideas about the physicochemical transformations of pyritic ores and concentrates during pyrometallurgical operations.

The effect of a low concentration of hydrogen sulfide (H2S) on corrosion resistance of low-carbon pipe steel in media with a moderate carbon dioxide gas content is studied. Presence of hydrogen sulfide within carbon dioxide atmospheres in an amount of not more than 65 mg/liter reduces the continuous corrosion rate for low-carbon steels by a factor of 4–5. A reduction in corrosion rate is due to the formation of sulfide film corrosion products on the surface of specimens in the presence of hydrogen sulfide that protects a metal surface from subsequent carbon dioxide corrosion. [ABSTRACT FROM AUTHOR]

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In this work, three different tochilinite‐like materials have been obtained by sophisticated synthetic methods that allow to control the distribution of iron ions. The purity of the samples was confirmed by powder X‐ray diffraction. From elemental analysis and Mössbauer spectroscopy data, detailed compositions could be determined: T1) Fe0.76S*0.86 [Fe2+0.01Fe3+0.56Mg2+0.43(OH)2.01]; T2) Fe0.89S*0.85 [Fe2+0.55Fe3+0.11Al3+0.33(OH)1.84(O)0.16]; T3) Fe0.71S*0.79 [Fe2+0.25Fe3+0.73Mg2+0.01Al3+0.01(OH)1.98(O)0.02]. These compositions fit to typical compositions of tochilinite in regard of the amount of iron vacancies and the volume ratio of the hydroxide layers to the sulfide layers. Besides hydroxide ions, oxide ions are also present in the hydroxide layers as a result of surface oxidation after the synthesis due to the high reactivity of the particles. TEM and SEM investigations show that the obtained powders consist mainly of thin sheets accompanied by nanotubes with BET surface areas ranging between 20 m2/g and 40 m2/g. The thermal stability was investigated by TGA and DSC analysis and it depends significantly on the composition. [ABSTRACT FROM AUTHOR]

Pyrrhotite is a common iron sulfide mineral described as a non‐stoichiometric formula Fe1‐xS (0 < x < 0.125), permitting a lot of superstructures based on the hexagonal NiAs crystal subcell. Due to its abundance as well as its characteristic magnetic properties, many aspects of the research have been carried out both in geochemistry and material sciences. However, surprisingly, Raman spectra reported as "pyrrhotite" are remarkably different literature‐by‐literature. The reason for the differences is probably due to its reactive surface allowing the accelerated surface oxidation by laser‐induced heating in air and atmospheric weathering by long‐time exposure. However, to consider its crystal and/or surface structure, standard Raman spectra from fresh surfaces, that is, free from oxidation, are inevitable for the assignments of geological samples and for studying the chemical reaction that occurred on the surfaces. Here, we measured the Raman spectra of freshly cleaved surfaces of pyrrhotites sampled from different mines with changing the measurement conditions. As a result, only a very weak and broadened peak at around 130 cm−1 was observed from the fresh surfaces. It is suggested that the Raman measurements in air rapidly proceed the surface oxidation. In addition, the atmospheric weathering is also found to give new intense Raman bands, which have been sometimes assigned to the original peaks of pyrrhotite crystal. The Raman spectra of pyrrhotites both in lower‐wavenumber and in anti‐Stokes region were also measured for the first time, confirming the spectroscopic features of pyrrhotite above. [ABSTRACT FROM AUTHOR]

Due to pollution discharge and climate change, hypoxia is becoming more prevalent in water bodies such as lakes, rivers, and oceans. It leads to black blooms in lakes, black and odors in rivers, and dead zones in the oceans. Iron sulfide, especially amorphous mackinawite, is the main blackening substance. In this paper, the physical characteristics and detection methods of mackinawite were used to determine how to detect it in hypoxic water bodies. The population and metabolism of key microorganisms during mackinawite generation were analyzed to provide a reference for studying related microorganisms during the blackening process. Finally, the influence of macromolecular organic matter and microorganisms on the stable suspension of mackinawite was determined, and the existing patterns of mackinawite during the blackening process of hypoxic waters were illustrated. The generation of amorphous mackinawite and its stable suspension in a supernatant are two indispensable factors during the blackening process. The clarification of substance characteristics and key action processes are conducive to the accurate and targeted control of the blackening process and promote the restoration of the sustainable self-purification ability of water bodies. [ABSTRACT FROM AUTHOR]

