Synthesis and Characterization of Zinc Sulfide-Aluminium -Platinum Nanocomposites Produced by Coprecipitation Method

Abstract

In this investigation, Zinc Sulfide (ZnS) nanoparticles and nanocomposite powders such as Zinc- Aluminium (ZnS-Al), Zinc- Platinum (ZnS-Pt), and Zinc- Aluminium-Platinum (ZnS-Al-Pt) were fabricated using the co-precipitation method, employing zinc acetate and sodium sulfide as primary materials. The proposed composite powders were thoroughly characterized using techniques like Energy-dispersive X-ray Spectroscopy, X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Ultraviolet-Visible (UV-Vis) absorption spectroscopy, and photoluminescence analysis. To investigate the structural characteristics of the nanocomposites XRD was employed, and the Debye-Scherrer equation was applied to calculate their crystallite sizes. SEM examinations provided detailed insights into the morphology of the nanocomposites. The optical properties were assessed through UV spectroscopy, which showed that the ZnS nanocomposites displayed a prominent absorption peak in the 295-300 nm range, with the highest absorption at 299 nm, and a bandgap energy of 3.75 eV. This indicates a notable blue shift compared to the spectrum of bulk ZnS. Furthermore, the photoluminescence analysis indicated that the ZnS nanocomposites are capable of emitting light at a wavelength of 400 nm. These findings underscore the significant promise of ZnS nanocomposites and their possible use in supercapacitors as sophisticated electrode materials.

Keywords:
Nanocomposites; ZnS nanoparticles; Coprecipitation method; Aluminium; Platinum

1. Introduction

The increasing need for efficient and eco-friendly energy storage solutions has led to significant research into high-performance energy storage devices. As portable electronics and wearable technologies advance, there is a growing interest in developing flexible energy storage systems that are not only compact but also have superior electrochemical characteristics¹,². Among various electrochemical energy storage (EES) technologies—such as fuel cells, rechargeable batteries and supercapacitors³,⁴, supercapacitors stand out for their ability to fill the gap between conventional capacitors and batteries by offering higher energy density, making them suitable for larger energy storage applications⁵,⁶.

The supercapacitors includes three primary components: electrodes, separators, and electrolytes, with electrodes playing a crucial role in their performance. These electrodes often consist of metal-based oxides, which serve as electron materials, while electrolytes can be broadly categorized into aqueous and organic types⁷-¹⁰. Notably, metal oxides like TiO₂, nO₂, SnO₂, Fe₂O₃, Co₃O₄, NiO, and CuO are favored for electrode materials due to their exceptional performance¹¹. Nanoparticles (NPs), with their remarkably high surface area-to-volume ratio compared to bulk materials, have been employed as electrode materials in supercapacitors. Nanoparticles range from 1 to 100 nm in size and can exhibit size-dependent properties due to this vast surface area¹²,¹³.

The advantages of using metal oxide nanoparticles include potential structural modifications affecting lattice symmetry and cell parameters, alterations in electrochemical characteristics attributable to the quantum confinement effect and changes in surface properties that significantly influence conductivity and chemical activity¹⁴. Nanoparticles may possess singular properties such as being metallic, dielectric, semiconductor, magnetic, or multifunctional, which combines several of these characteristics, leading to a wide range of applications. Additionally, conducting polymers are explored for their high capacitance, conductivity, low cost, and simplicity in fabrication, despite their relative lack of mechanical stability and cycle life. Merging the distinct benefits of various nanoscale capacitive materials to create nanocomposite electroactive materials is a key strategy to enhance the structural and property optimization of electrode materials for supercapacitors¹⁵.

The characteristics of nanocomposite electrodes are influenced by the properties of the individual components, as well as their morphology and the nature of their interfaces. There has been significant research into developing a variety of nanocomposite materials for capacitive uses, emphasizing the need to consider several factors in their design and creation. These factors include the choice of materials, methods of synthesis, parameters of the fabrication process, characteristics of interfaces, electrical conductivity, the size of nano-crystallites, and surface area¹⁶-¹⁸.

