Sulfur Ions Research Articles

Formation of Nanodispersed Cuprous Sulfide Powder from Solutions Containing Copper and Sulfur Ions Under Electrolysis Conditions

Formation of Nanodispersed Cuprous Sulfide Powder from Solutions Containing Copper and Sulfur Ions Under Electrolysis Conditions

Effect of Sulfur Vacancies of CoNi2S4 on Its Electrochemical Performance in Hybrid Supercapacitors.

Ternary cobalt nickel sulfides are considered promising electrode materials due to their unique physical properties. However, its capacitive performance is still limited by the insufficient material utilization efficiency. Here, we design and fabricate CoNi2S4 with nanorods and hairy-petal-like nanosheets on nickel foam (NF) as an excellent self-standing electrode for a hybrid supercapacitor (HSC). The CoNi2S4 electrode material was synthesized on the NF substrate by cobalt organic framework (Co-MOF) conversion and introducing sulfur ion and nickel ion exchange. The CoNi2S4 electrode material with sulfur vacancies was controlled by regulating the reduction time, and then electrochemical analysis and comparison were performed. The results demonstrate that the synergistic effect of the MOF-derived CoNi2S4 skeleton and sulfur vacancies can significantly improve the electrochemical activity of nickel cobalt sulfide. The CoNi2S4 electrode exhibits a superior high specific capacitance of 5.24 F/cm2 at a current density of 3 mA/cm2. Furthermore, the assembled CoNi2S4-60//AC HSC displays a high energy density of 59.41 Wh/kg and a power density of 999.98 W/kg. Even after 10,000 continuous charge-discharge cycles, its initial capacitance was retained at 89.24%. These results demonstrate the feasibility and practicality of CoNi2S4-60 as an electrode material, showcasing its potential for real-world applications.

(Invited) Synthesis of Structured Transition Metal Sulfide Electrodes Via a Highly Active Sulfur Activation Process for Fast Energy Storage Applications

Transition metal sulfide (TMS) materials exhibit significant potential as high-performance supercapacitor electrodes for rapid charge-discharge cycles. Compared to their oxide counterparts, TMS materials generally show superior electrical conductivities, with the incorporation of sulfur atoms boosting their ionic conductivities.The fabrication and control of the structure and morphology of TMS electrodes are crucial in determining their physical and electrochemical properties for energy storage applications. Typically, the electrochemical efficiency correlates with the interactions between the electrode materials and electrolyte ions at the electrode's surface. Hence, electrodes with an optimally structured morphology can demonstrate enhanced electrochemical performance due to their increased surface area, reduced ion transport distances, and structural integrity. These characteristics contribute to higher specific capacitance, enhanced ion diffusion kinetics, and extended cyclability.Electrochemically active electrode materials are typically created with various micro/nanostructures using different synthetic methods, such as solvo-/hydrothermal synthesis, thermolysis, microwave irradiation, chemical vapor deposition, sputtering, and electrodeposition. These synthetic processes often require extended synthesis times (approximately 12–24 hours), electrochemical deposition and additional heat treatment to transform chemical reactants (above 400°C). Such methods impose significant high-temperature input, voltage damage, or mechanical strain on substrates, rendering them impractical for the industrialization of supercapacitors and likely degrading the practicalbility of diverse substrates. Consequently, identifying an effective method to fabricate electrochemically active electrode materials without thermal heat treatment is important. The low-temperature solution-based synthetic approach has been investigated as a viable alternative for depositing active materials on metal substrates.In this study, we introduce a novel and efficient method for synthesizing hierarchically structured TMS electrodes using a direct exposure approach with a highly reactive sulfide solution. The essence of this synthesis technique lies in the swift interaction between the ammonium sulfide solution and transition metal, wherein the ammonium ions catalyze the liberation of transition metal ions. Subsequently, these released ions react with sulfur ions in the solution, resulting in the formation of TMS materials. By modulating the synthesis conditions, it is possible to engineer TMS electrodes with diverse structures, leading to varying electrochemical properties. This approach offers a simple yet effective pathway to fabricate scalable, hierarchical TMS structures, highlighting the innovative capabilities of the solution-based sulfur activation method for high performance and fast energy storage applications.

