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Nanofluids have demonstrated incredible potential for application in various industries such as coolants. Metal oxides are widely used as solid particles in formulations of nanofluids due to their advantages. Metal oxide-based nanoparticles (NPs), ZnO NPs were fabricated by the ultrasonically assisted co-precipitation method. The structure and morphology of the synthesized ZnO NPs were characterized using an array of analytical techniques including X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The XRD results showed that the purity of ZnO was obtained. The investigated nanofluids remained stable for a long time without substantial sedimentation. The present study deals with the corrosion assessment of St37 steel in nanofluids prepared with various concentrations of ZnO NPs. A scanning electron microscope coupled with energy-dispersive X-ray spectroscopy was used to determine the surface characteristics and elemental composition of low-carbon steel specimens both before and after corrosion tests. Notably, the nanofluid containing 0.05% by weight of ZnO nanoparticles demonstrated the highest corrosion prevention efficiency among the prepared nanofluids. Furthermore, impedance spectroscopy measurements revealed that the corrosion resistance increased by 72.9% for the nanofluid containing 0.05 wt% ZnO NPs compared to the base fluid. These findings highlight the potential of ZnO nanoparticles as an environmentally friendly anti-corrosion compound in cooling systems, effectively reducing corrosion degradation. [ABSTRACT FROM AUTHOR]

In the current investigation, zinc oxide (ZnO) nanoparticles and Fe-doped ZnO nanoparticles were sustainably synthesized utilizing an extract derived from the Rumex dentatus plant through a green synthesis approach. The Scanning electron microscope (SEM), X-ray diffraction (XRD), Energy-dispersive x-ray spectroscopy (EDX), Ultra-violet visible spectroscopy (UV–vis) spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and Thermogravimetric analysis (TGA) techniques were used to examine the compositional, morphological, optical, and thermal properties of both samples. The doping of iron into ZnO NPs has significantly influenced their properties. The analysis firmly established that both ZnO NPs and Fe-doped ZnO NPs have hexagonal wurtzite structures and spherical shapes by XRD and SEM. The EDX analysis suggests that iron atoms have been successfully integrated into the ZnO lattice. The change in color observed during the reaction indicated the formation of nanoparticles. The UV–vis peaks at 364 nm and 314 nm confirmed the presence of ZnO NPs and Fe-doped ZnO NPs, respectively. The band gap of ZnO NPs by Fe dopant displayed a narrowing effect. This indicates that adding iron ions to ZnO NPs offers a control band gap. The thermal study TGA revealed that Fe-doped ZnO NPs remain stable when heated up to 600 °C. The antibacterial efficacy of ZnO NPs and Fe-doped ZnO NPs was evaluated against several bacterial strains. The evaluation is based on the zone of inhibition (ZOI). Both samples exhibited excellent antibacterial properties as compared to conventional pharmaceutical agents. These results suggest that synthesizing nanoparticles through plant-based methods is a promising approach to creating versatile and environmentally friendly biomedical products. [ABSTRACT FROM AUTHOR]

Non-enzymatic screen-printed chemiresistive interdigitated electrodes (SPCIE) were designed and fabricated using a low-cost screen-printing method for detection of the glucose. The interdigitated electrodes (IDE) pattern was printed using conductive graphene ink on the glossy surface of the photo paper. The proposed glossy photo paper-based SPCIE are functionalized with multi-walled carbon nanotubes-zinc oxide (MWCNTs-ZnO) nanofibers to create the chemiresistive matrix. Further, to bind these nanofibers with the graphene electrode surface, we have used the green synthesized silver nanoparticles (AgNPs) with banana flower stem fluid (BFSF) as a binder solution. AgNPs with BFSF form the conductive porous natural binder layer (CPNBL). It does not allow to increase the resistivity of the deposited material on graphene electrodes and also keeps the nanofibers intact with paper-based SPCIE. The synthesized material of MWCNT-ZnO nanofibers and green synthesized AgNPs with BFSF as a binder were characterized by Ultraviolet-visible spectroscopy (UV–vis), scanning electron microscope (SEM), x-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). The amperometric measurements were performed on the proposed SPCIE sensor to detect the glucose sample directly. The innovative paper-based SPCIE glucose sensor exhibits a linear corelation between current measurements and glucose concentration in the range between 45.22 μ m and 20 mm, with a regression coefficient (R 2) of 0.9902 and a lower limit of detection (LoD) of 45.22 μ m (n = 5). The sensitivity of the developed SPCIE sensor was 2178.57 μ AmM−1cm−2, and the sensor's response time determined was approximately equal to 18 s. The proposed sensor was also tested for real blood serum sample, and relative standard deviation (RSD) was found equal to 2.95%. [ABSTRACT FROM AUTHOR]

Plant‐based nanoparticles (NPs) have found great interest among various scientist in the present era and used in various sector including medicine, agriculture, and food industry. The various chemical constituents of plants aid in the bioreduction of metal ions to a nanoscale. Among the various NPs synthesized, zinc oxide (ZnO) NPs hold a premier position. ZnO NPs have use in textile, cosmetic, diagnostics, optoelectronics, photocatalysis, diodes, and many other areas. NPs synthesized through green synthesis have a potentially greater role in treating clinical pathogens. Present investigations show a simple eco‐friendly method for the synthesis of ZnO NPs from the husk of sunflower seeds. Sunflower is an economically important crop, for the formation of edible oil. The husk is considered to be a waste, product in oil industry, however, the biomolecules present in sunflower husk can be used to produce ZnO NPs. Present investigations reveal formation of ZnO NPs and investigations of their structure through scanning electron microscope (SEM), X‐ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. Their optical properties have been studied by ultraviolet–visible spectrophotometer (UV–Vis) and fluorophotometer. ZnO NPs have also been investigated for their potential phytoremedial properties. [ABSTRACT FROM AUTHOR]

Nanoparticle incorporation plays an active feature in heat transfer, ultimately enhancing the tribological process under boundary conditions of heat stress. Nanoparticles like zinc oxide (ZnO) and multiwall carbon nanotubes (MWCNT) are well known to significantly affect the cooling and lubrication applications, resulting in improved heat transfer and kinematic viscosity. The present work investigates the tribological performance of ZnO/MWCNTs hybrids as lubricant additive in the paraffinic type of mineral base oil of Group I (SN150) engine oil. The chemical composition of the modified and unmodified oil was examined by an inductively coupled plasma-optical emission spectrometer (ICP-OES), energy dispersive x-ray fluorescence (EDXRF) spectrometer, and Fourier-transform infrared spectroscopy (FTIR). A ring-ondisk tribotester was performed to investigate the tribological behaviour through the linear reciprocating mechanism alloy-steel contacts. The worn steel alloy surfaces morphology and chemical compositions were examined by scanning electron microscope (SEM), energy-dispersive x-ray spectroscopy (EDX), and 3D optical profilometer. Different ZnO/MWCNTs nanomaterial volumetric concentrations were examined in order to determine the most effective performance. According to the tribological results, ZnO/MWCNTs hybrid nanomaterials in the engine oil were found to have significantly higher friction temperature and antiwear capability than the base oil. A volumetric concentration of 3.00 wt% ZnO/MWCNTs nanomaterials to SN150 engine oil imparted excellent wear protection to the steel sample than the pure SN150 base oil. Based on the statistical analysis, the modified oil anti-wear performance was enhanced by reducing the wear loss by 80.5% and friction temperature by 55.8°C compared with the oil base. [ABSTRACT FROM AUTHOR]

