Zinc Oxide Phase Research Articles

Synthesis, Characterization, Structural, and Optical Properties of Polyvinyl Chloride/Zinc Oxide Nanocomposite Films for Photocatalysis Application

Poly(vinyl chloride) (PVC)/Zinc oxide (ZnO) nanocomposite films were synthesized by the sol–gel (spin coating) method using tetrahydrofuran as a solvent. Structural, Optical properties and photocatalytic activities with different nanosize zinc oxide (ZnO) concentrations (8%, 10% and 20%) have been studied. The samples were characterized by XRD, RAMAN, FTIR, UV–Vis spectrophotometer, and photoluminescence. X-ray diffraction measurements indicated that the average particle size of the ZnO is varying between 17 and 24 nm. Characterization by Raman spectrometry of the nanocomposites studied revealed the additional low-intensity lines which characterize the wurtzite phase of hexagonal ZnO (wurtzite type) in the host matrix (thin film) of PVC and highlights the good crystalline quality (low density of defects) of ZnO nanocomposites. The results of the FTIR infrared spectroscopy analysis of the PVC/ZnO nanocomposites confirmed the presence of peaks characteristic of the vibration of the Zn–O bond. This characterization also shows an increase in the visibility of the absorption band of ZnO with the increase in doping percentages. UV–Vis optical spectra revealed that the optical band of nanocomposites decreases with increasing concentration of ZnO nanoparticles in the PVC matrix. It was found that the band gap is 3.69, 3.64 and 3.52 eV for xZnO/PVC nanocomposites (x: 8%, 10%, and 20%). The photoluminescence spectra of the samples were found to be strong green luminescence. PVC/ZnO nanocomposites have revealed a wide band of luminescence that stretches from visible to near UV. These results confirm the introduction of ZnO in nanoscale form into PVC matrix. The photocatalytic reaction was depicted using MB in the UV-irradiation action of stacked films in methylene blue (MB) solution. The result showed 20ZnO/PVC films gave efficiency to remove MB by 80% at 60 min, similar to the films (8ZnO/PVC) and (10ZnO/PVC), which gave lower efficiency. The occurrence of dye degradation under light might attribute to the high-charge separation of ē-h pairs at the interfaces of PVC and ZnO nanoparticles in its excited state under irradiation.

Porosity Study in ZnO Films for Carbon Monoxide Sensing

The development of gas sensors to monitor the toxic and combustible gases is imperative due to the concerns for environmental pollution and the safety requirements for the industry. In general, sensors provide an interface between the electronic equipment and the physical world typically by converting nonelectrical physical or chemical quantities into electrical signals [1]. The fundamental sensing principle relies on the change of conductivity of the sensors when they are exposed to certain target gases at moderate temperatures. One of the demands on the gas sensors is the low power consumption because the sensors work from day-to-day [2]. A low resistance material provides the lower driving power when it is used as a sensor. Among various metal oxide semiconductors (SMOs), typical n-type Zinc oxide (ZnO) with merit features such as wide direct band gap of 3.37 eV, good morphology properties, high electron mobility, low production cost, excellent chemical properties and appropriate response toward gaseous species such as carbon monoxide gas (CO), is widely used in the resistance-type CO gas sensors[3-4]. This work reports the response to carbon monoxide by using ZnO films with controlled pore size. Zn films were deposited on silicon substrates by DC sputtering using Zn targets of 2 in diameter with a purity of 99.99%. The (0 0 1) P type silicon substrates have a size of 1.5 x 1.5 cm2. The substrates were cleaned using the conventional cleaning procedure based on xylene, acetone and propanol to eliminate probably residues of adhesives. A 30-Watt power and a pressure of 5.5 mTorr were used for the deposition. Under these processing conditions for a sputtering period of 20 min, Zn films of 50 nm in thickness were grown as measured by profilometry. The samples were placed in a quartz furnace with a chromatographic N2 flow of 20 (cm3x l), at a temperature of 350 ° C for 30 minutes. Subsequently, with the purpose of obtaining porosity in the precursor films and improve the crystalline quality of ZnO, after the first treatment they were annealed at 800 ° C for 1 hour in three different atmospheres, the first was N2 with a flow of 20 (cm3x l) (S1 ) , the second was air with a relative humidity of 42% (S2 ), finally the third atmosphere was dry air (nitrogen: oxygen = 70: 30) (S3 ), Aluminum interdigitated contacts were defined on the surface of the films by the lift-off photolithographic method. To evaluate the response of the device, it was placed inside a non-evacuated chamber of known volume and exposed to several different amounts of carbon monoxide. The concentrations used were 50, 100, 250, at different temperatures. The current produced through the sensor by a constant voltage was recorded as a function of the time while the atmosphere was periodically exchanged. The surface morphology of the samples changed according to the used oxidation atmosphere, featuring distinct uniform porous surfaces with nanosized diameters. The samples showed a uniform distribution of particles with a porosity generated after the complete sample oxidation with different size of porous (20nm-100nm), depending on the specific oxidizing atmosphere. The XRD patterns for the samples processed in dry N2 show preferential orientation in the plane (002) of the ZnO crystallites. Dry and wet air produced the wurtzite phase of ZnO according to the diffraction of the (100), (002), (101) planes as seen in Fig. 1. The sensing measurements were made for carbon monoxide. The results from the three samples are observed in Fig. 2, in which we can see that sample 3 shows a larger response. This can be attributed to the average pore size which turned to be 30 nm.