Computational Analysis of Mixed-Anion Inorganic Materials for Secondary Battery Cathode Materials

For decades, battery design and development were based on the idea that the only possible source of redox in Li-ion cathode was on the transition metal. More recently, there has been exploration into the notion that anions could provide an extra capacity and energy density source for batteries. Nonetheless, anion redox is frequently linked with the irreversible discharge of oxygen from battery cathodes, presenting a notable obstacle to utilizing anion redox for creating enhanced batteries. Many studies have been conducted to effectively harness the reversible oxygen redox while preventing irreversible oxygen loss.1 However, various methods and their understandings are still insufficient.In this situation, an anion substitution approach could be one of the remedies to utilize oxygen redox reversibility and understand its mechanism. Recently, Leube et al. reported on sulfur selenide mixed-anion cathode, which actually stored energy through stable anion redox reactions and also showed good cycle performance.2 We suggest that oxysulfides form a class of mixed-anion compounds that have properties making them potentially promising cathode materials. We apply isovalent anion substitution to oxide cathodes, with a fraction of oxygen ions replaced by sulfur ions. This isovalent substitution leaves the oxidation state of metals unchanged, thus having no impact on the overall quantity of available cation redox. At the same time, substituting sulfur ions allows us to regulate the anion p-states within the materials, which control the activity of anion redox in the system.We first calculate the solubility limit of sulfur in oxide forming the solid solution oxysulfide. We model lithium cathode materials with oxygen and sulfur mixed in anion sites from 0 to 100%, based on structural prototypes known for anion redox behavior, considering 19 transition metals. We also model sulfur and selenium mixed cathodes, which have been experimentally reported.2 By comparing these two systems within the same prototype, we can identify the factors that make mixed-anion cathode difficult to synthesize. In fact, there are relatively few experimental or theoretical reports on oxysulfide synthesis. Therefore, this study aims to provide a theoretical interpretation of why it is challenging to form solid solution oxysulfide compared to sulfoselenide. We perform featurization on materials, including basic information, local and global structure features, etc. Using these features, we apply a machine learning technique to identify the key factors that hinder mixed-anion system synthesis. Our findings suggest the features that make it difficult to dissolve sulfur into oxide, offering a theoretical guide for constructing other types of mixed-anion systems. Reference A. S. Menon, M. J. W. Ogley, A. R. Genreith-Schriever, C. P. Grey, and L. F. J. Piper, Annu Rev Mater Res, 54, 199–221 (2024)B. Leube, C. Robert, D. Foix, B. Porcheron, R. Dedryvère, G. Rousse, E. Salager, P. Cabelguen, A. Abakumov, H. Vezin, M. Doublet, J. Tarascon, Nature Communications 2021 12:1, 12, 1–11 (2021)

High sensitive and discriminating colorimetric assay for S2− overload in adaptogenic herbs utilizing ZnS nanoparticle-enhanced S, N-doped eggshell membrane-derived biochar

BackgroundWith the rapid development of industrialization, the excessive emission of S2− have become increasingly serious, leading to a surge in the content of S2− in nature. Rapid and accurate detection of S2− contamination in natural adaptogens is crucial for food safety. Annually, discarded eggshell waste, rich in organic and inorganic materials, poses environmental risks if landfilled. Utilizing waste eggshell membrane biomass for S2− detection is cost-effective, yet designing biochar materials for sensors requires balancing catalytic enhancement and anti-interference capabilities. Improving the catalytic performance of biochar for colorimetric S2− detection without metal ion interference presents a challenging issue. ResultsWe first modified biochar (EBc) derived from waste eggshell membranes using a combination of thiourea and ZnS nanoparticles, fabricating ZnS-decorated, S–N co-doped biochar (ZnS-SN-EBc) nanozymes, which were applied for the colorimetric assay detection of S2− contamination. The addition of thiourea significantly increases the proportion of pyridinic-N in biochar, enhancing the peroxidase-like activity of the nanozyme. The growth of ZnS nanoparticles on the biochar not only enhances the catalytic performance by increasing the S content but also reduces the content of oxidized S, thereby improving resistance to interference. The detection range for S2− was expanded from 0.1 to 45 μM for EBc to 0.05–225 μM for ZnS-SN-EBc, and the limit of detection improved to 0.0397 μM. Additionally, ZnS-SN-EBc significantly enhanced metal ion interference resistance. S2− detection in five types of adaptogenic herbs verified the accuracy and practicality of the colorimetric assay, with recovery rates comparable to national standards. SignificanceWe innovatively repurposed waste eggshell membranes to develop a selective and catalytic peroxidase-like nanozyme, ZnS-decorated S–N co-doped biochar (ZnS-SN-EBc). The developed colorimetric assay utilizing ZnS-SN-EBc demonstrates significant potential for the detection of sulfur ions in adaptogenic herbs, thus contributing to both waste resource utilization and the advancement of food safety detection technologies.