The presence of organic matter in carbonaceous chondrites provides valuable information about the early composition of the Solar System. Although they are considered primitive, the majority of these chondrites have undergone secondary processes subsequent to their formation. These processes, such as aqueous alteration, have altered their composition. The effect of aqueous alteration on minerals is well known, but the effect on organic matter and/or on an organo-mineral system have been little studied. Here, we report experimental results devoted to investigate the chemical evolution of a hypothetical initial chondritic material subjected to hydrothermal alteration under reducing conditions at low-temperature. The mixtures consist of different anhydrous minerals (peridot, feldspar, troilite) together with hexamethylenetetramine (HMT) chosen as a model molecule inherited from the interstellar grains. After different times at 80 °C, the large molecular diversity formed is highly influenced by the presence and the nature of the minerals, as highlighted in particular by the evolution of the amide produced. The presence of minerals in the mixture appears to influence the reactivity of the system more through the formation of salts and chelates than through surface adsorption mechanisms. The most pronounced effect is observed in the presence of troilite, both in the degradation of HMT and in the abundance of amides formed. The study of the mutual influence of minerals and organic matter, and their intrinsic transformations in the media during the processes, could help to understand about the origin of organic molecules observed in carbonaceous chondrites. • Organic composition in carbonaceous chondrites may result from aqueous alteration. • We made chondritic analogs with hexamethylenetetramine and non-hydrated minerals. • Mineral type, pH, red-ox and complexation influence the organic diversity formed. • Mixing minerals shows a synergistic effect on molecular complexity. • Minerals can impact organics in carbonaceous chondrites during aqueous alteration. [ABSTRACT FROM AUTHOR]

Faced with worldwide mercury (Hg) contamination in groundwater, efficient in situ remediation technologies are urgently needed. Carboxymethyl cellulose (CMC) stabilized iron sulfide (CMC-FeS) nanoparticles have been found effective for immobilizing mercury in water and soil. Yet, the potential use of the nanoparticles for creating an in situ reactive zone (ISRZ) in porous geo-media has not been explored. This study assessed the transport and deliverability of CMC-FeS in sand media towards creating an ISRZ. The nanoparticles were deliverable through the saturated sand bed and the particle breakthrough/deposition profiles depended on the injection pore velocity, initial CMC-FeS concentration, and ionic strength. The transport data were well interpreted using an advection-dispersion transport model combined with the classical filtration theory. The resulting ISRZ effectively removed mercury from contaminated groundwater under typical subsurface conditions. While the operating conditions are yet to be optimized, the Hg breakthrough time can be affected by groundwater velocity, influent mercury concentration, dissolved organic matter, and co-existing metals/metalloids. The one-dimensional advection-dispersion equation well simulated the Hg breakthrough data. CMC-FeS-laden ISRZ effectively converted the more easily available Hg species to stable species. These findings reveal the potential of creating an ISRZ using CMC-FeS for in situ remediation of Hg contaminated soil and groundwater. [Display omitted] • CMC-FeS transport in saturated porous media is controllable by manipulating injection conditions. • Gravitational sedimentation is the predominant removal mechanism of CMC-FeS. • CMC-FeS-laden ISRZ efficiently removes Hg from groundwater under typical subsurface conditions. • CMC-FeS-laden ISRZ performs much better than that of CMC-FeS PRBs. • One-dimensional advection-dispersion equation well simulates mercury breakthrough data. [ABSTRACT FROM AUTHOR]