Preparation and Structural and Electrochemical Characteristics of a Carbon-Containing Material Based on Aspen Bark Modified with Zinc and Iron Chlorides

The possibility of using aspen bark modified with zinc and iron chlorides for preparing highly porous materials with specific properties was examined. The effect of the treatment temperature and modifiers on the structural and electrochemical parameters of the carbon-containing product was revealed. Carbonization of aspen bark modified with ZnCl2 yielded a material with the specific surface area of up to 1350 m2 g–1, containing a crystalline zinc oxide phase. The material obtained using a mixture of aspen bark with FеCl3 had the specific surface area of up to 300 m2 g–1 and contained magnetite and maghemite. Modification of the bark with zinc and iron chlorides simultaneously yielded a highly porous product with ferromagnetic properties. The apparent capacitance of the samples carbonized at 800°С was found to be 150–400 F g–1. The possibility of using these materials in electrochemical devices was suggested.

Effects of Hydrolysable Tannins as Zinc Oxide Substitutes on Antioxidant Status, Immune Function, Intestinal Morphology, and Digestive Enzyme Activities in Weaned Piglets.

Simple SummaryZinc oxide (ZnO) is generally used to control diarrhea and improve gut health in weaned piglets. To protect weaned pigs from intestinal injuries and to decrease environmental zinc load, it is essential to find an alternative to ZnO. In the present study, hydrolysable tannins (HT) showed decreased diarrhea rate and improving gut health via multiple pathways. Herein we demonstrate that HT supplementation may be a potential alternative of ZnO in weaned piglets.Zinc oxide (ZnO) has negative environmental effects and bioavailability in weaned piglets. Thus, finding safe and effective ZnO substitutes to improve intestinal health and to prevent diarrhea of weaned piglets is urgently required. Therefore, this experiment was conducted to evaluate the effects of hydrolysable tannins (HT), ZnO and HT versus ZnO on growth performance, antioxidant status, serum immunity, intestinal morphology, and digestive enzyme activities in weaned pigs. A total of 144 piglets (28 d-old, initial body weight 7.81 ± 0.99 kg) were assigned to 4 treatments with 6 replicates of 6 piglets each. The experiment lasted 28 d (d 1 to 14 as for phase 1 and d 15 to 28 as for phase 2). The dietary treatments include a corn-soybean meal basal diet (CON); ZnO diet (CON + 2000 mg/kg ZnO in phase 1 and 137.5 mg/kg ZnO in phase 2); HT diet (CON + 1000 mg/kg HT in the overall period (d 1 to 28); HT + ZnO diet (CON + 2000 mg/kg ZnO + 1000 mg/kg HT in phase 1, and 137.5 mg/kg ZnO + 1000 mg/kg HT in phase 2). In phase 1, the incidence of diarrhea was lower (p < 0.05) in the HT + ZnO group than CON. Serum catalase (CAT) and glutathione peroxidase (GSH-Px) were increased (p < 0.01) and malondialdehyde (MDA) was decreased (p < 0.01) in the HT + ZnO group than CON. Compared with CON, immunoglobulin M (IgM), immunoglobulin A (IgA) were increased (p < 0.05) in the HT + ZnO group. In phase 2, both HT and HT + ZnO had a trend to improve (p < 0.10) daily gain. The concentration of total antioxidant capacity (T-AOC) and IgM in serum was higher (p < 0.01) in HT compared with CON. Supplementation of HT improved (p < 0.01) GSH-Px activities in ileum mucosa than the ZnO group. Compared with CON, trypsin, lipase activities, and villus height of jejunum were improved (p < 0.05) in HT and HT + ZnO. The ratio of villus height to crypt depth in the jejunum was improved (p < 0.05) in the HT + ZnO group and which also was increased (p < 0.05) in ileum in the HT group compared with CON. Propionic acid, butyric acid, and acetic acid concentrations in the colon were increased (p < 0.05) in the HT group than CON. Overall, HT + ZnO treatments could be used to replace ZnO for reducing diarrhea and improving antioxidant capacity, immunity, and digestive enzyme activities in weaned piglets.

