Morphology 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.

Synthesis of flower-like ZnO nanoparticles for label-free point of care detection of carcinoembryonic antigen

In this work, flower-like ZnO nanoparticles (ZnONPs) were synthesized using zinc nitrate (Zn(NO3)2 6H2O) as a precursor with KOH. The morphology of the ZnONPs was controlled by varying the synthesis temperature at 50, 75 and 95 °C. The morphology and structure of ZnONPs were characterized using Scanning Electron Microscopy, and X-Ray Diffraction and Brunauer-Emmett Teller analysis. ZnONPs were successfully synthesized by a simple chemical precipitation method. A synthesis temperature of 75 °C produced the most suitable flower-like ZnONPs, which were combined with graphene nanoplatelets to develop a label-free electrochemical immunosensor for the detection of the colon cancer biomarker carcinoembryonic antigen in human serum. Under optimum conditions, the developed immunosensor showed a linear range of 0.5–10.0 ng mL−1 with a limit of detection of 0.44 ng mL−1. The label-free electrochemical immunosensor exhibited good selectivity, reproducibility, and repeatability, and recoveries were excellent. The immunosensor is used with a Near-Field Communication potentiostat connected to a smartphone to facilitate point-of-care cancer detection in low-resource locations.

Biosynthesis of ZnO Nanoparticles Mediated by Crescentia cujete L Leaves Extract and The Photocatalytic Activities Towards Methylene Blue

ZnO nanoparticles were synthesized using the precipitation method and using water extract of Crescentia cujete L leaves as a capping agent. ZnO nanoparticles with a hexagonal wurtzite structure were successfully synthesized with low production cost and environmentally friendly. According to XRD characterization, there is no impurity peak, indicating the ZnO nanoparticles have high purity and crystallinity. SEM images show the morphology of ZnO nanoparticles with semi-spherical shapes and an average size of 32.49 nm. The photocatalytic activity of ZnO nanoparticles was evaluated using a UV A lamp as a source of photonic energy toward methylene blue dye. Various irradiation times were carried out from 0, 10, 20, 30, 40, to 50 minutes, and a UV spectrophotometer was used to detect the concentration of methylene blue remains in collected samples. Increasing the irradiation times leads to increasing the photocatalytic activity of ZnO nanoparticles. At 50 minutes of exposure to a UV A lamp, the degradation percentage of methylene blue dye is 36.37%.

Synthesis, Characterization and Optical Morphology of ZnO Nanoparticles

Synthesis, Characterization and Optical Morphology of ZnO Nanoparticles

Influence Variation Concentration Zn(NO3)2·6H2O Against Group Function, Size Particles, and Morphology Particle Nanoparticles ZnO with Method Green Synthesis Using Extract Leaf Moringa

This research was conducted to determine the effect of varying concentrations of Zn(NO3)2·6H2O (zinc nitrate hexahydrate) on functional groups, particle size, and particle morphology of ZnO nanoparticles using the green synthesis method using Moringa leaves. The materials was used in this study were moringa leaf extract, Zn(NO3)2·6H2O with various concentrations of 0.2, 0.4, 0.6, and 0.8 M, and NaOH of 0.1 M. Based on the results of characterization using FTIR, it shows that the functional groups in the content of Moringa leaves play a role in the formation of ZnO nanoparticles. Meanwhile, the results of the XRD characterization showed a diffractogram difference with standard ZnO at concentrations of 0.6 M and 0.8 M Zn(NO3)2·6H2O with the appearance of the NaNO3 phase. SEM characterization results show that the morphology of ZnO nanoparticles using the green synthesis method is irregular in shape.

Structure and Morphology of ZnO Nanoparticles Prepared by Sonochemical Method

Ultrasonic wave has been utilized to synthesize the ZnO nanoparticle. ZnO is formed from a mixture of zinc acetate (ZnAc) and Natrium Hydroxide (NaOH) with various concentrations of ZnAc 0.5 M (ZnO 1:1) and 1.5 M (ZnO 3:1) and the concentration of NaOH remained at a concentration of 0.5 M. The Structure and crystal size were characterized using X-ray Diffraction (XRD), while its morphology was examined by Scanning Electron Microscopy (SEM). The results show that ZnO 1:1 has a higher (stronger) diffraction intensity than the ZnO 3:1. The crystallite size of ZnO 1:1 averaged 30.57 ± 4.31 nm while the ZnO 3:1 had an average crystallite size of 20.25 ± 7.12 nm. From the size of the crystallites ZnO particles that are formed include nanoparticles. ZnO 1:1 SEM image shows the shape of microrods in the 1:1 ZnO sample while in the 3:1 ZnO sample no microrods are formed. Based on the morphology, the 1:1 ZnO sample has an average size of 230 nm and is larger than the 3:1 ZnO sample which has an average size of 50 nm.

