Zinc Sulfur Research Articles

Oxidative Degradation of Basic Red 29 by Persulfate Activated by Sulfur Composite Zinc

Herein, a composite zinc formed by ZnO and different zinc sulfur species is synthesized via a simple reduction of zinc sulfate by sodium sulfite under air. The obtained product is found to be very efficient in the activation of persulfate (PS) when compared to commercial ZnO. Diluted PS at 2 mM in homogeneous system allows the degradation of 24.83% of Basic Red 29 (BR29) after 120 min at 40 °C. The addition of 5 mg of the composite zinc increases the yield to 74.89%, while commercial ZnO registers 50.21% under the same conditions. The effectiveness of the composite sample is found to be due to the presence of ZnS and SO32− species that act as dopants for PS activation. The degradation reactions follow the pseudo‐first order with both catalysts. The main components involved in the degradation process are superoxide radical followed by singlet oxygen and then sulfate radical. Further application of ultrasounds at 40 kHz and addition of H2O2 at 1 mM reduces the reaction time for total degradation to 40 min with the composite zinc and 70 min with commercial ZnO.

Bifunctional electrolyte additive with redox mediation and capacity contribution for sulfur cathode in aqueous Zn-S batteries

Aqueous zinc-sulfur (Zn-S) battery has attracted much attention due to the ultrahigh theoretical capacity of S (1675 mA h g−1). Nevertheless, its lifespan is far from satisfactory owing to the sluggish reaction kinetics for ZnS conversion to S, and the formation of irreversible by-product of SO42− during charging. Herein, a novel bifunctional electrolyte additive thiourea (TU) was introduced to solve the above problems. It has been found that TU can undergo reversible redox reactions during cycles, which not only enhances the reversibility between ZnS and S but also contributes to extra capacities. Based on the ex-situ FTIR and XPS characterization, in combination with the electrochemical performance of thiourea and its derivatives, the influential mechanism of TU on the S@KB electrode was proposed. Its negative centers and positive centers of the intermediates can interact with ZnS to weaken the Zn-S bonds to improve the electrochemical dynamics. Simultaneously, the carbonium ions in the intermediate of TU show strong reactivity to ZnS so that the formation of SO42− can be inhibited. As a result, the S@KB electrode shows excellent cyclic performance with 763.7 mA h g−1 capacity after 300 cycles at 5 A/g, corresponding to a low decay rate of only 0.11 % per cycle. This work provides a promising electrolyte additive and an effective strategy to improve the reaction kinetics and cycle stability of Zn-S batteries.

Multifunctional Quasi-Solid-State Zinc-Sulfur Battery.

The introduction of structural energy storage devices into emerging markets, such as electric vehicles, is predominately hindered by weak energy density, safety concerns, and immaturity of the field in materials. Herein, fabrication and testing of a freeze-resistant, multifunctional quasi-solid-state zinc-sulfur battery (ZnS) are reported. To this end, an electrostatic spray coating technique was used to deposit a thin layer of sulfur on the highly porous, unidirectional activated carbon nanofibers (A-CNFs) as a load-bearing cathode. This technique could fill micro- and mesopores, and microsized channels with sulfur, achieving an extensive sulfur loading of 60 wt %. Several drawbacks of structural energy storage devices (applicability under varied climate conditions, poor electrochemical performance and mechanical properties) are addressed by initiating an antifreezing hydrogel electrolyte with a failure strain of over 200%. This electrolyte possesses ethylene glycol and an I2 additive as an antifreezing agent and redox mediator, respectively. The as-assembled ZnS battery offers a high energy density of 283 Wh/kg based on the CNF-S cathode (149 Wh/kg based on the ZnS cell) and mechanical properties beyond state-of-the-art structural energy storage devices with a tensile strength of 377 MPa, Young's modulus of 16.7 GPa, and energy-to-failure of 4.5 MJ/m3. The electrochemomechanical properties of the ZnS battery were also investigated to elucidate the effects of electrochemical energy storage on mechanical properties and vice versa. Overall, the ZnS battery outperforms state-of-the-art structural energy storage devices in terms of energy storage and load-bearing capabilities.

