Incorporation Of ZnO Research Articles

Realization of high-quality RF sputtered ZnMgO (x=15%) thin films by post-growth annealing treatment

ZnMgO, a direct wide-bandgap material with high exciton binding energy, has received widespread research attention in optoelectronics. However, its inherent n-type doping facilitates defect-related visible emission, which hampers the required luminescence properties in the UV region. Also, ZnMgO requires post-growth treatment which releases accumulated strain energy, modulates defect states, expands crystallite size, and augments ad-atoms interdiffusion, thereby affecting its bandgap. This work reports the influence of post-deposition annealing parameters like temperature and time on RF sputtered Zn0.85Mg0.15O thin films using rapid thermal annealing. The study showed that high temperature annealing aided Mg incorporation in ZnO lattice together with an increase in the grain size due to aggregation of grains. Highest activation energy, 78 meV, and narrowest line width, 34 meV, for D°X peak of 900 °C annealed film was obtained from photoluminescence study. Increasing annealing temperature also showed dissociation of bound exciton peaks into corresponding localized and delocalized exciton states.

Effect of different red palm oil volume on characteristics and degradation of polylactic acid/zinc oxide film

PLA/ZnO combination caused agglomeration, especially at a high concentration of ZnO. This condition improved by adding a plasticizer to smoothen the incorporation of ZnO into PLA. The work’s objective was to study the changes in polylactic acid/zinc oxide (PLA/ZnO) film’s properties incorporated with red palm oil (RPO) that acted as a plasticizer. The films were prepared using the solvent casting method. RPO’s impact as a plasticizer was determined on the film’s thickness, moisture content, functional group, mechanical properties, and solubility. More RPO increased the thickness because of the formation of more free volume in the polymer matrix. Otherwise, the moisture content has shown a different trend, which decreased with more RPO content. Fourier transform infrared spectroscopy proved that interaction occurred between each material in this film by sharpening the peak representing the ester group, C = O stretching bonds, 1365 cm−1 (C-H bending), and 1216 cm−1 (C-O stretching). The highest tensile strength obtained by PLA/ZnO/0.25RPO, showing the lowest performance in elongation at break. ZnO increased the solubility of PLA film, but the presence of RPO proportionally reduced the solubility. These results counsel that the PLA/ZnO/RPO films could be applied as an alternative to manufacture film packaging that needs high tensile strength and low elongation at break. Further study should be conducted for a range of one until 25 weight % of RPO over 100% PLA to determine the optimum formulation.

Incorporation of Metal-Based Nanoadditives into the PLA Matrix: Effect of Surface Properties on Antibacterial Activity and Mechanical Performance of PLA Nanoadditive Films.

In this work, the modification process of poly(lactic acid) (PLA) with metal-based nanoparticle (NPs) additives (Ag, ZnO, TiO2) at different loading (0.5, 1.0, and 2.5 wt%) and by melt-mix extrusion method followed by film formation as one of the advantageous techniques for industrial application have been investigated. PLA nanoparticle composite films (PLA-NPs) of PLA-Ag, PLA-ZnO, PLA-TiO2 were fabricated, allowing convenient dispersion of NPs within the PLA matrix to further pursue the challenge of investigating the surface properties of PLA-NPs reinforced plastics (as films) for the final functional properties, such as antimicrobial activity and surface mechanical properties. The main objective was to clarify how the addition of NPs to the PLA during the melt extrusion process affects the chemistry, morphology, and wettability of the surface and its further influence on the antibacterial efficiency and mechanical properties of the PLA-NPs. Therefore, the effect of Ag, ZnO, and TiO2 NPs incorporation on the morphology (SEM), elemental mapping analysis (SEM-EDX), roughness, surface free energy (SFE) of PLA-NPs measured by goniometry and calculated by OWRK (Owens, Wendt, Rabel, and Kaelble) model was evaluated and correlated with the final functional properties such as antimicrobial activity and surface mechanical properties. The developed PLA-metal-based nanocomposites, with improved mechanical and antimicrobial surface properties, could be used as sustainable and biodegradable materials, offering desirable multifunctionalities not only for food packaging but also for cosmetics and hygiene products, as well as for broader plastic products where antimicrobial activity is desirable.