Revealing the Dependency of Dye Adsorption and Photocatalytic Activity of ZnO Nanoparticles on Their Morphology and Defect States.

ZnO is an effective photocatalyst applied to the degradation of organic dyes in aqueous media. In this study, the UV-light and sunlight-driven photocatalytic activities of ZnO nanoparticles are evaluated. A handheld Lovibond photometer was purposefully calibrated in order to monitor the dye removal in outdoor conditions. The effect of ZnO defect states, i.e., the presence of zinc and oxygen defects on the photocatalytic activity was probed for two types of dyes: fuchsin and methylene blue. Three morphologies of ZnO nanoparticles were deliberately selected, i.e., spherical, facetted and a mix of spherical and facetted, ascertained via transmission electron microscopy. Aqueous and non-aqueous sol-gel routes were applied to their synthesis in order to tailor their size, morphology and defect states. Raman spectroscopy demonstrated that the spherical nanoparticles contained a high amount of oxygen vacancies and zinc interstitials. Photoluminescence spectroscopy revealed that the facetted nanoparticles harbored zinc vacancies in addition to oxygen vacancies. A mechanism for dye degradation based on the possible surface defects in facetted nanoparticles is proposed in this work. The reusability of these nanoparticles for five cycles of dye degradation was also analyzed. More specifically, facetted ZnO nanoparticles tend to exhibit higher efficiencies and reusability than spherical nanoparticles.

In Situ Pressure Controlled Growth of ZnO Nanoparticles: Tailoring Sizes, Defects, and Optical Properties.

ZnO, being an inexpensive, wide band gap semiconductor that possesses high mechanical, thermal, and chemical stabilities and suitable for a wide range of optical and electronic applications, is the preferred semiconductor of this era. In an effort to fully utilize its potential features, ZnO research is receiving increasing attention. This study investigates the influence of pressure on the crystallinity, defect density, size, and morphology of ZnO nanoparticles, synthesized using nonaqueous sol-gel method, and their respective impact on the optical properties. High-crystalline ZnO nanocrystals with a hexagonal wurtzite structure were synthesized at various pressures, including ambient pressure, 25, 37.5, 50, and 100 bars inside a high-pressure reactor. With the increase in pressure, a reduction in particle size was observed, reaching a minimum size (∼10 nm) at 50 bar pressure (ZnO-50). Further increase in pressure causes an enhancement in the particle size. This trend of size variation with pressure is attributed to a tradeoff between esterification and nucleation processes. Contrary to the expectation, smaller ZnO nanocrystals synthesized by the present method possess lesser number of defects, suggesting that high-pressure synthesis is a unique way that offers smaller ZnO nanocrystals of sub-10 nm sizes having high crystallinity and lesser defects in a shorter time span. Also, the optical transmittance of the systems could be greatly enhanced by carefully tuning the particle sizes, with ZnO-50 (∼10 nm particle size) having the highest transmittance (∼95% at 600 nm) among all samples. High crystallinity, uniform morphology, excellent visible transparency, wide band gap, and low defect density make these smaller ZnO nanocrystals a preferred choice for ultraviolet sensors and other optoelectronic devices.

Biogenic fabrication of ZnO@EC and MgO@EC using Eucalyptus leaf extract for the removal of hexavalent chromium Cr(VI) ions from water.

