JOURNAL OF NANOSTRUCTURES
Year:2016 | Volume:6 | Issue:2|Papers Count:10

Nano-crystalline particles of CeO2 have been synthesized by a low temperature chemical precipitation method. The precursor materials used in this research were Ce (NO3)3.6H2O, NaOH and diethylene glycol as surfactant. X-ray powder diffraction results showed that face centered cubic CeO2 nanoparticles with crystalline size in nanometer scale were formed. Scanning electron microscopy measurement showed that by increasing the calcinations temperature the crystallite size decreases. The particle size of CeO2 was around 20 nm as estimated by X-ray powder diffraction technique and direct high-resolution transmission electron microscopy observation. High-resolution transmission electron microscopy studies showed the size of CeO2 particles increase from 10-90 nm by increasing the ratio of diethylene glycol surfactant. The sharp peaks in Fourier transform infrared spectrum determined the purity of CeO2 nanoparticles and absorbance peak of ultraviolet–visible spectroscopy spectrum showed the small bandgap energy of 3.26 ev.

Herein, we prepared a V/SBA-16 catalyst using vanadyl acetylacetonate as a precursor and SBA-16 nanoporous silica as a support via an immobilization technique. The ordered mesoporous structure of catalyst was determined by X-ray diffraction and transmission electron microscopy techniques, and the catalyst was evaluated in the benzene hydroxylation to phenol with hydrogen peroxide (H2O2) as a green oxidant. The effects of three key factors, namely reaction temperature (oC), H2O2 content (mL) and catalyst amount (g) at five levels (“1.68, “1, 0, +1, +1.68), and also their interaction on the phenol yield were investigated using response surface methodology combined with central composite design. The high correlation coefficient (R2), i.e., 0.983, showed that the data predicted using RSM were in good agreement with the experimental results. The optimization results also exhibited that high phenol yield (17.09%) was achieved at the optimized values of the operating variables: the reaction temperature of 61oC, H2O2 content of 1.69 mL and a catalyst amount of 0.1 g. In addition, response surface methodology provides a reliable method for optimizing process variables for benzene hydroxylation to phenol, with the minimum number of experiments.

In this work firstly CoFe2O4 nanoparticles were synthesized via a hydrothermal method. The temperature, surfactant and capping agent effects on the size of CoFe2O4 nanoparticles were investigated. 2-hydroxyacetophenone used as a good capping agent to produce cubic-like nanostructure. When SDBS used as surfactant, particles had spherical morphology. Nanoparticle was studied by scanning electron microscopy, X-ray diffraction, and Fourier transform infrared. We found that the CoFe2O4 nanoparticles were prepared exhibit a ferromagnetic behavior with a saturation magnetization of 20emu/g and a coercivity of 250 Oe. The photocatalytic behavior of CoFe2O4 was studied by the degradation of a methylene blue aqueous solution under ultraviolet light irradiation.

In this research cobalt ferrite (CoFe2O4) nano-crystalline powders were prepared by simple chemical precipitation method using cobalt sulfate. The CoFe2O4 nanoparticles were characterized by X-ray diffraction, scanning electron microscopy and Fourier transform infra-red spectroscopy. The crystallite size of CoFe2O4 nanoparticles was calculated by Debye-Scherrer formula. The effect of precursor, capping agent, temperature and concentration on the morphology and particle size of the products was investigated. Starch and gelatin as green, safe, water-soluble and cost-effective capping agents were used. Alternative gradient field magnetometer confirms dominant influence of temperature on the morphology and magnetic domains. Results approve magnetic samples exhibit either ferromagnetic or super-paramagnetic behavior.

In this work, we used a simple and totally green method for synthesizing silver nanoparticles using kappa-carrageenan as reducing and stabilizing agent. The beads were prepared in aqueous medium by microwave heating, and then followed by cross-linking with K+ cations without using any additional toxic and expensive chemical agents. The preparation method of the carrageenan-based beads is easy, fast, simple, effective, and safe. The synthesized beads loaded with were characterized by ultraviolet-visible absorbance spectra, transmition electron microscopy and X-Ray diffraction techniques. The as-prepared beads were evaluated to remove cationic crystal violet dye from aqueous solutions. The thermodynamic parameters shown that the sorption process was feasible, spontaneous and endothermic. The kinetics and isotherm of crystal violet adsorption were found to well fit to pseudo-second-order kinetic and Langmuir isotherm model, respectively. Moreover, the antibacterial activity of the obtained beads was examined using the nutrient agar disc diffusion method.

