Journal of Nano Structures
Volume:10 Issue: 1, Winter 2020

In this research, Ag/ZnO nanocomposites were prepared and characterized by transition electron microscopy (TEM), the energy dispersive X-ray spectrum (EDS) and X-ray diffraction patterns (XRD). These nanocomposites were used as catalysts for the oxidation of toluene to benzaldehyde and benzoic acid with hydrogen peroxide (H2O2) and tert-butylhydroperoxide (TBHP) as oxidizing agent in the liquid phase. For these Ag/ZnO nanocomposites, acetonitrile was used as a solvent, since all the reagents dissolved and show the highest yields. The oxidation products of toluene are benzaldehyde and benzoic acid. The results of this study showed that oxidant and the catalyst type affected the efficiency of toluene oxidation. TBHP was found to be better oxidizing agent than H2O2 since higher efficiency of product were observed when TBHP was used. The catalytic performance of 2.5%Ag/ZnO nanocomposite was better than the 1% and 5%Ag/ZnO nanocomposites. Under the optimal reaction conditions, the catalytic system of 2.5%Ag/ZnO nanocomposite gave about 76.3% efficiency of toluene.

Nanostructured doped As2Ni3O8 samples were synthesized via facile one step solid state reactions at 850 °C for 8 h using As2O3, Ni(NO3)2.6H2O, Gd2O3, Tb2O3 and Ho2O3 raw materials. The synthesized nanomaterials were characterized by powder X-ray diffraction (PXRD) technique. The rietveld analyses showed that the obtained materials were crystallized well in monoclinic crystal structure with the space group P121/c1. The morphology of the synthesized materials was studied by field emission scanning electron microscope (FESEM). Photocatalytic performance of the as-synthesized sample was investigated for the degradation of pollutant Malachite Green (MG) in aqueous solution under direct visible light irradiation. The light source was a white color fluorescent lamp with the 40 W power and light intensity of 1.34 W/m2 measured by a digital lux meter. The distance between the lamp and the surface of the solution was 50 cm. The degradation yield at the optimized condition (0.1 mL H2O2, 60 mg catalyst and 90 min) was 94 % for pure Ni3As2O8.

Plant-mediated synthesis of metal oxide nanoparticles is a promising alternative to the traditional method of physical and chemical synthesis. In this paper, we report the green synthesis of zinc oxide nanoparticles (ZnONPs) by a biological method. During the study, Zinc oxide nanoparticles were synthesized by Allium sativum skin (garlic skin) extract. Formation of zinc oxide nanoparticles has been confirmed by UV-visible spectroscopy, UV diffuse reflectance spectroscopy (UV-DRS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope with Energy dispersive X-ray studies (EDX) and transmission electron microscope (TEM), Atomic force Microscopy (AFM), Brunauer-Emmet-Teller (BET), Thermogravimetric analysis (TGA). UV-vis spectroscopy confirms the synthesis of zinc oxide nanoparticles and showed the characteristic of absorption peak at 370nm. The scanning electron microscope and Transmission electron microscope confirms the formation of the rod and hexagonal shaped nanoparticles having average size 7.77 nm. Energy dispersive X-ray analysis states the formation of highly pure zinc oxide nanoparticles. The zinc oxide nanoparticles synthesized using garlic skin are expected to have applications in biotechnology, biomedical, catalysis, coatings, sensors and water remediation. This green approach for the synthesis is a cheap, novel, eco friendly and convenient method.

Series of Copper Ruthenium (Cu-Ru) bimetallic catalysts supported on γ-Al2O3 with different metal loading are prepared and investigated for catalytic wet air oxidation of ammonia to nitrogen. The ammonia decomposition activity was studied at three different temperatures i.e. 150oC, 200oC, and 230 oC and it is found that catalytic activity increases with the increase in temperature along with the high selectivity towards nitrogen production. The results also revealed that the bimetallic Cu-Ru/ γ-Al2O3 are much more efficient especially stable than the corresponding monometallic Cu and Ru catalysts. Up to 99 % ammonia decomposed to N2 without any undesirable nitrites and nitrates at 230 oC by optimizing catalysts to ammonia ratio. So, it can be considered as a potential method to remove a large amount of ammonia from wastewater. Furthermore, the catalysts characterization results strongly suggested that there is a strong relationship between catalytic activity and Ru and Cu contents in bimetallic catalysts. The presences of both metals (Cu and Ru) affect the reactivity and coverage of oxygen species, as well as protecting each other from leaching. The combination of all effects including the strong interaction between metals, synergistic effect, proper oxygen coverage and resistance against leaching could be attributed to the enhancement of the catalytic activity of Cu-Ru/ γ-Al2O3 catalyst.

