Formation Of Zinc Sulfide Research Articles

Unleashing Ultrahigh Capacity and Lasting Stability: Aqueous Zinc‐Sulfur Batteries

AbstractDespite of multifarious dominance of sulfur‐based batteries, polysulfide‐shuttling and use of high‐cost organic electrolytes with flammability risks hinder their applicability as commercial devices. Herein a polysulfide‐free aqueous zinc‐sulfur (Zn─S) rechargeable battery is explored, which offers a low‐cost and environmentally friendly energy storage system being Zn and Sulfur (S) highly abundant with high theoretical capacity. However, the stability of Zn anode is quite challenging due to dendritic growth and corrosion leading to the capacity decay. This work showcases the utilization of ethylene glycol (EG) and iodine (I2) as an electrolyte additive in aqueous zinc acetate [Zn(OAc)2] electrolyte for stabilizing the Zn─S battery performance. EG as an additive is able to mitigate the corrosion rate of the Zn electrode by 15 times which is supported by molecular dynamics simulation. The assembled Zn─S battery delivered an outstanding capacity of 1210 mA h g−1 at 0.1 C with a 91% capacity retention even after 250 cycles, along with remarkable reversible prolonged cycling stability of 3000 cycles at 1 C, with 64.5% capacity retention. More importantly, in situ electrochemical Raman spectroscopy is utilized to monitor the real‐time formation of zinc sulfide (ZnS) as a single discharge product and simultaneously debunking the polysulfide shuttling in the system which is further supported by XPS, UV‐Vis and IR spectroscopy.

CHEMISORPTION-CATALYTIC PROPERTIES OF ZINC OXIDE IN THE PROCESS OF REDUCTION OF PROPYL MERCAPTAN

In this work, the adsorption and catalytic properties of zinc oxide, which it exhibits in the process of desulfurization of propyl mercaptan, are studied. It is shown that zinc oxide obtained by ammonia-carbonate technology has a specific surface area of 40.34 m2/g. Nitrogen adsorption-desorption isotherms refer to type IV according to the IUPAC classification, which is typical for mesoporous materials. The calculation of the pore size distribution shows that ZnO contains pores with a diameter of 2 to 40 nm. The characteristics of the chemisorption-catalytic activity of zinc oxide are given. It has been established that during the catalytic reduction of C3H7SH with hydrogen, the formation and absorption of H2S with the formation of zinc sulfide occur. In this case, depending on the time of operation, there is a gradual decrease in the average size of crystallites of the ZnO phase and an increase in the size of crystallites of the zinc sulfide phase. The study of catalytic activity in the hydrogenation reaction of propyl mercaptan with hydrogen was studied during the full cycle of ZnO operation at temperatures of 350 and 400 °C in a flow-type installation. The stages of the process of interaction of the components of the gas mixture (propyl mercaptan and hydrogen sulfide) with zinc oxide are revealed. It is shown that in the initial period of ZnO operation, intense absorption of hydrogen sulfide occurs with the formation of a zinc sulfide phase. The appearance of hydrogen sulfide at the outlet of the catalytic reactor is fixed after 100-200 min of operation. The second stage is characterized by a rapid increase in the concentration of hydrogen sulfide at the outlet of the catalytic reactor with a simultaneous decrease in the concentration of propyl mercaptan. The third stage occurs after 450-550 min of operation and is characterized by the constancy of the composition of the gas mixture at the outlet of the reactor.

Control of particle growth and enhancement of photoluminescence, adsorption efficiency, and photocatalytic activity for zinc sulfide and cadmium sulfide using CoAl-layered double hydroxide system