Tuning the dielectric behavior and energy storage properties of Mn/Co co-doped ZnO

The synthesis of pure ZnO along with nominal Mn and Co co-doping using a time-efficient and cost-effective wet chemical route to explore their detailed dielectric response is reported. Structural investigations revealed the development of hexagonal crystal symmetry of pristine ZnO. When 5% Mn is substituted, a slight decrease in lattice parameters is observed. However, Co doping did not affect the crystal symmetry as well as lattice parameters. The morphological study exposed that Mn and Co incorporation in ZnO significantly affected the shape, size, and distribution of particles. The maximum porosity is noticed when 5% of Mn is doped in pure ZnO. The elemental analysis confirmed the presence of all elements according to their stoichiometric formula. The relatively higher value of the dielectric constant is noticed in the present case while the value of loss tangent is explained based on oxygen vacancies generated during the auto-combustion process. Short-range electron transport is distinguished from long-range on the basis of relaxation peaks present in electric modulus. The effective contribution of conducting grains and insulating grain boundaries in different frequency regimes is explained by their impedance response.

Recovery of chromium using membrane containing charged material

Chromium (Cr) is one of the important materials of metal family with large applications in formation of ferrous alloys viz., steel. Due to its excellent chemical, mechanical and thermal properties it is largely used in mineral, leather tanning, dye, steel, and other alloy industries. Effluents of these industries containing traces of Cr are polluting water bodies and soil in surrounding. It would result in entering in food chain, where it has highly adverse effect on humans, animals, and environment. Hence its recovery from effluent and other streams is highly essential before disposal and exposure to surrounding. The polysulfone (PSF) based membranes were optimized using polyethylene glycol (PEG) as porogen, while ZnO as an additive either treated with or without acid for removal of Cr from water. A reduction in molecular weight of PEG resulted in decrease in water flux indicates reduction in pore size. Further incorporation of ZnO increases the Cr removal. The Cr removal increases further with incorporation of acid treated ZnO. Additionally, HCl treated ZnO showed higher rejection properties, while the effect is not that prominent in HNO3 treated ZnO. This shows the importance of optimization of membrane surface charge for heavy metal removal.

Pour point and yield simultaneous improvement of alkyl esters produced by ultrasound-assisted in the presence of αFe2O3/ZnO: RSM approach

αFe2O3/ZnO nanoparticles were synthesized as a heterogeneous catalyst to produce biodiesel by transesterification of canola oil under ultrasonic irradiation. Nanocatalysts were characterized using XRD, FT-IR, SEM, TEM, BET, and CO2− TPD. The RSM and the BBD were employed to analyze the effect of variables. An acceptable agreement was achieved between the experimental and predicted data using RSM for yield (R2 = 0.9837) and pour point (R2 = 0.9901). Maximum yield and minimum pour point were obtained as 90.75% and −20 0C, respectively. The optimal reaction conditions were achieved at alcohol to triglyceride molar ratio, catalyst concentration, ultrasonic time, and alcohol type of 12:1 mol: mol, 2.53 wt% 30.98 min and 2-butanol, respectively. The incorporation of ZnO to αFe2O3 improved the basicity of the nanocatalyst. Moreover, the αFe2O3/ZnO nanocatalysts displayed a very good stability (83.19% yield) after 7 cycles. Kinetic studies indicated that the production rate of biodiesel corresponds well to the first-order equation.

Cellulose Nanofiber-Based Nanocomposite Films Reinforced with Zinc Oxide Nanorods and Grapefruit Seed Extract.

Here, we report the fabrication and characterization of cellulose nanofiber (CNF)-based nanocomposite films reinforced with zinc oxide nanorods (ZnOs) and grapefruit seed extract (GSE). The CNF is isolated via a combination of chemical and physical methods, and the ZnO is prepared using a simple precipitation method. The ZnO and GSE are used as functional nanofillers to produce a CNF/ZnO/GSE film. Physical (morphology, chemical interactions, optical, mechanical, thermal stability, etc.) and functional (antimicrobial and antioxidant activities) film properties are tested. The incorporation of ZnO and GSE does not impact the crystalline structure, mechanical properties, or thermal stability of the CNF film. Nanocomposite films are highly transparent with improved ultraviolet blocking and vapor barrier properties. Moreover, the films exhibit effective antimicrobial and antioxidant actions. CNF/ZnO/GSE nanocomposite films with better quality and superior functional properties have many possibilities for active food packaging use.