Synthesis, Characterization and Anti-Biofilm Efficacy of Polypyrrole-Zinc Oxide Composites.

A nanocomposite of Polypyrrole (PPy) and zinc oxide (ZnO), termed as PPy-ZnO, was synthesized by two step route. In the first step, synthesis of PPy was carried out by chemical oxidative route. In the second step, the PPy-ZnO nanocomposite was synthesized under hydrothermal conditions. The as-synthesized PPy-ZnO nanocomposites were characterized using X-ray Diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform Infra-red (FTIR) and Ultra violetvisible (UV-vis) spectroscopy to reveal the phase, morphology, chemical and optical properties. The physical and chemical characterizations confirmed presence of both PPy and ZnO phases in the nanocomposite. In the present work, antimicrobial activity of the PPy-ZnO nanocomposite against human pathogen Y. lipolytica has been investigated. Attempts have been made to reveal the influence of PPy percentage on the antimicrobial activity. Interestingly, all PPy-ZnO nanocomposites, irrespective of PPy percentage, showed 90 to 95% inhibited growth of Yarrowia lipolytica. The results obtained herein imply the potential of PPy-ZnO biofilm in inhibiting the growth of Y. lipolytica and thus preventing infections caused due to Y. lipolytica in humans.

Synthesis and characterization of single phase ZnO nanostructures via solvothermal method: influence of alkaline source

Single phase ZnO nanostructures were synthesized by simple and low temperature solvothermal process from two different alkaline sources; Potassium hydroxide (KOH) and Sodium hydroxide (NaOH) with zinc acetate dihydrate (Zn(CH3COO)2∙2H2O) as precursor. This facile and rapid synthesis technique achieve high purity of Zinc oxide (ZnO) nanostructures on large scale negating the use of complex and high temperature routes. The synthesized particles were characterized by X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy (TEM), Energy-dispersive X-ray spectroscopy (EDX), Fourier Transform Infrared (FT-IR) Spectroscopy, Ultraviolet Visible (UV-Vis) spectroscopy and Brunauer-Emmett-Teller (BET) analysis. ZnO synthesized using KOH and NaOH exhibit wurtzite hexagonal and flake-like nanostructures with average crystallite size of 11.0 nm and 14.9 nm respectively. Surface area of 59.50 m2/g and 31.43 m2/g were determined for KOH and NaOH sources respectively. The optical absorption spectra of the two samples showed absorption bands of 367.70 and 365.30 nm. The results showed the effect of alkaline sources on the surface morphology, structural and optical properties of ZnO.

Structural and Electrochemical Behaviour of Cucurbita Seed Like Zinc Oxide Nanoparticles by Chemical Reflux Route

Cucurbita seed like zinc oxide (ZnO) nanoparticle is synthesised via chemical reflux method. The phase, size and structure of ZnO elucidates by X-ray diffraction method. Infrared spectrum is revealed its functional groups which are present in the synthesised nanoparticles. The cucurbita seed like morphology of prepared zinc oxide nanoparticles were examined by SEM analysis. Optical absorption property and bandgap of synthesized ZnO nanoparticles are investigated. The electrochemical activity of Cucurbita seed like ZnO nanoparticles measurement carry out through electrochemical impedance analysis, galvanostatic charge discharge and cyclic voltammetry results

Studies on the regularities of the steelmaking zinc-bearing dusts leaching in ammonium chloride solutions