ZnO and cadmium (Cd)-doped ZnO (Zn1-xCdxO) nanoparticles with various compositions (0.0 ≤ x ≤ 0.8) were synthesized by sol-gel method. Structural, morphological, and photocatalytic properties as well as blood compatibilities of Zn1-xCdxO nanoparticles were investigated. While X-ray diffraction (XRD) applying the Rietveld refinement method was used to characterize the structural properties, scanning electron microscope (SEM) and transmission electron microscope (TEM) were used to investigate the surface morphology. It was found that the nanoparticles up to x < 0.03 Cd concentration had single phase of ZnO hexagonal wurtzite structure. Above x ≥ 0.03 Cd concentration, two phases (ZnO and cadmium oxide (CdO)) were observed. SEM images with different magnifications revealed the dense, quasi-spherical, and agglomerated morphology of Zn1-xCdxO nanoparticles. The elemental compositions of Zn1-xCdxO nanoparticles have also been studied by EDX analysis. The photocatalytic activities and blood compatibilities of Zn1-xCdxO nanoparticles were studied by the photocatalytic degradation tests of crystal violet (CV) and hemolysis tests and respectively. In the photocatalytic activity tests, two samples Zn0.90Cd0.10O and Zn0.80Cd0.80O stood out with photodegradation percentages of 69.9% and 72.8%. Among the Cd-doped nanoparticles, the Zn0.40Cd0.60O sample showed the highest blood compatibility with the weakest photocatalytic performance (degradation percentage; 32.2%). Structural properties, photocatalytic performance, and hemolytic potential of Zn1-xCdxO nanoparticles were investigated and compared with those of pure ZnO nanoparticles. [ABSTRACT FROM AUTHOR]

Natural leather still represents great importance among the materials used by humans in modern times, although it is the oldest-known fiber used by humans. Adding new features to the leather, such as bacteria and fungi resistance, electrical conductivity and magnetic properties, is an ambitious goal for leather developers. In our study, production and characterization of anti-microbial sole leather coated with zinc oxide nanoparticles were achieved. For this purpose, the ZnONPs have been prepared through green synthesis and the prepared nanomaterial loaded on the sole leather by a padding mangle. The surface morphology of the nano coated sole leather was studied using a scanning electron microscope (SEM). Antimicrobial performance of the treated leather to some microorganisms was evaluated by applying the qualitative agar disc diffusion method. The SEM image of the treated leather samples showed successive leather coating, and the nanoparticles completely adhere to the leather surface. The nano-treated leather samples showed significant resistance to the tested bacteria and fungi. Results are promising for the utilization of zinc oxide nanoparticles as additives for sole leather coating. Accordingly, the study succeeded in producing a natural microorganism-resistant sole leather, which can be used in the production of healthy and microorganisms-resistant shoes. [ABSTRACT FROM AUTHOR]

In this paper, we discuss the preparation of Li-doped ZnO nanostructures through combustion and report on their structural, morphological, optical, and electrocatalysis properties. X-ray diffraction analyses show that the samples have a structure crystallized into the usual hexagonal wurtzite ZnO structure according to the P63mc space group. The scanning electron microscope images conceal all samples' nanosphere bundles and aggregates. The reflectance spectra analysis showed that the direct bandgap values varied from 3.273 eV (for pure ZnO, i.e., ZnL1) to 3.256 eV (for high Li-doped ZnO). The measured capacitance concerning frequency has estimated the variation of dielectric constant, dielectric loss, and AC conductivity against AC electric field frequency. The dielectric constant variations and AC conductivity are analyzed and discussed by well-known models such as Koop's phenomenological theory and Jonscher's law. The Raman spectra have been recorded and examined for the prepared samples. Rhodamine B was electro-catalytically degraded in all prepared samples, with the fastest time for ZnL5 being 3 min. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus (S. aureus) is a Gram-positive bacteria considered one of the leading causes of community and hospital-acquired illnesses or public health concerns. Antibiotic resistance in this microorganism is one of the greatest issues in global health care. The use of metal nanoparticles and their oxides is one of the potential approaches to combating bacteria resistance to antibiotics. The antibacterial properties of ZnO NPs against enterotoxigenic S. aureus were studied. ZnO NPs were tested in vitro by agar diffusion test. They resulted in 26 and 22 mm zones of inhibition for a size of 20 nm and a concentration of 20 mM against 105 and 107 CFU/mL S. aureus, respectively. The MIC of ZnO NPs of various sizes, 20 and 50 nm, with 105 CFU/mL was 2.5 and 5 mM, respectively. MIC with 107 CFU/mL was five mM for 20 and 50 nm ZnO NPs. Further, the highest growth reduction percentage, 98.99% in the counts of S. aureus was achieved by ZnO NPs of size 20 nm and concentration of 10 mM. Moreover, the obtained ELISA results indicated a significantly decreased concentration of enterotoxin A with all concentrations and sizes of ZnO NPs. PCR analysis showed a significant effect on sea gene in response to ZnO NPs treatments leading to loss of the gene, unlike the unaffected nuc gene. Moreover, morphological changes and cell shape distortion were detected by scanning electron microscope for bacterial cells treated with ZnO NPs. [ABSTRACT FROM AUTHOR]

In the present study, self-assembled ZnO nanoparticles were synthesized via a hydrothermal method utilizing an aqueous extract of mentha pepperita L (peppermint) leaves. The effect of parameters, including the amount of extract, reaction time, and pH was investigated on the structure and morphology of synthesized nanoparticles. X-ray diffraction (XRD) patterns confirmed the formation of pure well-crystallized ZnO nanoparticles using a zinc nitrate solution (50 mM) and peppermint extract in a volume ratio of 6:1 at pH of 8 and 12. However, the morphology and crystallite size of the particles were different in pH of 8 and 12. Fourier transform infrared (FTIR) spectra confirmed the modification of the ZnO surface with peppermint extract components. Analysis of N 2 adsorption and desorption cycles showed the increment of surface area by about 5 times using peppermint extract. Scanning electron microscope (SEM) images revealed the formation of a self-assembled sphere structure using peppermint extract. Mechanism of dissolution-precipitation was proposed for green hydrothermal synthesis of ZnO nanoparticles, based on XRD and SEM results at various reaction times. The synthesized ZnO nanoparticles (reaction time of 24 h and pH of 8) were used to remove methylene blue (MB) dye from an aqueous solution, and adsorption and photocatalytic process were studied. The mass of the dye adsorbed per mass of the adsorbent, q t , grew up by increasing the initial dye concentration. Conversely, the photocatalytic degradation percent decreased. In addition, the final adsorption capacity in 50 mL of 30 ppm dye solution was almost the same in 0.01 and 0.05 g of ZnO, although it was smaller in 0.1 g of ZnO. The maximum degradation efficiency was derived by using 0.05 g ZnO. Self-assembled structure, high capacity of adsorption, and excellent photocatalytic properties were unique characteristics of the synthesized ZnO nanoparticles. [ABSTRACT FROM AUTHOR]