The properties of nanomaterials can be adjusted according to specific requirements by carefully managing their size, shape, conditions of synthesis, and by applying suitable functional groups. To prepare the Nps Various synthesis methods are available, broadly categorized into top-down and bottom-up approaches. Among these, coprecipitation is often used for generating inorganic and metal-based nanoparticles due to its advantages like high yield, use of environmentally friendly solvents and the production of particles with a uniform size distribution¹⁹. Recent advancements in this field have been contributed by researchers worldwide. In particular, semiconductor compounds from the II–VI group are of great technological significance across diverse scientific and technological domains because their bandgap can be adjusted. This group includes ZnO, CdS, ZnSe, ZnS, and CdTe, which are notable for their outstanding electronic and optical properties, making them suitable for applications in luminescence and display technologies²⁰,²¹.

Among these Zinc Sulfide (ZnS) is recognized as a primary direct band-gap semiconductor, distinguished by two distinct structural forms, each offering unique bandgap values. The capacity of ZnS nanoparticles to swiftly generate electron-hole pairs through photo-excitation, coupled with their highly negative reduction potentials, positions them as effective photocatalysts²². Their conduction band level is higher compared to other semiconductors such as TiO2 and ZnO, which facilitates greater interaction between the active ZnS material and electrolyte ions, thus enhancing capacitance. The improved conductivity and increased surface area of ZnS nanoparticles contribute to the superior electrochemical performance of supercapacitors²³,²⁴. Murugan et al.²⁵ synthesized pure ZnS and MgS quantum dots (QDs) using a co-precipitation method, observing that the absorption increased with higher concentrations of MgS in the composite. Ali et al.²⁶ successfully created ZnO/ZnS nanocomposites through a hydrothermal process, noting a decrease in resistance with increased NaOH concentration. Alnehia et al.²⁷ employed a green synthesis method to produce zinc sulfide nanoparticles with favourable properties for potential biomedical applications. Oskenbay et al.²⁸ successfully synthesized ZnS/ZnO nanocomposites using a two-stage solid-phase method. Choi et al.²⁹ reported the synthesis of various crystal phases (cubic and hexagonal) and sizes (1–3 μm and 200–300 nm) of ZnS, Ag-ZnS, and Au-ZnS microspheres using a solvothermal method.

The subsequent sections detail the synthesis and characterization of Zinc Sulfide (ZnS) based nano composites. The morphology of the composite powders has been analysed using SEM. The optical and Photoluminescence property of the proposed composite powders have been reported. The combination of zinc sulfide (ZnS), aluminum (Al), and platinum (Pt) in a single nanocomposite result in unique properties that are not present in the individual components. The resulting nanocomposites demonstrate enhanced electrical and optical characteristics.

2. Materials and Methodology

2.1. Materials

Zinc Acetate Dihydrate ((CH₃COO)2Zn·2H₂O), Sodium Sulfide Nonahydrate (Na₂S·xH₂O), Sodium Hydroxide (NaOH), and other chemicals required for the experiments were sourced from High Purity Chemicals Private Limited in Mumbai, each with a purity of 99.99%. Double-distilled (DD) water was the medium of choice for entire study.

2.2. Synthesis of nanomaterial

Initially, a 0.1 M solution of Zinc Acetate Dihydrate was prepared by mixing it with 100 mL of double-distilled water, serves as the Zinc ion source for nanoparticle formation. Similarly, a 0.1 M solution of Sodium Sulfide was prepared in another beaker with 100 mL of distilled water to provide a clear solution, acting as the sulfide ion source for the reaction. The sodium sulfide solution was then slowly added to the zinc acetate solution while stirring continuously. This step initiates a precipitation reaction, resulting in the formation of ZnS nanoparticles. After 40 minutes, to adjust the solution's pH to the desired level, 100 mL of hydrochloric acid (HCl) solution was prepared at a 0.1 M concentration by diluting approximately 0.833 mL of concentrated HCl with distilled water to achieve a total volume of 100 mL. The mixture was stirred for approximately four hours on a magnetic stirrer. Following this, the mixture underwent centrifugation at 3000 rpm for 30 minutes. The resulting precipitate was repeatedly washed with acetone and then dried at 150°C for 1 hour in a hot air oven to eliminate any residual moisture. The dried product, now primarily in the Zn^2+ state, was then placed in a Silica crucible and subjected to an oxidation process through annealing in a muffle furnace at 600°C for 4 hours. The detailed procedure is displayed in Figure 1. To embellish the ZnS nanoparticles with metal nanoparticles of Al, Pt and a combination of Al/Pt, 0.1 grams of ZnS nanoparticles were thoroughly mixed into 50 mL of water. Subsequently, a metal precursor with a concentration of 0.1 M was introduced into the solution. For the decoration with both Al and Pt, a concentration of 0.05 mM for each precursor was used to keep the total metal precursor concentration at 0.1 M.

