Properties Of ZnO Nanoparticles Research Articles

Morphological, structural, and electronic properties of green synthesized ZnO nanoparticles by experimental and DFT+U method – A review

In these decades, researchers have paid much attention to green synthesis methods because of their low cost and eco-friendliness. Among all other semiconductors, ZnO nanoparticles have huge applications in optoelectronics devices, solar cells, photocatalysis, transistors, etc. This review article explains the green synthesis methods and factors affecting the morphology of ZnO nanoparticles. The morphology shows different structures such as nanowires, cubic, hexagonal, flower-like structures, etc. The XPS peaks Zn-2p1/2, Zn-2p3/2, and O-1S suggest that the synthesized nanoparticles are ZnO. The theoretical review part explains the electronic and structural properties of wurtzite ZnO nanoparticles. The implementation of the Hubbard-U scheme in the d and p shells using Local Density Approximation (LDA) and Generalized Gradient Approximation (GGA) shows the drastic change in the electronic and structural properties of ZnO nanoparticles. The optimized lattice parameters and band gap using Hubbard parameters by different DFT codes are tabulated. Also, we compared computational and experimental results.

A study on structural and optical properties of the synthesized PVP capped Zinc Oxide Nanoparticles

Zinc Oxide Nanoparticles, capped with a polymer, have been effectively synthesized using a chemical precipitation method at a relatively low reaction temperature of 60 °C. The present study examines the structural and optical properties of ZnO Nanoparticles (NPs) that have been synthesized and capped with different weight percentages of PVP (Polyvinyl Pyrrolidone). To investigate these properties, advanced analytical techniques including X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Ultra Violet-visible (UV–vis) absorption spectroscopy are employed. The XRD analysis reveals that the synthesized ZnO samples have a hexagonal wurzite structure, regardless of adding capping agent. The Williamson-Hall (W-H) analysis, a commonly used method, estimates the strain present in synthesized materials. The SEM image depicts ZnO NPs that have a nearly spherical form and are seen to be agglomerated. The UV–vis absorption measurements demonstrate a phenomenon known as blue shift when compared to the absorption characteristic of bulk ZnO.

Tuning of structural, magnetic, and optical properties of ZnO nanoparticles by Co and Cu doping

Undoped, Cu, and Co-doped ZnO nanoparticles were synthesized by a simple co-precipitation method. We studied the structural, chemical, magnetic, and optical properties of synthesized nanoparticles by using X-ray Diffraction, Fourier Transform Infrared, Scanning Electron Microscopy, Vibrating-Sample Magnetometer, and UV–VIS spectroscopy. The X-ray Diffraction analysis discovers the crystalline hexagonal wurtzite structure and confirms the incorporation of Cu2+ and Co2+ in the ZnO lattice. The SEM photographs show that the nanoparticles are agglomerated, and the grain size of pure ZnO is decreased upon doping, showing inhibition of grain growth through doping. From VSM the coercivity and saturation magnetization of Co-doped (0.0189 emu/g and 84.044Oe) is higher as compared to pure and Cu-doped ZnO. The energy gap of doped and un-doped nanoparticles determined from the absorption spectrum indicates that it increases by doping of Copper and cobalt.

A Novel Study on Antioxidant Activity and Catalytic Reduction of Methylene Blue using ZnO Nanoparticles Synthesized via the Middle Part of Walnut Shell (Juglans regia) Extract

Abstract: The synthesized ZnO nanoparticles were characterized using UV-Vis spectroscopy, SEM, XRD, FTIR, and TEM analysis. The catalytic activity of the prepared green catalyst ZnO nanoparticles was also investigated in the dye methylene blue (MB) decomposition. The catalytic decomposition reaction completed within 20 minutes, demonstrating the excellent catalytic properties of ZnO nanoparticles in reducing MB. This research describes the green synthesis of ZnO nanoparticles using an extract of the middle part of a walnut shell (Juglans regia). The antioxidant activities (radical capture capacity) of the synthesized ZnO nanoparticles were evaluated by the 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) assay at different ZnO nanoparticle concentrations, and the radical capture activity was achieved at IC50 = 146.32 μg / mL. The radical capture activity was achieved at IC50 = 146.32 μg / mL. The biosynthesis of ZnO nanoparticles was caused by hydroxide precipitation at room temperature after calcination at 450°C.