Real-Time Monitoring and Control System Enhances Drilling-Fluid Management

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 216322, “Next-Generation Drilling-Fluid Management: Real-Time Monitoring and Autonomous Control,” by Zhicai Zhang, Rached M. Rached, SPE, and Yunbo Xun, Sinopec, et al. The paper has not been peer reviewed. _ Accurate measurement and control of drilling-fluid properties are crucial for safe and successful drilling operations. Traditional manual methods are slow and require significant manpower, underscoring the need for real-time monitoring. This paper highlights a new online system for monitoring drilling fluids, enabling intelligent control of drilling-fluid performance. The online monitoring system improves drilling-industry safety and success by measuring properties of drilling fluids in an accurate, timely, and automated matter. Introduction The primary objectives of this project are to develop an innovative online system for monitoring drilling fluids with a focus on facilitating intelligent control of drilling-fluid performance. The system aims at measuring 10 key parameters continuously, including apparent viscosity, plastic viscosity, yield point, density, pH, and ion concentrations. By incorporating online, real-time, continuous monitoring capabilities, the system offers several advantages, including improved data quality and frequency, reduced on-site labor requirements, and a corresponding decrease in associated health and safety hazards. System Description Overview of the Online Drilling-Fluid-Monitoring System. The online drilling-fluid-monitoring system is available in four distinct configurations: land modular, land skid-mounted, offshore cabin, and indoor small modular, providing customization options to meet specific space requirements. The system is designed to measure 10 crucial parameters essential for drilling operations. These include rheology factors, density, pH, sulfur ion content, and chloride ion content. Density and rheology measurements are performed at a 1-Hz sampling rate, offering near-continuous monitoring. The system is capable of operating within an ambient temperature range from –35 to 50°C, and the testing temperature can be adjusted between 4 and 80°C. Enabled by real-time data transmission, the system allows for the online, real-time monitoring of drilling-fluid properties. The system has proven its utility extensively, with more than 30 sets having been deployed successfully across more than 200 wells. Ideally, the monitoring system is positioned near the circulation tank to enable efficient fluid transfer (Fig. 1a). When space near the circulation tank is limited, an alternative placement can be on the opposite side of the blowout-prevention pipeline (Fig. 1b). However, this alternative may lead to a slight delay in data because of extended circulation times.

Anti-sulfur poisoning electrochemical sensor for sulfur ions based on nitrogen-doped graphene-encapsulated cobalt-nickel nanoparticles

Electrochemical sensor for S2- based on a novel anti-sulfur poisoning strategy of “chainmail for material” was developed. Nitrogen-doped graphene-encapsulated cobalt-nickel nanoparticles (CoNi@NGs) was synthesized and used as sensing material. The graphene shells can physically isolate the core metal from the external environment to prevent formation of metallic sulfides and corrosion. In addition, CoNi@NGs is sulfurophobe and therefore repels sulfur, resulting in a self-cleaning process. Therefore, the developed sensor exhibited much better anti-sulfur poisoning performance than those reported in the literatures, as the current didn’t decrease after continuous detection of S2- 80 h with a self-developed on-line flow measurement system. The sensor had a wide S2- detection range (from 0.5 to 1000 μM) with LOD of 0.47 μM (S/N=3). It was worth mentioning that the sensor showed excellent specificity to S2- with selectivity of more than 100 to the common interfering substances in water. Finally, the developed sensor was applied to detect S2- in real water samples including industrial wastewater, pond water and seawater with recoveries of 86.9–118.1 %.