Investigating the Effect of ZnO on the Structural and Optical Properties of (MgO)1-x(ZnO)x via Pulsed Laser Deposition

This work concerned with effect of zinc oxide concentrating on the structural and optical properties of (MgO)1-x(ZnO)x thin films. (MgO)1-x(ZnO)x compounds were produced by mixing the two oxides powders accordance to the atomic ratios and compressed as pellets, these pellets were sintered in an oven at temperature1273K for five hours. Thin films from (MgO)1-x(ZnO)x compounds were obtained using pulsed laser deposition technique using Nd:YAG laser . The results of x-ray diffraction as well as UV-Visible- spectrophotometer measurements transmittance of (MgO)1-x(ZnO)x thin films were presented From the x-ray pattern it was observed reflection peaks (200) and (111) for cubic structure MgO and (100),(002) and (101) for ZnO wurtzite-phase reflections planes corresponding to the MgO cubic structure and ZnO wurtzite-phase while the prepared thin films with x content from 0 to 0.75 seemed to gather and rearranges their atoms until reveals some little peaks reveals at x=1.0 which give an indication to attend polycrystalline structure. The optical results declare a reducing of band gap i.e. red shift by the growth of ZnO incorporation in the prepared thin films.The data reveals that energy gap reduces from 4.0 eV to 3.20 eV . This affirms that the ablation of ZMO targets results in a tuneable band gap ZMO thin films. The calculated optical constants are greatly effected by ZnO incorporation in the prepared thin films.

Geçiş Metali Katkılı ZnO’in Ferromanyetizma ve Büyüme Korelasyonunun İncelenmesi

In this study, a series of 3d transition metal (TM) (Co, Ni and Fe) doped ZnO particles synthesized by simple co-precipitation method. Structural, morphological and magnetic properties were investigated to determine correlation between growth process and ferromagnetism of metal doped ZnO samples. All samples had ZnO hexzagonal würtzite structure and slightly shift of ZnO indexed peaks was observed by TM incorporation in ZnO. Although ZnO samples had granular forms, agglomerative forms had emerged in TM:ZnO samples due to the fast growth process. The pure ZnO sample transformed paramagnetic to ferromagnetic by TM incorporation due to carrier mediated exchange interaction between TM ions. The results demonstated that doping with Fe3+ ions in ZnO structure had enhanced ferromagnetism although fast growth and high particle agglomeration.

Wear behavior of alkaline pulsed electrodeposited nickel composite coatings reinforced by ZnO nanoparticles

Nickel-ZnO nanocomposite coatings were fabricated by pulse electrodeposition in an alkaline bath. The effect of different deposition parameters such as current density, duty cycle, and pulse frequency as well as the impact of addition of 10 g/l ZnO nanoparticles into the nickel matrix on the friction behavior of fabricated coatings were investigated. X-ray diffraction, atomic force microscopy, scanning electron microscopy, microhardness test, and pin-on-disk wear test were utilized to assess the coatings characteristics, mechanical behavior, and wear resistance and a thorough comparison was performed between the pure nickel coating and its reinforced composite counterpart, with respect to their surface morphology, surface topography, and wear resistance properties. Our results indicate that by ZnO incorporation into the coating, the number of nucleation sites for nickel crystals increases, the crystal growth is retarded, and a nanocomposite coating with smaller grains can be fabricated. The incorporation of ZnO led to significantly increase in microhardness, changed the wear mechanism from adhesion to abrasion, and improved the wear rate. By increasing the electrodeposition current density (from 4 to 10 A/dm2), the wear rate was noticeably decreased while the friction coefficient was significantly enhanced. As the electrodeposition duty cycle and pulse frequency were increased to 75% and 100 Hz, respectively, wear rate of the composite coating increased noticeably as a consequence of the changes in the coating properties. The optimum electrodeposition condition for Ni–ZnO nanocomposite coatings was achieved at 10 A/dm2, γ = 50% and f = 10 Hz resulting in a coating with the lowest wear rate (3.2539 × 10−4 mm3/Nm), minimum weight loss (0.0014 gr), highest microhardness (290 Hv), maximum ZnO incorporation rate (4.04 vol% ZnO), and highest friction coefficient (0.972) among all investigated coatings. It was concluded that increasing current density improved the wear resistance while the enhancement of duty cycle and pulse frequency led to worsen it.