• Pollutant dynamics in mixotrophic bioretention systems were modeled. • Iron sulfide generation in pyrite-woodchip bioretention systems were quantified. • Nitrogen removal is more sensitive to anoxic DOC dissolution rate. • Iron sulfide generation was affected by DOC distribution and microbial interaction. • DOC has an antagonistic effect on iron production and sulfate reduction. Dual electron donor bioretention systems have emerged as a popular strategy to enhance dissolved nitrogen removal from stormwater runoff. Pyrite-woodchip mixotrophic bioretention systems showed a promoted and stabilized removal of dissolved nutrients under complex rainfall conditions, but the sulfate reduction process that can induce iron sulfide generation and reuse was overlooked. In this study, experiments and models were applied to investigate the effects of filler configuration and dissolved organic carbon (DOC) dissolution rate on treatment performance and iron sulfide generation in pyrite-woodchip bioretention systems. Key parameters govern that DOC dissolution and microbe-mediated processes were obtained by experiments. The water quality models that integrate one-dimensional constant flow, sorption and microbial transformation kinetics were used to predict the performance of bioretention systems. Results showed that the mixotrophic bioretention system with woodchip mixed in the vadose zone and pyrite in the saturated zone achieves a better performance in both nitrogen removal efficiency and by-product control. Comparably, woodchip and pyrite mixed in the saturated zone could encounter a high secondary pollution risk. The sensitivity coefficients of oxic/anoxic DOC dissolution rates to total nitrogen removal are 0.36 and -2.43 respectively. Iron sulfide generation was affected by DOC distribution and the competition between heterotrophic denitrifiers, autotrophic denitrifiers, and sulfate-reducing bacteria (SRB). DOC accumulation has an antagonistic effect on iron production and sulfate reduction. Extra DOC accumulation favors sulfate reduction while high DOC concentration inhibits pyrite-based denitrification and reduces Fe(III) production. The recycling of iron sulfide can improve the robustness and sustainability of bioretention systems. [Display omitted] [ABSTRACT FROM AUTHOR]

This study employed an electrodeposition approach to synthesize multiphasic CuS x and FeS x on nickel foam (NF) for application in saline water splitting. This multiphasic electrocatalyst exhibits a cauliflower morphology and develops a porous fused-type morphology upon partial oxidation. The NF/CuS x /FeS x electrode with partial oxidation exhibits the lowest overpotential of 181 mV at 10 mA/cm2 and a Tafel slope of 163 mV/decade for the oxygen evolution reaction (OER). The overpotential of 73 mV at 10 mA/cm2 and a Tafel slope of 165 mV/decade were found for the hydrogen evolution reaction (HER). A charge transfer coefficient value of ∼0.5 in OER and HER indicates that the rate-determining step depends on the surface adsorption of reaction species. The presence of an unpaired electron during partial oxidation can create additional active sites and reduce solution resistance (R s). This can improve the interaction between reactants and intermediates, improving OER and HER performance. NF/CuS x /FeS x composites demonstrated robust stability using real seawater splitting over 80 hours in HER with negligible degradation. However, catalyst breakdown in OER after 10 hours due to prolonged exposure to higher potentials, resulting in oxidative corrosion. This study offers a multiphasic electrode design using the electrodeposition technique to produce green hydrogen energy through seawater splitting. • Electrodeposition of CuSx/FeSx electrocatalyst for saline water splitting. • Catalyst transitions from cauliflower to porous fused morphology after partial oxidation. • Low overpotential of 181 mV for OER and ultralow 73 mV for HER at 10 mA/cm2. • Research unveils insights into multiphasic electrode for green hydrogen from seawater. [ABSTRACT FROM AUTHOR]

Abstract Metal sulfides have shown great potential as the anodes of the asymmetric supercapacitors ascribed to their superior theoretical specific capacitance. However, their specific capacitance and rate performances are still far from the expectation due to the intrinsic poor electronic conductivity and sluggish kinetics. Herein, we employ the anion and cation double‐substitution strategy to prepare iron sulfide nanoparticles on graphene composite (denoted as NiFeSP/G) to improve the electronic conductivity of FeS2. The NiFeSP/G composite exhibits greatly improved electrochemical performances with a high specific capacity of 765 C g−1 (765 F g−1) at 5 A g−1 and a remarkable rate capability of 65% at 100 A g−1. Moreover, an aqueous asymmetric supercapacitor is fabricated with the NiFeSP/G as anode and NiCo‐LDH/graphene as cathode presents an impressively high energy density up to 109 Wh kg−1 at 1591 W kg−1 and cycling performance (89% of the initial capacity retained after 8000 cycles).