Dust from steelmaking production, in particular electric arc furnace dust (EAFD), is a rich secondary source of zinc. Different approaches to the EAFDs processing with the production of zinc oxide and metal phases as a final product have been studied. Ammonium chloride leaching is selective for zinc, does not require special acid-resistant equipment, and is relatively cheap. The advantages of this method are the possibility of obtaining metallic zinc as a commercial product and the absence of the need for additional solution purification from iron and chlorine ions. Chemical and mineral characterization of Waelz-oxide after the first stage of calcination are presented, the main identified phase is zinc oxide (ZnO), a small amount of Zn associated with iron (Zn2Fe2O4) in the ferrites form and lead in the oxide phase (PbO) are also determined. The thermodynamic analysis of the Zn(II) &ndash; NH4Cl &ndash; NH3 &ndash; H2O system in the HYDRA software medium was carried out, the main zinc compounds were determined under leaching conditions. A matrix of changing conditions is compiled with using the full three-factor experiment method. Based on the obtained results, in the Statistica-10 program, three-dimensional dependences of zinc extraction on varied parameters were constructed and equations describing these dependencies were obtained. The optimal leaching parameters were determined: the concentration of ammonium chloride 4 mol/dm3, the concentration of ammonia 4 mol/dm3, the ratio L:S = 15.

Effect of Ethanol on the Photovoltaic Performance of ZnO Based Dye Sensitized Solar Cells

In this study, ZnO particles were grown at different ethanol–water concentrations by using a simple hydrothermal method at 97°C. The changes in structure and morphology of particles were investigated by varying the ethanol concentration. Scanning electron microscope images indicated that ethanol concentration was the main factor affecting the morphology and size of the ZnO particles. X-ray diffractometer pattern showed that crystal structures of the ZnO particles changed with the change in ethanol concentration of the starting solution. Zinc hydroxide phases rather than zinc oxide phases were found in ethanol-rich solutions during hydrothermal synthesis. Photovoltaic properties of the as-synthesized ZnO nanocrystals, as photoanode materials, were tested in dye-sensitized solar cells. Dye-sensitized solar cells were fabricated using a natural black carrot dye, and the performances of these cells were investigated for the electrode materials produced at different ethanol–water concentrations. The best solar energy conversion was obtained with ZnO electrodes fabricated at 100% ethanol concentration.

Fabrication of ZnO nanoparticles adorned nitrogen-doped carbon balls and their application in photodegradation of organic dyes

In the present study, a novel ZnO nanoparticles adorned nitrogen-doped carbon balls (ZnO@CBs) were successfully synthesized from polybenzoxazine and ZnO nanoparticles through a simple carbonization method. The typical wurtzite hexagonal zinc oxide phase in ZnO@CBs and degree of graphitization were revealed by the X-ray diffraction pattern. The field emission scanning electron microscopy confirmed that the synthesized carbon materials have well dispersed ball-like structure, wherein, the ZnO nanoparticles are distributed evenly on the carbon balls (CBs). The synthesized ZnO@CBs with different wt.% (20, 40, 60 and 80) and bare ZnO nanoparticles were investigated for methylene blue (MB) dye degradation experiment. The synthesized ZnO@CBs exhibited high activity in the degradation of MB. Among the different wt.% of ZnO@CBs, 60 wt.% of ZnO@CBs showed the highest MB degradation ratio (99%) with a fast degradation rate (1.65% min−1) under the following optimum conditions: 20 mg of ZnO@CBs in 50 mL of MB solution at room temperature.

Microstructure and Electrical Properties of Low-Voltage Barium Titanate Doped Zinc Oxide Varistor Ceramics