Study on structural, morphological, elastic and electrical properties of ZnO nanoparticles for electronic device applications

The present study investigates the synthesis and analysis of zinc oxide nanoparticles (ZnO NPs) intended for use in electronic devices. ZnO NPs with an average crystallite size of 33 nm and a hexagonal wurtzite structure were produced by the combustion process. Scanning Electron Microscopy (SEM) revealed a densely packed, spherical morphology. Elastic properties, studied through the General Utility Lattice Program (GULP) and Elastic Tensor Analysis (ELATE), reveal the ductile nature of ZnO NPs. Optical studies exhibited a characteristic absorption peak at 366 nm, with a calculated optical band gap of 2.36 eV. Additionally, efforts are being made to determine refractive index (n), electronic polarizability (α) and optical susceptibility (χ). Electrical properties, including dielectric behaviour, AC conductivity, and I–V characteristics, demonstrated the influence of relaxation phenomena and revealed non-ohmic conduction. The dielectric studies show that dielectric constant, dielectric loss, and impedance are frequency and temperature dependent. Richardson-Schottky emission was identified as the predominant conduction mechanism, highlighting the potential of ZnO NPs in electronic devices.

Magnetic and optical properties of ZnO nanoparticles and nanorods synthesized by green chemistry

ZnO nanostructures have attracted considerable attention because of their physicochemical properties and applications as antibacterial agents, photocatalytic reactions for pollutant removal, and electronics. Hence, efficient production and knowledge of their properties under different synthesis conditions are essential. Biosynthesis has emerged as an excellent growth-directing method for synthesizing nanomaterials, representing a soft and cleaner alternative for their production. In this study, we synthesized different ZnO nanostructures using a soft chemistry method at different growth temperatures, from 200 to 800 °C every 200 °C. The crystalline structure was estudied by x-ray Diffraction (XRD) and High-Resolution Transmission Electron Microscopy (HRTEM). The shape and size were studied by Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM), which revealed a ZnO hexagonal phase with two shapes: nanoparticles (NPs) with irregular shapes and nanorods of different sizes. The optical properties were studied by Raman and UV-visible spectroscopy, and optical absorption measurements showed bandgap tuning of the produced nanostructures. Finally, the magnetic characteristics of the samples demonstrated magnetic anisotropy due to the preference for crystalline formation and the size of the nanoparticles. The magnetic interaction between the two types of NPs increased the diamagnetism associated with the nanorods.

Antibacterial Activity of Prepared Zinc Oxide Nanoparticles by Eco-Friendly Method Using Olive Leaves and Roselle Flower Extracts

This research looked at the antimicrobial properties of zinc oxide nanoparticles (ZnO NPs) made from roselle flower extracts and olive leaves as part of a green synthesis method. We used field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), ultraviolet-visible (UV–vis) spectroscopy and Fourier-transform infrared (FTIR) spectroscopy to study the morphological, structure and optical properties of ZnO NPs. The Field Emission Scanning Electron Microscopy (FESEM) test revealed that the ZnO NPs (Olive leaves) had round particles with sizes ranging from 29.03[Formula: see text]nm to 53.59[Formula: see text]nm, while the ZnO NPs (Roselle flower) had nanoflakes with sizes ranging from 42[Formula: see text]nm to 80[Formula: see text]nm. By using UV–vis spectroscopy, it was found that the optical energy gap for ZnO NPs derived from olive leaves was about 2[Formula: see text]eV and for ZnO NPs derived from rose flowers it was 2.2[Formula: see text]eV. The antimicrobial properties of ZnO nanoparticles (NPs) were assessed against two types of bacteria: gram-negative bacteria (Klebsiella pneumoniae) and gram-positive bacteria Staphylococcus aureus (S. aureus). Both plant extracts exhibited a maximal inhibitory zone of 21[Formula: see text]mm against gram-positive bacteria, specifically S. aureus.