Figure 1
Procedure for synthesis of nanomaterial.

2.3. Synthesis of nanocomposites

2.3.1. ZnS-Aluminium (ZnS /Al)

Dissolve 0.08 g of aluminium chloride in 50 mL of distilled water and stir. Slowly add 10 mL of sodium hydroxide solution while stirring for 20 minutes. In another beaker, mix ZnS nanoparticles with 100 mL of distilled water and stir for 20 minutes. Combine this with the aluminium solution and stir for an additional 20 minutes. Conduct centrifugation at 3000 rpm for 30 minutes, wash the precipitate with acetone, and dry in a hot air oven at 150°C for 1 hour. Finally, anneal the dried product in a muffle furnace at 600°C for 4 hours to obtain white ZnS-Al nanocomposites.

2.3.2. ZnS-Platinum (ZnS / Pt)

Dissolve 0.08 g of platinum (IV) oxide hydrate in 25 mL of distilled water and stir. Gradually add 10 mL of sodium hydroxide solution while stirring for 20 minutes. In another beaker, mix ZnS nano powder with 100 mL of distilled water and stir for 20 minutes. Combine this with the platinum solution and stir for an additional 20 minutes. After that complete centrifugation and the calcination process.

2.3.3. ZnS-Aluminium-Platinum (ZnS/Al/Pt)

In a beaker, mix 0.08 g of ZnS powder with 100 mL of distilled water and stir for 20 minutes. In another beaker, stir 0.08 g of platinum nano powder with 25 mL of distilled water for 20 minutes, and combine 0.08 g of aluminium nano powder with 50 mL of distilled water, stirring for 40 minutes. Combine all solutions in a single beaker and stir for an additional 20 minutes. Following that, complete the centrifugation and calcination processes.

2.4. Analytical characterization

The optical properties of synthesized nano composite materials were examined using the SHIMADZU UV 2600 UV-visible spectrophotometry method, with a spectral range of 200 nm to 800 nm. The presence of several functional molecules within the nanomaterials was identified through Fourier transform infrared spectroscopy analysis using a Perkin Elmer Spectrum 2, which covered a range from 400 cm^-1 to 4000 cm^-1. Structural characteristics were investigated via X-ray diffraction analysis with an X' Pert Pro – PANalytic, in the 20-80° range. The morphological features of nano composite powders were assessed through SEM using a Carl Zeiss EVO 18. The elemental composition of the synthesized nanomaterials was determined using an energy-dispersive X-ray (EDX) test.

2.5. Electrochemical characterization

Cyclic voltammetry serves as a technique for assessing the energy storage properties of nanomaterials through a system consisting of three electrodes: a working electrode, a reference electrode, and a counter electrode³⁰. To prepare the working electrode, 80% active material is combined with 10% carbon powder and 10% PVDF binder (Polyvinylidene Fluoride) to form a slurry with N-Methyl-2-pyrrolidone (NMP) solvent. This slurry is then spread onto copper foil and dried in a vacuum oven at 80°C for 12 hours. An electrolyte solution is made by dissolving 0.745 g of solid KCl in 100 mL of water, resulting in a 0.1 M KCl solution³¹. Measurements are done using a VersaSTAT MC electrochemical workstation.