Superparamagnetic few-layer graphene nanocomposites (FLG- NCs) can be used for many technological applications, such as solar cells, batteries, touch panels and supercapacitors. In this work, we applied electrochemical exfoliation method as a simple, one step and economical technique to fabricate FLG- NCs. The fabricated Superparamagnetic FLG- NCs were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), field emission scanning electron microscope (FESEM), energy dispersive spectroscopy (EDS) and vibrating sample magnetometer (VSM). Analysis of XRD pattern shows the formation of graphene iron oxide nanocomposites due to the existence of magnetite (Fe3O4) and graphite picks. Hysteresis curve of the sample represents superparamagnetic effect with saturation magnetization, MS=57.3 emu. g-1. The results of XRD and VSM indicate that the size of ferromagnetic particles reduced to critical size to form into superparamagnetic. FLG- Fe3O4 with high saturation magnetization is very useful in hyperthermia, drug delivery, supercapacitors, removal dye, etc.

In the present work, we demonstrate a facile way to study the biosynthesis of silver nanoparticles (Ag-NPs) with strong bactericidal properties using an aqueous extract of Scrophularia striata Boiss. The bio-reduction of Ag+ ions resulted in FCC cubic structures of Ag-NPs with spherical shapes of about 16 nm. As a main aim of the present work, the antibacterial activity of the bio-synthesized Ag-NPs against Gram-negative (Escherichia coli and Salmonella typhi ATCC) and Gram-positive (Staphylococcus aureus and Bacillus cereus) bacteria was evaluated by disk diffusion method and results were compared with those of ciprofloxacin antibiotic. Interestingly the antibacterial activity of as-prepared Ag-NPs against all pathogenic bacteria was considerably higher than those obtained for Ciprofloxacin, and also better than the recent reports on the bactericidal activity of bio-synthesized Ag-NPs. As a simple, cost-effective and biocompatible method, the present work proposes a facile way toward bio-synthesis of large-scale Ag-NPs with an excellent antibacterial activity which can be suitable for future biological applications.

the Sol–gel nanocomposite coatings have been investigated for copper metal as a potential replacement for the hazardous and banned hexavalent chromate conversion coatings. TiO2–CdO nanocomposite thin films were deposited on copper using the sol–gel method. The sol-gel coatings were prepared using a sol obtained by the hydrolysis and condensation of tetra-o-butyl titanate. They were doped with cadmium oxide inhibitor to provide active corrosion protection. The synthesized coatings were characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM). The anticorrosion performances of TiO2-CdO nanocomposite coatings were investigated in 3.5% NaCl solution by the potentiodynamic polarization technique Tafle and electrochemical impedance spectroscopy (EIS). The potential corrosion increases from -210 mV versus Ag/AgCl (3M) for uncoated copper to -202 mV versus Ag/AgCl (3M) for TiO2-CdO nanocomposite-coated copper electrodes. The results of this study clearly ascertain that the TiO2-CdO nanocomposite has outstanding potential to protect the copper against corrosion in a chloride environment..

The lack of a high-yield, renewable and low-cost synthesis method limits the potential applications of boron nitride with impressive characterizations. In this study, a facile method is developed for the preparation of chemically functionalized boron nitride nanosheets (BNNSs) by considering the quantity and quality of chemical materials involved in the synthesis process. The proposed green method is a suitable and high-efficiency method for replacing other production methods of BNNSs. Ultrathin BNNSs is produced by chemical reactions and subsequent liquid exfoliation. The possibility of chemical reaction is the highest at the defect sites especially at the upper/lower surfaces as well as the edge of bulk material. Due to hydroxyl functional groups that are coupled to the surface during the synthesis, the obtained products can well be dispersed in polar solutions such as water, ethanol, acetone and isopropyl alcohol. AFM, TEM, and SEM techniques are utilized to confirm the quality of the used method and illustrated that the produced-BNNSs have minimum thicknesses in the range of 1–5.6 nm and with lateral sizes ranging from 0.8–2.5 μm. The existence of functional groups and the structure of the BNNSs are verified by FTIR, EDX, XPS, XRD and Raman analyses. It was seen that the hexagonal structure was retained during the functionalization procedure. One can expect that the functionalization and sonication process introduces functional groups onto the surface of BNNSs. By this method, the obtained yield of BN dispersion is improved up to 17-20%.

