ZnS Nanospheres Research Articles

In Situ Built ZnS/MXene Heterostructure by a Mild Method for Inhibiting Polysulfide Shuttle in Li-S Batteries.

With high specific surface area, excellent polysulfide conversion activity, and fast electron/ion transfer at the interface, MXene-derived heterostructures can be employed as catalysts for lithium-sulfur (Li-S) batteries to accelerate sulfur redox kinetics and suppress shuttle effect. However, the preparation of MXene-derived heterostructures often requires high-temperature reactions, which can easily lead to the oxidation of MXene and sacrifice the electrical conductivity. Herein, a catalytic two-dimensional heterostructure (ZnS/MXene) was successfully synthesized via a mild method. The MXene skeleton retains the original nanosheet structure without oxidation. The in situ-grown ZnS nanospheres prevent the restacking of MXene nanosheets, which not only increases the active sites, but also guarantees channels for the fast passage of lithium ions. The interfacial built-in electric field further promotes electron/ion migration, thereby expediting the polysulfide conversion and suppressing the shuttle effect. Consequently, the batteries using ZnS/MXene modified separators exhibit a high initial discharge capacity of 1230 mAh g-1 at 0.1 C and a low decaying rate of 0.082% per cycle after 500 cycles at 0.5 C. This work offers a reference for the fabrication of MXene-based heterostructure in Li-S batteries.

Inorganic/organic hybrid interfacial internal electric field modulated charge separation of resorcinol-formaldehyde resin for boosting photocatalytic H2O2 production

The strategy of inorganic/organic semiconductor material hybridization is of great significance for the development of highly active photocatalysts. Resorcinol-formaldehyde (RF) resin with a special donor-acceptor (D-A) structure shows excellent performance in the photocatalytic production of H2O2. However, the lack of an internal driving force for the separation and transfer of photogenerated electrons and holes in RF resin greatly limits the performance of H2O2 production. Herein, an inorganic/organic hybrid core-shell structure ZnS@RF photocatalyst was prepared by directionally induced coating of RF resin shells of different thicknesses on the surface of monodisperse ZnS nanospheres. Consequently, the photocatalytic H2O2 performance of ZnS@RF with the optimal RF resin shell thickness reaches 367.9 μmol L−1, which is 69 and 2 times that of ZnS and HRF, respectively. Density functional theory (DFT) calculations and related characterization results collectively demonstrate that the excellent photocatalytic H2O2 production performance of ZnS@RF photocatalyst is mainly attributed to the internal electric field (IEF) formed at the hybrid interface of ZnS and RF heterojunction and the optimization of RF shell thickness, which significantly enhances the separation and transfer of photogenerated carriers and modulates the interfacial catalytic reaction kinetics. This work opens up an avenue for designing inorganic/organic hybrid heterojunction photocatalyst materials with excellent photocatalytic activity.

Enhanced photocatalytic efficiency of BaTiO3 augmented by ZnS nanospheres via Type-II heterojunction for methyl orange degradation

The degradation of organic pollutants is significantly influenced by the recombination of photogenerated electron–hole pair, electron transfer and surface area of a photocatalyst. Barium titanate (BaTiO3) exhibits low photocatalytic activity due to the rapid recombination of photoinduced charge carriers. Hence, the photocatalytic performance of BaTiO3 (BTO) nanoparticles was improved by the construction of heterostructure with the addition of ZnS. BaTiO3 and ZnS were prepared using solid-state metathesis (SSM) and hydrothermal methods, respectively. Subsequently, a series of [(1-x)BaTiO3/(x)ZnS, x = 10, 30, 50 and 70 wt%] heterostructures were successfully constructed through a simple calcination method using pre-prepared BaTiO3 and ZnS. The XRD, FTIR, Raman, XPS and HRTEM analyses revealed the formation of heterostructure between the BTO and ZnS. The positron annihilation lifetime spectroscopy (PALS) results suggest the existence of defects within the materials. To explore the photocatalytic activity, the photodegradation of methyl orange (MO) dye was carried out under UV light illumination for 3 h. Among all the compositions, the heterostructure 70 BaTiO3/30 ZnS (BTZS(70-30)) demonstrated remarkable photocatalytic activity (91.38 %) which is 5.3 times higher than the pristine BTO (17.16 %). The improved photocatalytic activity of heterostructures may result from the effective charge carrier separation facilitated by the type –II band alignment structure between BTO and ZnS, as well as surface defects like oxygen (Vo), and sulphur (Vs) vacancies. The lowest photoluminescence of BTZS (70-30) clearly substantiated the observed high photocatalytic activity. The scavenger outcomes validated that superoxide radicals (•O2−) and holes (h+) played predominant role in the degradation of MO and a detailed explanation was provided for the plausible mechanism.