2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol (UV328) is a commonly used benzotriazole ultraviolet stabilizers (BUVs) with bioaccumulative properties. Since it's stubbornly degraded in the environment, it poses significant environmental risks in soil. However, the removal of UV328 from soil is challenging, and existing treatment methods have low efficiency. This study focuses on UV328 in soil and proposes an efficient method for its removal using persulfate (PS) activated by iron sulfide (FeS). The research demonstrates that with FeS and PS dosages of 20 and 100 mM respectively, and a soil-to-water ratio of 5:1, 12 h-removal efficiency of UV328 with an initial concentration of 12 mg/kg reaches 93.0%. Furthermore, employing electron paramagnetic resonance spectroscopy and quenching experiments, key reactive oxygen species (ROSs) are identified. SO 4 •- , •OH, 1 O 2 and •O 2 - contribute 31.76%, 28.77%, 26.52% and 12.95%, respectively. Four main reaction pathways of amination, hydroxylation, sulfate substitution, and bond cleavage, are identified with 14 transformation products characterized. Calculated energy profiles based on density functional theory (DFT) identify the most susceptible reaction sites for different ROSs. Five different types of agricultural soils were selected to explore the impact of soil characteristics on UV328 removal. The degradation performance of natural mackinawite demonstrates the effectiveness and accessibility of raw materials. Toxicity assessments of transformation products confirm the environmental friendliness of this system. This study proposes an efficient degradation method for UV328-contaminated soil, providing scientific insights and theoretical guidance for addressing environmental removal of BUVs from soil., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

In electrocatalysis we seldom think about the competing direct reduction reactions that may happen alongside catalytically mediated reduction‐ with direct redox chemistry often happening slower but in competition with, catalysis. One class of compounds of interest from this perspective are iron sulfides. In addition to being structurally similar to many metalloproteins, iron sulfides are also among nature's strongest chemical reductants and reported to act as catalysts for key chemical reactions including proton, nitrite, and nitrate reduction. It is important that iron sulfides can act as catalysts because they are also strong enough reductants to mediate some of the same reactions directly. This is paradoxical because in order to be a catalyst for reduction, an iron sulfide cannot also be oxidised. To investigate this phenomenon further, we assembled a test set of iron sulfides spanning both amorphous iron sulfide (FeSam) as well as the crystalline iron sulfides greigite, pyrite, and troilite. These were used to explore the relationship between direct reduction and catalysis of a reduction reaction with a secondary electron source, NO2− was chosen as a test substrate. The trends in direct reduction followed the least stable material (FeSam) to the most stable material (FeS2). Of the phases studied, troilite (FeS) showed the largest difference between direct and catalytic reduction, however amorphous iron sulfide showed the greatest selectivity for NH3/NH4+ production as both a direct reductant and a catalyst. [ABSTRACT FROM AUTHOR]

[Display omitted] As a desirable candidate for lithium-ion batteries, potassium-ion batteries (PIBs) have aroused great interest because of their low cost and high power and energy densities. However, the insertion/extraction of K+ with a large radius (1.38 Å) usually bring about the destruction of the electrode materials. Here, ultrafine Fe 7 S 8 nanocrystals are successfully implanted into hollow carbon nanospheres (Fe 7 S 8 @HCSs) via a facile solvothermal method and subsequent novel low-temperature sulfurization, which avoid the aggregation of Fe 7 S 8 nanoparticles produced during high-temperature sulfidation. The ultrafine Fe 7 S 8 nanoparticles and hollow carbon spheres can not only buffer the severe expansion/shrinkage of electrode materials caused by the repeated insertion/extraction of K+, but also provide additional accessible pathways for the high-rate K+ transmission. When tested as an anode material for PIBs, Fe 7 S 8 @HCSs achieve impressive K+ storage capacity of 523.2 mAh g−1 at 0.1 A g−1 after 100 cycles and remarkable rate capacity of 176.3 mAh g−1 at 5 A g−1. Further, assembling this anode with a K 2 NiFe(CN) 6 cathode yields stable cycling performance, revealing its great potential for large-scale energy storage applications. [ABSTRACT FROM AUTHOR]

Abstract Aluminum-ion batteries (AIBs) are promising next-generation batteries systems because of their features of low cost and abundant aluminum resource. However, the inferior rate capacity and poor all-climate performance, especially the decayed capacity under low temperature, are still critical challenges toward high-specific-capacity AIBs. Herein, we report a binder-free and freestanding metal–organic framework-derived FeS2@C/carbon nanotube (FeS2@C/CNT) as a novel all-climate cathode in AIBs working under a wide temperature window between −25 and 50 °C with exceptional flexibility. The resultant cathode not only drastically suppresses the side reaction and volumetric expansion with high capacity and long-term stability but also greatly enhances the kinetic process in AIBs with remarkable rate capacity (above 151 mAh g−1 at 2 A g−1) at room temperature. More importantly, to break the bottleneck of the inherently low capacity in graphitic material-based all-climate AIBs, the new hierarchical conductive composite FeS2@C/CNT highly promotes the all-climate performance and delivers as high as 117 mAh g−1 capacity even under −25 °C. The well-designed metal sulfide electrode with remarkable performance paves a new way toward all-climate and flexible AIBs.