Zinc and magnesium oxide nanoparticles were fabricated using green synthesis method for the sequestration of hexavalent chromium Cr(VI) from the aqueous medium. The biogenically prepared ZnO@EC and MgO@EC nanoparticles were successfully loaded on the Eucalyptus. The prepared nanomaterials were characterized using various techniques such as FESEM, TGA, XRD, EDX, FTIR, BET, and elemental mapping. FE-SEM analysis has revealed the surface morphology of ZnO nanoparticles, which were rod-like and spherical in shape, whereas MgO nanoparticles were of irregular shape. Batch mode was selected to remove the hexavalent chromium from aqueous solution using the prepared nanomaterials. The Cr(VI) adsorption was carried out under optimized conditions, viz., pH (3.0), adsorbent dose (0.05g), contact time (150min), temperature (25 ± 2°C), and initial concentration (50mg/L). The experimental results were compared using the different isotherm models; The observations have indicated that experimental data fit better with Freundlich (R2 = 0.99) and Langmuir (R2 = 0.99)isotherms, respectively. The maximum adsorption capacity of ZnO@EC and MgO@EC for Cr(VI) was found to be 49.3 and 17.4mg/g, respectively. The regeneration study of the adsorbents was conducted using different desorbing agents viz., ethanol, NaOH, and NaCl. The desorbing agent NaOH performed better and showed removal percentage of 34.24% and 20.18% for ZnO@EC and MgO@EC, respectively, after the three reusability cycles. The kinetics of reaction was assessed using the pseudo-first-order and pseudo-second-order kinetic models. The experimental data of both the nanomaterials ZnO@EC and MgO@EC obeyed pseudo-second-order model with correlation coefficient values 0.999 and 0.983, respectively. The thermodynamic study confirmed that adsorption was feasible, spontaneous, and endothermic. The adsorbents were tested for spiked real water which confirms their applicability and potential in real water systems also. The results indicated fair removal of chromium suggesting applicability of both adsorbents.

Surface functionalization of ZnO nanoparticles by Schiff base oriented tetrapodal ligands at room temperature and their photocatalytic applications: A comparative account on effect of structure directing agent on photocatalysis

Surface modification of ZnO nanoparticles at room temperature and their photocatalytic activity • Synthesis of surface modified ZnO NPs i.e. P-ZnO, Q-ZnO, R-ZnO and S-ZnO by ligands P , Q , R and S respectively at room temperature of different shape and size. • Photocatalytic efficiency of P-ZnO, Q-ZnO, R-ZnO and S-ZnO towards photocatalytic degradation of Rh B dye in 90 min is ∼92%, 80%, 89% and 79% respectively. • ZnO nanoparticles modified by tetrapodal ligands having urea linker moieties (P-ZnO and R-ZnO) have shown very high photocatalytic degradation (∼89-92%). ZnO is very popular and extremely sought after semiconductor material and more so as in the nanocrystalline form. It is biocompatible having a tunable band gap (3-3.7 eV) at room temperature and popular for several optical properties of interest in many fields. Nanoparticles have a lot of surface defects which affect their stability, properties and applications. We use structure directing agents to control the morphology of ZnO nanoparticles and also to control surface defects. We utilised four Schiff base oriented tetrapodal ligands (P, Q, R and S) as the structure directing agents for synthesis of surface modified ZnO nanoparticles i.e. P-ZnO [nanospheres (50-55 nm)], Q-ZnO [nanorods of length (∼1-2 µm) and breadth (∼130-170 nm)], R-ZnO [fibrous/entangled mesh] and S-ZnO [nanorods of length (30-40 nm) and breadth (5-20 nm)] at room temperature i.e. 30-40°C. The application of P-ZnO, Q-ZnO, R-ZnO and S-ZnO are further explored for photocatalytic degradation of Rhodamine B dye under UV lamp (90 min). The efficiency of P-ZnO, Q-ZnO, R-ZnO and S-ZnO towards photocatalytic degradation of Rhodamine B dye was ∼92%, ∼80%, ∼89% and ∼79% respectively.

Novel synergistic Combination of W and Co Co‐doped ZnO Nanoparticles Incorporated as a Photoanode in a Dye Sensitized Solar Cell

AbstractIn this study, a low‐cost and simple Sol‐gel technique has been used for the synthesis of W/Co co‐doped ZnO nanoparticles. XRD examinations demonstrate the hexagonal wurtzite structure. To investigate the morphology of ZnO nanoparticles was demonstrated by using SEM and TEM. EDS and FTIR spectra verify the triumphant doping of the W and Co into the ZnO lattice. The optical measurement shows that as the concentration of Co increases the band gap decreases from 3.2 eV to 2.73 eV. The DSSCs based on 0.5 % W and 1.6 % Co co‐doped ZnO photoanode achieved the highest open‐circuit voltage of 0.69 V having a short circuit current density of 8.46 mAcm−2, and PCE of 3.16 %.