N/S‐Doped Hierarchical Porous Bamboo Carbon Fibers with Ultra‐Large Surface Area and Highly Exposed Active Sites for Flexible Zinc‐Air Battery†

Comprehensive SummaryFacile mass transport channel and accessible active sites are crucial for binder‐free air electrode catalysts in rechargeable flexible zinc‐air battery (ZAB). Herein, a ZnS/NH3 dual‐assisted pyrolysis strategy is proposed to prepare N/S‐doped hierarchical porous bamboo carbon cloth (HP‐NS‐BCC) as binder‐free air electrode catalyst for ZAB. BCC fabric with abundant micropores is firstly used as flexible carbon support to facilitate the heteroatom‐doping and construct the hierarchical porous structure. ZnS nanospheres and NH3 activization together facilitate the electronic modulation of carbon matrix by N/S‐doping and optimize the macro/meso/micropores structure of carbon fibers. Benefiting from the highly‐exposed N/S‐induced sites with enhanced intrinsic activity, the optimized mass transport of biocarbon fibers, as well as the ultra‐large specific surface area of 2436.1 m2·g–1, the resultant HP‐NS‐BCC catalyst exhibits improved kinetics for oxygen reduction/evolution reaction. When applied to rechargeable aqueous ZABs, it achieves a significant peak power density of 249.1 mW·cm−2. As binder‐free air electrode catalyst, the flexible ZAB also displays stable cycling over 500 cycles with a minimal voltage gap of 0.42 V, showcasing promising applications in flexible electronic devices.

Design of ZnS nanospheres antireflective structure for mid and far infrared applications

Developing high-performance mid and far infrared antireflection films is a significant requirement in the field of infrared optics. This study successfully prepared AR films composed of ZnS nanospheres for mid and far infrared bands using a combination of hydrothermal and sol-gel methods. Initially, ZnS nanospheres with uniform size and good monodispersity were synthesized via the hydrothermal method and subsequently coated on CdSe substrate through dip coating. The refractive index of the ZnS film is adjusted between 1.36 and 1.52. A significant AR effect was observed in ZnS nanospheres film on CdSe substrate at 3–5 μm and 8–14 μm, and the reflectance is approximately 3 % which is about 25 % lower than that of the uncoated sample. Upon coating with a TiO2 protective layer, the reflectivity further decreased to about 0.6 % and the film demonstrated excellent weather resistance and mechanical properties. This work provides a novel approach for the preparation and regulation of mid and far infrared AR film, significantly contributing to the development of optical film.

Upcycling electrode materials from spent single-use zinc‑carbon/alkaline batteries into rechargeable lithium-ion battery application

Battery recycling/upcycling is a key component of modern e-waste reduction by transforming discarded electrode powder to value-added materials and chemical feedstocks for the proposed applications. In this study, electrode powder from spent zinc‑carbon/alkaline batteries was upcycled into LiMn2O4 cathode and carbon anode for rechargeable lithium-ion battery. The main metallic contents (zinc and manganese) in electrode powder were quantitatively leached using diluted H2SO4 with the presence of H2O2 as a reducing agent. By applying sequential precipitation, ZnS nanospheres and MnCO3 nanocubes were obtained as determined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The recovered MnCO3 was heated with a stoichiometric amount of Li2CO3 to produce high crystalline and pure LiMn2O4. For the electrochemical performance, the results show that upcycled LiMn2O4 exhibits initial discharge capacity of 99.0 mAh g−1 for zc-LiMn2O4 and 111.0 mAh g−1 for al-LiMn2O4, compared to 90.4 mAh g−1 for pristine LiMn2O4. Moreover, recovered carbon materials obtained as an insoluble powder after acid leaching possess unique morphology and crystallinity. The zc‑carbon shows superior cycling performance with reversible charge capacity of 552 mAh g−1 at 1C rate after 100 cycles. This study provides the great potential for upcycling waste battery electrodes to high-value LiMn2O4 cathode and carbon anode for lithium-ion battery application.