Zinc oxide and zinc sulphide nanoparticles were produced using the sol-gel method. We employed nanoparticle identification methods for the examination of several factors. The precursor solutions are converted into an intermediate state that mimics gel during the sol-gel process, and then solidified. This technique provides fine control over the size, shape, and crystallinity of the resultant ZnO nanoparticles, hence modifying their electrochemical behaviour in the context of supercapacitor applications. An X-ray diffraction (XRD) examination revealed that the synthesized ZnO nanoparticles had a hexagonal character, while the ZnS nanoparticles had a cubic nature with diameters of around 22 nm and 36 nm, respectively. A transmission electron microscope (TEM) and a scanning electron microscope (SEM) are used to study the morphology and structural analysis. A particle size, surface area, production methods and testing settings are only a few of the variables that affect certain capacitances. In general, ZnO is recognized for displaying a certain capacitance that is frequently cited as being higher than ZnS. At a scan rate of 5 mV, the specific capacity of ZnO nanoparticles was found to be 33.2 F/g, whereas that of ZnS nanoparticles was found to be 6.5 F/g at a scan rate of 10 mV. One way to monitor pseudo capacitive behavior is by cyclic voltammetry. [ABSTRACT FROM AUTHOR]

Background: Nanotechnology is a fast developing science which has various applications in agriculture. Nanoparticles are broadly defined as the small particles with at least one-dimension size between 1 and 100 nm in diameter. Nanomaterials have the potential to penetrate the seed coat and enhance the ability of absorption and utilization of water, which stimulates enzymatic system and ultimately improves germination and seedling growth. The present study was undertaken to investigate the effects of nanoparticles and commercially used chemicals on breaking dormancy of Amorphophallus corms. Methods: Silver (Ag), zinc oxide (ZnO), titanium dioxide (TiO2 ), cerium oxide (CeO) and zero valent iron (ZVI) nanoparticles were synthesized successfully using chemical method and characterized for its size, shape and properties using Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Particle Size Analyzer (PSA) and Raman spectroscopy. Freshly harvested corms of Amorphophallus were treated with different concentrations (50 and 100 mg kg-1) of these five nanoparticles and commercially used chemicals viz., thiourea (100 and 200 mg kg-1) and potassium nitrate (1000 and 2000 mg kg-1), with three different soaking periods (2, 4 and 6 h). Result: The analysed data indicated that corms treated with ZnO @ 100 mg kg-1 for six hours registered the minimum number of days (47.0 days) for sprout emergence. The maximum sprout length (23.50 cm), sprout diameter (6.35 cm), pseudo stem length (31.00 cm), pseudo stem girth (7.35 cm) and vigour index (1591.7) were recorded in TiO2 @ 50 mg kg-1 for two hours. [ABSTRACT FROM AUTHOR]

This study is aimed to synthesize zinc oxide nanoparticles (ZnO NPs) from Aloe barbadensis Miller leaf extract using the green synthesis method at room temperature. The biosynthesized NPs are characterized by X‐ray diffraction (XRD), UV–vis spectroscopy (UV–vis), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscope (SEM). The XRD pattern has revealed the hexagonal wurtzite structure with a crystallite size of 16 nm for synthesized ZnO NPs. The FTIR results display the formation of ZnO NPs and the presence of other functional groups. The UV–vis absorption spectrum shows an absorption band at 347 nm and the value of the bandgap is found to be 3.75 eV. The surface morphology of synthesized NPs is visualized by SEM images, it is observed that most of the NPs are needle in shape. Further, these NPs will find applications in biosensing and photocatalytic activity. [ABSTRACT FROM AUTHOR]

This study proposed a nonenzymatic sensor for lactic acid detection based on copper doped zinc oxide (CZO) modified by graphitic carbon nitride (g-C3N4) and iron–platinum nanoparticles (FePt NPs). The silver paste electrodes of the sensor were prepared using screen printing technology, and the CZO sensing film was deposited using radio frequency (R.F.) sputtering system. The g-C3N4 nanosheet solution was prepared through liquid exfoliating of the g-C3N4 in water. The sensing film was modified by adding different contents of the FePt NPs in g-C3N4 solution. The various concentrations of the FePt NPs were 0.03, 0.1, and 0.3 wt%. The ${V}$ – ${T}$ measurement system was applied to investigate the sensing characteristics of the lactic acid sensors based on CZO sensing film modified by g-C3N4 and FePt NPs. The surface morphology of the sensor was analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD), and dynamic light scattering (DLS). In this work, the 0.1 wt% FePt NPs-g-C3N4 lactic acid sensor has the best sensitivity, linearity, response time, and the limit of detection (LOD). [ABSTRACT FROM AUTHOR]

Current research work focuses on the effects of zinc oxide nanoparticles (ZnONPs) on drought-sensitive wheat variety (Faisalabad-2008) under two experimental conditions (normal irrigation and drought conditions). ZnONPs were prepared by utilizing water extract of black pepper. The formation of nanoparticles was confirmed by UV-VIS spectrophotometer, particle size analyzer, and Scanning Electron Microscope (SEM). To screen the optimum concentration of ZnONPs, a range of doses (10-2000 mg L-1) was applied to wheat seeds. Results indicated that ZnONPs (250 mg L-1) improved germination. This concentration was selected for further studies with two control treatments i.e., negative control (water) and positive control (ZnSO4 salt 250 mg L-1). ZnONPs treatment (250 mg L-1) improved germination (26.82%), shoot length (7.4%), root length (36%), fresh weight (28.6%), and dry weight (26.6%). Treatment of wheat plants with ZnONPs during drought stress increased germination percentage, root length, fresh & dry weight by 53.33, 40, 50, and 28.6 % respectively. Moreover, studies showed that chlorophyll, carotenoids and phenolic content were also increased by ZnONPs treatment by 57.4, 77.27, and 25% respectively as compared to control. Malondialdehyde content was significantly lower in nanoparticles treated plants as compared to Zn salt-treated plants. Zn content of seeds was also significantly higher for ZnONPs treated plants. It suggests the potential of ZnONPs designed by the green method as a nano fertilizer in ameliorating drought stress conditions. [ABSTRACT FROM AUTHOR]

Green synthesis of zinc oxide nanoparticles (ZnO NPs) through simple, rapid, eco-friendly and an economical method with a new haloalkaliphilic bacterial strain (Alkalibacillus sp. W7) was investigated. Response surface methodology (RSM) based on Box-Behnken design (BP) was used to optimize the process parameters (ZnSO4.7H2O concentration, temperature, and pH) affecting the size of Alkalibacillus-ZnO NPs (Alk-ZnO NPs). The synthesized nanoparticles were characterized using UV–visible spectrum, X-ray diffraction (XRD), Scanning electron microscope-energy dispersive X-ray spectroscopy (SEM–EDX), Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and Zeta potential. The UV–Vis spectrum of ZnO NPs revealed a characteristic surface plasmon resonance (SPR) peak at 310 nm. XRD pattern confirmed the hexagonal wurtzite structure of highly pure with a crystallite size 19.5 nm. TEM proved the quasi-spherical shape nanoparticles of size ranging from 1 to 30 nm. SEM–EDX showed spherical shaped and displayed a maximum elemental distribution of zinc and oxygen. FTIR provided an evidence that the biofunctional groups of metabolites in Alkalibacillus sp.W7 supernatant acted as viable reducing, capping and stabilizing agents. [ABSTRACT FROM AUTHOR]