Glass Finds from the Elite House of Roue, a Sasanian City Building in Western Iran: Composition and Classification Using XRF and Raman Spectroscopy

The Silk Road connected the east of Iran to the western world. Roue city is close to the Road. Six glass samples from Roue were classified on the basis of morphology, archaeological context and compositions. The samples were analysed by means of XRF and Raman spectroscopy and two specific groups, namely Roue type 1 and Roue type 2, with close composition to high alumina plant-ash glass in circulation from the 6th to 10th centuries CE in Mesopotamia, Iran and Syria, were identified. The simultaneous occurrence of two types of glass in the excavated layers shows that the house was inhabited in the early Islamic period. Colours (black, amber-green, light and aqua blue) were produced mainly by the amount of iron and sulphur ions required for the amber chromophore and copper ions for the blue colour and the controlling of reducing conditions in the furnace.

Mo-doped carbon-dots nanozyme with peroxide-like activity for sensitive and selective smartphone-assisted colorimetric S2− ion detection and antibacterial application

Sulfur ion (S2−) plays a significant and considerable role in many living organisms and ecosystems, while its abnormal content can pose a serious hazard to human health and ecological environment. Hence, it is extremely meaningful to construct a highly sensitive and selective analytical platform for S2− detection in complex microenvironment, particularly in biological systems. In this study, phosphomolybdic acid and L-Arg were utilized to prepare a new molybdenum doped carbon-dots nanozyme (Mo-CDs) with great peroxidase-like activity by one-step hydrothermal approach. In the presence of H2O2, Mo-CDs converted 3,3′,5,5′-tetramethyl benzidine (TMB) into blue oxTMB, but S2− strongly reduced the blue solution to colorless and then brown, which established significant selectivity toward S2−. Mo-CDs illustrated a wide linear range (2.5 μM–900 μM) and low detection limit (LOD = 76 nM) by ultraviolet and smartphone-assisted visualized colorimetric analysis. Especially, the smartphone-assisted analysis platform successfully realized quick, portable, sensitive and visible identification of S2− with high recovery (95.7–106.7 %) and excellent specificity in water samples. More importantly, Mo-CDs was developed to antibacterial applications based on good peroxidase-like activity. This research not only constructed a new and efficient carbon-dots nanozyme and a low-cost, portable, visual analysis platform for real-time detection of S2−, but also proposed a novel design strategy and methodology for exploiting multifunctional nanozyme detection tool with great practical application.

Partially Amorphous Ru-Doped CoSe Nanoparticles with Optimized Intermediates Adsorption for Highly Efficient Sulfur Oxidation Reaction.

The application of thermodynamically more favorable sulfur oxidation reaction (SOR) to replace oxygen evolution reaction (OER) in electrocatalytic water electrolysis is an appealing strategy to achieve low-energy hydrogen production while removing toxic sulfur ions from wastewater. However, the study of SOR catalysts with both activity and stability still faces great challenges. Herein, this study prepares partially amorphous Ru-doped CoSe (pa-Ru-CoSe) nanoparticles for SOR. The doping of Ru keeps Co in an electron-deficient state, which enhances the adsorption of SOR intermediates and improves the catalytic activity. Meanwhile, the partially amorphous selenide possesses great corrosion resistance to sulfur species, thus ensuring stability in long-term SOR. In addition, the pa-Ru-CoSe requires only 0.566V to reach a current density of 100mA cm-2 in the SOR-HER coupled system and remains stable for 200 h. This work provides a promising partially amorphous strategy for SOR catalysts with both catalytic activity and long-term stability, enabling hydrogen production with low energy consumption and simultaneous sulfur production.