Lithium-Sulfur (Li-S) batteries are considered as one of the promising candidates for next-generation Li batteries in near future. Although, these batteries are suffering from certain drawbacks such as rapid capacity fading during the charge and discharge process due to the dissolution of polysulfides. In this paper, Sulfur/metal oxide (TiO2 and SiO2) yolk–shell structures have been successfully synthesized and utilized to overcome this problem and improve the electrochemical performance of sulfur cahtode material. Prepared materials have been characterized using Scanning Electron Microscopy(SEM), Transmission Electron Microscopy(TEM) and X-ray diffraction (XRD) techniques. The results show significant improvement in the battery performance as a result of using Sulfur-SiO2 and Sulfur-TiO2 yolk–shell structures. The obtained Sulfur-TiO2 electrode delivers a high initial discharge capacity (>2000 mA h g−1) and discharge capacity of 250 mA h g−1 over 8 charging/discharging cycles with Coulombic efficiency of 60%, while initial discharge capacity for Sulfur-SiO2 electrode was lower (>1000 mA h g−1) compared to Sulfur-TiO2. Sulfur-SiO2 electrode shows the discharge capacity of 200 mA h g−1 over 8 charging/discharging cycles with Coulombic efficiency around70%. The obtained galvanostatic ressults demonstrated that Sulfur-TiO2 electrode possess stronger capability to prevent sulfur and its intermediate reaction products from dissolving into the electrolyte.

Magnesium ferrite (MgFe2O4) as a core magnetic nanostructure was synthesized via auto combustion method by using grapefruit extract as a biocompatible and cost-effective material. Then flower and star-like PbS were synthesized using thioglycolic acid as a sulfur source without using any chemical template. After that for preparation of magnetic and photocatalyst MgFe2O4-PbS nanocomposites, lead sulfide were coated on the magnetic core by hydrothermal procedure. Morphology of the prepared products was estimated by transmission electron microscopy (TEM), scanning electron microscopy (SEM), also X-ray diffraction (XRD) pattern show purity and phase of the product. Fourier transforms infrared (FT-IR) spectroscopy show vibration modes of the bonds. Vibrating sample magnetometer (VSM) illustrated that magnesium ferrite nanoparticles have a soft magnetic behaviour with 18 emu/g magnetization and coercivity about 90Oe. The photocatalytic behaviour of MgFe2O4-PbS nanocomposites were examined using the degradation of two various azo dyes acid brown and acid violet under visible light irradiation. This magnetic photocatalyst can easily separate from water with an external magnetic field and can be used under solar irradiation.

The application of nanoparticles in order to enhance the composites properties has been recently attracted many researchers' attentions. To increase the mechanical and physical properties of the composites, the nanoparticles have no significant effect on the weight and nanostructure of composites. One of the well-known nanoparticles is the Nanoclay (NC) that have been widely used in industries due to its unique geometric shape and some specific chemical properties. In this research, the effect of NC on the mechanical behavior of epoxy hybrid/glass fibers composite has been investigated. Samples containing (1, 2, 3, 5 and 7) wt% of NC with constant amount of epoxy hybrid /glass fibers composite were produced. Samples with 3 wt% NC has shown proper impact, tensile properties. The scanning electron microscopy (SEM) and X-ray diffraction (XRD) technique were used to analysis the morphology and phase characterization of the samples. The results of tensile, bending and impact tests on hybrid samples showed improvement in these properties compared to the primary sample without nanoparticles incorporated. On the other hand, the energy absorbed by the target was increased, due to the sensitivity of the glass fiber to the strain rate. The novel hybrid epoxy/glass fibers composite reinforced with 3 wt% NC present proper mechanical properties compared to another specimen.