The unforeseen relationship of Fe2O3 and ZnO on fibrous silica KCC-1 catalyst for fabricated Z-scheme extractive-photooxidative desulphurization

Fibrous silica KAUST Catalysis Centre (KCC-1) was prepared via a hydrothermal-microwave method, followed by incorporation of Fe2O3 and ZnO by an electrochemical technique to give ZnO-Fe2O3/KCC-1 (ZFK) catalysts. XRD, FESEM, N2 physisorption, FTIR, XPS, ESR and UV–Vis DRS were employed to characterize the catalysts. A varied amount of Fe2O3 and ZnO seems have insightful impact on the physicochemical behaviours of the KCC-1 while prominently enhanced the extractive-photooxidative desulphurization of dibenzothiophene (DBT). 5Z10FK demonstrated the best performance mainly due to a well distribution of both metal oxides on KCC-1, the highest Si-O-Fe and Si-O-Zn bonds, an appropriate amount of surface defect and suitable band gap energy. Besides, the suitable band positions of 10FK and 5ZK in 5Z10FK composite has allowed the formation of Z-scheme heterojunction for conserved strong redox potential. Kinetic studies revealed that the adsorption of DBT was the rate determining step, thus this reaction obeyed the Langmuir-Hinshelwood pseudo-first order.

Electrodeposition of Ni–ZnO nano-composite for protecting the agricultural mower steel knives

There is little information about the improvement of agricultural reciprocating mower knives against wear and corrosion using nanotechnology. Therefore, in the present study, the electrodeposition of pure Ni and Ni–ZnO nano-composite coatings has been used. The influence of pH values and the applied current density on the surface morphology, corrosion resistance, and mechanical properties as abrasion resistance, scratch, and fretting tests of Ni and Ni–ZnO nano-composite coatings using nanoindentation machine have been investigated. The results demonstrated that Ni deposited on steel from the alkaline bath displayed fine grain sizes than that deposited from the acidic bath. EDX analysis proved that the maximum incorporation of ZnO (2.7 wt%) into the Ni matrix was achieved with an alkaline bath at 5A/dm2. High-performance properties were obtained with the steel coated by Ni–ZnO nano-composite coating from an alkaline bath. The surface is harder (4.8 Gpa) than the steel coated by pure Ni (2.8 Gpa) and consequently exhibited a higher ratio of the hardness, the resistance to the plastic indentation, elastic recovery, scratching, fretting, abrasion, and corrosion resistance (in 3.5% NaCl solution). The highest corrosion resistance (0.0047 mm/year) compared with uncoated steel (0.094 mm/year) was obtained with the steel coated by Ni–ZnO nano-composite from the alkaline bath containing 1 g/L ZnO operated at 5 A/dm2 and pH 10. The testing results concluded that the steel coated by Ni–ZnO nano-composite coating from an alkaline bath appears promising to protect mower knives.

Electronic Tuning of Zinc Oxide by Direct Fabrication of Chromium (Cr) incorporated photoanodes for Visible-light driven Water Splitting Applications

Herein, we report the synthesis of Cr incorporated ZnO sheets arrays microstructures and construction of photoelectrode through a direct aerosol assisted chemical vapour deposition (AACVD) method. The as-prepared Cr incorporated ZnO microstructures were characterized by transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, powdered X-ray spectroscopy, X-ray photoelectron spectroscopy and UV-Vis diffused reflectance spectroscopy. The Cr incorporation in ZnO red shifted the optical band gap of as-prepared photoanodes. The 15% Cr incorporation in ZnO has shown enhanced PEC performance. The AACVD method provides an efficient in situ incorporation approach for the manipulation of morphological aspects, phase purity, and band structure of photoelectrodes for an enhanced PEC performance.