The fabrication of zinc sulfide (ZnS) and cadmium sulfide (CdS) hybrids was carried out by the sulfidization of Zn(II) or Cd(II) adsorbed in dodecylsulfate modified CoAl-layered double hydroxide through solid-liquid reaction. The TEM images showed the nanocrystals of ZnS (2.61 nm) or CdS (3.29 nm) orderly distributed on the nanosheets. The BET surface area of ZnS (1.13 m2/g) and CdS (0.78 m2/g) was largely improved by intercalating in the interlayer space of CoAl-layered double hydroxide system (15-20 m2/g). The spectroscopic observations further confirmed the formation of ZnS or CdS nanoparticles in the hybrid as the evidence of the blue-shifted absorption onset (39-44 nm), and the increase of the photoluminescence intensity (3-4 times) relative to those of bare ZnS and CdS. The nanohybrids could be applicable as the adsorbent and photocatalyst on purifying wastewater contaminated with Congo red dye. By the adsorptive removal, the hybrids exhibited the maximum adsorption capacity of 216-234 mg/g, resulting from the effect of CoAl-layered double hydroxide. In addition, the photocatalytic degradation was completely conducted by using CdS hybrid with the rate constant of 0.0115 min-1, because the host-guest and/or guest-guest interactions promoted the greater optical performance, and adsorption and photocatalytic efficiencies.

Electrochemical Deposition of ZnS Films from Electrolyte Based on Na2SO3

The paper considers the features of electrochemical growth of zinc sulfide from an aqueous electrolyte based on sodium sulfite and zinc sulfate. The conditions for the electrochemical production of ZnS films are determined. It is shown that the value of the potential at which a ZnS layer is formed is limited by the achievement of the critical current due to the diffusion limitations of the electrochemical process of reducing the sulfite ion. It is shown that the resulting films contain an excess of sulfur, which is removed, and the stoichiometric composition is obtained by heat treatment. Aed mechanism of reactions resulting in the formation of zinc sulfide is proposed.

The Influence of CBD Parameters on the Energy Gap of ZnS Narcissus-Like Nanostructured Thin Films

Recently, the efficient preparation techniques of zinc sulfide (ZnS) nanostructured films have drawn great attention due to their potential applications in optoelectronics. In this study, the low-cost and high-yield chemical bath deposition (CBD) technique was used to deposit ZnS nanostructured thin films. The effect of various deposition parameters such as time, pH, precursor concentration, and temperature on the morphology and energy bandgap (Eg) of the prepared thin films were investigated. The characterization of the prepared thin films revealed the formation of polycrystalline ZnS with Narcissus-like nanostructures. Moreover, the optical characterization showed inverse proportionality between both the transmission and Eg of the nanostructured thin films and the variation of the deposition parameters. A range of different Eg values between 3.92 eV with 20% transmission and 4.06 eV with 80% transmission was obtained. Tuning the Eg values and transmission of the prepared nanostructured films by manipulating the deposition parameters of such an efficient technique could lead to applications in optoelectronics such as solar cells and detectors.

Structural, optical and antimicrobial activity of Ferric doped zinc sulphide (ZnS) nanoparticles

The current study focuses on the preparation of pure and Ferric doped zinc sulphide (ZnS) using a wet chemical process. The formation of cubic ZnS was verified by X-ray diffraction (XRD) analysis of all prepared samples. The average crystallite particle size of pure and Fe (3%) and Fe (5%) doped ZnS is 33.95 nm, 23.50 nm, and 15.18 nm, respectively. With increasing Fe ion doping concentration, the optical band gap of doped ZnS nanoparticles decreases. Fourier transform infrared spectra confirmed the existence of chemical bonding. The antimicrobial tests were tested against standard bacterial strains.

Investigation of molybdenum dopant effect on ZnS thin films: Chemical composition, structural, morphological, optical and luminescence surveys

Zinc sulfide (ZnS) thin films are prepared by chemical bath deposition (CBD) method on glass substrates. The effect of molybdenum (Mo) doping concentration on chemical composition, structural, morphological, optical and luminescence properties of zinc sulfide thin films is investigated. Chemical composition study by X-ray fluorescence (XRF) confirms the presence of molybdenum in the deposited films. Structural analysis by means X-ray diffraction (XRD) shows that Mo doped ZnS (Mo:ZnS) films crystallize into cubic crystalline structure with (111) preferred crystallographic orientation. X-ray photoelectron spectroscopy (XPS) proves the formation of ZnS by showing the Zn 2p and S 2p spin-orbit doublets. The incorporation of Mo is confirmed by the detection of Mo 3p and Mo 3d lines. Fourier transform infrared (FTIR) spectroscopy reveals some impurities adsorbed on the films surfaces. Mo dopant induces also changes in the surface morphology of the studied films. The optical properties are enhanced for 6 at.-% Mo doping concentration in both visible and infrared regions. The refractive index n(λ) and the extinction coefficient k(λ) are estimated revealing transparency feature for the elaborated films. Photoluminescence intensity quenching is found by Mo incorporation.