Pressure-Induced Enhancement of Photoelectric Properties of ZnO Nanoparticles in the Ultraviolet Band: Implications for Electronic Device Applications

Pressure-Induced Enhancement of Photoelectric Properties of ZnO Nanoparticles in the Ultraviolet Band: Implications for Electronic Device Applications

Optical and Crystal Structure Properties of ZnO Nanoparticle Synthesized through Biosynthesis Method for Photocatalysis Application

In this study, zinc oxide nanoparticles (ZnO NPs) were synthesized from zinc nitrate hexahydrate precursor and mango leaf extract (MLE). The purpose of this research was to investigate the crystal structure and optical properties exhibited by ZnO NPs for photocatalytic applications. ZnO NPs produced from various concentrations of sodium hydroxide (NaOH) and the addition of MLE during the synthesis stage demonstrated intriguing physical structure and optical properties. XRD characterization results revealed the attainment of a pure ZnO phase with a high crystallinity degree in all samples. Biosynthesis with MLE unveiled minor peaks corresponding to the cellulose phase. The achieved crystallite size ranged from 15–28 nm. The FTIR patterns detected in the wavenumber range of 600–4000 cm−1 indicated successful crystallization of all ZnO NPs samples. The band gap energy for each sample (ZnO-A to ZnO-E) is indicated to be in the range of 3.25, 3.25, 3.26, 3.31, and 3.17 eV, as demonstrated by the Tauc relation. The effect of MB degradation by the ZnO-E photocatalyst is revealed by the photodegradation of 96.46%.

Investigating the effect of acidic and basic precipitation on the antibacterial activity of ZnO nanoparticles against Gram-negative and Gram-positive bacteria.

In the present work, acidic (direct) and basic precipitation (indirect) methods were used to demonstrate the influence of the mode of precipitation on the structural properties of ZnO nanoparticles (NPs). Four samples of ZnO nanoparticles were prepared, two samples via each mode of precipitation. DZOa and IZOa were the aged samples prepared via acidic and basic precipitation methods, and DZOwa and IZOwa were processed without aging. Both precipitation processes were carried out without using any surfactant reagents. Zinc hydroxide precipitate, which was formed during the basic precipitation method, could be critical in deciding the properties of ZnO NPs, unlike zinc hydroxide formed during acidic precipitation. Aging of zinc hydroxide, synthesised by basic precipitation method for 48 hours was found to be an added advantage in controlling the properties of ZnO NPs. The influence of the mode of precipitation on the structural properties and antibacterial activity of ZnO NPs against Gram-positive and Gram-negative bacterial strains was tested. The antibacterial activity of all four ZnO NPs was analysed via zone of inhibition measurements at a concentration dose of 200 μg ml-1. IZOa nanoparticles prepared using the basic precipitation method showed a higher antibacterial activity against three Gram-negative and one Gram-positive strains, namely, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli. DZOa nanoparticles synthesized through acidic precipitation showed relatively high antibacterial activity against Salmonella typhimurium, a Gram-negative strain. ZnO NPs prepared without aging, IZOwa and DZOwa, showed a higher antibacterial activity against E. coli and Bacillus sp. strains, respectively. All ZnO NPs were characterized via UV-visible, FTIR, XRD, and HRSEM techniques.

Synthesis, characterization, and photocatalytic activities of green sol-gel ZnO nanoparticles using Abelmoschus esculentus and Salvia officinalis: A comparative study versus co-precipitation-synthesized nanoparticles

BackgroundThe development of green chemistry methods involving plant-based nanoparticle synthesis presents an affordable and eco-friendly approach for wastewater treatment and color removal. This study aimed to synthesize ZnO nanoparticles using the sol-gel method with Salvia officinalis and Abelmoschus esculentus plants, examining their photocatalytic efficiency for organic dye removal. MethodsTo compare the properties of ZnO nanoparticles, another type of ZnO-NPs was synthesized using the co-precipitation method. The characterization of synthesized nanoparticles was performed using thermogravimetric analysis (TGA-DTG), X-ray diffraction (XRD), Dynamic Light Scattering (DLS), Zeta potential (ZP), field emission scanning electron microscopy (FE-SEM), Energy Dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FTIR), and UV–Vis spectrophotometry. ResultsBased on XRD results, the average crystalline size of nanoparticles was calculated using the Debye-Scherer equation for synthesized nanoparticles using the S. officinalis at 22.99 nm and for the A. esculentus at 29.79 nm, and for the co-precipitation method at 18.83 nm. The FE-SEM images showed spherical ZnO nanoparticles. Photocatalytic properties of ZnO-NPs were investigated for remove of methylene blue organic dye in the presence of UV light. The pH 10 was identified as the best pH, which had the highest percentage of color degradation. All three types of nanoparticles were tested by up to 360 min to optimize the dyeing time. For A. esculentus, the highest percentage of color removal occurred in the first 90 min (41.0 %), for S. officinalis nanoparticles between 75 and 90 min (86.9 %), and for chemically synthesized nanoparticles between 30 and 45 min (100 %). ConclusionsIn conclusion, the best MB dye degradation capacity belonged to co-precipitation ZnO nanoparticles followed by S. officinalis and A. esculentus nanoparticles.