• Peening with fine iron sulfide particles (FeS-peening) was introduced. • FeS-peening formed a layer of FeS particles without the use of aqueous Na 2 S 2 O 3. • FeS-peening increased the fatigue limit of steels by 125 MPa. • Improvement of fatigue limit (24 MPa) by residual stress was quantitatively investigated. • The fatigue limit of FeS-peened steels was 95 MPa higher than conventional processed one. Low alloy steels were subjected to peening with fine iron sulfide particles (FeS-peening) under ambient conditions to transfer a layer of such particles, which can improve seizure resistance and sliding properties, and thus enhance the fatigue characteristics of the steel. This process was performed without the use of aqueous Na 2 S 2 O 3 and the specimens were assessed using electron probe microanalysis and rotating bending fatigue tests. Treated specimens exhibited higher fatigue limits as a result of high degree of compressive residual stress generated on the steel surface. The effects of residual stress on the fatigue limit were quantitatively investigated using a modified Goodman diagram. Sample cross-sections were observed using electron backscattered diffraction, which confirmed that FeS-peening formed fine surface grains. Grain refinement was determined to be at least partly responsible for the improved fatigue properties of the steel following FeS-peening. [ABSTRACT FROM AUTHOR]

Mercury (Hg) contamination in soil has been a worldwide environmental concern. We prepared and investigated a novel Mg 2 Al layered double hydroxide supported iron sulfide composite (FeS@Mg 2 Al-LDH) for immobilization of mercury in two high-profile Hg-contaminated field soils (TJ soil represents freshly Hg-contaminated soil and GY soil represents historically aged Hg-contaminated soil). Amending the two soils with FeS@Mg 2 Al-LDH effectively immobilized mercury. The addition of 0.02% of FeS@Mg 2 Al-LDH immobilized 97.0% of mercury in TJ soil within 80 d. Similarly, the addition of 0.05% of FeS@Mg 2 Al-LDH immobilized 84.9% of mercury in GY soil. Increasing the FeS@Mg 2 Al-LDH dosage enhanced the immobilization efficiency. Increasing the dosage from 0.02% to 1% boosted the Hg immobilization efficiency in TJ soil from 97.0% to 99.4%. Increasing the dosage from 0.05% to 1% enhanced the Hg immobilization efficiency in GY soil from 84.9% to 86.2%. FeS@Mg 2 Al-LDH reacted with Hg via chemical precipitation and surface complexation, and transformed Hg from more available Hg fractions (exchangeable and carbonate bound fractions) into less available forms (organic and residual fractions), thus, reducing the environmental risk of mercury. The addition of FeS@Mg 2 Al-LDH inhibited the production of methylmercury while enhanced the soil enzyme activities. This study proves the potential and feasibility of FeS@Mg 2 Al-LDH to effectively immobilize mercury in soil. [Display omitted] • FeS@Mg 2 Al-LDH effectively immobilizes mercury in freshly and historically aged Hg-contaminated soil. • The immobilized mercury demonstrates a long-term stability. • Mercury is immobilized via surface complexation and chemical precipitation. • The composite transforms mercury from more available into less accessible fractions. • The addition of the composite enhances soil properties and inhibited methylmercury production. [ABSTRACT FROM AUTHOR]