Effect of thermal treatment on synthesized Cu doped ZnS nanoparticles

Abstract Zinc sulphide (ZnS) nanoparticles are well known as one of the important inorganic semiconductors. Bandgap, shape, size and synthesis processes are the important parameters which decide the properties of NPs. Therefore the properties of nanoparticles (NPs) can be modified for a specific application by engineering it bandgap and size. In this paper ZnS and Cu doped ZnS (Cu-ZnS) nanoparticles were synthesized by chemical co-precipitation method. The Effect of thermal treatment on Cu-ZnS nanoparticles have been investigated via various characterization techniques. XRD studies confirm the formation of ZnS and Cu-ZnS NPs. Desulphurization of synthesized Cu-ZnS NPs has been observed at temperature 450 °C and above. From UV–Vis spectra, we observed the absorption wavelength of as synthesized ZnS and Cu-ZnS NPs around 215 nm and 218 nm respectively. Red shift in the bandgap of Cu-ZnS NPs has been observed due to annealing. There is a lack of reports on the effect of annealing temperature on magnetism in transition metal doped ZnS nanoparticles. Therefore Magnetic behaviour of synthesized sample has been studied via Vibrating Sample Magnetometer measurement. We have observed that the Cu-ZnS NPs exhibit ferromagnetism. We have reported the increased saturation magnetization at 450 °C. Maximum coercivity of 270 Oe has been observed for Cu-ZnS samples annealed at 350 °C. Thus this paper highlights the effect of annealing temperature of optical, structural and magnetic properties of Cu doped ZnS nanoparticles.

“Compulsory co-precipitation”, a novel and rational route for the synthesis of nanomaterials; mesoporous zinc sulfide as the first case

In the present research work, a novel approach named as compulsory co-precipitation has been introduced for the synthesis of nanoparticles. In this approach a liquid in which the precursors of the target chemical compound are insoluble has been selected as the media of the synthesis reaction. Compulsory co-precipitation was employed for the synthesis of mesoporous zinc sulfide (ZnS) particles which normally were synthesized in the soluble atmospheres. The mesoporous ZnS particles with relatively large surface area were synthesized in the cyclohexane atmosphere as a non-solvent reaction media for Zn(NO3)2·6H2O and Na2S·5H2O precursors. Successful synthesis of cubic zinc blende ZnS particles was confirmed by X-ray diffraction (XRD) analysis. Nitrogen adsorption-desorption analysis was exploited to elucidate the surface porosity characteristics of the particles. The results validated the formation of a mesoporous structure with the maximum specific surface area of about 191 m2 g−1, mean pore diameter of 2.6 nm, and pore volume of about 0.12 cm3 g−1. Forced solution of Zn2+ and S2− as a result of ultrasonic irradiation followed by immediate precipitation of the synthesized ZnS particles was proposed as the ZnS formation mechanism. Also the removal the by-product of the synthesis reaction during the post synthesis treatments was suggested as the main factor for the induction of porosity in the ZnS structure.

Observation of Novel Superparamagnetism in ZnS:Co Quantum Dots

Cobalt-doped zinc sulfide quantum dots with different cobalt concentrations were prepared by the solution route. Structural, optical, morphological, and magnetic responses of the prepared quantum dots were analyzed. X-ray diffraction study confirmed that cubic (zinc blende) structure is the dominant structure of synthesized samples. Crystallite size and lattice constant were found to decrease with cobalt dopant. Transmission electron microscope analysis shows that the mean size of the particles lies in the range of 7–10 nm. The absorption edge of cobalt-doped zinc sulfide nanoparticles is shifted to lower wavelength as compared to that of bulk zinc sulfide which confirmed the quantum confinement effect. The bandgap variation was observed with doping, and it varied from 4.3 to 5.6 eV. The emission spectrum reveals that the cobalt dopant suppresses the ultraviolet emission and enhances the visible emission. Fourier-transform infrared spectrum confirmed the formation of zinc sulfide and the substitution of cobalt ion. Magnetization versus magnetic field result demonstrates that the zinc sulfide and cobalt-doped zinc sulfides are superparamagnetic. Electron spin resonance spectra also confirmed the superparamagnetic nature of zinc sulfide and cobalt-doped zinc sulfide samples. Micro-Raman study also confirmed the incorporation of cobalt in the lattice and the size of the order of the exciton Bohr radius for ZnS.