ZnO/ZrO2 samples were obtained by impregnation ZnO on three different ZrO2 polymorphic phases: monoclinic, tetrahedral and amorphous. The catalysts were tested for CO2 hydrogenation to methanol and the structure was determined using nitrogen physisorption, scanning electron microscope (SEM), Fourier transform infrared (FT‐IR) pyridine adsorption, hydrogen temperature‐programmed desorption (H2‐TPD), CO2‐TPD and X‐ray photoelectron spectroscopy (XPS). The results showed that the ZnO/tm‐ZrO2‐500 catalyst, with a mixture of both tetrahedral and monoclinic ZrO2 phases, had the highest CH3OH yield among all the samples. The yield of methanol is correlated to the lattice oxygen content for all the catalysts. During the reaction, formate and methoxy species seemed to be the active intermediate species. [ABSTRACT FROM AUTHOR]

An azo complex was prepared from the reaction of Zn(II) with the ligand 8-[(4-hydroxyphenyl) azo] guanine. A reaction with Zn(II) gave a new complex Bis(8-[(4-hydroxyphenyl) azo] guanine) zinc (II) chloride at pH = 8. Spectrophotometry of the prepared complex was performed using UV-Visible and infrared spectra and micro-elemental analysis. Zinc oxide nanoparticles were then prepared from the prepared complex by thermal decomposition method. The nano particles characteristic to know its structural properties was conducted by using a scanning electron microscope, atomic force microscopy and X-ray diffraction. The biological activity of the azo-zinc complex and the zinc oxide nanoparticles was studied against E. coli, Ps. aeruginosa and S. aureus. The iso-zinc oxide nanocomplex was more effective than the iso-zinc complex against these genera of bacteria. [ABSTRACT FROM AUTHOR]

A well-organized, simplistic, and green route of chitin-glucan based zinc oxide nanoparticles (ChGC@ZnONPs) was synthesized using reducing and capping agent both in one as chitin-glucan complex (ChGC). Herein we report the bio-synthesis of Cur-ChGC@ZnONPs by the conjugation of curcumin (Cur) with ChGC@ZnONPs for the improvement of antioxidant and antibacterial activity. The synthesized nanoparticles were characterized by the UV–Visible (UV–Vis), particle size analyser, scanning electron microscope (SEM) with Energy-dispersive X-ray spectroscopy (EDX), Transmission electron microscope (TEM), X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR). Structure analysis, shape and crystalline size of nanomaterials were confirmed by scanning electron microscopy (SEM) and Transmission Electron Microscopy (TEM). The particle size analyser showed the particle size of nanomaterials and stability. Crystalline nature of both ChGC@ZnONPs and Cur-ChGC@ZnONPs were confirmed by the XRD spectra and FT-IR spectrum was used to examine the functional groups of nanomaterials. The antioxidant potential of conjugated nanomaterials were estimated using a DPPH free radical scavenging assay and ABTS+⁎ assay. This analysis showed that after loading of Cur, antioxidant activity increases. The antibacterial assessment of conjugated nanomaterials were tested by different microorganisms and showed excellent antibacterial activity. [ABSTRACT FROM AUTHOR]

Infection and inflammation during wearing contact lenses are the problems for the users of daily soft contact lenses. All Gram-positive bacteria, Gram-negative bacteria, and fungi play a role in this problem. In past decades, nanoparticles have largely been studied and shown good antimicrobial activity against various microorganisms. The present study aimed to prepare, characterize, and evaluate zinc oxide nanoparticles (ZNPs) as antimicrobial agents against different microorganisms. The ZNPs were synthesized in a special structure using the sol-gel process and characterized by XRD, TEM, and EDX. Antimicrobial properties of ZNPs suspension were investigated against different microorganisms (i.e., Staphylococcus aureus, Staphylococcus epidermidis, Listeria monocytogenes, Bacillus subtilis, Pseudomonas aeruginosa, Salmonella typhi, Escherichia coli, and Candida albicans) by the Scanning Electron Microscopy of lens surfaces and pour plate method of immersed lens suspension for microbial enumeration. The XRD, TEM, and EDX spectrum showed hexagonal structure and no impurity in the nanoparticles with a size of about 20 to 40 nanometers. Sterilized suspension of ZNPs was applied against bacterial species, and the results indicated 4 logarithms (CFU/mL) microbial growth reduction for most Gram-positive and Gram-negative species, except for Pseudomonas aeruginosa that showed 3.5 logarithms (CFU/mL) growth reduction. Furthermore, 1 and 1.7 logarithms (CFU/mL) growth reduction were observed for Candida albicans, applying 250 and 500 ppm ZNPs suspension, respectively, which is an acceptable result for fungal growth inhibition. Findings of this study indicated that the suspensions of ZNPs with 250 and 500 ppm showed acceptable bacteriostatic and bactericidal effects. In vitro antimicrobial activity showed that the suspension of ZNPs with 250 ppm concentration could effectively cause a proper reduction and inhibition in the growth of both Gram-positive and Gram-negative microorganisms. Therefore, the results revealed the efficacy of the antibacterial properties of synthesized ZNPs suspension in aqueous media. ZNPs: Zinc oxide nanoparticles; XRD: X-ray diffraction; FWHM: Full width at half maximum; TEM: Transmission electron microscope; SEM: Scanning electron microscope; EDX: Energy-dispersive X-ray spectroscopy; S. aureus: Staphylococcus aureus; S. epidermidis: Staphylococcus epidermidis; L. monocytogenes: Listeria monocytogenes; B. subtilis: Bacillus subtilis; P. aeruginosa: Pseudomonas aeruginosa; S. typhi: Salmonella typhi; E. coli: Escherichia coli; C. albicans: Candida albicans; MK: Microbial keratitis; CLARE: Contact lens-induced acute red eye; CLPU: Contact lens-induced peripheral ulceration; IK: Infiltrative keratitis; AIK: Asymptomatic infiltrative keratitis; MIC: Minimum inhibitory concentration; MBC: Minimum bactericidal concentration; BHI: Brain heart infusion; TSB: Tryptic soy broth; BHIA: Brain heart infusion agar; TSA: Tryptone soya agar. [ABSTRACT FROM AUTHOR]

This work is a critical preventive study for providing a healthy life and enhancing people's safety at work in which introduces of highly efficient and durable UV-protection and antibacterial textiles. With this aim, ZnO nanoparticles are in situ synthesized on the modified cotton fabric to produce the multifunctional fabrics. Herein, the cotton fabric is oxidized by periodate and then treated by 4-aminobenzoic acid ligand (PABA). The modified cotton fabrics are characterized via X-ray powder diffraction, Fourier-transform infrared spectroscopy-attenuated total reflectance, scanning electron microscope, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Moreover, the anti-bacterial, UV-protection, hydrophilicity, and mechanical properties of samples are investigated. The results show that pre-oxidization cotton fabric provides better active sites for the treatment with PABA. Then, PABA treatment provides significant sites for the growth of the ZnO nanoparticles and maintains cross-linking property between oxidized cellulosic fibers and the ZnO nanoparticles which improves the formation and durability of ZnO nanoparticles. The simultaneous sample treatment with ZnO and PABA had synergistic effects on UV protection, stability, and mechanical properties. Moreover, the ZnO PABA oxidized cotton fabrics show excellent UV-protection and significant antibacterial efficacy after 20 washing cycles and 100 abrasion cycles, which can be used in advanced protective textiles. [ABSTRACT FROM AUTHOR]