Anaerobic biotechnology for wastewaters treatment can nowadays be considered as state of the art methods. Nonetheless, this technology exhibits certain inherent limitations when employed for industrial wastewater treatment, encompassing elevated substrate consumption, diminished electron transfer efficiency, and compromised system stability. To address the above issues, increasing interest is being given to the potential of using conductive non-biological materials, e,g., iron sulfide (FeS), as a readily accessible electron donor and electron shuttle in the biological decontamination process. In this study, Mackinawite nanoparticles (FeS NPs) were studied for their ability to serve as electron donors for p -chloronitrobenzene (p -CNB) anaerobic reduction within a coupled system. This coupled system achieved an impressive p -CNB removal efficiency of 78.3 ± 2.9% at a FeS NPs dosage of 1 mg/L, surpassing the efficiencies of 62.1 ± 1.5% of abiotic and 30.6 ± 1.6% of biotic control systems, respectively. Notably, the coupled system exhibited exclusive formation of aniline (AN), indicating the partial dechlorination of p -CNB. The improvements observed in the coupled system were attributed to the increased activity in the electron transport system (ETS), which enhanced the sludge conductivity and nitroaromatic reductases activity. The analysis of equivalent electron donors confirmed that the S2- ions dominated the anaerobic reduction of p -CNB in the coupled system. However, the anaerobic reduction of p -CNB would be adversely inhibited when the FeS NPs dosage exceeded 5 g/L. In a continuous operation, the p -CNB concentration and HRT were optimized as 125 mg/L and 40 h, respectively, resulting in an outstanding p -CNB removal efficiency exceeding 94.0% after 160 days. During the anaerobic reduction process, as contributed by the predominant bacterium of Thiobacillus with a 6.6% relative abundance, a mass of p -chloroaniline (p -CAN) and AN were generated. Additionally, Desulfomonile was emerged with abundances ranging from 0.3 to 0.7%, which was also beneficial for the reduction of p -CNB to AN. The long-term stable performance of the coupled system highlighted that anaerobic technology mediated by FeS NPs has a promising potential for the treatment of wastewater containing chlorinated nitroaromatic compounds, especially without the aid of organic co-substrates. [Display omitted] • FeS NPs as inorganic electron donor enables high p -CNB anaerobic reduction. • Interspecies mass and electron transfer was facilitated using FeS NPs as mediators. • The anaerobic sludge granular process was accelerated under FeS NPs stimulation. • The ability to resist environmental stress was enhanced in the coupled system. • Species related to reduction, Fe and S metabolism were enriched in coupled system. [ABSTRACT FROM AUTHOR]

N‐rich carbon nitride (CN) is a promising framework that can generate innovative hybrid structures for energy applications. However, the low thermal stability of N atoms in the CN matrix is a major drawback as the crystallization of the hybridized counterpart requires a high temperature. Herein, we report the successful synthesis of the hybrid of N‐rich CN and Fe1‐xS at 700 °C by constructing a stable C−N−Fe−S heterointerface using a Fe‐incorporated metal‐organic framework (MOF) and dithiooxamide containing C, N and S atoms. The hybrids display promising capacities toward Li+ and Na+ ions storage, highlighting the beneficial role of N‐rich CN on battery performance. By systematically investigating their structure and electrochemical properties, we show that N‐rich CN, along with the heterointerface, not only acts as a hybridization matrix that helps facilitate the charge transfer kinetics but also generates substantial capacity. This unique study reveals a powerful platform for the rational design of N‐rich CN based hybrids from MOF. [ABSTRACT FROM AUTHOR]

The kinetics of the roasting of iron and copper sulfides in a pulsating layer was studied, and the kinetic parameters of the processes were determined. The determination of the order of the roasting reactions and activation energy in the MeS – Na2CO3 - O2 system is based on the differential method. Using the dependences of the degree of conversion of copper and iron sulfides in the reactor of the vibratory pulsating layer at a pulsation frequency of 50 Hz and a pulsation amplitude of 0,1 - 0,5 mm, the values of the apparent activation energy in the temperature ranges of 500 – 550 - 600 °C were obtained for FeS 1,60 - 1,64 and for Cu2S 1,44 - 2,41 J*mol. (CO2).