In the present, varistor ceramics through the combination of zinc oxide (ZnO) with a perovskite material have become widespread because of their unique properties for a wide range of applications in electronic protection devices. Low-voltage zinc oxide (ZnO) varistors with fast response and highly nonlinear electrical properties for overvoltage protection in an integrated circuit are increasingly significant in the application of low-voltage electronics. The present study highlights the interaction between barium titanate (BaTiO3) and ZnO varistors through the employment of solid-state reaction method in the production of low-voltage varistors. The effects of BaTiO3 on the microstructure of ZnO varistors were analyzed through scanning electron microscopy (SEM), energy dispersive X-ray analysis spectroscopy (EDS) and X-ray diffraction (XRD). The EDS analysis and XRD measurements suggest the presence of ZnO and BaTiO3 phases. The electrical properties of BaTiO3-doped ZnO varistors were examined based on the current density-electric field (J-E) characteristics measurement. The varistor properties showed the nonlinear coefficient (α) from 1.8 to 4.8 with the barrier height (φB) ranged from 0.70 to 0.88 eV. The used of BaTiO3 additive in ZnO varistors produced varistor voltages of 4.7 to 14.1 V/mm with the voltage per grain boundary (Vgb) was measured in the ranges 0.03 to 0.05 V. The lowest leakage current density was 348 μA/cm2, obtained at the samples containing 12 wt.% BaTiO3 with high barrier height. The reduction in barrier height with increasing BaTiO3 content was associated with the excessive amount of BaTiO3 phase, hence cause the deterioration of active grain boundary due to the variation of oxygen (O) vacancies in the grain boundary.

Phase composition reproportioning of the plasma dynamic synthesisproduct of the zinc-bismuth-oxygen system

This article shows the possibility of obtaining nanosized materials based on zinc oxide and bismuth oxide by plasma dynamic synthesis. The main research in the article is the results on the influence of the precursors mass on the products phase composition of the Zn-Bi-O system. X-ray phase analysis allowed to establish the possibility of zinc oxide and bismuth oxide synthesis in one short cycle of the coaxial magnetoplasma accelerator. Changing the metal bismuth batch weight allows to adjust the bismuth oxide content in the final product. Transmission electron microscopy confirms the presence of zinc oxide phases in the bismuth oxide shell in the obtained material. Evaluation of the bismuth oxide shell thickness by determining the average size of the coherent scattering region showed that it is 30 nm.

The role of Yb doped ZnO in the charge transfer process and stabilization

This work aims to investigate the role of Yb dopant in the ZnO photoactivity. A new material based on ZnO doped with a small amount of Yb (1% molar) has been synthesized, characterized and tested respect to an enhancement of the photoactivity via Electron Paramagnetic Resonance spectroscopy. The prepared material has been characterized via X Ray diffraction, UV visible spectroscopy and in particular with the transmission electron microscopy. The morphological analysis with high resolution TEM allowed us to identify the formation of a new species not visible with XRD and assigned to isolated Yb2O3 nanoparticles supported on the surface of larger particles of the more abundant zinc oxide phase. The as obtained material exhibits a band gap corresponding to UV light (≈3.3 eV), but nevertheless it shows a relevant photo-activity under irradiation with photons with λ > 420 nm (visible light). This phenomenon has been investigated by means of several methods. A specific EPR-based approach allowed to monitor and quantify the charge separation following the formation of holes in the valence band (VB) of the two materials.

Lignin-Mediated Biosynthesis of ZnO and TiO2 Nanocomposites for Enhanced Antimicrobial Activity

In this work, we report the synthesis of fragmented lignin (FL) assisted zinc oxide (ZnO) and titanium oxide (TiO2) nanocomposites. The fragmented lignin synthesized from biomass (sugarcane bagasse) was used as a template to generate the morphology and crystallite structure of metal oxide nanomaterial. The nanocomposites were synthesized by a simple precipitation method, wherein fragmented lignin is used in alkaline medium as a template. X-ray diffraction (XRD) analysis shows the phase formation of hexagonal wurtzite ZnO and mixed phase formation of TiO2 as rutile and anatase. The morphology was studied by using field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HRTEM). The FE-SEM of pristine ZnO nanocomposites showed a cluster of particles whereas FL–ZnO NPs showed self-aligned nanoparticles in the form of rod shaped having average size 30–70 nm. Pristine TiO2 nanoparticles showed clusters of particles and FL–TiO2 nanocomposites showed well crystalline 41nm size nanocomposites. The FL acts as a surfactant which restrict the cluster formations. The band gap determined by diffuse reflectance spectra is 3.10 eV and 3.20 eV for FL–ZnO and FL–TiO2 nanocomposites, respectively. Photoluminescence spectra of both nanocomposites showed structural defects in the visible region. Further, the antimicrobial activity of pristine ZnO and TiO2 nanoparticles, and FL–ZnO and FL–TiO2 nanocomposites against Escherichia coli (ATCC25922), Staphylococcus aureus (ATCC25923) were studied under UV-A (315-400 nm) (8W) for 30min.