Co/B co-doped ZnO (Zn 0.93-x Co x B 0.07 O, x = 0.00, 0.01, 0.02, 0.03, 0.04, and 0.05) nanoparticles were synthesized by the hydrothermal method to investigate the effect of cobalt and boron on the structural, microstructural, and optoelectronic properties of ZnO nanoparticles. The X-ray diffraction method was used for the structural analysis and single phases were found for all Co/B co-doped ZnO nanoparticles. Scanning Electron Microscope (SEM) technique was used to determine the surface morphology, particle size, and the shapes of the nanoparticles. The elemental compositions of the nanoparticles were obtained by electron dispersive spectroscopy (EDS). Hexagonal Wurtzite structure was proved by c/a ratios of the ZnCoBO nanoparticles. The Fourier transform infrared (FTIR) studies were performed and explained. The energy band gaps of the samples were calculated and the effects of dopant elements on optical properties were discussed. The maximum band gap occurred for Zn 0.93 B 0.07 O with a band gap energy of E g = 3.26 eV. The refractive index was calculated using the energy band gap with five different models. The grain sizes and the band gap energies fluctuated as the doping ratio increased. The results showed that the refractive index strongly depends on the Co concentration nonlinearly. It was found that doping cobalt increased the Urbach energy value of B-doped ZnO nanoparticles. The increase in E u indicates that the structural disorder and the number of defects in the Zn 0.93-x Co x B 0.07 O structures increased with increasing concentration of Co in the Zn 0.93-x Co x B 0.07 O structures. The highest value of Urbach energy was approximately found in the range of 1259 and 1469 meV for 3% Co. Moreover, for 3% Co the concentration-dependent microstrain (Ɛ) values also reached the maximum, dislocation density δ had also the maximum value. [ABSTRACT FROM AUTHOR]

In this work, atypical zinc oxide nanorods (ZnO NRs) on quartz substrates were successfully synthesized using simple, low-cost, and environmentally friendly hydrothermal method. The ZnO NRs were grown on a pre-seeded seed layer of ZnO nanocrystals using the spin coating process. Gold nanoparticles (Au NPs) were sputtered on the ZnO NRs film. The structure and morphology of the produced nanostructures were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The XRD analysis revealed that the ZnO NRs were single crystalline with hexagonal wurtzite structure grown with preferred orientation of (002). The SEM morphology shows a semi-hierarchical ZnO NRs with an estimated diameter of 200–400 nm and length of 4–5 μm. The optical properties of the ZnO NRs film were investigated using UV-visible spectrophotometers. The obtained bandgap of ZnO film was 3.0 eV. Electrical and thermal properties were also measured. The resistance changes versus temperature variation of ZnO NRs were given a semiconductor behavior. The gas sensor was fabricated based on bare ZnO NRs and Au NPs/ZnO NRs hybrid. The second nanostructure exhibited an enhanced sensor sensitivity toward ethanol gas at an optimized working temperature of 325 °C. [ABSTRACT FROM AUTHOR]

A rapid breakdown anodization process was used to fabricate a ZnO sensor for sensing pressure, humidity and vapors. The X-ray diffraction technique confirmed that this electrochemical process transformed Zn metal to its oxide ZnO. Scanning electron microscope images showed that semispherical ZnO nanoparticles were formed with sizes ranging from 10 to 20 nm. These nanoparticles were deposited on Zn substrates using an electrophoretic deposition method. After deposition, ZnO nanoparticles aggregated and formed large continuous bodies. Atomic force microscopy images showed the vertical growth of ZnO nanoparticles and confirmed the existence of porosity among these particles. Sensing parameters of ZnO to pressure were 0.3417 MΩ/bar for average sensitivity and 1.01 MΩ.bar for hysteresis area. Resistance of ZnO varied exponentially with relative humidity (RH%), and its average humidity sensitivities were 52% (from 20 to 50 RH%) and 95% (from 50 to 90 RH%). The sensing responses to ammonia, ethanol and methanol vapors were recorded using three concentrations (5,10,20 ppm). The sensitivity of the ZnO sensor was greater for methanol, while selectivity was better for ammonia. [ABSTRACT FROM AUTHOR]

The influence of different calcination temperatures on the molecular structure, optical, morphological and antimicrobial activity were investigated for Zinc Oxide nanoparticles (ZnO NPs) synthesized using green sol-gel method. The prepared ZnO NPs are calcined at 70 °C, 300 °C, 400 °C and 800 °C. The effect of different calcinations temperature on the characterization of the prepared samples were studied using X-ray Diffraction (XRD), High Resolution Transmission Electron Microscope (HRTEM), High Resolution Scanning Electron Microscope (HRSEM), Fourier Transform Infrared (FT-IR), and Ultraviolet–Visible Spectroscopy (UV–Vis). In addition, the potential antimicrobial activity of ZnO NPs were investigated against four different pathogenic bacterial strains: two strain of gram negative bacteria (Pseudomonas Aeruginosa and Klebsiella Pneumonia) and two strain of gram positive bacteria (Bacillus subtilis and Staphylococcus Aureus). The results showed that XRD, UV–Visible and FT-IR confirmed the presence of ZnO nanoparticles. HRTEM and HRSEM reveal that as the temperature increase the size of prepared sample increased and the agglomeration increases. The best size of rod shape ZnO NPs found at 300 and 400 °C. Zinc oxide NPs prepared at 300 °C calcination temperature have the superior antibacterial effect on the gram positive and gram-negative pathogenic bacteria. Image 10946 • Synthesized ZnO NPs by the Sol-Gel method with different calcination temperatures. • As the temperature increased both the size and agglomeration increases. • HRSEM and HRTEM showed the best size of rod shape ZnO NPs found at 300 and 400 °C. • ZnO NPs at 300 °C have the superior antibacterial effect on pathogenic bacteria. [ABSTRACT FROM AUTHOR]

Submicrometer spherical particles (SMSPs) are reported to be fabricated by pulsed laser irradiation with a frequency of 10 or 30 Hz onto raw nanoparticles dispersed in liquid. Here, the effect of the pulse frequency on particles obtained by laser irradiation onto the suspension in a vessel, especially at higher pulse frequencies up to 800 Hz, is investigated. At 200 Hz or lower, SMSPs of similar size can be fabricated, as at 10 or 30 Hz, by the same number of pulses. This indicates that the time required for particle fabrication can be greatly reduced and production efficiency can be improved using a high-frequency laser. In contrast, at 400 Hz or above, nanospherical particles (NSPs) are formed in addition to SMSPs, and the mass fraction of SMSPs is drastically decreased. This result suggests that consecutive laser pulse irradiation induces heat accumulation in particles and suspensions, resulting in a temperature increase and partial evaporation of the particles at 400 Hz or above. From the temperature increase of the suspension, the local temperature of the liquid surrounding the particles is believed to be increased by heat dissipation from the heated particles. Calculations suggest that an increase in the local liquid temperature would cause further heating of the particles. [ABSTRACT FROM AUTHOR]