3. Results and Discussions

3.1. Morphological studies

The morphology of nanocomposites was examined through SEM (Scanning Electron Microscopy) images. Figure 2a-h indicated that the ZnS nanomaterials were predominantly spherical in shape, with a tendency for the spheres to cluster together, exhibiting particle sizes in the range of 30–40 nm. The scanning electron microscopy (SEM) images clearly show the unique shapes and structures of the metal nanoparticles, making them easily distinguishable from the zinc sulfide (ZnS) nanoparticles. Figure 2a and 2b show the SEM images of ZnS particle synthesized via co-precipitation method. Little bit of clusterig of particles have been observed from these images. Figure 2c and 2d show the SEM images of Al-ZnS nano-composites powders. It is observed that, low amount of Al content is presented in ZnS powders and the shape of the powders is flakey. Figure 2e and 2f show the SEM images of Pt-ZnS nano-composites powders. Flakey and sperical shape of powders are seen in the images and the low amount of Pt powders are presented. Figure 2g and 2h show the SEM images of Al-Pt-ZnS hybrid nano-composites powders. The sperical shape of the powders are seen for the SEM images. The low amount of Al and Pt powders are spreaded in the ZnS powders.

Figure 2
(a-h). SEM images of (a,b) ZnS nanoparticle (c,d) Al-ZnS nanocomposites(e,f) Pt- ZnS nanocomposites (g,h) Al-Pt-ZnS nanocomposites.

3.2. Structural studies

Energy-dispersive X-ray Spectroscopy (EDAX) serves as an analytical method for determining the elemental composition of a sample³²,³³. It facilitates both qualitative and quantitative examination. To confirm the specific elements and their proportions within the sample, EDAX was conducted, Figure 3a-d shows the EDAX pattern of ZnS, Al-ZnS, Pt-ZnS and Al-Pt-ZnS powders.

Figure 3
EDAX of (a) ZnS powders (b) Al - ZnS (c) Pt - ZnS (d) Al-Pt -ZnS composite powders.

Figure 3a shows the EDAX of ZnS nano powders prepared by co-precipitation method. It evident the both the elements of Zn and S. Figure 3b shows the EDAX pattern of Al-ZnS powders and the peaks evident the presence of Al and Zn as well as S. The EDAX pattern of Al-Pt-ZnS composite powders is shown in Figure 3c and the peaks ensure the occurrence of Al, Pt, Zn and S.

The X-ray diffraction (XRD) pattern provides a unique reflection of the crystalline stages found within a material, offering critical insights into its crystallographic structure, phase makeup, and additional structural characteristics. According to Figure 4a-d, the XRD pattern of the ZnS nanoparticles corresponded closely with the cubic crystal structure outlined in JCPDS No. 80-0020 with the lattice planes (111), (220), (311)³⁴,³⁵. Additional peaks observed in the XRD patterns for ZnS/Al and ZnS/Pt aligned with the Face-Cantered Cubic (FCC) structures of Aluminium and Platinum, as documented in JCPDS cards 53-61386 and 04-0802³⁶, respectively. Utilizing the Debye-Scherrer formula, $\text{D}=\text{k}\lambda /\beta \cos \theta$, the average size of the crystallites was determined to be 24.57 nm for the ZnS nanoparticles.

Figure 4
(a-d). XRD images of (a) ZnS nanoparticle (b) Al-ZnS nanocomposites (c) Pt- ZnS nanocomposites (d) Al-Pt-ZnS nanocomposites.

From Figure 4a-d, observed that the minor shifts occur in the 2θ values of the X-ray diffraction (XRD) patterns of ZnS nanocomposites due to variations in strain and composition as shown in Table 1.

Table 1
2θ values of the XRD patterns.

COMPOSITES	PEAK 1	PEAK 2	PEAK 3	PEAK 4
ZnS	***	28.588	47.7892	57.3648
Al-ZnS	10.239	28.6882	47.5887	56.6128
Pt-ZnS	10.289	28.3373	47.5887	56.5125
Al-Pt-ZnS	10.038	28.3874	47.1903	56.2117

An additional peak with a minimal magnitude observed in the XRD patterns for ZnS/Al, ZnS/Pt and ZnS/Al/Pt composites corresponds to the (001) lattice planes as shown in Table 2.

Table 2
Lattice planes of XRD patterns.