Augmented optical and electrical properties of PMMA-ZnS nanocomposites as emissive layer for OLED applications

We report the laboratory synthesis of Poly methyl methacrylate (PMMA)-Zinc sulfide (ZnS) nanocomposite via free radical polymerization method and its structural, optical, electrical, and dielectric properties for various concentration of ZnS nanoparticles. The formation of PMMA, ZnS and PMMA-ZnS nanocomposites was examined by X-ray diffraction technique, Fourier transforms infrared spectroscopy and FT-Raman spectrometer. Morphological structure of PMMA-ZnS nanocomposites showed the combination of pebbled and nanosphere like structure. The in-depth topological images were examined by transmission electron microscopy which indicated that the particles were fairly in good contact. The optimized and reduced band gap was calculated ∼3.30 eV. The photoluminescence spectra showed blue, green and yellow band with increased rate of e−-h+ recombination. The decay time of the PMMA-ZnS (5.0%) nanocomposite was ∼4.8413 ns, and the color purity was calculated ∼ 34.08%. The current density increased ∼249% which indicated the enhancement in conductivity. The dielectric properties of the PMMA-ZnS (5.0%) showed high dielectric constant with a very low dielectric loss. The reduction in optical band gap, high dielectric constant, and increased conductivity with increased in recombination rate confirmed that the as-prepared PMMA-ZnS nanocomposite can be used as an emissive layer in OLED devices.

Гидрохимический синтез пленок халькогенидов металлов. Часть 39. Химическое осаждение тонких пленок ZnS тиоацетамидом

ZnS thin films are promising as a buffer layer in solar cells, which can be basis of photovoltaic cells, photoelectric sensors, and light-emitting diodes. For the preparation of thin ZnS films by chemical bath deposition, thioacetamide or thiourea is used as a chalcogenization agent, and ammonia, triethanolamine and sodium citrate are mainly used as ligands, carrying out the process in an alkaline medium. In the present work, in order to predict the conditions of hydrochemical deposition of ZnS films, we have analyzed ionic equilibria in two reaction systems “ZnCl2 – NH4OH – CH3CNH2” and “ZnCl2 – CH3CSNH2 – KHC8H4O4” that differ in acidity of the medium. An analysis of ionic equilibrium showed that in the first bath ~80% of the metal is in the form of a neutral hydroxo complex Zn(OH)2 at pH > 7, and in the second more than 98% of zinc is present as acetate complexes Zn(CH3COO)+ and Zn(CH3COO)2 in the range of pH from 0 to 7. The thermodynamic evaluation of the boundary conditions for the formation of zinc sulfide made it possible to conclude that a zinc sulfide film can be formed in both systems without the admixture of Zn(OH)2 hydroxide. ZnS films were obtained by hydrochemical deposition with thick about 100 nm from both systems. Using local energy-dispersive elemental analysis, it was found that the average ratio between the main elements of Zn and S in the layers obtained in an alkaline medium is 49.48 and 50.52 at.%, and in the synthesized from acidic solutions – 50.35 and 49.65 at.%. According to the data of electron microscopy, up to 85% of the agglomerates have an average size of 200-450 nm that formed from ZnS particles growing in an alkaline reaction bath. At the same time, there are aggregates whose dimensions reach 700 nm. The layers that deposited from relatively acidic solutions are distinguished by a higher degree of dispersion. Here up to ~90% of the film-forming particles is in the nanoscale range from 50 to 90 nm.