ZnO nanostructures coated no-core fiber refractive index sensor

The combination of optical fibers with nanostructured films deposition offers potential opportunities and perspectives for the realization of novel optical sensors. A refractive index (RI) sensor based on ZnO as outer layer coating over no-core fiber (NCF) sensing region is proposed and experimentally demonstrated here. Different morphologies of ZnO nanoparticles have been achieved via hydrothermal method by controlling the growth time, temperature, and concentration of reacting solution. The proposed sensor detects power variation of transmitted light propagating through the fiber caused by a change in RI of the surrounding medium. Few basic material characterizations like FESEM, UV–Vis, PL spectroscopy, and XRD's were done to confirm the formation of ZnO nanolayer. The superior sensing performance are obtained for vertically oriented ZnO nanorods among the various nanostructures. It may be attributed due to the large and uniform surface area, better crystallinity, higher average dispersion relation, and excellent adhesion of analyte molecules. The most heightened average sensitivity of 799.42%/RIU with stable results is found for a wide RI range of 1.33–1.40 which could be applied in multipurpose chemical, physical, and biomedical sensing applications.

Characterization and Antibacterial Activity Test of Green Synthetic ZnO Nanoparticles Using Avocado (Persea americana) Seed Extract

The ability of cotton fabrics to absorb water creates several problems, such as providing an environment for bacterial growth. Antibacterial properties of textiles can be conducted by coating with nanoparticles with antibacterial activity. This study aimed to synthesize ZnO via green process nanoparticles using avocado seed extract (Persea americana), then characterize and evaluate its antibacterial activity on cotton fabrics. This research began with extracting avocado seed powder with distilled water. Then the avocado seed extract was mixed with Zn(CH3COO)2.2H2O and heated in a water bath at 70°C. The mixture was stirred while NaOH was added until the mixture reached pH 7, 8, and 9. The FTIR measurement of the avocado seed extract showed the presence of free hydroxyl and amino groups that act as reducing agents, capping agents, and stabilizers in the synthesis of ZnO nanoparticles. The XRD pattern of synthesized ZnO nanoparticles was hexagonal. The SEM results showed that the morphology of ZnO nanoparticles was spherical, with a particle size of 19.965 nm. Antibacterial activity was carried out on the cotton cloth coated with ZnO nanoparticles, resulting in an inhibition zone of 1.8 cm against E. coli and 1.97 cm against S. aureus bacteria. This study result indicated that ZnO nanoparticles have antibacterial activity by producing inhibition against E. coli and S. aureus.

Investigation of morphology, crystal structure and property of ZnO/poly (methylstyrene-co-chloromethyl styrene) nanocomposite

A nanocomposite composed of ZnO and poly (methyl styrene-co-chloro methyl styrene) P (MSt-co-CMSt) by in situ polymerization method were prepared successfully. For this purpose, firstly, the zinc oxide surface was treated with 3-(trimethoxysilyl) propyl methacrylate (TMSPMA), a silane coupling agent, and following that this functionalization nano-ZnO particle was reacted with PMSt to prepare PMSt-grafted TMSPMA-ZnO. The resulting PMSt-grafted TMSPMA-ZnO was brominated with N-bromosuccinimide and coupled with 1-hydroxy-2, 2, 6, 6-tetramethyl-1-piperidinyloxy (TEMPO-OH) to produce an NMRP macroinitiator (PMSt-TEMPO/nano-ZnO). The well-controlled graft polymerization of 4-chloromethyl styrene (CMSt) with macroinitiators were carried out to produce nanoparticles based-ZnO (PMSt-co-PCMSt)/zinc oxide nanocomposite). Properties, crystal structure, and the morphology of (PMSt-co-PCMSt)/zinc oxide nanocomposite was studied using 1H-NMR, FT-IR, XRD, TGA, DSC, TEM, and UV-Vis spectroscopy. The results of FT-IR investigation and observations of TEM images represented clear and strong evidence for the preparation of PMSt and PMSt-co-PCMSt with spherical morphology of ZnO nanoparticles. The synthesized nanocomposites can be utilized a compound to attenuate the UV irradiation in the range of pointed wavelength.

Bioactive properties of ZnO nanoparticles synthesized using Cocos nucifera leaves.

The online version contains supplementary material available at 10.1007/s13205-022-03110-9.

Investigation on structural and optical properties of ZnO nanoparticles ingrained grafitic carbon nitrides

The present study focus on nanoparticles of ZnO incorporated in grafitic carbon nitrides. Synthesis of ZnO nanoparticles grafted grafitic carbon nitride was successfully achieved by thermal decomposition of zinc acetate dihydrate and urea at 600˚C in muffle furnace . Urea is nitrogen rich precursor that act as a reducing agent as well as gets converted to grafitic carbon nitride .The crystal structure of the sample has been explored by X-ray diffraction spectra. The average crystallites size before and after the grafting are 31.89 nm, 20.86 nm, respectively. The optical properties of the grafted sample has been studied using UV–VIS. measurements. Scanning electron microscopy (SEM) shows the morphology of ZnO nanoparticles ingrained in graphitic carbon nitride with size ̴ 30 nm. Elemental composition by EDX image confirms the composite consisting of Zn, O, C and N elements.