Controllable hydrothermal synthesis of hollow ZnS nanospheres: Morphological evolution mechanism and photocatalytic performance

ZnS hollow nanostructures have attracted much attention due to their special structural advantages and wide range of application. Exploring a convenient method for controllable synthesis of ZnS hollow nanostructures and clarifying the formation mechanisms are important prerequisites for subsequent performance regulation. In this article, we propose a facile method for controllable preparation of homogeneous ZnS hollow nanospheres and clarified the morphological evolution mechanism. ZnS hollow nanospheres with uniform size and good dispersibility were synthesized by adding PVP and excessive thiourea during the hydrothermal process. By systematically studying the influence of experimental parameters on the morphology, the influence diagram of thiourea and PVP on the product morphology was drawn. It is found that excess thiourea is the determining factor for the formation of hollow structures, and PVP plays a key role in the size uniformity and dispersion of the product. The formation mechanism is proposed in which thiourea serves as the reaction source and adsorbed molecule, while PVP serves as a dispersant, both of which worked together to the product morphology and size. The photocatalytic experiments indicate that hollow nanospheres with small size and good dispersibility exhibit a better photocatalytic degradation effect. This work elaborates on how the adsorption of thiourea molecules and the steric hindrance of PVP affect the grain aggregation and growth, which inspirational for the controllable synthesis of the required ZnS nanostructures and further research on their properties.

Efficient removal of mercury from aqueous medium using polyvinyl pyrrolidone-capped ZnS nanospheres

This study reports the generation of polyvinyl pyrrolidone (PVP)-capped ZnS nanospheres using the solvothermal method with PVP as a surfactant. Field emission scanning electron microscopic examination of the prepared sample verified its nanosphere form. The elemental composition was confirmed using EDX and elemental mapping. The effectiveness of the synthesized material’s ability to bind mercury was examined using a variety of isotherm and kinetic models, and it was found that the Freundlich isotherm model and pseudo-second-order kinetics, respectively, govern the mercury removal adsorption process. The prepared sample eliminated 95.8% of the mercury from the aqueous solution in 6 h. PVP-capped ZnS nanospheres showed the highest adsorption efficacy of 319 mg/g towards the mercury removal process.

Synthesize, construction and enhanced performance of Bi2WO6/ZnS heterojunction under visible light: Experimental and DFT study

With the simple perovskite structure, Bi2WO6 could be utilized as a modifier to overcome the low visible light response of the wide energy band photocatalyst ZnS. Flower-like Bi2WO6 was simply synthesized by hydrothermal method and Bi2WO6/ZnS heterojunction was constructed via solvothermal reaction. The results showed that ZnS nanospheres were uniformly loaded on the flower-like structure, which was well kept under low concentration loading (≤20%ωt ZnS). The degradation of MB and Rh.B under visible light was used to measure the photocatalytic activity of the photocatalysts. The degradation rates of MB and Rh.B by 20%ωt-Bi2WO6/ZnS were as high as 94.3% and 92.8%, respectively. Moreover, the degradation performance of photocatalyst still maintained 89.3% after 4 times recycling tests. The visible light absorption ability of modified ZnS was improved, and the recombination of photogenerated electrons and holes was inhibited due to the formation of heterojunction. According to the data from density functional theory calculation, the composition of the valence band and conductive band of the Bi2WO6/ZnS system has been altered. The band gap of Bi2WO6/ZnS was reduced by roughly 1.12 eV compared to that of pure ZnS, and the work function analysis were in good agreement with the experimental results. Under light stimulation, electrons were transferred from Bi2WO6 to ZnS to produce superoxide radicals which played key roles in the degradation reaction of dyes.

Controllable Synthesis of Well-Monodispersed ZnS Nanospheres Through a Simple Sol–Gel Method and a Rapid Co-Phase Precipitation Method

In this study, the sol–gel method was used to prepare well-monodispersed ZnS nanopowders with a powder size of approximately 0.5 μm. The starting materials used were Zn(NO3)2 · 6H2O and C2H5NS. However, the agglomeration problem of the powders was addressed by adding an appropriate amount of (C6H9NO)n. The sol–gel method successfully produced submicron-sized ZnS powders. To further reduce the powder particle size, a rapid co-phase precipitation method was employed. This method involved using ZnCl2 and C2H5NS, which yielded ZnS nanopowders with a particle size of approximately 50 nm. The key focus of this method was on selecting the precipitating agent and emulsion to control the precipitation of ZnS nanoparticles. Both methods resulted in finer powder particle sizes and higher powder purity compared to commercial ZnS powders. These improvements in the optical and mechanical properties of ZnS IR-transmitting ceramics are significant. Overall, this study demonstrates the effectiveness of using these methods for synthesizing high-quality ZnS nanopowders.