In this work, we describe a simple, green and general procedure for the purification and fractionation of carbon dots (CDs). CDs coated with oxygen-containing functional groups were synthesized by thermal pyrolysis of citric acid. The product of the reaction was first Purified and then fractionated into two distinct kinds of CDs (f4 and f1) using pH-controlled cloud point extraction (CPE) technique. Characterization of f4 and f1 fractions by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-Vis absorption, and FT-IR spectroscopy not only lead to study and explain the mechanism of the extraction procedure but also revealed that the two fractions were different from each other in terms of their different optical properties and surface chemistry (the number or surface-density of oxygen-containing functional groups) which in turn plays the main role in their fractionation at different pH values. Comparing fluorescence spectra of f4 and f1 fractions indicated that the surface-density or number of the oxygen-containing functional groups has a marked effect on photoluminescence behavior of CDs. The developed general procedure method can be used for large-scale production of different fractions of any pure CDs in the industry as well as research laboratory preparation purposes.

Here, the effect of lightly Niobium doped TiO2 layer on the performance of perovskite solar cells has been studied by using solar cell capacitance simulator (SCAPS). N addition, the effects of Niobium concentration, buffer film thickness and operating temperature on the performance of the perovskite solar cell are investigated. For doping level of 3.0 mol% into the TiO2 layer, cell efficiency of 18.26% with Voc of 0.96 V, Jsc of 22.45 mA/ cm2 and FF of 84.25% has been achieved. Calculations show that thickness widening of Nb-doped TiO2 layer would decrease the efficiency and Voc of the cells. Increase in operating temperature from 300 k to 400 k would weaken the performance of the perovskite solar cell with both pure and Nb-doped TiO2 layers. However, the cell with Nb-doped TiO2 layer shows higher stability than the cell with pure TiO2 buffer at higher temperatures. The efficiency of the cell with pure and doped buffer layers decreased from 15.52% to 11.47% (with 26.09% reduction) and 18.26% to 14.07% (with 22.9% declination), respectively. Therefore, the cell with doped buffer layer shows better stability at higher operating temperatures

In this study a facile approach to employ Copper nanoparticle (CuNPs) and multi-walled carbon nanotubes (MWCNT) as the nanomaterial for selective detection of asulam have been investigated. This work reports the electrocatalytic oxidation of asulam on glassy carbon electrodes (GCE) modified with multi-walled carbon nanotubes (MWCNT), ionic liquids (IL), chitosan (Chit) and copper nanoparticles (CuNPs).Using the proposed nanocomposite provides a specific platform with increased surface. The surface morphology of this modified electrode was characterized by field-emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectrometer (EDX) techniques. The electrochemical behaviors of the fabricated sensor were investigated by cyclic voltammetry (CV) and chronoamperometry modes. Under optimal conditions, the amperometric study exhibits two linear ranges of 1–11 and 11–200 μmol L-1 with a detection limit (LOD) of 0.33 nmol L-1 (at an S/N of 3) and sensitivity of 1.9 nA μmol L-1 for Asulam determination. This novel sensor was used to analyze the real sample. The sensor provides a convenient, low-cost and simple method for Asulam detection and proposes new horizons for quantitative detection of Asulam.

Cancer is a fatal disease and relatively widespread in the world; Breast cancer is the most prevalent cancer among women. Hydroxyurea (HU) is a chemotherapy drug for the cure of cancer different types in patients, for example breast cancer, but has several defects, for to remove these problems in this study a nanoliposome (NL) suspension for Hydroxyurea (HU) delivery in breast cancer cell therapy was developed.HU was encapsulated into NLs. Size was measured by nanosizer. The release of the liposomal formulation was assessed during 36 h. FTIR analysis for liposomal Hydroxyurea and free Hydroxyurea was carried out. The uptake capacity of the formulation was determined by transfection of nanoliposomal hydroxyurea (NL-HU) in MDA-MB231 cells via flow cytometer and fluorescence microscopy studies, the cytotoxicity of NL-HU and free HU was evaluated in cells. Size of NL-HU was 174nm, HU encapsulation efficiencies in NLs was 81%. FTIR analysis showed the stability of HU in the liposome and no improper interaction between liposome and HU, release after 36h depicted sustained release behavior.NL-HU had suitable uptake in MDA-MB231 cells. Cytotoxicity of NL-HU on cells was considerable. We confirmed these nanoliposomes are potentially useful for delivery of Hydroxyurea in breast cancer cells treatment.