Lithium Localization by Anions in Argyrodite Solid Electrolytes from Machine‐Learning‐based Simulations

AbstractThe introduction of density functional theory (DFT) has improved the study of material properties. This has enabled significant breakthroughs in solid electrolytes, which have emerged as promising candidates for next‐generation energy storage systems. However, DFT faces limitations due to the extremely high computational costs required for large atomic cells and long simulation times. In the current study, AI‐based simulations using neural network potentials (NNPs) are introduced to extend the capabilities of DFT to explore the effect of anions on lithium diffusion in Li argyrodite (Li6PS5X, X = Cl and Br). The investigation categorizes lithium frameworks into two distinct cages, demonstrating that sulfur ions in these cage centers bind the surrounding lithium ions. From the results, a strategy is proposed to enhance lithium ion conductivity by minimizing the occupation of sulfur ions in cage centers. This research provides a benchmark for evaluating lithium ionic conductivity based on anion configuration in cage centers and advances the understanding of ionic transport in Li argyrodite, informing potential improvements in energy‐storage technologies.

Insights into the flotation performance of ethylenediamine surface modified hemimorphite: Experimental and DFT study

Upon utilizing micro-flotation, contact angle, AFM, ToF-SIMS, XPS, ICP-OES, and DFT calculations, the influence of ethylenediamine (EDA) on the flotation mechanism of hemimorphite was investigated. The addition of EDA to the flotation system led to a 25.15 % increase in flotation recovery efficiency. Contact angle and AFM analysis indicated that EDA enhanced both the hydrophobicity and surface roughness of hemimorphite. Subsequently, ToF-SIMS deep profiling analysis indicated that EDA modification facilitated the incorporation of sulfur ions into the internal structure of hemimorphite, forming a uniform zinc sulfide film. Furthermore, XPS and ICP-OES analysis demonstrates an increase in sulfides on the surface of the hemimorphite after EDA modification. Additionally, the results of DFT calculations showed that the adsorption energy of an EDA molecule on the hemimorphite (1 1 0) surface was −956.492 kJ/mol.

Stabilizing the Layer-Structured Oxide Cathode by Modulating the Oxygen Redox Activity for Sodium Ion Batteries.

The layer-structured oxide cathode for sodium-ion batteries has attracted a widespread attention due to the unique redox properties and the anionic redox activity providing additional capacity. Nevertheless, such excessive oxygen redox reactions will lead to irreversible oxygen release, resulting in a rapid deterioration of the cycling stability. Herein, sulfur ion is successfully introduced to the O3-NaNi0.3Mn0.5Cu0.1Ti0.05W0.05O2 material through high-temperature quenching, thereby developing a novel Na2S-modified O3/P2-NaNi0.3Mn0.5Cu0.1Ti0.05W0.05O2 composite with extended cycling life. The S2- is analyzed for the ability to enhance the reversibility of oxidation-reduction reactions under high voltage and suppress the loss of lattice oxygen during cycling. The stable S─O covalent bonds are found to inhibit the oxygen generation and release within the structure. Benefiting from these improvements, the Na₂S-modified O3/P2-NaNi0.3Mn0.5Cu0.1Ti0.05W0.05O2 exhibited a high reversible capacity of 173.1mA h g-1 over a wide voltage range of 1.5-4.3V under test conditions at 0.1 C and 81.5% capacity retention after 120 cycles at 1 C. The Na₂S-modified O3/P2-NaNi0.3Mn0.5Cu0.1Ti0.05W0.05O2 demonstrates the excellent rate capability with the reversible capacities of 173.1,137.0,114.7,96.7, and 80.1mA h g-1 at 0.1, 0.2, 0.5, 1, and 2 C.

Synergistic Gas Therapy and Targeted Interventional Ablation With Size-Controllable Arsenic Sulfide (As2S3) Nanoparticles for Effective Elimination of Localized Cancer Pain.

The elimination of localized cancer pain remains a globally neglected challenge. A potential solution lies in combining gas therapy with targeted interventional ablation therapy. In this study, HA-As2S3 nanoparticles with controlled sizes are synthesized using different molecular weights of sodium hyaluronate (HA) as a supramolecular scaffold. Initially, HA co-assembles with arsenic ions (As3+) via coordinate bonds, forming HA-As3+ scaffold intermediates. These intermediates, varying in size, then react with sulfur ions to produce size-controlled HA-As2S3 particles. This approach demonstrates that different molecular weights of HA enable precise control over the particle size of arsenic sulfide, offering a straightforward and environmentally friendly method for synthesizing metal sulfide particles. In an acidic environment, HA-As2S3 nanoparticles release hydrogen sulfide(H2S) gas and As3+. The released As3+ directly damage tumor mitochondria, leading to substantial reactive oxygen species (ROS) production from mitochondria. Concurrently, the H2S gas inhibits the activity of catalase (CAT) and complex IV, preventing the beneficial decomposition of ROS and disrupting electron transfer in the mitochondrial respiratory chain. Consequently, it is found that H2S gas significantly enhances the mitochondrial damage induced by arsenic nanodrugs, effectively killing local tumors and ultimately eliminating cancer pain in mice.