COMPOSITES	PEAK 1	PEAK 2	PEAK 3	PEAK 4
ZnS	***	1 1 1	2 2 0	3 1 1
Al-ZnS	0 0 1	1 1 1	2 2 0	3 1 1
Pt-ZnS	0 0 1	1 1 1	2 2 0	3 1 1
Al-Pt-ZnS	0 0 1	1 1 1	2 2 0	3 1 1

3.3. Optical studies

A band gap of 3.75 eV represents the energy difference between the valence and conduction bands in a semiconductor, indicating absorption in the ultraviolet (UV) part of the electromagnetic spectrum. This is demonstrated by UV-DRS (Diffuse Reflectance Spectra) image of ZnS (Figure 5a) nanoparticles, which show a peak at 299 nm³⁷. ZnS/Al nanocomposites have a band gap of 3.8 eV, corresponding to a peak at 294 nm. The optical spectrum for ZnS/Pt nanocomposites shows a peak at 295 nm with a band gap of 3.69 eV. Lastly, ZnS/Al/Pt nanocomposites display a band gap of 3.73 eV, with a peak at 296 nm.

Figure 5
a) Absorption Spectra b) Reflectance Spectra c) Transmittance Spectra of ZnS nanocomposites.

Reflectance values observed in Figure 5b were higher in the visible spectrum, indicating that the nanomaterials are well-suited for use in electrochemical studies due to their optical properties. Higher reflectance can lead to lower absorption of solar radiation, which can reduce heating. It enhances durability and resistance to environmental factors.

The level of absorbance is influenced by various factors including the energy of the band gap, the presence of impurity centres, and oxygen deficiencies. It is noted that as the size of the particles decreases, the energy of the band gap increases. In semiconductors, the outermost electrons absorb energy, moving from the valence band to the conduction band. This energy gap is referred to as the band gap energy.

The UV-visible spectrophotometer spectrum, capturing this electron transition, aids in examining the band gap energy. To enhance the precision in evaluating optical properties, an in-depth analysis of the band gap energy (Figure 6a-d) was performed employing the Tauc equation: $\alpha \text{h}\vartheta =\text{A}(\text{h}\vartheta -Eg)$. In this equation, α represents the absorption coefficient, h is Planck's constant (6.624 × 10^-34 m^2 kg/s), ϑ denotes the light frequency, A is a constant, and n is a variable dependent on the sample's characteristics³⁸.

Figure 6
Energy gap images of (a) ZnS nanoparticle (b) Al-ZnS nanocomposites (c) Pt- ZnS nanocomposites (d) Al-Pt-ZnS nanocomposites.

The direct band gap of ZnS nanomaterials was determined from Tauc's plot, which graphs (αhϑ)² against hϑ, with the band gap derived by extrapolating the linear portion of the x-axis. This analysis revealed that the synthesized ZnS nanomaterials exhibit a band gap energy of 3.75 eV. Spectroscopic analysis using photoluminescence provided critical insights into the materials' band gap energy, carrier lifetimes, and quantum efficiency. This data is indispensable for designing and improving optoelectronic devices. The experiments involved exciting the samples and recording their spectral data from 350 to 650 nm, as shown in Figure 7a and 7b.

Figure 7
Photoluminescence Spectra of a) ZnS / Al-ZnS / Pt-ZnS / Al-Pt-ZnS nanocomposites b) Pt-ZnS / Al-Pt-ZnS nanocomposites.

For all samples, emission peaks were detected above 400 nm, leading to their identification as ZnS nanoparticles, as noted in reference³⁹,⁴⁰. To boost the emission peaks, Al and Pt were incorporated as composite materials with ZnS. The enhanced emission intensity observed in the nanocomposite samples surpassed that of other samples. This enhancement is attributed to the efficient transfer of hot electrons from the localized surface plasmons of Al and Pt nanoparticles to the conduction band of ZnS, thereby increasing the electron density in the conduction band and subsequently boosting the emission intensity.

3.4. Electrochemical studies

The electrochemical performance of ZnS and ZnS nanocomposites was evaluated using cyclic voltammetry (CV). The CV measurements were conducted in a standard three-electrode setup with a 1 M KCl electrolyte. Figure 8a presents the typical CV curves for ZnS nanoparticles at scan rates of 10, 20, 30, 40, and 50 mV/s, covering a voltage range from −1.3 to 0.8 V. Each CV curve exhibits two pairs of redox peaks, indicating the presence of typical battery-type Faradaic processes, with the electrochemical characteristic peaks primarily resulting from the Faradaic redox reactions.