This article deals with the synthesis and characterization of undoped and zinc doped nickel oxide nanoparticles. Prepared nanopowders have been characterized by x-ray diffraction method, high resolution scanning electron microscope, ultraviolet visible spectrometer, photoluminescence spectrometer, Fourier transform infrared spectrometer, impedance meter and thermal gravimetric analyzer. X - ray diffraction study confirmed the average crystallite sizes of the nanopowders are less than 20 nm. Ultraviolet-visible spectrometer recorded the absorption peaks between 336 - 346 nm, corresponds the energy gap of 3.70 - 3.58 eV. Photoluminescence spectrum confirms the near band edge emission. Fourier transform infrared spectroscopy analysis established the formation of the nickel oxide and the doping of zinc. The high resolution scanning electron microscope image depicts that the particles are uniform in size and they are in severe agglomeration. The dielectric studies recognized the decrease in dielectric losses with increasing the temperature as well as frequency. Thermo gravimetric study shows that the prepared samples have good stability. [ABSTRACT FROM AUTHOR]

The effect of time and pH on ZnO nanoparticles were observed as prepared via microwave-assisted approach. Zinc acetate dihydrate Zn (CH3COO)2.2H2O used as precursor and 2 Propanol as solvent, NaOH was used as pH controller. ZnO nanoparticles (band gap 3.91 ev) of size within the range 50 nm to 80 nm were obtained by controlling the pH (6-8). Characterization techniques of synthesized samples were investigated by Xray diffraction (XRD), UV Visible spectroscopy, Raman spectroscopy, scanning electron microscope (SEM). Porous structure of ZnO nanoparticles was clearly observed with agglomeration. Above-mentioned variables, influenced the shape and size of prepared nanoparticles prominently. Briefly, the microwave irradiation technique with pH control was highlighted as quick, cheap and single step approach to control the morphology of semiconductor nanoparticles in present work. [ABSTRACT FROM AUTHOR]

Nanoparticles of Europium oxide doped with Zinc oxide were synthesized via microwave-assisted combustion method. Citric acid as a simultaneous fuel and chelating agent and glycine as a fuel and mixture of these fuels were sleeted. X-Ray diffraction patterns (XRD) indicated the formation of ZnO structure with a few amount of Eu2O3 phase. Fourier transformation infra red (FTIR) spectra reveal the increase of ZnO4 bonds with glycine content of fuels mixture. Scanning electron microscope (SEM) images showed the conversion of nanosphere to spongy-like structure with respect to change of fuel mixtures from citric to glycine. From transmission electron microscopy (TEM) nanoparticles of a mean size 30 nm are observed Green fluorescence emission of different samples was due to activation of self activated center of ZnO structure through transition of electron from Eu3+ to Vzn sites. [ABSTRACT FROM AUTHOR]

The present study deals with synthesis of titanium doped zinc oxide (Ti:ZnO) nanoparticles (NP) using solid state reaction and subjected to vacuum annealing. The Ti doped ZnO nanoparticles were prepared at different titanium concentrations (Ti = 0%,1%, 3%, 5% & 7%) and studied the role of Ti on physical properties of the Ti:ZnO nanoparticles. The prepared titanium doped zinc oxide nanoparticles were subjected to various characterization techniques such as X-ray diffractometer (XRD), UV–Vis-spectrophotometer (UV–Vis–NIR), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and Keithley source meter to study the structural, optical, surface, spectroscopic, elemental and electrical properties, respectively. From the XRD studies, it was found that the Ti:ZnO NP were in hexagonal structure with average crystallite size of 39 nm. The SEM images confirms the formation of the clusters in spherical shape. The EDAX spectrum confirms the presence of the host (Zn & O) and dopant (Ti) elements in the synthesized nanoparticles. The functional groups were confirmed from FT-IR spectrum. The valence states of the elements such as Ti, Zn and O were studied and found as Ti+3, Zn+2 and O−2. The electrical properties of the bulk Ti:ZnO NP were studied using Keithley source meter. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide (RGO) sheets decorated by ZnO nanoparticles were synthesized using wet impregnation method. The composite material was characterized by means of X-ray diffraction (XRD), Williamson-Hall Plot (W-H Plot) and Scanning Electron Microscope (SEM) analysis. The XRD pattern revealed orderly hexagonal (wurtzite) structure of the ZnO nanoparticles. Surface morphology of ZnO, RGO and RGO-ZnO was investigated using SEM analysis. SEM images indicated the uniform distribution of ZnO onto the RGO surface. The photocatalytic activity of nanocomposite was demonstrated by determining the degradation of methylene blue dye. The degradation of dye took place due to efficient electron-hole recombination of photo-induced electrons. Finally, plausible mechanism was explained with the help of scavengers. Overall, wet impregnation method was found efficient to produce RGO with uniform ZnO loading. The prepared RGO-ZnO composite can efficiently degrade the dye under UV radiation. [ABSTRACT FROM AUTHOR]

The pure and Zn-doped SnO 2 nanoparticles were prepared successfully by hydrothermal route on large scale having different doping concentration of zinc from 0 to 0.20%. The calcined nanoparticles were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) for structural and morphological studies. XRD analyses reveal that the nanoparticles of these doping concentrations are polycrystalline in nature and existed as tetragonal rutile structure, SEM study of images confirms the existence of very small, homogeneously distributed, and spherical nanoparticles. The particles size of the nanoparticles was calculated by Scherrer formula and was found in the range of 9–21 nm. The presence of dopant (i.e. zinc) and formation of Sn–O phase and hydrous nature of Zn-doped SnO 2 nanoparticles are confirmed by EDX and FTIR study. The gas sensing properties of pure and Zn-doped SnO 2 nanoparticles were investigated for various concentrations of methanol, ethanol and acetone at different operating temperatures and it has been found that with doping concentration of zinc (x = 0.20%) shows the maximum response 78% to methanol, 65% to ethanol and 62% to acetone respectively at different operating temperature within the measurement limit for a concentration of 100 ppm of each gases. [ABSTRACT FROM AUTHOR]

Purpose: The aim of the paper was to investigate the antifungal activity of zinc oxide nanoparticles (ZnONPs) against Candida albicans. Some attempts have been made to find out the best way to introduce ZnONPs into polymethyl methacrylate (PMMA) resin material and to determine some parameters of a newly formed composite. Material and methods: Zinc oxide nanoparticles were manufactured and their basic physical parameters were determined (average particle size, density, specific surface area). Minimal inhibitory concentration (MIC) of ZnONPs was determined for the Candida albicans standard strain. The average size of ZnO conglomerates in the monomer solution of PMMA resin was measured using a dynamic light scattering instrument. PMMA resin samples with incorporated ZnONPs were produced. The morphology of nanopowder and the newly formed composite was examined under a scanning electron microscope (SEM). In addition, the roughness parameter of PMMA resin material was investigated before and after ZnONPs modification. Results: Nanopowder with the average particle size of 30 nm, density of 5.24 g/cm³ and surface area of 39 m²/g was obtained. MIC was determined at the level of 0.75 mg/mL. The average size of ZnO conglomerates in the monomer solution of acrylic resin dropped by 11 times after ultrasound activation. SEM examination of a newly formed composite showed a successful introduction of ZnONPs confirmed by the energy dispersive X-ray spectroscopy (EDS) analysis. There were no statistically significant differences in the biomaterial roughness before and after the modification of ZnONPs. Conclusion: Zinc oxide nanoparticles were successfully incorporated into acrylic resin used for the production of denture bases. The presence of nanoparticles with sizes below 100 nm was confirmed. Nevertheless a newly created composite needs to be further investigated to improve its homogeneity, and to check its microbiological properties, strength and biocompatibility prior to its possible clinical use. [ABSTRACT FROM AUTHOR]