Highly Sensitive Detection of Sulfur Ion in Water by Four-Color Fluorescence Based on Cu-Containing Metal-Organic Framework.

In this paper, a highly sensitive method for sulfur ion (S2-) detection was developed based on a four-color fluorescence probe constructed from copper-containing metal-organic framework (CuBDC) and four dye-labeled single-strand DNA (ssDNA). In the absence of S2-, dye-labeled ssDNA can be adsorbed on the surface of CuBDC, and the dyes are close to copper ion on the CuBDC surface, their fluorescence is quenched by copper ion, and their fluorescence signals are weak. In the presence of S2- in the system, S2- reacts with copper ion in CuBDC to form CuS, which has a more stable structure than complex CuBDC, resulting in the decomposition of CuBDC. In this case, dye-labeled ssDNA are detached from the CuBDC surface and dissolved in the solution, and the fluorescence of the dyes is restored. Under the optimized conditions, there is a good linear relationship between the total fluorescence intensity of four dyes and the concentration of S2- in the range of 2 × 10-9 to 5 × 10-8 mol/L; the detection limit is 2.2 × 10-10 mol/L. The method has a good selectivity and accuracy, and it can be applied to the analysis and detection of S2- in actual water samples.

Ultrafast X-ray laser-induced explosion: How the depth influences the direction of the ion trajectory

Single particle imaging using X-ray lasers is a technique aiming to capture atomic resolution structures of biomolecules in their native state. Knowing the particle's orientation during exposure is crucial for method enhancement. It has been shown that the trajectories of sulfur atoms in a Coulomb exploding lysozyme are reproducible, providing orientation information. This study explores if sulfur atom depth influences explosion trajectory. Employing a hybrid collisional-radiative/molecular dynamics model, we analyze the X-ray laser-induced dynamics of a single sulfur ion at varying depths in water. Our findings indicate that the ion spread-depth relationship depends on pulse parameters. At a photon energy of 2 keV, high-charge states are obtained, resulting in an increase of the spread with depth. However, at 8 keV photon energy, where lower charge states are obtained, the spread is essentially independent with depth. Finally, lower ion mass results in less reproducible trajectories, opening a promising route for determining protein orientation through the introduction of heavy atoms.

Assimilatory sulphate reduction by acidogenesis: The key to prevent H2S formation during food and green waste composting for sustainable urbanization

Food and green waste composting is a nature-based process for sustainable management of municipal organic waste. Although widely used for these organic wastes, composting is hindered by rapid organic acidification and malodor emission, particularly hydrogen sulphide (H2S). Using genome-resolved metagenomics, this study aimed to decipher the underlying mechanisms of sulphate reduction to H2S by acidogenesis during food and green waste composting. Results showed that both volatile fatty acids (VFAs) and H2S were significantly produced within the first week of composting. Further analysis identified that bacteria (e.g. Lactobacillus) with acid-producing genes (ackA and LDH) were key accomplices to assimilatory sulphate reduction for producing H2S by providing VFAs, especially acetic and lactic acids, as a carbon source. Such sulphate reduction could be directly induced by bacteria (e.g. Bacillus, and Ureibacillus) with intact assimilatory sulphate-reducing genes (cysNC, cysH, and cysJ/I). Nevertheless, individual bacteria (e.g. Paenibacillus and Acetobacter) without any sulphate-reducing genes could collaborate with their partners carrying complemented genes to complete sulphate reduction toward H2S. Furthermore, VFAs production could acidify composting substrates to abiotically aggravate the conversion of sulphur ions (e.g. S2- and HS-) to H2S. Nevertheless, alkaline additives suppressed these mechanisms to prevent both acidogenesis and H2S production, thereby, reducing the global acidification and human toxicity potentials of food and green waste composting.