Boosting visible-light-driven photocatalytic H2 evolution of C/Znln2S4 hollow tubes by Ni doping

• A unique Ni doped CZIS photocatalyst was synthesized by a simply method. • Ni atoms partially replaced Zn atoms to form Ni/CZIS. • Ni/CZIS showed a high H 2 release capacity of 3537.04 μmol g -1 h −1 . • The good photocatalytic activity was attributed to Ni doping and special structure. An n-type nickel-doped carbon indium zinc sulfur (Ni/CZIS) hollow tube structure photocatalyst was synthesized for the first time through a simple solvothermal combination with an oil bath. Then it was characterized by a series of tests such as SEM, TEM, XRD, XPS, photoelectric properties and so on. The results showed that the addition of nickel acetate in the oil bath achieved uniform doping of nickel atoms and partially replaced the positions of zinc. The optimized Ni/CZIS material had lower overpotential, broadened the light absorption region, promoted photo-induced carrier separation and better hydrophilicity. Thus it showed an excellent visible-light photocatalytic hydrogen production rate (3035.75 μmol/g/h) and cyclic stability. In view of density functional theory calculations, Ni atomic doping narrowed the band gap width, changed the positions of the valence and conduction bands, and also generated a new hybridization level near the Fermi level. This energy level provided a new electronic channel for photo-generated electrons, facilitated the transfer of electrons and suppressed the recombination of carrier, thereby enhancing the photocatalytic hydrogen production performance.

Experimental and DFT study of the sulfidation of smithsonite: Impact of water and oxygen

Water and oxygen have a significant effect on the sulfidation of smithsonite. However, few studies considered the water and oxygen effects, and the roles of water and oxygen in the sulfidation process remain ambiguous. In this work, the impact of water and oxygen in the sulfidation of smithsonite was creatively investigated by flotation tests, XPS measurements, and DFT calculations. The flotation test results showed that the sulfidation level of smithsonite by directly adding Na2S was not good enough to get a high recovery. The XPS measurement results showed that the sulfidation product of ZnSOn can be formed on smithsonite surface apart from Zn-S under oxygenated aqueous conditions. The DFT simulation results showed that mixed molecular and dissociated adsorption of H2O was observed on smithsonite surface, which prevented the HS adsorption. Besides, it further illustrated the formation of sulfidation products of zinc sulfur oxides in the presence of H2O and O2. Moreover, the sulfidation product of Zn-S can be oxidized by the O2. Thus, it was unstable. In summary, oxygen can be involved in the sulfidation process by dissociated adsorption. This work is crucial and helpful for understanding the sulfidation flotation of smithsonite.

The promises and challenges of aqueous Zinc-Sulfur batteries

The aqueous Zinc-Sulfur (Zn-S) batteries hold significant promise for next-generation batteries due to their high theoretical specific capacity S (1,672 mA h g−1), their high safety, and the low price of sulfur. Nevertheless, the electrochemistry of the aqueous Zn-S batteries is still unclear, and their multifarious irreversible reactions also indicate their complexity. In this perspective, we have summarized the fundamental properties of and the current challenges for aqueous Zn-S batteries. Moreover, future opportunities for the development of aqueous Zn-S batteries are proposed.

High impact of thiol capped ZnS nanocrystals on the degradation of single and binary aqueous solutions of industrial azo dyes under sunlight