Evaluation of diffusion mechanism and structural characterizations of ZnS compound during chemical reaction of Zn and S in liquid phase

ABSTRACTThe present study investigates the diffusion mechanism, morphology and structural characteristics of crystalline zinc sulfide (ZnS) during the reactive diffusion process. The samples with nominal composition of Zn50S50 were prepared via capsulation of high purity of zinc and sulfur followed by the annealing process at various reaction temperatures. The prepared samples were characterized using X-ray diffraction, differential scanning calorimetry and scanning electron microscopy. The structural measurements confirm the formation of zinc sulfide with wurtzite structure during the annealing process at 550°C. The wurtzite allotrope of ZnS is not stable at a high annealing temperature and is transformed to cubic zinc-blende structure. During the annealing process, a continuous layer of ZnS compound forms at the Zn/S interface. Both Zn and S diffuse into the formed ZnS layer and the growth of that occurs mainly toward the Zn side. Under this condition, Kirkendall voids form and accumulate near the ZnS/S interface.

A Systematic Investigation of Factors Affecting the Formation of Zinc Sulfide (ZnS)

Summary Work was undertaken to systematically investigate the factors that affect the formation of zinc sulfide (ZnS) in an aqueous system. Experiments were performed at a series of temperatures from room temperature up to 90°C, at a range of initial pH values and in two brine systems. The effect of pH was examined further by changing the salt from Na2S·9H2O to NaSH·xH2O, therefore changing the initial sulfide source from S2– to HS–, as part of an ongoing method-development strategy. The formation of ZnS was achieved by the equivolume mixing of two preheated bottles, which contained aqueous “H2S” and zinc ions, respectively. Having pH adjusted the zinc brine to values calculated by an in-house thermodynamic model, the brines were preheated to the required temperature and mixed. Aliquots were removed at 2, 4, and 24 hours to perform elemental analysis by inductively coupled plasma optical emission spectrometry (ICP-OES), and pH measurements were performed on all samples after they had returned to room temperature. In addition, particle-size analysis and environmental scanning electron microscopy (ESEM) examination of the resulting precipitate were also performed for a subset of the samples prepared. The reaction between zinc ions and aqueous “H2S” was quantitative at all temperatures up to 90°C and in both brines. The final pH values of the supernatant were independent of the zinc brine pH, and instead were dependent on the molar ratio of zinc and sulfide ions. With a high pH, sulfide-dominated, and a low pH, zinc-dominated, plateau regions were seen with a sharp inflection between the two. As a consequence, reaching field-representative pH values was seen to be extremely difficult while retaining the ability to alter the relative concentrations of the reacting ions. Altering the sulfide source yielded the same trend, although with different absolute values. These observations have been rationalized with reference to the thermodynamic constants governing the reaction through scale-prediction modeling. The work presented here provides a greater understanding of the factors governing the formation of ZnS scale and the considerations required for more industrially relevant formation and inhibition experiments in the future.

Synthesis of ZnS Thin Films by Chemical Bath: From Room Temperature to 90°C

A physicochemical analysis was performed on the solution used for synthetizing zinc sulfide (ZnS) films by chemical bath; such solution contained zinc chloride, potassium hydroxide, ammonium nitrate and thiourea as chemical reagents. Solubility curves and species distribution diagrams were used to obtain the best conditions for ZnS deposition in a wide range of bath temperatures between 25 and 90°C. Solubility curves evidenced the necessity to adjust the thiourea concentration for each bath temperature in order to obtain enough amounts of sulfur ions needed for ZnS formation. The thiourea concentrations were fixed at 0.2 M (90°C), 0.6 M (60°C), 1.25 M (40°C), and 2.25 M (25°C) to get higher quality films. Characterization results of films deposited at the conditions described above showed the films to have a bandgap energy value between 3.65 and 3.72 eV, stoichiometry of [Zn]/[S] ≈1, and homogeneous and agglomerate-free surfaces, which make them proper for solar cells applications.

The Effect of Different Complexing Agents on the Properties of Zinc Sulfide Thin Films Deposited from Aqueous Solutions

The zinc sulfide (ZnS) thin films were prepared on glass substrates by chemical bath deposition using the aqueous solutions of zinc chloride, thiourea, pH regulator and complexing agent (ammonia and hydrazine hydrate, trisodium citrate or sodium hydroxide). The calculations of boundary conditions for formation of zinc sulfide and zinc hydroxide were made at various zinc salt concentrations with different complexing agents. The structural, morphology and optical properties of the ZnS thin films were investigated. The thickness of ZnS films was measured and the recalculation of zinc mass per cm2 of the substrate surface was held for comparison. The deposition mechanism is discussed.