Combustion Synthesis of ZnO/ZnS Nanocomposite Phosphors.

In the present study, combustion synthesis of zinc oxide and zinc sulfide nanoparticles as well as their composite was studied using zinc nitrate and thioacetamide as starting materials, and ethylene glycol as fuel. The influence of different parameters such as oxidizer to fuel (O:F) ratios and calcination process on the structure, microstructure, photoluminescence and optical properties was studied. X-ray diffraction (XRD) patterns showed different combinations of wurtzite structure for zinc oxide and zinc sulfide phases obtained using different O:F ratios of 1:1 and 2:3. Scanning electron microscopy (SEM) micrographs revealed that particles with different morphologies were synthesized depending on the O:F ratio. Besides, nanometer particles, or even quantum dots, could be obtained. Transmission electron microscopy (TEM) micrographs also showed the formation of zinc oxide/ zinc sulfide quantum dots composite using ethylene glycol fuel with O:F ratio of 2:3. Fourier transformed infrared (FTIR) analysis of samples showed carbon bonds of carbonaceous matters in addition to Zn-O and Zn-S bonds due to incomplete combustion. Photoluminescent emission spectra indicated that the highest intensity of emission in blue-green region was obtained from the particle synthesized using ethylene glycol and O:F ratio of 2:3, which may be related to the high density of lattice defects. Band gaps estimated using UV-visible (UV-Vis) spectra were 3.4 and 5.4eV which can be assigned to the dual nature of particles: in some parts quantum size and in the other parts nanosize particles.

The effect of Zn2+ on the anion vacancies in ZnO thin-films grown using chemical bath deposition.

Zinc Oxide (ZnO) thin-films were grown on glass substrate using chemical bath deposition method (CBD) from precursors containing varying molar concentrations of zinc acetate. The structure, morphology, optical and luminescence properties of the films were investigated using X-ray diffraction (XRD), Scanning electron microscopy (SEM), Ultraviolet visible spectroscopy (UV/VIS/NIR) and Photoluminescence spectroscopy (PL). The XRD result showed that at low molar concentrations of zinc acetate the structure consists of Zn(OH)2 and ZnO phases. As the molar concentration of zinc acetate increases the well-known hexagonal wurtzite structure of ZnO was developed. The average crystalite size estimated using Scherrer’s formula was about 41.19 nm. It was found that the average crystallite size increased with an increase in the molar concentration of zinc acetate. SEM observations showed the presence of nanoparticles forming aggregated nanoflakes. The surface morphology was found to be dependent on the concentration of zinc acetate. The UV-Vis spectra showed that the absorption band edge shift to the higher wavelength with an increase in molar concentration of zinc acetate. The band gap energy of ZnO thin-films determined from UV reflectance spectra was found to decrease from 3.17 to 2.73 eV with an increase in the zinc acetate concentration. The PL results showed that the luminescence intensities decrease with an increase in the molar concentration of zinc acetate without any noticeable shift in position.

Synthesis of Chitosan/Zinc Oxide Nanoparticles Stabilized by Chitosan via Microwave Heating

Nowadays, zinc oxide (ZnO) has attracted attention in research and development because of its remarkable antibacterial properties. Chitosan/ZnO nanoparticles were successfully synthesized via microwave heating. The objectives of this work were to investigate the effect of stabilizer, power heating and time heating on size of chitosan/ZnO nanoparticles and to determine antibacterial activity against pathogenic bacteria, where chitosan was used as a stabilizing agent. Chitosan/ZnO nanoparticles were analyzed by Fourier Transform Infra Red (FTIR), X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), and Zetasizer instrument. The power heating and time heating were varied from 400 to 800 Watt and 4 to 8 minutes, respectively. The presence of chitosan has role on preventing the nanoparticles from agglomeration by producing a milky solution of chitosan/ZnO nanoparticles without any suspensions. The increase of power and time heating improved the size of nanoparticles. The peak in FTIR spectrum at around 427 cm-1 was confirmed the existence of the ZnO phase. XRD patterns showed that the chitosan/ZnO nanoparticles materials were pure phase with average crystalline size is 130 nm. FESEM revealed that chitosan/ZnO nanoparticles were uniformly distributed with the mean value of size is 70 nm and spherical shaped. Further impact of power and time heating on the size of the chitosan/ZnO nanoparticles can be shown by a nanoparticles size distribution with the average of 30 to 90 nm. The results showed that chitosan/ZnO nanoparticles have displayed an antibacterial inhibition zone against Gram-positive S. aureus and Gram-negative E. coli which 16.0 and 13.3 mm, respectively. Chitosan/ZnO nanoparticles were synthesized in this work presented have potential application to prevent bacterial infections.