Sulfur zinc (ZnS) nanocrystals were prepared using an aqueous colloidal route with thioglycolic acid (TGA) as a stabilizer. These ZnS-TGA nanocrystals were used as a low-cost and environmental friendly alternative for the photodegradation of methylene blue (MB) and methyl orange (MO) from aqueous solutions using sunlight irradiation. Structural and optical properties of nanocrystals were determined via X-ray diffraction, Fourier transform infrared spectroscopy, Transmission electron microscopic, UV–Visible and photoluminescence spectroscopy. Results showed a blue shift of absorbance band and higher energy band gap values than bulk ZnS materials, which was in agreement with the quantum confinement effect. X-ray diffraction confirmed the formation of cubic phase of ZnS-TGA containing also a slight wurtzite phase. Calculated average size of ZnS nanocrystals by the Debye Scherrer relation was 3.5 nm. Characterization results showed the fixation of TGA on ZnS-NCs via sulphur and carboxylic functionalities on catalyst surface. Photoluminescence spectra obtained under excitation wavelength at 325 nm showed three emission bands (416, 441 and 484 nm), which were mainly related to band edge and defect-activated emissions. The photocatalytic activity of ZnS-TGA nanocrystals under sunlight irradiation to degrade tested MB and MO dyes and their mixture in aqueous solutions was evaluated. High dye degradation efficiency was achieved at a very short time (27 min) and this performance was attributed to the negative surface charge, surface area, surface defects and high dispersion of ZnS-TGA nanocrystals on the aquatic medium. Overall, this study demonstrates that these nanocrystals could be employed as low-cost nanocatalyst for the degradation of organic dyes in wastewater treatment.

Maximizing Energy Storage of Flexible Aqueous Batteries through Decoupling Charge Carriers

AbstractFlexible aqueous rechargeable batteries that integrate excellent mechanical flexibility and reliable safety hold a great promise for next‐generation wearable electronics. Unfortunately, currently available options are unsatisfactory due to their low specific capacity, limited energy density, and unstable voltage output. Herein, to overcome these challenges, high theoretical specific capacity zinc and sulfur as the anode and cathode are selected, respectively. Furthermore, a strategy is proposed, that decoupling charge carriers in anolyte and catholyte to simultaneously endow the zinc anode and sulfur cathode with optimal redox chemistry, maximizes the energy storage of flexible aqueous batteries. The new zinc–sulfur hybrid battery possesses merits of ultrahigh theoretical specific capacity (3350 mAh gS−1) and volumetric energy density (3868 Wh L−1), low cost, ecofriendliness, and ease of fabrication and is a promising next‐generation aqueous energy storage system. The fabricated flexible aqueous zinc–sulfur hybrid battery delivers a stable output voltage (release 92% of its full capacity within a small voltage drop of 0.15 V) and an ultrahigh reversible capacity of 2063 mAh gS−1 at 100 mA gS−1, thus setting a new benchmark for flexible aqueous batteries and is promising to play a part in future flexible electronics.

Study of the temperature effect on the morphology and structure of ZnS nanoparticles synthesized by hydrothermal method

AbstractThe control over the materials structure is crucial for the modulation of its properties, in order to achieve this control is important to know the formation mechanism of the material as function of parameters used. For this purpose, the effect of temperature (120, 140, 160 and 180 °C) on the hydrothermal synthesis of zinc sulphide is evaluated and a proposal of the sequence of reactions formation of zinc sulphur is presented. ZnS nanostructures with blend-phase were obtained, the temperature increment induces the growth of the nanostructure ranged between .62 and 12.72 nm, furthermore, increase the crystallinity of the ZnS nanostructures. The proposed reactions suggest the formation of a complex of thioacetamide with the Zn+2 and its subsequent decomposition into ZnS.

A Low Cost Aqueous Zn-S Battery Realizing Ultrahigh Energy Density.