Effect of yttrium doping on structural and optical properties of zinc sulfide nanoparticles

Present work deals with the effect of Yttrium (Y) doping on the structural and optical properties of Zinc Sulfide (ZnS) nanoparticles synthesized by chemical co-precipitation method. The incorporation of Y in ZnS structure and the resulting elemental composition were confirmed using EDAX analysis. The SEM and HR-TEM images depicted the formation of ZnS agglomerates with narrow size distribution. Using XRD spectra it was analyzed that with increase in concentration of Y atoms, the crystallinity of ZnS lattice structure decreases, a significant deviation in the lattice structure was observed at 15wt% Y doping. Raman analysis showed a monotonic decrease in vibration frequency of ZnS lattice with the incorporation of bulky Y ions. A decrease in the band gap from 3.97 to 3.75eV was also observed with increase in Y doping upto 15wt%. The photoluminescence spectra depicted that Y doping has a strong effect on the emission properties of the ZnS nanoparticles. Initially, it enhances the band edge emission by occupying the Zn vacancies in the lattice structure but at higher doping levels their tendency to move into the interstitial sites suppresses back the band edge emission. The blue emission from S vacancies is also observed to increase with Y doping.

Effect of anionic concentration on the structural and optical properties of nanostructured ZnS thin films

Nanostructured Zinc Sulfide (ZnS) thin films with wurtzite structure were prepared by chemical spray pyrolysis method at low temperature. The effect of sulfur concentration on the structural and optical properties of ZnS thin films was studied. The films were analysed by x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), UV–Vis spectroscopy and photoluminescence (PL). Nano grain formation of ZnS was observed from XRD and SEM. Variation in band gap of different films is in agreement with size effects. But there is a red shift in the band gap of these films compared to bulk ZnS. This is due to band tailing effect experienced by the films due to the presence of large number of defects which was verified by PL spectrum. The overall emission was blue in colour for all the films and it was confirmed by Commission International d'Eclairage (CIE) diagram.

Preparation, structural organization, and thermal behavior of the ion-polymeric gold(III)–zinc(II)–dibutylammonium complex ([NH2(C4H9)2][Au{S2CN(C4H9)2}2][ZnCl4)] n

Structural organization and thermal behavior of a new polymeric heteronuclear of gold(III)-zinc-dibutylammonium complex ([NH2(C4H9)2][Au{S2CN(C4H9)2}2][ZnCl4])n (I), obtained by a heterogeneous reaction between freshly precipitated binuclear zinc dibutyldithiocarbamate [Zn2{S2CN(C4H9)2}4] and a H[AuCl4] solution in 2M HCl, is studied. According to single crystal XRD data the crystal structure of the obtained compound is determined and its main structural units are complex [NH2(C4H9)2]+ and [Au{S2CN(C4H9)2}2]+ cations and complexе [ZnCl4]2– anions. Dibutylammonium cations are hydrogen bonded to tetrachlorozincate ions, forming zigzag polymer chains. On the side of the chains there are discrete complex [Au{S2CN(C4H9)2}2]+ cations characterized by a planar tetragonal structure and a uniform spatial orientation. The thermal behavior of I is investigated by synchronous thermal analysis. The multistage process of thermal destruction involves the thermolysis of the cation and anion parts (with the release of metallic gold, zinc chloride and a partial formation of zinc sulfide).

Ultra-violet C absorption and LPG sensing study of zinc sulphide nanoparticles deposited by a flame-assisted spray pyrolysis method

Solvent processed spray pyrolysis is a technique that has attracted worldwide interest for the synthesis of nanoparticles. Zinc sulphide (ZnS) belongs to a category of practical semiconductors known as metal sulphides, and it is used extensively as an optical material. In the present article, ZnS nanoparticles were successfully synthesized using flame-assisted spray pyrolysis. X-ray diffraction confirmed the formation of ZnS with an excellent crystalline structure, while scanning electron microscopy indicated that the as-synthesized materials were nanoparticles. Ultraviolet–visible spectroscopy was utilized to evaluate the optical property of the resulting product and revealed that ZnS nanoparticles have the capacity to absorb ultra-violet C. In addition, various liquefied petroleum gas (LPG) sensing properties of the ZnS nanoparticles were also evaluated.