Structural and photoluminescence properties of green synthesized ZnO nanoparticles from Calotropis gigantea leaves

This study explores the properties of ZnO nanoparticles produced using a green method involving Calotropis gigantea leaves. The nanoparticles were created by extracting materials from the plant leaves and then subjected to annealing at 350 °C in an air environment for crystallization. X-ray diffraction results represent the formation of pure hexagonal ZnO with an average crystallite size of 48–51 nm. Fourier Transform Infrared spectroscopy also confirms the synthesis of hexagonal ZnO NP as evident from a sharp band observed at 524.55 cm−1 in IR spectra. Energy dispersive X-ray spectroscopy results reveal nucleation of pure ZnO. Photoluminescence emission results revealed that PL bands observed at wavelengths of 399.93 nm and 469 nm in the near UV to violet and blue regions, respectively, demonstrating their potential applications in optoelectronics. Color chromaticity coordinates diagram reveal that color coordinates presence in the blue region. This demonstrate that synthesized ZnO has high purity and hold promise materials using for blue LED and also use as biomaterials with antibacterial properties. Additionally, a detailed exploration of mechanisms is discussed.

Structural, Optical, and Magnetic Properties of Pure and Ni-Fe-Codoped Zinc Oxide Nanoparticles Synthesized by a Sol-Gel Autocombustion Method.

Pure and Ni-Fe-codoped Zn1-2xNixFexO (x = 0.01, 0.02, 0.03, and 0.04) nanoparticles were effectively synthesized using a sol-gel autocombustion procedure. The structural, optical, morphological, and magnetic properties were determined by using X-ray diffraction (XRD), ultraviolet-visible (UV-vis), scanning electron microscopy, and vibrating sample magnetometer techniques. The XRD confirmed the purity of the hexagonal wurtzite crystal structure. XRD analysis further indicated that Fe and Ni successfully substituted the lattice site of Zn and generated a single-phase Zn1-2xNixFexO magnetic oxide. In addition, a significant morphological change was observed with an increase in the dopant concentration by using high-resolution scanning electron microscopy. The UV-vis spectroscopy analysis indicated the redshift in the optical band gap with increasing dopant concentration signifying a progressive decrease in the optical band gap. The vibrating sample magnetometer analysis revealed that the doped samples exhibited ferromagnetic properties at room temperature with an increase in the dopant concentration. Dopant concentration was confirmed by using energy-dispersive X-ray spectroscopy. The current results provide a vital method to improve the magnetic properties of ZnO nanoparticles, which may get significant attention from researchers in the field of magnetic semiconductors.

Exploring the synergistic influence of Cu and Co co-doping on the optical properties of ZnO nanoparticles

In this study, we synthesized Cu and Co co-doped ZnO nanoparticles, denoted as Zn1-2xCuxCoxO (x = 0.01, 0.02, 0.03), using the sol-gel auto-combustion method. Successful integration of Cu and Co elements into the ZnO host lattice was confirmed through a comprehensive array of spectroscopic techniques. Structural analysis revealed the persistence of a hexagonal wurtzite crystal structure with some distinct microstructural variations across all samples. Alteration in lattice parameters and dislocation density strongly suggests the successful incorporation of Cu2+ and Co2+ ions within the ZnO lattice. A prominent increase in crystallite size from 27.19 nm to 33.46 nm was observed with the increase in doping concentration. Field emission scanning electron microscopy showed a combination of uniformly distributed spherical and hexagon-like structures. Furthermore, UV–Visible absorption spectra demonstrated a proportional enhancement in energy band gap from 2.14 eV for Zn0.98Cu0.01Co0.01O to 2.40 eV for Zn0.94Cu0.03Co0.03O. The Burstein−Moss effect was invoked to elucidate the observed blue shift in absorption spectra and energy band gaps, further solidifying our findings. The systematic and substantial correlation between dopant concentration and energy band gap signifies that the co-doping of Cu and Co is a viable strategy for engineering the band gap of ZnO. This collective investigation unveils the substantial potential of Cu and Co co-doping in ZnO nanoparticles for advanced optoelectronic applications, paving the way for tailored optical and photonic functionalities.