Rechargeable aqueous zinc ion batteries are enabled by the (de)intercalation chemistry, but bottlenecked by the limited energy density due to the low capacity of cathodes. In this work, carbon nanotubes supported 50 wt% sulfur (denoted as S@CNTs‐50), as a conversional cathode, is employed and a high energy density aqueous zinc–sulfur (Zn–S) battery is constructed . In the electrolyte of 1 m Zn(CH3COO)2 (pH = 6.5) with 0.05 wt% I2 additive where I2 can serve as medium of Zn2+ ions to reduce the voltage hysteresis of S@CNTs‐50 and stabilize Zn stripping/plating, S@CNTs‐50 delivers a high capacity of 1105 mAh g−1 with a flat discharge voltage of 0.5 V, realizing an energy density of 502 Wh kg−1 based on sulfur, which is one of the highest values reported in aqueous Zn‐based batteries that use mild electrolyte. Moreover, the chemical materials cost of this aqueous Zn–S battery can be lowered to be $45 kWh−1 due to the cheap raw materials, reaching to the level of pumped energy storage. Ex situ X‐ray diffraction, Raman spectra, X‐ray photoelectron spectrum, and transmission electron microscopy measurements reveal that sulfur cathode undergoes a conversion reaction between S and ZnS.

Unraveling the RNA Binding Properties of the Iron-Sulfur Zinc Finger Protein CPSF30.

Cleavage and polyadenylation specificity factor 30 (CPSF30) is a "zinc finger" protein that plays a crucial role in the transition of pre-mRNA to RNA. CPSF30 contains five conserved CCCH domains and a CCHC "zinc knuckle" domain. CPSF30 activity is critical for pre-mRNA processing. A truncated form of the protein, in which only the CCCH domains are present, has been shown to specifically bind AU-rich pre-mRNA targets; however, the RNA binding and recognition properties of full-length CPSF30 are not known. Herein, we report the isolation and biochemical characterization of full-length CPSF30. We report that CPSF30 contains one 2Fe-2S cluster in addition to five zinc ions, as measured by inductively coupled plasma mass spectrometry, ultraviolet-visible spectroscopy, and X-ray absorption spectroscopy. Utilizing fluorescence anisotropy RNA binding assays, we show that full-length CPSF30 has high binding affinity for two types of pre-mRNA targets, AAUAAA and polyU, both of which are conserved sequence motifs present in the majority of pre-mRNAs. Binding to the AAUAAA motif requires that the five CCCH domains of CPSF30 be present, whereas binding to polyU sequences requires the entire, full-length CPSF30. These findings implicate the CCHC "zinc knuckle" present in the full-length protein as being critical for mediating polyU binding. We also report that truncated forms of the protein, containing either just two CCCH domains (ZF2 and ZF3) or the CCHC "zinc knuckle" domain, do not exhibit any RNA binding, indicating that CPSF30/RNA binding requires several ZF (and/or Fe-S cluster) domains working in concert to mediate RNA recognition.

Effect of Ingredient Loading and Temperature on Tensile Properties of Surfactant-Loaded Natural Rubber Vulcanizates

Tensile properties are among the measures that give rubber products value. In this study, the effect of ingredient loading and temperature on the tensile properties of surfactant-loaded natural rubber vulcanizates (NRV) are investigated. Rubber dogbone samples are compounded using an L12 orthogonal array of Taguchi design of experiment, where ingredients are treated as factors varied at low and high loadings. Rubber specimens for each formulation are thermally aged for 20 days in ovens with temperatures of 40, 50, and 60 °C. Results show that zinc oxide (ZnO), paraffin wax, sulfur, mercaptobenzothiazole (MBT), and diphenylguanidine (DPG) significantly have the highest effect on increasing the elastic modulus while decreasing the tensile strength, tensile strain, and tensile set. Used oil has the highest effect on decreasing the elastic modulus but has the highest effect on increasing tensile strength, tensile strain, and tensile set. High loading of cocamide diethanolamide (coca DEA) significantly increases tensile strength at 60 °C. High loading of glycerol monostearate (GMS) significantly decreases tensile strength and strain at 40 °C. Highest elastic modulus, tensile strength, strain, and set are achieved when NRV are thermally aged at 50 °C.