Influence of chromium concentration on the structural, optical, magnetical, and thermal properties of ZnS nanocrystals

Pure ZnS and Zn1-xCrxS nanoparticles were successfully prepared using the coprecipitation method, where x represents the concentration (x = 0.00, 0.10, and 0.05). There are many analytical methods used, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and Spectroscopy of energy dispersive (EDS). The magnetism structure of the catalysts was investigated using spectrophotometry (VSM), thermogravimetric analysis (TGA), and differential thermal analysis (DTA). X-ray diffraction studies determine the nanocrystal arrangement and size of microcrystals. As seen in SEM analysis, the particles are agglomerated. The coordination of sulfur ions around zinc ions was examined using FTIR analysis. The energy band gap of the Cr-doped sample increases. Photoluminescence spectroscopy showed that the violet emission around 424 nm could be attributed to the excitation process of electrons from the low energy of the conduction band to the valence band of sulfur intermediate atoms. The front amplitude of doped ZnS nanocrystals remains constant regardless of the amount of Cr present. The results show that the ZnS nanocrystals were replaced by dilute Cr3+ ions. Cr-doped ZnS exhibits diamagnetic properties under hightemperature conditions. The results show that these materials are improved by the Cr doping process, making them suitable for many applications.

Copper–Nickel Oxide Nanosheets with Atomic Thickness for High‐Efficiency Sulfur Ion Electrooxidation Assisted Nitrate Electroreduction to Ammonia

AbstractThe nitrate electroreduction reaction (NO3RR) offers an eco‐friendly alternative to the Haber–Bosch technology for ammonia (NH3) synthesis. However, the complex reaction process and diverse products make efficient NH3 synthesis challenging. Therefore, the rational design and preparation of highly efficient electrocatalysts are crucial for NO3RR. Herein, ultrathin copper‐nickel oxide (Cu‐NiO) nanosheets (Cu‐NiO UTNSs) are synthesized via the cyanogel‐NaBH4 hydrolysis‐reduction method, which are applied for the cathodic NO3 RR to NH3‐assisted with the anodic sulfur ion (S2−) oxidation reaction (SOR) in an electrolyzer. The ultrathin nanosheet structure, the interaction between NiO and Cu, and the formation of oxygen vacancy contribute to generating the rich active sites, regulating the electronic structure, and improving the substance adsorption. Thus, the Cu‐NiO UTNSs exhibit excellent electrocatalytic performance for NO3RR and SOR. As a bifunctional Cu‐NiO UTNSs||Cu‐NiO UTNSs electrolyzer, it can reach 10 mA cm−1 at only 0.1 V for NO3−‐to‐NH3 conversion at the cathode and S2−‐to‐S8 conversion at the anode. This work provides a promising approach for producing value‐added chemicals at a low electrolysis voltage and a strategy for pollutant treatment.

Gold nanoparticle-enhanced D-shaped optical fiber sensor for mercury ion detection.

Mercury ions (Hg2+) are highly toxic heavy metal ions that pose serious health risks to humans when present at concentrations above the safety threshold. Therefore, the development of a rapid and effective Hg2+ detection method is of significant importance. In this study, based on surface plasmon resonance (SPR) technology integrated with COMSOL simulation analysis, a highly sensitive and selective Hg2+ sensing system is constructed. Initially, gold nanoparticles and the surface of a fiber-optic gold film are modified by sodium sulfide (Na2S). In the presence of Hg2+, the sulfur ions on the modified gold film and gold nanoparticles specifically bind to Hg2+, forming the composite structure Au/S-Hg2+-S/AuNPS. Due to the strong electromagnetic coupling between the gold nanoparticles and the gold film, a significant SPR wavelength shift occurs. These results show that the Hg2+ sensor has high sensitivity and enhanced selectivity. The detection limit for mercury ions was 8.15 nM, and the recovery rate in real environmental samples was up to 90.1-97.3%. This sensing system provides an alternative method for rapid and accurate determination of mercury content.