Effect of organic ligand on ZnO nanostructures and to investigate the photocatalytic activity under visible light illumination

Controlled morphology of zinc oxide (ZnO) was synthesized by simple hydrothermal method. Morphology and size of ZnO nanostructures was controlled by using pyridine as a passivating agent. Pyridine played a crucial role in modifying the morphological size of ZnO nanostructures. The structural analysis confirms the formation of hexagonal phase of ZnO with good crystalline nature. The elemental and composition analysis confirm the presence of ZnO and the existence of pyridine in the composition. The morphological analysis was performed by field emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM) and high-resolution transmission electron microscope (HR-TEM). The degradation property of organic pollutant was studied under visible light irradiation. Maximum degradation efficiency was observed for 0.6 mL of pyridine sample which disappeared completely after 18 min of irradiation. Furthermore, the degradation property of ZnO was studied by different value of pH, concentration of dye and photocatalyst dosage. The optimum values of solution pH, dye concentration, and photocatalyst dosage was 11, 10 ppm, and 75 mg/L, respectively.

Ultrasound assisted preparation and characterization of Ag supported on ZnO nanoparticles for visible light degradation of methylene blue dye

The present work reports sonochemical preparation of zinc oxide (ZnO) and silver decorated ZnO (9wt%) with the use of zinc acetate, silver nitrate and sodium carbonate as precursors in 60min duration. The resulted ZnO and silver decorated ZnO nanoparticles were characterized with SEM, FE-SEM, FTIR, XRD and UV–Vis techniques. XRD analysis reveals hexagonal quartzite crystalline phase of ZnO with highest purity. The doping of silver differs the ionic radii of the elements and that produces the strain in Ag-ZnO nanocomposites. The average crystallite size of ZnO and Ag-ZnO estimated to be 17.53 and 18.73nm, respectively with the use of XRD analysis. The lattice parameters, crystallite size and unit cell volume was observed to be increased with the loading of Ag on ZnO nanoparticles during its preparation with the aid of ultrasonic irradiations. The observed lesser size of nanoparticles and nanocomposites is due to the use of ultrasonic irradiations. Photocatalytic properties of ZnO and Ag-ZnO (doped) nanocomposite was examined for the degradation of methylene blue (MB) dye in aqueous solution under solar light irradiations. Influence of the initial dye concentration, catalyst loading, pH, and temperature on the degradation of MB dye was investigated and optimized conditions were obtained. Furthermore, a relative study of photocatalytic properties of ZnO and Silver doped ZnO nanocomposites prepared by conventional and sonication method was accomplished and the results were discussed. A maximum degradation of MB dyes was achieved (~96.2%) under optimized conditions for Ag doped ZnO nanocomposite prepared by ultrasound assisted method.

Controlling the growth of single crystal ZnO nanowires by tuning the atomic layer deposition parameters of the ZnO seed layer

Semiconducting nanowires (NWs) offer exciting prospects for a wide range of technological applications. The translation of NW science into technology requires reliable high quality large volume production. This study provides an in-depth investigation of the parameters using an atomic layer deposition system to grow zinc oxide (ZnO) seed layers followed by the chemical bath deposition (CBD) of ZnO NWs to demonstrate the low-cost production of uniform single crystal wurtzite phase ZnO NWs that is scalable to large area substrates. The seed layer texture and the morphology of the NWs grown were systematically investigated using atomic force microscopy as a function of the seed layer deposition parameters. It is shown that the NWs growth orientation can be controlled by tuning the seed layer deposition parameters while maintaining the same CBD conditions. Likewise, the diameters and the surface densities of the NWs varied from 23 to 56 nm and 40 to 327 NWs μm−2, respectively. Significantly, the relationship between the seed layer structure and the NW density indicates a clear correlation between the density of seed layer surface features and the resulting surface NW density of NWs grown.