Abstract: Al, La doped ZnO nano particles were prepared through sol–gel method. The prepared ZnO: (Al, La) was coated on cotton fabric, forming a thin film to reduce infrared emissivity of the cotton fabric. Effects of Al contents on microstructure, infrared emissivity and infrared stealth of ZnO: (Al, La) coated fabrics were investigated by XRD, SEM, ICP, IR_2 dual-band emissivity measuring instrument and the infrared camera instrument. The addition of Al and La was favorable for providing more free electrons, improving scattering of infrared photon, and decreasing the infrared emissivity of ZnO: (Al, La) coated fabric in the range of 8–14 μm wavelengths. The hand covered by the coated fabric gave as low thermal radiation as the environment. [Copyright &y& Elsevier]

This study has been carried out to synthesize nano ZnO on wool fabric and also to investigate influences of nano photo reactors on wool fabric characteristics. Zinc acetate has been used as a precursor and the synthesis process has been done in water and water/ethanol media. The treated wool fabrics were heated at 80°C for 10 h to dehydrate Zn(OH)2 obtaining ZnO. The fabric samples were then subjected to daylight for 7 days to examine the influence of nano ZnO photo reactor on the fabric properties. SEM images revealed the embedding of ZnO nanoparticles on the fabrics and X-ray diffraction verified the nanoparticles composition. The Yellowness Index ( YI) of the fabrics was measured with Color Eye XTH that has been reduced with increasing pH, Zn(CH3COO)2 concentration, ethanol and heating. The lower water contact angle and time of water absorption confirmed higher hydrophilic properties of the treated fabrics. Interestingly, a higher tensile strength obtained on the wool fabrics proved the interaction of ZnO with protein chains of wool, which was verified through lower alkali solubility of treated fabric with nano ZnO and confirmed more benefits of the in situ synthesis process. [ABSTRACT FROM AUTHOR]

In this work, effects of ZnO on response and selectivity of SnO2-based sensors for selective detection of C2H5OH and CO in the presence of CH4 are studied. ZnO-doped SnO2 fibers were synthesized by electrospinning method using SnCl4·5H2O and Zn(CH3COO)2·2H2O as precursors and poly vinyl alcohol (PVA) in distilled water as the polymer solution. The ZnO content and tip-to-collector distance were varied in the range of 0.5–5wt% and 10–20cm, respectively. The electrospun samples were dried at 80°C, calcined at 600°C, and characterized by SEM, XRD and BET. Diameters of the fibers are in the range of 200–650nm. The highest BET surface area of 41m2/g, corresponding to nanoparticle sizes of 21nm, is obtained for 1.0wt% ZnO-doped SnO2. The sensors responses were measured in presence of 300ppm of CO or ethanol and 5000ppm methane in air at 200–400°C in a flow system. 1.0wt% ZnO-doped SnO2 selectively detects both CO and ethanol in presence of methane with the highest responses, while 0.5wt% one has the highest response to methane. Also the highest surface area of 46m2/g and sensor response is obtained for SnO2 fibers electrospun at 20cm tip-to-collector distance. [ABSTRACT FROM AUTHOR]

Abstract: In this report, ZnO nanoparticles embedded cellulose acetate (CA) fibrous membrane with multifunctional properties have been prepared through electrospinning method. The morphology of the electrospun composite membrane was analyzed by Scanning Electron Microscope (SEM). It was found that the polymer concentration in the solution has a significant effect on the morphology of the fibers. The optical property of the sample was tested using Photo Luminescence (PL) spectra. There is no significant change in the emission features of cellulose acetate with the addition of ZnO. The anti-bacterial property of the sample was studied using disc diffusion method. The wettability of the pure and composite fibrous membrane was also studied by measuring the contact angle of water on the membrane. It was observed that the embedded ZnO in the CA was responsible for the hydrophobic nature of the surface. [Copyright &y& Elsevier]

Zinc Oxide (ZnO) nanoparticles have been synthesized by precipitation method using different precursors, under different conditions. ZnO nanoparticles were characterized by surface analytical methods such as x-ray diffraction (XRD), scanning electron microscope (SEM) and ultraviolet-visible spectroscopy. The XRD patterns of different ZnO nanoparticles suggest that the synthesized ZnO crystallites have hexagonal wurtzite structure. Variations in several parameters during synthesis process and their effects on crystallite size, morphology and photocatalytic activity of ZnO nanoparticles were investigated. The photocatalytic activity of ZnO nanoparticles was tested by photocatalytic removal of C.I. Acid Red 27 (AR27) as a model contaminant from monoazo textile dyes. Results show that photocatalytic activity of ZnO nanoparticles is very sensitive to precursors and synthesis process conditions. [ABSTRACT FROM AUTHOR]

The effect of copper oxide and zinc oxide nanoparticles (NPs) on the mechanical and thermal properties of ground waste concrete inorganic polymers (GWC IPs) has been investigated. NPs are added to GWC IPs at loadings of 0.1, 0.5, 1, and 2% w/w. The phase composition and microstructure of NPs GWC IPs have also been examined using X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscope (SEM/EDS) techniques. Results show that the mechanical properties of GWC IPs are improved (23 MPa) due to addition of NPs (1% ZnO). In particular, GWC IPs embedded with 0.5% CuO and 1% ZnO NPs exhibited relatively improved compressive strength. The addition of NPs decreases the macroporosity and increases the mesoporosity of IPs matrix and decreases relatively the ability of IPs matrix to water absorption. The antimicrobial activity of GWC IPs doped with 0.5 and 1% CuO NPs against E. coli was also determined. [ABSTRACT FROM AUTHOR]

Zinc oxide (ZnO) nanowires have attracted great interest in nanodevices. In this work, the tribological characteristics of vertically grown ZnO nanowires obtained by metalorganic chemical vapor deposition were investigated by using an atomic force microscope (AFM). The ZnO nanowires were slid against flattened silicon and diamond-coated AFM probes under 50–150 nN normal force while monitoring the frictional force. The wear of the ZnO nanowires was observed by a scanning electron microscope and quantified based on Archard’s wear law. Also, the wear debris accumulated on the silicon probe was analyzed by using a transmission electron microscope (TEM). The results showed that the wear of ZnO nanowires slid against the silicon probe was extremely small. However, when the ZnO nanowires were slid against the diamond-coated probe, the wear coefficients ranged from 0.006 to 0.162, which correspond to the range of severe wear at the macroscale. It was also shown that the friction coefficient decreased from 0.30 to 0.25 as the sliding cycles increased. From TEM observation, it was found that the ZnO wear debris was mainly amorphous in structure. Also, crystalline ZnO nanoparticles were observed among the wear debris. [ABSTRACT FROM AUTHOR]