One‐Step Hydrothermal Synthesis of ZnS Quantum Dots‐Reduced Graphene Oxide Composites with Enhanced Photocatalytic Activity

Zinc sulfur quantum dots‐reduced graphene oxide (ZnS QDs‐rGO) composites are successfully synthesized by a one‐step hydrothermal method. The ZnS QDs are well scattered on the surface of the wrinkled rGO with smaller particle size compared with initial ZnS QDs. The influence of the content of rGO in composites on the photocatalytic effect is also investigated in detail. The ZnS QDs‐1.0% rGO has the highest photocatalytic activity and the degradation kinetics of methylene blue is more consistent with the zero order kinetic model than the pseudo first order kinetic model in this experiment. The mechanism for the enhancement of photocatalytic activity is mainly due to promoting separation of the photogenerated carriers with the introduction of rGO and the increase in specific surface area of ZnS QDs due to decrease in size. These results reveal that the effective synergistic action between ZnS QDs and rGO is the key factor to determine the photocatalytic degradation efficiency of the ZnS QDs‐rGO composites.

Modeling solid-state detonation based on thermochemical equilibrium calculations

ABSTRACTThe present work describes the application of a recently developed Calculation of Phase Diagrams (CALPHAD) method to perform condensed-phase thermochemical equilibrium calculations of Chapman–Jouguet (CJ) detonation properties for a number of new mixtures speculated to support gasless detonation. Mixtures in question are titanium–silicon (Ti–Si), the common thermite mixture of aluminum–iron oxide (Al–Fe2O3), and zinc–sulfur (Zn–S). The high-pressure products of these reactive mixtures were found to be stable, and thus suitable for gasless CJ detonation calculations. The CJ calculation method was found to be successful for these mixtures, and the results showed CJ detonation properties with high temperatures, but only marginal volume increase. While this is expected for condensed-phase products, the calculations nevertheless show that gasless detonation may be possible under a very narrow range of conditions.

Hydroxyundecanethiol-Modified Steel Fibers for the Selective Solid-Phase Microextraction of Polycyclic Aromatic Hydrocarbons from River and Wastewater

ABSTRACTA novel organic–inorganic composite-coated fiber was developed for selective solid-phase microextraction (SPME) by direct electrodeposition of zinc oxide microparticles on a pretreated stainless steel wire followed by self-assembly of hydroxyundecanethiol with zinc–sulfur bonds. The performance of the hydroxyundecyl-modified zinc oxide-coated steel fiber was then assessed for SPME of polar aromatic compounds coupled to high-performance liquid chromatography with ultraviolet detection. Excellent extraction and selectivity were obtained for polycyclic aromatic hydrocarbons. The extraction and desorption times, temperature, stirring rate, and ionic strength were optimized. The limits of detection were from 0.034 to 0.132 µg L−1. The relative standard deviations were from 3.4 to 4.9% for a single fiber and from 5.1 to 6.4% for multiple fibers. The recovery of polycyclic aromatic hydrocarbons in environmental water fortified at 5.0 and 50 µg L−1 was from 83.1 to 103% with relative standard deviations below 8.4%. This fiber was shown to withstand at least 200 extraction and desorption cycles. The method was used for the preconcentration and determination of polycyclic aromatic hydrocarbons in environmental water.

Preparation and thermal stability of fluoroalkyl end-capped vinyltrimethoxysilane oligomeric silica/poly(acrylonitrile-co-butadiene) nanocomposites—application to the separation of oil and water

Fluoroalkyl end-capped vinyltrimethoxysilane oligomeric silica nanocomposites-encapsulated poly(acrylonitrile-co-butadiene) (NBR) [RF-(VM-SiO2) n -RF/NBR] were prepared by the sol-gel reactions of the corresponding oligomer [RF-(VM) n -RF] in the presence of NBR under alkaline conditions. Interestingly, it was demonstrated that these obtained fluorinated nanocomposites can afford no weight loss corresponding to the contents of NBR in the composites even after calcination at 800 °C. On the other hand, the nanocomposites, which were prepared under the cross-linking conditions at 150 °C for 30 min by using NBR containing zinc oxide and sulfur (S8) as the cure activator and the cross-linker, respectively, were found to exhibit a clear weight loss corresponding to the contents of the NBR after calcination at 800 °C. The fluoroalkyl end-capped oligomeric silica nanocomposites-encapsulated the cross-linked NBR were applied to the surface modification of glass to supply the superoleophilic/superhydrophobic characteristic on the surface. The nanocomposites possessing such superoleophilic/superhydrophobic characteristic were applied to the packing material for the column chromatography to separate not only the mixture of oil and water but also the W/O emulsion. In contrast, the nanocomposites, which were prepared under no cross-linking conditions, were not applicable to the packing materials for the separation of these mixtures due to the oleophilic characteristic of the encapsulated NBR in the nanocomposite cores.