Variation of Alkali Concentration and Temperature: Its Effect on the Morphology of ZnO Nanoparticles Synthesized via Solvothermal Technique

This study reports on synthesis of ZnO nanostructures using Zinc chloride (ZnCl2) as precursors and Potassium hydroxide (KOH) as alkaline source in a solvothermal process with varying molar concentrations (Zn2+/OH-) of 1:1, 1:3 and 1:5 for temperatures of 30 °C and 50 °C. The synthesized nanostructures were characterized by X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared (FT-IR) Spectroscopy, and Ultraviolet Visible (UV-Vis) spectroscopy. ZnO nanostructures synthesized at lower ratios (1:1) exhibited wurtzite hexagonal shapes. However, as the concentration ratios increases in both cases, spherical structures were formed with the emergence of some rod-like structures dominating, and finally aggregated to form flower-like structures at 30 °C temperature. The average crystallite size for nanostructures from XRD (30-50 °C) were in the range 15-21 nm whereas the average particle size from TEM analysis (30-50 °C) were in the range 39-76 nm. Increase in temperature and molar concentration of the alkaline source generally decreased the crystallite and particle size of the as well as a decrease in the wavelength of ZnO nanostructures as a result of blue-shifting of the absorption peak. FT-IR spectra of ZnO NSs prepared from concentration ratios of Zn2+: OH- (1:1, 1:3 and 1:5) at 30 °C and 50 °C showed characteristic peak bands at 461-467 cm-1 and 460-462 cm-1 respectively.

Synthesis and Optical Properties of B-Mg co-Doped ZnO Nanoparticles

Doping impurity into ZnO is an effective and powerful technique to tailor structures and enhance its optical properties. In this work, Zn1−xMgxO and Zn1−x−yMgxByO nanoparticles (x = 0, 0.1, 0.2, 0.3, 0.4; y = 0, 0.02, 0.04) were synthesized via one-pot method. It shows that the Mg and B dopants has great influence on crystallinity and surface morphology of ZnO nanoparticles, without changing the wurtzite structure of ZnO. The band structure study indicates that the competition of Conductive Band (CB) shift, Burstein–Moss (B-M) shift and Shrinkage effect will cause the band gap energy change in ZnO.

Green Synthesis ZnO Nanoparticles Using Rinds Extract of Sapindus rarak DC

The green synthesis of ZnO nanoparticles was carried out using a natural capping agent, Sapindus rarak DC rinds extract at low-temperature calcination and environmentally friendly solvent. The mixture of Zn(CH3COO)2, NaOH, and rinds extract was sonicated for 4 h at room temperature. The calcination was carried out at low temperature, 95oC for 8 h, and resulted in pale brown powder. XRD and SEM were used to confirm the structure and to analyze the morphology of ZnO nanoparticles respectively. XRD pattern of ZnO nanoparticles was corresponding to JDCPS card no 36-1451 with hexagonal structure. The average crystal size of ZnO nanoparticles was calculated using the scherrer equation and the average size was about 35.8 nm. From this study, the extract of the rind of Sapindus rarak DC was found to be a natural capping agent to synthesis ZnO nanoparticles because Sapindus rarak DC contain a pythochemical compound to limit the interaction between crystal seeds.

Humic acid involved chelation of ZnO nanoparticles for enhancing mineral nutrition in plants

Humic acid has been used to study the chelation of ZnO nanoparticles to improve plant micronutrition. ZnO nanoparticles were prepared using the ball milling process, and the prepared nanoparticles were chelated with Humic acid (Biomolecule). ZnO nanoparticles and surface modified Humic acid blended ZnS nanoparticles were studied for their structural, morphological, optical, and particle stability. XRD, FTIR, and TEM were used to examine the structural parameters. Humic acid affects the crystallite size and surface morphology of ZnO nanoparticles. The stability of humic acid blended ZnO nanoparticles is higher (38.45 mV) than that of ZnO nanoparticles alone (32.3 mV). The Zn mineral nutrition in plants is improved by humic acid blended ZnO nanoparticles.