Photocatalytic properties of ZnO nanoparticle coating on porous ceramic substrates with varying porosities produced from fly ash and red mud

AbstractIn order to improve filtering efficacy, nanoparticles are often deposited as photocatalytic degrading agents onto porous ceramics. This study aimed to deposit ZnO nanoparticles on ceramic substrates produced from fly ash and red mud with adjustable porosity and investigate their photocatalytic properties. To achieve this goal, at first porous ceramics were produced and sintered at various temperature/time intervals. It was observed that sintering at 800°C for 120 min provided a proper structure and porosity. In addition, MgO replacement with MgCO3 lowered the water absorption of the samples from 25.63% to 11.45%. The samples were then coated with ZnO nanoparticles using the sol–gel method and the ZnO structures obtained were micron‐sized plates. It was observed that increasing porosity increased the ZnO amount and accordingly the photocatalytic properties of the products. During the adsorption tests conducted in the dark, the coated ceramic samples were stained with MB with a maximum MB adsorption ratio of ∼14%. On the other hand, no visible MB stain was observed on the samples that were exposed to UV irradiation, and the MB removal after the UV irradiation was 93.6%; therefore, it was concluded that the dominant MB removal mechanism was photocatalytic.

Insight into the role of Mg/B and Mg/Cu dual dopant on the properties of ZnO nanoparticles prepared by facile one-step combustion route for photocatalytic and antibacterial application

ZnO semiconductors are widely known to have benefits in photocatalytic and antibacterial applications. In this study, (Mg/B)–ZnO and (Mg/Cu)–ZnO were synthesized using the combustion method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), UV–Vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectroscopy. The XRD results confirmed a decrease in the crystal size and an increase in the crystallinity of the doped ZnO samples. SEM analysis confirmed the morphological changes in the structure from rod-shaped to spherical, and the particle size decreased in the doped ZnO samples. EDS analysis validated the nanoparticle composition of Zn, O, Mg, B, and Cu without impurities. Raman spectra confirmed the formation of defects due to the substitution of dopants in the ZnO lattice. All samples for FTIR analysis showed functional chemical group vibrations from Zn–O, C–H, and O–H stretching. The existence of dopant bonds with oxygen was also validated from this analysis. The change in band gap energy was observed from 3.13 to 3.10 eV in Mg/Cu–ZnO and 3.12 eV in Mg/B–ZnO sample due to the influence of the addition of dopant ions. The XPS spectra show the chemical composition of the nanoparticle samples and the oxidation numbers that correlate with the results of EDS and XRD analyses. A decrease in the emission intensity in the PL measurement was observed in the green emission region in the Mg/B–ZnO sample, which correlated with the decrease in electron recombination. The Photocatalytic application was performed by measuring its ability to degrade methyl violet dye under visible-light irradiation. The maximum deterioration after 120 min of irradiation was obtained for the Mg/Cu–ZnO, Mg/B–ZnO, and ZnO samples at 92.62 %, 92.20 %, and 80.89 %, respectively. Antibacterial activity increased against S. aureus bacteria in co-doped ZnO samples with inhibition zones of 12.15 mm, 8.15 mm, and 6.45 mm for Mg/B–ZnO, Mg/Cu–ZnO, and ZnO samples, respectively.

Tailoring Optoelectronic Properties of ZnO Nanoparticles via Incorporation of Multiwalled Carbon Nanotube Contents on of ZnO/MWCNT Nanocomposites

The present study demonstrates the tailoring of optoelectronic properties of ZnO nanoparticles (NPs) by adding multi-walled carbon nanotubes (MWCNTs) at different weight ratios. ZnO/MWCNT nanocomposites were successfully prepared using the solution blending method, and the optical spectra of all samples were determined using a UV–vis spectrometer. An increase in the optical absorption coefficient (α) and extinction coefficient (k) was observed with an increase in MWCNT content, resulting in the significant ability to attenuate incident light in ZnO/MWCNT nanocomposites compared to pure ZnO NPs. The optical band gap of pure ZnO NPs decreased from 3.26 eV to 2.58 eV in the ZnO/50 wt% MWCNT nanocomposite. The refractive index values ranged from 1.66 to 1.61 as the wavelength varied between 400 nm and 700 nm. Furthermore, the incorporation of MWCNTs in the ZnO/MWCNT nanocomposite had an impact on various dispersion parameters related to the refractive index. With increasing MWCNT content, the dielectric constant (ε 0) decreased from 2.40 to 1.96, while the mean oscillator wavelength (λ 0) increased from 157.7 nm to 164.2 nm and the oscillator strength (S0) decreased from 5.93 × 10−5 nm−2 to 3.70 × 10−6 nm−2. The localized density of state (N/m*) increased from 7.45 × 1057 to 20.8 × 1057 (m3 Kg) −1, and the long wavelength refractive index (ε ∞) rose from 3.683 to 4.745. Moreover, the plasma frequency (ω p) of the electron exhibited an increase from 2.15 × 1031 to 6.01 × 1031 Hz. These findings highlight the potential of tailoring the optoelectronic properties of ZnO NPs through the incorporation of MWCNTs, paving the way for the development of novel materials with improved optoelectronic characteristics for a wide range of applications.