Figure 8
CV response of a) ZnS at various scan rates b) ZnS / Al-ZnS / Pt-ZnS / Al-Pt-ZnS anocomposites.

Figure 8b illustrates the CV curves of ZnS and its nanocomposites at different scan rates, ranging from −1.3 to 0.8 V. The area of the CV curves significantly increases while maintaining the shape of the peaks at higher scan rates, indicating the excellent rate capability of these electrode materials⁴¹,⁴². Notably, the area under the CV curve for the ZnS-Al-Pt nanocomposite is greater than that of the ZnS, Al-ZnS, and Pt-ZnS nanocomposites, suggesting a higher areal capacity for the ZnS-Al-Pt nanocomposite at the same scan rate. Additionally, the positions of the redox peaks show slight shifts compared to the other composites, reflecting differences in electrode polarization behaviors.

4. Conclusion

• ZnS nanomaterials were synthesized by coprecipitation method using Zinc Acetate as base material. The synthesized particles were subjected to several studies such as optical, structural, morphological and electrochemical analysis.

• The size of the particles was very much smaller in order to achieve higher band gap, thereby attaining more absorbance values. This was done with the help of UV–Vis spectroscopy method.

• To confirm the crystalline nature of ZnS nanomaterials, it was subjected to XRD and found to be in good accordance with the literature values. The size and shape of the synthesized ZnS particles were investigated by SEM analysis. On comparing the result of the present work with that of the previously reported works, this research offers insights into ZnS nanocomposites and their potential future application in super-capacitors.

• This study concentrates on the development, modification and utilization of ZnS nanocomposites through careful alteration of the electrode's composition to overcome current challenges and advance supercapacitors into sophisticated energy storage systems that align with the escalating needs of contemporary applications.