Study on colloidal synthesis of ZnS nanospheres embedded in reduced graphene oxide materials for sodium-ion batteries and energy storage mechanism

With growing demands for large-scale energy storage, metal sulfides have received great attention due to their high theoretical capacity as anode materials for sodium-ion batteries (SIBs). However, metal sulfides have a problem of poor stability. Thus, it is important to find suitable solutions. In this work, uniform ZnS nanospheres (ZnS NSs) are synthesized through a wet chemical method. And then, by compounding with reduced graphene oxide (rGO), ZnS NSs@rGO are synthesized in which ZnS NSs are evenly distributed on rGO. When we evaluate the cycle performance, ZnS NSs@rGO deliver a high discharge capacity of 634.6 mA h g−1 at a current density of 0.5 Ag−1 after 1000 cycles. Through charge/discharge processes of in-situ XRD analysis, we confirm the sodiation/desodiation mechanism of ZnS NSs@rGO.

Topologically Zn2+ hybridized ZnS nanospheres (Zn2+/nZnS) efficiently restrained the infection of Fusarium verticillioides in rice seeds by hyphal disorganization and nutritional modulation

Schematic illustration of the synthesis of topologically modified ZnS NPs and their in vitro effects on a fungal pathogen, mechanistic electrostatic interactions and seed treatment for the uptake of Zn in rice seedlings.

ZnS Nanospheres Coated with ZnSe/MoSe2 Shells as Dual Heterojunctions with Wide Spectral Responses for the Photoreduction of Cr(VI)

Cr(VI) is a kind of heavy metal ion with strong toxicity to the environment. A better treatment strategy is to reduce Cr(VI) to low toxic Cr(III). However, how to implement this process cleanly and efficiently is still a challenge. In this study, ZnS/ZnSe/MoSe2 (ZZM) nanocomposites with dual type-II heterojunctions are synthesized by solvothermal and ion exchange methods for the first time. The photocatalytic performance of ZZM nanocomposites is evaluated by the photocatalytic reduction of Cr(VI) under visible light irradiation. The ZZM-1:1 nanocomposites can reduce 96.0% of Cr(VI), and the reaction rate constant is 2.476 × 10–2 min–1, which is 3.67, 3.44, and 10.49 times higher than those of MoSe2, ZnSe, and ZnS, respectively. The improved photocatalytic activity can be assigned to the dual heterostructures, which effectively promotes the separation and transmission of photogenerated charge carriers. Meanwhile, the extended light response range and the increased specific surface area also contribute to the improvement of the photocatalytic efficiency. After five cycles, the ZZM-1:1 nanomaterial still shows an 81.1% photoreduction efficiency for Cr(VI). The experimental results show that the ZZM nanocomposites have great potential in removing Cr(VI) from wastewater.

ZnS-assisted evolution of N,S-doped hierarchical porous carbon nanofiber membrane with highly exposed Fe-N4/Cx sites for rechargeable Zn-air battery

Binder-free bifunctional electrocatalysts are attractive for rechargeable Zn-air batteries (ZABs) in grid-scale energy storage and flexible electronics, but suffering from the sluggish mass transport and inadequate catalytic capability. Herein, we propose a scalable approach of in-situ engineering highly exposed Fe-N4/Cx sites on the N,S-doped porous carbon nanofiber membrane as a binder-free air electrode catalyst for ZABs. ZnS nanospheres are firstly used as integrated structure-directing agents to facilitate the electronic modulation of Fe-N4/Cx sites by S doping and construct the hierarchical macro/meso/micropores at high temperature. Neither additional step for removal of ZnS nanospheres nor doping process is required, significantly simplifying the pore formation process and improving the S doping efficiency. Benefiting from the enhanced intrinsic activity of high-density Fe-N4/Cx sites (23.53 μmol g−1) and the optimized mass transport of carbon nanofibers, as-synthesized electrocatalyst shows a positive half-wave potential of 0.89 V for oxygen reduction reaction and a small overpotential of 0.47 V at 10 mA cm−2 for oxygen evolution reaction. When used as the air cathode catalyst for ZABs, it delivers a high specific capacity of 699 mAh g−1 at 5 mA cm−2, a large peak power density of 228 mW cm−2 and a prolonged cycling over 1000 h. At 10 mA cm−2, a robust structure with atomically dispersed Fe is also remained after cycling for 420 h. Due to the flexible properties of the electrocatalyst, as-assembled quasi-solid-state ZAB shows stable cycling over 90 h at alternately flat/bent states, demonstrating great prospects in flexible electronic device applications.

Photocatalytic degradation of organic pollutants in water by N-doping ZnS with Zn vacancy: enhancement mechanism of visible light response and electron flow promotion.