W-doped TiO2 with nanoporous structure was synthesized by a one-step low temperature hydrothermal method using TiOSO4 and (NH4)6H2W12O40•xH2O as titanium and tungsten sources. Structure, morphology, specific surface area and chemical state of samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). W-doped nanoporous TiO2 samples were used as sensing materials of indirect-heating sensors and their gas-sensing performances were studied to detect acetone. The experimental results show that 7.5% W-doped nanoporous TiO2 can adsorb more oxygen molecules on the surface and provide large amount of active reaction sites on interface to profit reaction between material and gas molecules. The gas sensor based on 7.5% W-doped nanoporous TiO2 exhibits good gas-sensing performances, including high gas response value, shortened response/recovery time and good reproducibility, which make it a promising candidate in acetone detection. Apart from these, the mechanism related to the advanced properties was also investigated and presented.

In this experimental work, nitrogen-doped carbon quantum dots were successfully synthesized with hydrothermal of the milk. The product was composed of a powder and a stable colloid. The structure of the product was examined by XRD, EDS and FT-IR analysis. Also the particle size of the product was investigated by SEM and TEM images and the results showed the product is mainly composed of the particles with less than 5 nm in diameter. The photoluminescence intensity of the product was obtained by PL analysis and it was found the product has high photoluminescence intensity that can be improved by surface modification with N-Methyl-2-pyrrolidone. Due to high photoluminescence intensity of the obtained quantum dots they were used as sensor to detection of Cu2+ and it was observed they can detect this ion in the aqueous medium for 0-80 uM concentration range. Also it was found by surface modification of carbon dots with N-Methyl-2-pyrrolidone, the detection sensitivity is improved. The optical properties of the product were studied by UV-Vis spectroscopy.

Barium Oxide(BaO) nanoparticles were synthesized by simple co-precipitation method and were investigated by the catalytic activity of synthesized barium oxide nanopaticles was enumerated by epoxidation of styrene. The reaction was carried out and the product was obtained at higher efficiency. Particularly, the photocatalytic efficiency was estimated by degradation of Rhodamine-B (RhB) dye using barium oxide nanoparticles under visible light illumination. The degraded dye concentration decreases nearly to zero at 60 minutes of its contact with photocatalyst. The humidity sensing properties of the material was measured by using DC resistance measurement at room temperature that reveals the sensitivity factor of 1926. Barium oxide nanoparticles shows the response and recovery characteristics of 40s and 110s respectively. The dye started to degrade and the concentration of the dye decreases to almost zero at 1 hour of irradiation that was predicted from the degradation rate which was the plot of C/C0. The degradation efficiency was found to be 98% for 1 hour degradation.The evaluation outline on performancebasis revealed that synthesized barium oxide acts as a promising catalyst,photocatalyst and humidity sensing material were reported in detail.

A high flux thin-film nanocomposite membrane epoxy/ zeolite NaA nanocomposite films prepared by using ultrasonic mixing and spin coating. The synthesized nanocomposites film was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermal gravity analysis (TGA), and FTIR spectroscopy. Water softener and water flux characteristics of the epoxy/ zeolite NaA nanocomposite film investigated. The results show the water softener, and hydraulic permeability of the membranes, remarkably improve by the wt.% of the zeolite NaA loading. Antibacterial activity was investigated by use modification of zeolite NaA with silver ions (Ag+) and copper ions (Cu2+) for nanocomposite.The target of this work was to expand the thin high-performance nanocomposite membranes with the combination of the zeolite NaA and epoxy polymer for effective calcium removal from water also to improve the water permeability at the same time. NaA zeolite ion exchange with silver and copper were used to improve the anti-bacterial nanocomposite membrane.

ZnO nanostructure films were deposited by radio frequency (RF) magnetron sputtering on etched silicon (100) substrates using dry Ar/SF6 plasma, at two etching times of 5 min and 30 min, and on non etched silicon surface. Energy dispersive X-ray (EDX) technique was employed to investigate the elements contents for etched substrates as well as ZnO films, where it is found to be stoichiometric. Surface and growth evolution of films were explored by scanning electron microscope (SEM) images and found to have morphological development from spherical forms into nanowires with increasing substrate etching time. 2D atomic force microscope (AFM) images clarify this modification of the morphology and roughness values are deduced. Structural study was investigated using X-ray diffraction (XRD) patterns. The films had (002) preferential orientation with various etching time substrates. Optical characterization illustrated a decrease of reflectance with the morphological modification. Photoresponse measurement has been investigated and correlated with the crystallinity.