A two-stage pilot plant study has been completed that evaluated the performance of a reverse osmosis (RO) membrane process for the treatment of feedwater that consisted of a blend of a nanofiltration (NF) concentrate and brackish groundwater. Membrane performance was assessed by monitoring the process operation, collecting water quality data, and documenting the blended feedwater's impact on fouling due to microbiological or organic means, plugging, and scaling, or their combination. Fluorescence and biological activity reaction tests were used to identify the types of organics and microorganisms present in the blended feedwater. Additionally, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were used to analyze suspended matter that collected on the surfaces of cartridge filters used in the pilot's pretreatment system. SEM and EDS were also used to evaluate solids collected on the surfaces of 0.45 µm silver filter pads after filtering known volumes of NF concentrate and RO feedwater blends. Water quality analyses confirmed that the blended feedwater contained little to no dissolved oxygen, and a significant amount of particulate matter was absent from the blended feedwater as defined by silt density index and turbidity measurements. However, water quality results suggested that the presence of sulfate, sulfide, iron, anaerobic bacteria, and humic acid organics likely contributed to the formation of pyrite observed on some of the membrane surfaces autopsied at the conclusion of pilot operations. It was determined that first-stage membrane productivity was impacted by the location of cartridge filter pretreatment; however, second-stage productivity was maintained with no observed flux decline during the entire pilot operation's timeline. Study results indicated that the operation of an RO process treating a blend of an NF concentrate and brackish groundwater could maintain a sustainable and productive operation that provided a practical minimum liquid discharge process operation for the NF concentrate, while the dilution of RO feedwater salinity would lower overall production costs.

The present work addresses the limitations by fabricating a wide range of negative electrodes, including metal nitrides/sulfides on a 3D bimetallic conductive porous network (3D-Ni and 3D-NiCo) via a dynamic hydrogen bubble template (DHBT) method followed by vapour phase growth (VPG) process. Among the prepared negative electrodes, the 3D-Fe 3 S 4 -Fe 4 N/NiCo nanostructure demonstrates an impressive specific capacitance (C s ) of 1125 F g -1 (2475 mF cm -2 ) at 1 A g -1 with 80% capacitance retention over 5000 cycles. Similarly, a 3D-Mn 3 P nanostructured positive electrode fabricated via electrodeposition followed by a phosphorization process exhibits a maximum specific capacity (C g ) of 923.04 C g -1 (1846.08 mF cm -2 ) at 1 A g -1 with 80% stability. A 3D-Mn 3 P/Ni//3D-Fe 3 S 4 -Fe 4 N/NiCo supercapattery is also assembled, and it shows a notable C S of 151 F g -1 at 1 A g -1 , as well as a high energy density (ED) of 51 Wh kg -1 ,a power density (PD) of 782.57 W kg -1 and a capacitance efficiency of 76% over 10 000 cycles. This may be ascribed to the use of a bimetallic 3D porous conductive template and the attachment of transition metal sulfide and nitride. The development of negative electrodes and supercapattery devices is greatly aided by this exploration of novel synthesis techniques and material choice., (© 2024 Wiley‐VCH GmbH.)

Polysulfide, as the discharge products of the lithium–sulfur batteries, could easily dissolve into the electrolyte and cause severe shuttle effect between the cathode and anode side. This phenomenon will lead to rapid capacity fading during the electrochemical cycles and poor cycling stability. Therefore, it is important to mitigate the polysulfide shuttle effect and accelerate the polysulfide conversion in the lithium–sulfur batteries. Herein, iron sulfide nanosheets were successfully prepared and developed as sulfur host materials in the lithium–sulfur batteries. Due to the presence of the iron sulfide, the as-prepared iron sulfide/sulfur composites exhibit superior electrochemical performance, including high specific capacity, high rate performance, and stable cycling performance. This is attributed the efficient polysulfide conversion catalyzed by iron sulfide. [ABSTRACT FROM AUTHOR]

Monomethylmercury (CH3Hg) is a neurotoxic pollutant that biomagnifies in aquatic food webs. In sediments, the production of CH3Hg depends on the bacterial activity of mercury (Hg) methylating bacteria and the amount of bioavailable inorganic divalent mercury (HgII). Biotic and abiotic reduction of HgII to elemental mercury (Hg0) may limit the pool of HgII available for methylation in sediments, and thus the amount of CH3Hg produced. Knowledge about the transformation of HgII is therefore primordial to the understanding of the production of toxic and bioaccumulative CH3Hg. Here, we examined the reduction of HgII by sulfidic minerals (FeS(s) and CdS(s)) in the presence of dissolved iron and dissolved organic matter (DOM) using low, environmentally relevant concentrations of Hg and ratio of HgII:FeS(s). Our results show that the reduction of HgII by Mackinawite (FeS(s)) was lower (