In order to improve the visible light response, N-doping ZnS (N-ZnS) nanospheres with Zn vacancy and porous surface were prepared by a simple one-pot hydrothermal method. Characterizations and density functional theory simulations showed excellent visible light response of N-ZnS. N-doping introduced impurity energy levels, which led to orbital hybridization and changed the original dipole moment. The presence of ortho Zn vacancy (O-Znv) can effectively reduce e--h+ recombination and photocorrosion. Furthermore, O-Znv caused lattice distortion (twisted the -S-Zn-N-(O-Znv)-S-Zn-S- chemical bond chain), resulting in "vacancy effect" to accelerate e- flow. Under visible light, the photocatalytic degradation efficiency of tetracycline (TC) and 2,4-dichlorophenol (2,4-DCP) was 90.31% and 60.84%, respectively. TOC degradation efficiency was 31.4% and 25.6%, respectively. Combined with Fukui index and LC-MS methods, it was found that TC and 2,4-DCP were degraded under the constant attack of active substances such as ·OH. This work can provide a reference for the application of catalytic materials in the field of visible light photocatalysis.

Rational Design of Cu-Doped ZnS Nanospheres for Photocatalytic Evolution of H2 with Visible Light

Rational Design of Cu-Doped ZnS Nanospheres for Photocatalytic Evolution of H₂ with Visible Light

Enhanced activity of ZnS (111) by N/Cu co-doping: Accelerated degradation of organic pollutants under visible light

High-efficiency photocatalysts are of great significance for the application of photocatalytic technology in water treatment. In this study, N/Cu co-doped ZnS nanosphere photocatalyst (N/Cu-ZnS) is synthesized by a hydrothermal method for the first time. After doping, the texture of nanosphere becomes loose, the nanometer diameter is reduced, making the specific surface area of catalyst increased from 34.73 to 101.59 m2/g. The characterization results show that more ZnS (111) crystal planes are exposed by N/Cu co-doping; the calculations of density functional theory show that N/Cu co-doping can increase the catalytic activity of the ZnS (111) crystal plane, enhance the adsorption capacity of (111) crystal plane to O2, and promote the generation of •O2−. The energy levels of the introduced impurities can be hybridized with the energy levels of S and Zn at the top of valence band and the bottom of conduction band, which makes the band gap narrower, thus enhancing the absorption of visible light. Compared with pure ZnS, the degradation rates of 2,4-dichlorophenol (2,4-DCP) and tetracycline (TC) by N/Cu-ZnS under visible light (>420 nm) are increased by 83.7 and 51 times, respectively. In this research, a promising photocatalyst for photocatalytic degradation of organic pollutants in wastewater is provided.

Carbon-quantum-dot-modified ZnS nanospheres for highly efficient electrocatalytic hydrogen evolution

CQDs modified ZnS nanospheres are modulated by tuning the addition of l-cysteine, and the CQDs attached on ZnS nanospheres plays an important role in improving the electron mobility and active areas, which determine the electrocatalytic performance.

Study on Colloidal Synthesis of Zns Nanospheres Embedded in Reduced Graphene Oxide Materials for Sodium-Ion Batteries and Energy Storage Mechanism

Study on Colloidal Synthesis of Zns Nanospheres Embedded in Reduced Graphene Oxide Materials for Sodium-Ion Batteries and Energy Storage Mechanism

Synthesis and characterization of P-doped g-C3N4 nanosheet hybridized ZnS nanospheres with enhanced visible-light photocatalytic activity

Phosphorus-doped g-C3N4/ZnS (PCN/ZnS) composite photocatalyst was prepared by element doping and structuring heterojunction by solvothermal methods. The heterojunction composite was characterized by XRD, SEM/TEM, XPS and UV–vis DRS. The photocatalytic properties of PCN, ZnS and PCN/ZnS were studied by photodegradation of tetracycline (TC) with visible light irradiation. The 15%PCN/ZnS showed the highest photocatalytic degradation performance of TC with the reaction rate constant of 0.0529 min−1, which was 40.7 times of ZnS and 6.3 times of PCN. Superoxide radicals and holes played a major role in the photocatalytic degradation process, but not hydroxyl radicals. Besides, according to the conduction and entrainment positions of PCN and ZnS, they form a type II heterojunction structure, which could extend the range of light response, enhance the charges transfer and efficient separation. In general, the design and synthesis of PCN/ZnS provide a new way to photodegrade pharmaceutical wastewater with enhanced photocatalytic properties.