Codeposition of electroless Ni-P/ZnO nano composites and evaluation of corrosion resistance of the coatings

Codeposition of nano ZnO with Ni-P coatings was carried out on 99% pure copper substrates. The ZnO nano particles were prepared by simple Sol-Gel method using Zinc acetate dihydrate as precursor. The particle size of the same was found to be <100 nm. The process optimization for codeposition of nano ZnO with Ni-P coatings was carried out by varying the composition of nano ZnO particles using ultrasonicator. An adherent and uniform coating of Ni-P/ZnO was obtained. Presence of ZnO in the coatings was confirmed by EDAX. Surface morphology of the coatings was studied by SEM which shows the smooth homogenous surface in Ni-P/ZnO composite coating. Corrosion resistance of the coatings was evaluated by Salt spray test and Galvanostatic Polarization method using 5% NaCl solution. Corrosion resistance of the Ni-P and Ni-P/ZnO nano composite coatings were compared. Incorporation of nano ZnO in the coatings found to enhance the corrosion resistance and microhardness of the coatings.

Theoretical insights into hydrogen sensing capabilities of black phosphorene modified through ZnO doping and decoration

This paper has addressed the sensing capabilities of black phosphorene (BP) modified through ZnO decoration and doping at the HSE06/TZVP level of theory. For the ZnO-decorated (PZ) material, the hydrogen molecule adopted a parallel configuration with respect to the ZnO bond. On the two ZnO-doped (ZP) nanosensors, however, the first hydrogen molecule preferred the placement above the Zn atom. An ideal substitution of ZnO with retrieving lattice structures of defective BP to the pristine arrangement was highly favored (−127.03 kcal/mol). The stabilization of hydrogen molecules on all sensors was relatively weak (up to −3.03 kcal/mol), however. Indirect band structures were observed for both PZ (decorated) and ZP (doped) sensors. The PZ sensor performed quite better (with a gas sensitivity of 410.0%) compared to the ZP counterpart. The work function was decreased in all cases after the incorporation of ZnO or the adsorption of hydrogen molecules. The obtained data confirmed that the pristine BP could be converted into a reusable hydrogen sensor through ZnO doping and particularly decoration, having a recovery time of 43 ps at room temperature. We also made an account of the effect of temperature, selectivity, surface diffusion, and the electronic properties of the improved sensors. Importantly, the PZ sensor was found to be more selective toward hydrogen.

Antimicrobial ZnO Nanoparticle–Doped Polyvinyl Alcohol/Pluronic Blends as Active Food Packaging Films

AbstractToday, plastic waste has been highlighted as one of the greatest threats to the environment. These environmental concerns and the increased necessity for safe food packaging have inspired scientists to focus on the development of active biodegradable materials. Herein, a novel poly(vinyl alcohol)/pluronic/ZnO nanocomposite film (PVA/PLUR/ZnO) is introduced as an active packaging material with enhanced antimicrobial activity. Gamma irradiation is used as a “green” route to prepare ZnO nanoparticles via a polymer pyrolysis method. The as‐prepared ecofriendly ZnO nanoparticles are characterized and incorporated into the PVA/PLUR matrix in different concentrations. Transmission electron microscopy and dynamic light scattering measurements prove that ZnO nanoparticles have a mean particle size of 30 nm with a spherical‐like morphology. Morphological and structural characterization confirm the successful incorporation of ZnO into the PVA/PLUR matrix, which in turn enhances the thermal and barrier properties of PVA/PLUR/ZnO nanocomposite films. On the other hand, the opacity of blends is increased. The PVA/PLUR/ZnO composites exhibit broad‐spectrum antimicrobial activity against Gram‐positive, Gram‐negative bacterial pathogens, and fungi, and the activity increases with increasing concentrations of ZnO nanoparticles. These results introduce PVA/PLUR/ZnO films as effective antimicrobial materials for active food‐packaging applications.

Investigations on microstructure, optical, magnetic, photocatalytic, and dielectric behaviours of pure and Co-doped ZnO NPs