5. References

• ¹ Huang S, Zhu X, Sarkar S, Zhao Y. Challenges and opportunities for supercapacitors. APL Mater. 2019;7(10):100901.
• ² Li C, Balamurugan J, Kim NH, Lee JH. Hierarchical Zn–Co–S nanowires as advanced electrodes for all solid state asymmetric supercapacitors. Adv Energy Mater. 2017;8(8):1-12.
• ³ Saranya PE, Selladurai S. Facile synthesis of NiSnO₃/graphene nanocomposite for high-performance electrode towards asymmetric supercapacitor device. J Mater Sci. 2018;53(23):16022.
• ⁴ Wan S, Peng J, Jiang L, Cheng Q. Bioinspired graphene -based nanocomposites and their application in flexible energy devices. Adv Mater. 2016;28(36):7862.
• ⁵ Huang P, Lethien C, Pinaud S, Brousse K, Laloo R, Turq V, et al. On-chip and freestanding elastic carbon films for micro-supercapacitors. Science. 2016;351(6274):691-5.
• ⁶ Chen T, Hao R, Peng H, Dai L. High-performance, stretchable, wire-shaped supercapacitors. Angew Chem Int Ed. 2014;53:1-6.
• ⁷ Yu D, Goh K, Wang H, Wei L, Jiang W, Zhang Q, et al. Scalable synthesis of hierarchically structured carbon nanotube-graphene fibres for capacitive energy storage. Nat Nanotechnol. 2014;9(7):555-62.
• ⁸ Tie D, Huang S, Wang J, Ma J, Zhang J, Zhao Y. Hybrid energy storage devices: advanced electrode materials and matching principles. Energy Storage Mater. 2019;21:22-40.
• ⁹ Yao F, Pham DT, Lee YH. Carbon-based materials for lithium-ion batteries, electrochemical capacitors, and their hybrid devices. ChemSusChem. 2015;8(14):2284-311.
• ¹⁰ Wang Y, Song Y, Xia Y. Electrochemical capacitors: mechanism, materials, systems, characterization and applications. Chem Soc Rev. 2016;45(21):5925-50.
• ¹¹ Javed MS, Chen J, Chen L, Xi Y, Zhang C, Wan B, et al. Flexible full-solid state supercapacitor based on zinc sulfide spheres growing on carbon textile with superior charge storage. J Mater Chem A Mater Energy Sustain. 2016;4(2):667-74.
• ¹² Yi T-F, Li Y, Li Y-M, Luo S, Liu Y-G. ZnS nanoparticles as the electrode materials for high-performance supercapacitors. Solid State Ion. 2019;343:115074.
• ¹³ Hussain I, Mohapatra D, Dhakal G, Lamiel C, Sayed MS, Sahoo S, et al. Uniform growth of ZnS nanoflakes for high-performance supercapacitor applications. J Energy Storage. 2021;36:102408.
• ¹⁴ Maron GK, Alano JH, Noremberg BS, Rodrigues L, Stolojan V, Silva SRP, et al. Electrochemical supercapacitors based on 3D nanocomposites of reduced graphene oxide/carbon nanotube and ZnS. J Alloys Compd. 2020;836:155408.
• ¹⁵ Baig N, Kammakakam I, Falath W. Nanomaterials: a review of synthesis methods, properties, recent progress, and challenges. Adv Mater. 2021;2(6):1821-71.
• ¹⁶ Yang D. Application of nanocomposites for supercapacitors: characteristics and properties. In: Ebrahimi F, editor. Nanocomposites: new trends and developments. London: IntechOpen; 2012. Chapter 12; p. 209-320.
• ¹⁷ Chameh B, Moradi M, Kaveian S. Sis of hybrid ZIF-derived binary ZnS/CoS composite as high areal capacitance supercapacitor. Synth Met. 2020;260:116262.
• ¹⁸ Hassan FM, Chen Z, Yu A, Chen Z, Xiao X. Sn/SnO₂ embedded in mesoporous carbon nanocomposites as negative electrode for lithium ion batteries. Electrochim Acta. 2013;87:844-52.
• ¹⁹ Hosein BME, Heidari MA, Nazarpour S, Karimi H. Compulsory co-precipitation”, a novel and rational route for the synthesis of nanomaterials; mesoporous zinc sulfide as the first case. J Alloys Compd. 2020;20:1-23.
• ²⁰ Nam NH, Luong NH. Nanoparticles: synthesis and applications. In: Grumezescu V, Grumezescu AM, editors. Materials for biomedical engineering: inorganic micro and nanostructures. Amsterdam: Elsevier; 2019. Chapter 7; p. 211-32.
• ²¹ Ma Y, Jia Y, Lin Y, Shi W. ZnS/MoS₂ film grown on Mo foil as binder free electrode for supercapacitor. Chem Phys. 2021;542:111030.
• ²² Kumar R, Sakthivel P, Mani P. Structural, optical, electrochemical, and antibacterial features of ZnS nanoparticles: incorporation of Sn. Appl Phys, A Mater Sci Process. 2019;125(8):543.
• ²³ Li T, Xin T, Ding Y, Zou J, Liu H, Liu B, et al. SnO₂ nanocrystal-Fe₂O₃ nanorod hybrid structures: an anode material with enhanced lithium storage capacity. J Solid State Electrochem. 2019;23(2):379-87.