Heterostructures with great modulation of electron transfer afford a great opportunity for gas-sensing applications. Herein, a hollow porous ZnO@ZnS core-shell structure with high gas-sensing performance has been successfully hydrothermally synthesized. The phase composition and the morphology of the as-prepared products were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope and energy dispersive X-ray spectroscopy. The results show that the pure ZnO and the ZnO@ZnS appear a mesoporous structure and a hollow porous structure, respectively. Gas-sensing measurements show that the gas-sensing performance of the ZnO@ZnS based sensor is obviously higher than that of the pure ZnO, and it has a high selectivity, quick response-recovery and stability to ethanol. Its response reaches 114.2 to 100 ppm ethanol, and the response and recovery time is 3 s and 8 s to ethanol, respectively. The gas-sensing enhancement of the ZnO@ZnS can be attributed to the Schottky barrier at the interface of the ZnO@ZnS and the special hollow porous structure. The strategy put forward is generally applicable to design efficient ethanol sensors with optimized sensing performances. • A hollow porous ZnO@ZnS Heterostructures have been successfully synthesized. • The ZnO@ZnS sensor shows excellent gas-sensing performance to ethanol. • The gas-sensing mechanism of the hollow porous ZnO@ZnS is discussed in detail. [ABSTRACT FROM AUTHOR]

• The Cr successfully doped on ZnO NPs. • The Cr doped ZnO NPs enhanced the antimicrobial activity against various bacteria and fungi at lowest concentration. • Intracellular damage and morphological alteration was successfully confirmed by Cr doped ZnO NPs treated pathogens. This study was involved to investigate the effect of Cr incorporation on various physic-chemical properties of ZnO nanopowder that including structural, morphological, optical and antibacterial. The synthesized powder reveals wurtzite hexagonal structure with decreased crystallite size from X-ray diffraction analysis. The scanning electron microscope (SEM) result confirmed that the formation of hexagonal shaped particles was observed on Cr doped ZnO nanoparticles. The presence of vibration band in the range of 450–600 cm−1 was confirm, the successful formation of Zn-O bond in bare and Cr doped ZnO nanoparticles. The decreased reflectance and red shift in the UV–vis diffused reflectance spectra was confirmed the decreased band gap energy. The antibacterial investigation of the nanopowder reveals, the higher zone of inhibition, membrane damage and intracellular alterations were observed against K. pneumoniae and C. albicans compared with other microorganisms. Thus, the result was suggested that the Cr doped ZnO nanoparticle as a promising candidate material for the development of new antibiotics against various bacteria. [ABSTRACT FROM AUTHOR]

The structural, morphological, optical and mechanical properties of Zinc oxide (ZnO) nanoparticles annealed at different temperatures from 500 °C to 1000 °C with a step size of 100 °C were synthesized from Sol-Gel method. The X-ray diffraction study revealed that ZnO has hexagonal Wurtzite structure. Scanning Electron Microscope(SEM) images of the studied materials possess spherical morphology with induced porosity due to change in annealing temperature. The computed size of nanoparticles from Transmission Electron Microscopy (TEM) was 21 nm. The UV–Visible Spectroscopy revealed that the band gap decreased with increase of the temperature from 3.05eV to 2.82eV. Photoluminescence (PL) spectrum of ZnO nanoparticles shows that oxygen vacancy related defects increased as the temperature increases from 500 °C to 800 °C and decreased beyond 800 °C. The wear resistance of ZnO nanoparticles is found to increase with increase of temperature owing to the generation of oxygen vacancies. The maximum friction coefficient was assigned to largest grain size. • The computed size of nanoparticles from XRD and Tem was approximately 21 nm. • The UV–Visible Spectroscopy revealed that the band gap decreased from 3.29 eV to 3.24 eV with the increase in temperature. • Photoluminescence(PL) spectrum of ZnO nanoparticles shows oxygen vacancy related defect emissions such as orange and red. • The wear resistance of ZnO nanoparticles is found to increase with increase of temperature due to the reduction in the brittle nature of ZnO which is resulted from the generation of oxygen vacancies. • The higher friction coefficient is due to the large grain size of ZnO nanoparticles. [ABSTRACT FROM AUTHOR]

Mn/Cu co-doped ZnO (Zn 0.99-x Mn x Cu 0.01 O) nanoparticles were synthesized by the solid state reaction method to investigate the relationship between the band gap and the refractive index. The stoichiometry was provided by increasing x values (x = 0.00, 0.01, 0.02, 0.03, 0.04, and 0.05). The X-ray diffraction (XRD) method was utilized for the structural analysis of all Mn/Cu co-doped ZnO nanoparticles. Hexagonal Wurtzite structure was established by making use of the c/a ratios of the ZnMnCuO nanoparticles. Photoluminescence (PL) properties were measured by employing the Agilent Cary Eclipse Fluorescence Spectrophotometer to discover the structural defects. The red emission with its wavelength within the range of 620–750 nm was observed. The red emission centered at 700 nm could be attributed to oxygen vacancy (V o) which was strongly dependent on the Mn concentration. The Fourier Transform Infra-Red (FT-IR) spectra (4000 - 400 cm−1) of the samples were recorded in the By PerkinElmer Spectrum Two FTIR-ATR spectrophotometer. Scanning Electron Microscope (SEM) technique was applied to determine the surface morphology, crystallite size, and the shapes of the nanoparticles. The elemental compositions of the nanoparticles were obtained by Electron Dispersive Spectroscopy (EDAX). The optical properties of the nanoparticles were obtained by using the Shimadzu 2600 Ultraviolet–Visible (UV-VIS) Spectrophotometer. The energy band gaps of the samples were calculated and the effects of dopant elements on optical properties were discussed. The refractive index was calculated by using the five different models. The maximum band gap occurred for Zn 0.97 Mn 0.02 Cu 0.01 O with a band gap energy of E g = 3.28 eV. • Mn/Cu co-doped ZnO nanoparticles were synthesized by the solid state reaction method. • XRD analysis of all Mn/Cu co-doped ZnO nanoparticles show single phase (ZnO). • The PL emissions in the green and red regions were found to be strongly depending on the Mn concentration. • Refractive index (>2) was calculated by using different models accurate within two decimal digits. [ABSTRACT FROM AUTHOR]

Abstract: Formation of ZnO nano-wire by a thermal evaporation method was studied in this work. The ZnO nano-wire has grown from metal Zn granule under O2 environments at high temperature. We investigated the behavior of the ZnO nano-wire growth with the change of oxygen content in carrier gas (N2). Zn granules were placed in an alumina boat. The boat was inserted in a horizontal tube furnace. The furnace temperature was maintained in the range of 700–1000°C for 0.5–2h. The oxygen contents were adjusted from 0.5 to 5vol% by mass flow controller. The as-grown ZnO nano-wires were characterized by scanning electron microscope (SEM). ZnO nano-wire grew only at 1.6–2.0vol% O2 conditions. ZnO nano-wire did not grow when the oxygen content is either 0vol% or higher than 2.5vol%. From these results, it was confirmed that oxygen content in the thermal evaporation method is an important factor for the synthesis of the ZnO nano-wire. [Copyright &y& Elsevier]