In this research, an effective usage of quantum size effect is a foregrounded strategy to produce and employ excellent visible light-driven photocatalytic materials. Zn100−xCoxO (x = 0, 2.5, 7.5) particles at nanoscale were synthesized successfully by chemical co-precipitation method and then investigated by some complimentary analytical techniques. Physical structure and chemical states were analysed by X-ray diffraction and X-ray photoelectron spectroscopy. XRD and HRTEM analysis confirmed the formation of wurtzite-type structure without any traces of secondary phase. XPS spectra exhibited the incorporation of Co2+ ions into ZnO lattice. Optical spectra of Zn100−xCoxO nanoparticles (NPs) indicated that bandgap is significantly narrowed with increasing Co concentration. Ferromagnetic behaviour was observed at room temperature in pure and Co-doped ZnO, due to the effect of quantum confinement and of Co2+ ions incorporation. The frequency and composition dependence of dielectric constant and dielectric loss have been analysed in detail using Maxwell–Wagner model and Cole–Cole plots. The activity of synthesized photocatalysts under simulated sunlight irradiation was characterized through decomposition of methylene blue (MB) dye in aqueous suspension, which revealed that Co2+ ions incorporation in ZnO greatly enhanced the photocatalytic degradation efficiency and hence employable in environmental cleaning.

Biocompatible supercapacitor electrodes using green synthesised ZnO/Polymer nanocomposites for efficient energy storage applications

In the era of rapid decline of renewable sources of energy, novel supercapacitor materials are essential to provide impetus to the growing energy demands arising from the commercialization of technology towards an electric-powered future which aims at both efficient and sustainable use of energy. The inspiration is to develop materials that effect specific applications without causing any damage to the environment. The use of inherently non-conducting but biocompatible polymers that can be functionally modified are thus imperative in this respect. Here, styrene maleic anhydride (SMA) copolymer has been structurally modified with a thiadiazole moiety along with the incorporation of green synthesized ZnO nanoparticles to prepare a polymer nanocomposite. The green synthesized ZnO nanoparticles display a flake-like structure with a size of about 20 nm. UV, FT-IR and XRD analyses validates the incorporation of ZnO in to the polymer matrix to form the polymer nanocomposite. Satisfactory supercapacitor behaviour with a specific capacitance of 268.5 F g−1 at 0.1 A g−1 is estimated for the polymer nanocomposite which is larger than ZnO nanoparticles and the bare polymer. It is demonstrated that the innate conductivity of the SMA copolymer is enhanced upon modification. The materials also exhibit good cycling stability with maximum capacitance retention. The biocompatibility of the nanocomposites has been established from the preliminary cell viability studies performed on 3T6 mouse fibroblast cells. The developed material shows great promise to provide a green alternative to existing supercapacitors.

Study on the performance of NiO/Zn x Zr1-x catalysts for CO2 hydrogenation.

The NiO/ZnxZr1−x (x represents the molar mass of Zn) catalyst was prepared by the impregnation method and tested in CO2 methanation. The activity results show that NiO/Zn0.3Zr0.7 has a higher CO2 conversion rate and methane selectivity than NiO/ZnO and NiO/ZnO–ZrO2. Combined with N2 adsorption–desorption, H2-TPR, CO2-TPD, H2-TPD, XRD, TEM, XPS and FTIR and other characterization methods, the physical and chemical properties of NiO/ZnO–ZrO2 were studied. The incorporation of ZnO into NiO/ZrO2 forms a ZnO–ZrO2 solid solution, and the combination of the solid solution weakens the interaction between NiO and the oxide support, thereby promoting the reduction and dispersion of NiO. The H2-TPR experiment results show that, because ZnO–ZrO2 forms a solid solution, NiO is better dispersed on the surface, resulting in a significant reduction in the reduction temperature of NiO. Using FTIR to conduct CO2 adsorption and methanation experiments on NiO/ZnxZr1−x to determine the adsorbed species and intermediates, the results show that CO2 methanation follows the formate pathway.

Optical, phonon and fluorescence properties of PVA-GO-ZnO free standing films

We report optical properties of ZnO nanorods dispersed graphene oxide (GO)—polyvinyl alcohol (PVA) free standing composite films (PVA-GO-ZnO) which are prepared by ex-situ method. It has been found that the loading of ZnO nanorods altered the influence of GO on PVA matrix. Optical absorption results show the band related to π → π* transitions of aromatic C–C bonds in GO, which is shifted to higher wavelength side when loading ZnO in GO-PVA. Raman spectral studies show that the incorporation of ZnO in GO-PVA film decreases the interaction of GO with hydroxyl groups in PVA matrix. Steady state and time resolved photoluminescence show the suppression of PVA luminescence and decay time due to interactions with GO, which is recovered after the loading of ZnO in the PVA-GO.