To prevent serious electromagnetic interference, a single-layer and double layer wave-absorbing coating employing complex absorbents composed of carbon black with epoxy resin as matrix was prepared. The morphologies of carbon black /epoxy composites were characterized by scanning electron microscope and atomic force microscope, respectively. The carbon black particles exhibit obvious polyaromatic were characterized by X-ray diffraction. The electromagnetic parameters of carbon black were measured in the frequency range of 8–12 GHz by transmission/reflection technology, and the electromagnetic loss mechanisms of the two particles were discussed, respectively. The microwave absorption properties of the coatings were investigated by measuring reflection loss using arch method. The effects of carbon black mass ratio, thickness and double-layer on the microwave absorption properties were discussed, respectively. The results showed that the higher thickness, higher ratio and double-layer of carbon black /epoxy content could make the absorption band shift towards the lower frequency range. Significantly, the wave-absorbing coating could be applied in different frequency ranges according to actual demand by controlling the content of carbon black in composites.

Fe2O3 and ZnO nanoparticles were synthesized by a fast microwave method. Nanostructures were characterized by X-ray diffraction and scanning electron microscopy. The goal of bio-fortification is to develop plants that have an increased content of bioavailable nutrients in their edible parts. The micronutrients magnesium (Mg), manganese (Mn) and copper (Cu), boron (B) and calcium (Ca) are essential for plants and the humans and animals that consume plants. Increasing the micronutrient density of staple crops, will greatly improve human nutrition on a global scale. In order to investigate the effect of Iron and Zinc on nutrient uptake of two line of wheat. The experimental design used for this research was a factorial experiment under complete randomized block design with three replications and two variety of wheat including Roshan back cross (V1) and C-78-14 line (V2), three levels of Iron from Fe-EDDHA (Sequestrene138) including no application (F0), Fe sulphate (F1) and Nano Fe2O3 (F2) and three Levels of Zinc as zinc sulphate (ZnSO4) including no application (Z0), 25 kg/ha-1 (Z1) and 50 kg/ha-1 (Z2) were used. The result is showed that application of nanoparticles increased the study of parameters such as magnesium, manganese, copper, boron and calcium. Highest levels of grain yield with 5.13 ton/ha-1 was obtained in C-78-14 variety.

Morphology and size of platinum nanoparticles are a crucial factor in improving their catalytic activity and stability. Here, we firstly report the synthesis of high loading Pt nanoparticles on polydopamine reduced Graphene. The loading concentration of Pt (nanoparticles) NPs on Graphene can be adjusted in the range of 60-70%.With the insertion of polydopamine between Graphene oxide sheets, stacking of Graphene can be effectively prevented, promoting diffusion of oxygen molecules through the Graphene sheets and enhancing the oxygen reduction reaction electrocatalytic activity. Compared to commercial catalysts (i.e., state-of-the-art Pt/C catalyst) the as synthesized Pt supported polydopamine grafted reduced graphite oxide (Pt@PDA-rGO) hybrid displays very high oxygen reduction reaction catalytic activities. We propose a unique 2D profile of the polydopamine-rGO role as a barrier preventing leaching of Pt into the electrolyte. The fabricated electrodes were evaluated with electrochemical techniques for oxygen reduction reaction and the obtained results were further verified by the transmission electron microscopy micrographs on the microstructure of the integrated pt@PDA-rGO structures. It has been revealed that the electrochemical impedance spectroscopy technique can provide more explicit information than polarization curves on the performance dependence on charge-transfer and mass transport processes at different overpotential regions.

The use of plant extract is generating interest of researchers toward cost effective and eco-friendly green synthesis of nanoparticles. In the present work, Cupric oxide nanoparticles were synthesized using coffee powder extracts by the sol-gel method at different calcination temperatures. The synthesized nanoparticles were characterized by X-ray diffraction, scanning electron microscopy, ultraviolet -visible spectroscopy and Fourier transform infrared spectroscopy. The powder X-ray diffraction analysis revealed the formation of single-phase copper oxide with a monoclinic structure.

This paper outlines the synthesis of CuFe2O4 nanoparticles and their catalytic applications. CuFe2O4 nanoparticles were synthesized via microwave-assisted co-precipitation method. The obtained nanoparticles characterized through Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. Vibrating sample magnetometer shows nanoparticles exhibit ferromagnetic behavior. CuFe2O4 nanoparticles are used as an efficient and effective catalyst for the one-pot three-component synthesis of 2-naphthol condensed 1, 3-oxazinone derivatives. This procedure includes some important aspects like the easy work-up, no need to column chromatography, simple and readily available precursors, and good to high yields.