Fabrication and Physiochemical Characterization of Zinc Oxide Nanoparticles via Citric Assisted Auto Combustion Synthesis

Background:: There are various synthetic routes to synthesize the ZnO particle. However, none of the routes is best suited for the synthesis of ZnO nanoparticles. Moreover, ZnO nanoparticles have potential industrial applications. Aims:: In this research article, ZnO nanoparticles were synthesized by auto combustion route using the low-cost reagents zinc nitrate hexahydrate and citric acid as a precursor at 90-120° C. Objective:: Herein, we have synthesized ZnO nanoparticles via auto combustion route using the low-cost reagents zinc nitrate hexahydrate and citric acid. The current route is very simple as well as energy-saving with the requirement of using low-cost precursor as compared to the traditional solid-state method and multi-step sol-gel route. Method:: Citric-assisted auto-combustion synthesis was employed to fabricate the ZnO nanoparticles. Result:: The formed precursor powder was calcinated at 500°C for 5 hours in an electrical furnace. It was found that these particles were in a single phase, and the crystallite size of the nanoparticles was found to be in the range of 10 to 15 nm. Conclusion:: We synthesized ZnO nanoparticles at a lower temperature via the citric acid-assisted combustion method. The thermal properties of ZnO nanoparticles were studied by TGA spectra, representing the total weight loss of around 47.71% and their thermal stability after 900 °C.

Effect of reduced graphene oxide on the structural and optical properties of ZnO nanoparticles

The co-precipitation method was used to synthesize ZnO nanoparticles (NPs). Then, graphene oxide (GO) sheets which were reduced during the reaction process to become (rGO), were embellished with ZnO NPs. The impact of rGO on the structure and morphology of ZnO was investigated using XRD, FTIR, TEM, and SEM techniques. Investigating the optical characteristics was done using UV–vis spectroscopy. ZnO exhibits a hexagonal phase, as proved by XRD. The average crystallite size reduced from 22 to 18 nm after being anchored on rGO sheets. TEM and SEM testify to the presence of ZnO in nanoscales with quasi-spherical shapes, which dispersed homogeneously along the GO sheets. The optical bandgap was increased from 2.57 eV to 3.17 eV for ZnO and ZnO-rGO, respectively. Based on the obtained optical bandgap, the refractive index of ZnO and ZnO-rGO nanocomposite was theoretically determined using different models such as Moss and Ravindra models. ZnO-rGO nanocomposite's ability to change optical characteristics makes it a superior nominee for optoelectronic applications.

Green Fabrication and Characterization of Zinc Oxide Nanoparticles using Eucalyptus Leaves for Removing Acid Black 210 Dye from an Aqueous Medium

This study uses an environmentally friendly and low-cost synthesis method to manufacture zinc oxide nanoparticles (ZnO NPs) by using zinc sulfate. Eucalyptus leaf extract is an effective chelating and capping agent for synthesizing ZnO NPs. The structure, morphology, thermal behavior, chemical composition, and optical properties of ZnO nanoparticles were studied utilizing FT-IR, FE-SEM, EDAX, AFM, and Zeta potential analysis. The FE-SEM pictures confirmed that the ZnO NPs with a size range of (22-37) nm were crystalline and spherical. Two methods were used to prepare ZnO NPs. The first method involved calcining the resulting ZnO NPs, while the second method did not. The prepared ZnO NPs were used as adsorbents for removing acid black 210 dye (AB210) from simulated wastewater. The removal efficiency using calcinated and uncalcinated ZnO NPs was 57 % and 59 %, respectively.