Solid Suspension Flow Batteries Using Earth Abundant Materials

The technical features of solid-electrode batteries (e.g., high energy density, relatively low capital cost ($/kWh)) and flow batteries (e.g., long cycle life, design flexibility) are highly complementary. It is therefore extremely desirable to integrate their advantages into a single storage device for large-scale energy storage applications where lifetime cost ($/kW-h/cycle) is an extremely important parameter. Here, we demonstrate a non-Li-based-flow battery concept that replaces the aqueous solution of redox-active molecules found in typical redox flow batteries with suspensions of hydrophilic carbon particles ("solid suspension electrodes") coated with earth-abundant redox-active metals. The solid suspension electrodes charge by depositing earth-abundant redox-active metals onto the carbon particle suspension, which are then stripped during discharge operation. The electrical contact to the solid suspension electrodes is fed through fixed redox-inert hydrophobic carbon current collectors through "contact charge transfer" mechanism. The hydrophobicity of the current collectors prevents direct plating of redox-active metals onto their surfaces. The above concept was successfully used to demonstrate several non-Li-based battery chemistries including zinc-copper, zinc-manganese oxide, zinc-bromine, and zinc-sulfur, providing a pathway for potential applications in medium and large-scale electrical energy storage.

Thermal efficiency evaluation of a ZnSI thermochemical cycle for CO2 conversion and H2 production – Complete system

In this paper, a flowsheet of a zinc–sulfur–iodine (ZnSI) thermochemical cycle is designed. The mass and heat balance are presented. Thermal efficiency is chosen as the evaluation criterion of the whole system, and the effects of three operating parameters (composition of the Bunsen reaction products, ZnI2 decomposition ratio, and hydroiodic acid concentration in ZnO–HI reaction) are also investigated. Results show that ZnI2 decomposition ratio and HI concentration in ZnO–HI reaction have little influence on the whole system, while optimizing the Bunsen reaction to obtain a high HI concentration in the over-azeotropic HI solution is effective to increase thermal efficiency. However, high ZnI2 decomposition ratio and HI concentration in ZnO–HI reaction would cut the complexity of the process and benefit the system. Moreover, thermal efficiency could exceed 40% under proper operating conditions.

Quantum Dot Light-Emitting Diodes for Uniform Eight-Segment Displays

Experimental Chemicals.— Cadmium oxide (CdO, 99.998%), selenium (Se, 99.999%), 1-octadecene (ODE, 90%), oleic acid (OA, 90%), sodium hydroxide (NaOH, 98%), zinc acetate (Zn(CH3COO)2, 99.98%) and octadecylamine (ODA, 98%) were purchased from Alfa Aesar. Trioctylphosphine oxide (TOPO, 90%), hexadecylamine (HDA, 90%) and trioctylphosphorus (TOP, 97%) were purchased from SigmaAldrich. Zinc oxide (ZnO, 99.99%) and sulfur (S, 99.99%) were purchased from Aladdin. All organic solvents were purchased from Sigma-Aldrich. The chemicals were used directly without further treatment.

Self-powered pendulum and micro-force active sensors based on a ZnS nanogenerator

A pendulum and micro-force active sensors have been first made from zinc sulfur nanowires based nanogenerator. The ZnS nanogenerator can be self-powered to trace a simple harmonic motion of a pendulum that released from different angle. A various momentums from 0.077 N s to 0.177 N s were able to detect owing to the output voltage and current of the ZnS nanogenerator were proportional to the momentum.