• ²⁴ Arya S, Riyas M, Sharma A, Singh B, Prerna PB, Bandhoria P, et al. Electrochemical detection of ammonia solution using tin oxide nanoparticles synthesized via sol-gel route. Appl Phys, A Mater Sci Process. 2018;124(8):538.
• ²⁵ Murugan S, Ashokkumar M, Sakthivel P. Preparation and characterization of ZnS:MgS nanocomposites for photocatalytic and antioxidant applications. Vacuum. 2023;215:112256.
• ²⁶ Ali S, Saleem S, Salman M, Khan M. Synthesis, structural and optical properties of ZnS–ZnO nanocomposites. Mater Chem Phys. 2020;248:122900.
• ²⁷ Alnehia A, Al-Odayni A-B, Al-Hammadi AH, Alramadhan SA, Alnahari H, Saeed WS, et al. Extract-mediated synthesis of ZnS nanoparticles: structural, optical, antibacterial, and hemolysis studies. J Nanomater. 2023;2023:1-9.
• ²⁸ Oskenbay A, Salikhov D, Rofman O, Rakhimbek I, Shalabayev Z, Khan N, et al. Solid-state synthesis of ZnS/ZnO nanocomposites and their decoration with NiS cocatalyst for photocatalytic hydrogen production. Ceram Int. 2023;49(19):32246-60.
• ²⁹ Choi YI, Lee S, Kim SK, Kim Y-I, Cho DW, Khan MM, et al. Fabrication of ZnO, ZnS, Ag-ZnS, and Au-ZnS microspheres for photocatalytic activities, CO oxidation and 2-hydroxyterephthalic acid synthesis. J Alloys Compd. 2016;675:46-56.
• ³⁰ Zhao Y, Wang W, Chen M, Wang R, Fang Z. The synthesis of ZnS@MoS₂ hollow polyhedrons for enhanced lithium storage performance. CrystEngComm. 2018;20(45):7266-74.
• ³¹ Amuthameena S, Dhayalini K, Balraj B, Siva C. Enhanced performance of SnO₂-noble metal composites on electrical energy generation and storage devices. IEEE Trans Electron Dev. 2021;68(10):5291-7.
• ³² Titus D, Samuel EJJ, Roopan SM. Nanoparticle characterization techniques. In: Shukla AK, Iravani S, editors. Green synthesis, characterization and applications of nanoparticles. New York: Elsevier; 2019. Chapter 12; p. 303-20.
• ³³ Joishy S, Antony A, Poornesh P, Choudhary RJ. Influence of Cd on structure, surface morphology, optical and electrical properties of nano crystalline ZnS films. Sens Actuators A Phys. 2020;303:111719.
• ³⁴ Khan S, Han JS, Lee SY, Cho S-H. ZnS nano-spheres formed by the aggregation of small crystallites and their photocatalytic degradation of eosin B. Chin J Chem. 2017;35(2):159-64.
• ³⁵ Arif N, Gul S, Sohail M, Rizwan S, Iqbal M. Synthesis and characterization of layered Nb₂C MXene/ZnS nanocomposites for highly selective electrochemical sensing of dopamine. Ceram Int. 2021;47(2):2388-96.
• ³⁶ Morris MC, McMurdie HF, Evans EH, Paretzkin B, Parker HS, Pyrros NP. Standard x-ray diffraction powder patterns. Section 19 – data for 51 substances. Washington, D.C.: National Bureau of Standards; 1982. p. 118-24. (Monograph; 25).
• ³⁷ Shanmugam N, Cholan S, Sundaramanickam A, Viruthagiri G, Kannadasan N. Temperature controlled synthesis of zns nanocrystals by simple chemical precipitation. Walailak J Sci Technol. 2013;10(2):149-57.
• ³⁸ Amuthameena S, Dhayalini K, Balraj B, Siva C, Senthilkumar N. Two step synthesis and electrochemical behavior of SnO₂ nanomaterials for electrical energy storage devices. Inorg Chem Commun. 2021;131:1-7.
• ³⁹ Tamrakar R, Ramrakhiani M, Chandra BP. Effect of capping agent concentration on photophysical properties of zinc sulfide nanocrystals. The Open Nanoscience Journal. 2008;2(1):12-6.
• ⁴⁰ Yi T-F, Chang H, Wei T-T, Qi S-Y, Li Y, Zhu Y-R. Approaching high-performance electrode materials of ZnCo₂S₄ nanoparticle wrapped carbon nanotubes for supercapacitors. J Materiomics. 2021;7(3):563-76.
• ⁴¹ Khan S, Je M, Ton NNT, Lei W, Taniike T, Yanagida S, et al. C-doped ZnS-ZnO/Rh nanosheets as multijunctioned photocatalysts for effective H₂ generation from pure water under solar simulating light. Appl Catal B. 2021;297:120473.
• ⁴² Mansour AF, Abdo MA, Maged FA, Agag GM. Synthesis, optical properties and stabilization of ZnS quantum dots by polymeric matrices. J Inorg Organomet Polym Mater. 2021;31(4):1443-50.

Publication Dates

• Publication in this collection
  17 Jan 2025
• Date of issue
  2024

History

• Received
  25 July 2024
• Reviewed
  10 Oct 2024
• Accepted
  01 Dec 2024