Sharif Digital Repository

The production of high-purity aluminum nanoparticles (Al-NPs) is challenging due to the highly reactive nature of Al metals. Electromagnetic levitation gas condensation (ELGC) is a promising method to produce high-purity metallic particles as it avoids the interaction between molten metal and refractory-lined, which guarantees the removal of impurities such as oxygen (O). In this research, high-purity Al-NPs were successfully fabricated via ELGC process and fully characterized. The effects of power input and gas flow rate on particle size and distribution were analyzed using field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), and dynamic light... 

A new heterogeneous and highly dispersive nanocatalyst in water was prepared by the immobilization of Cu2+ onto glucose on Fe3O4. The catalyst was fully characterized by FT-IR, TGA, CHN, SEM, EDX, and atomic absorption spectroscopy. The synthesized catalyst was used in the synthesis of different derivatives of 1,2,3-triazole via a one-pot three-component reaction of alkynes, alkyl halides, and sodium azide. To the best of our knowledge, this novel catalyst adheres to the principles of green chemistry. The nanocatalyst could be recycled and reused in several runs without significant loss of activity  

Activated layered manganese oxides with deposited nano-sized gold or silver were synthesized and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectrometry, atomic absorption spectroscopy and energy-dispersive X-ray mapping. Here, we report that Au or Ag nanoparticles deposited on layered Mn oxides improve the catalytic activity of the Mn oxides toward the epoxidation of olefins in the presence of H2O2 and NaHCO3  

Fe3O4@SiO2-Ag catalyst was found to be highly active and selective in the N-alkylation of amines with a variety of aromatic and linear alcohols. The heterogeneous nature of the Fe3O4@SiO2-Ag catalyst allows easy recovery and regeneration by applying an external magnet for six subsequent reaction cycles. The prepared catalyst was characterized using electron microscopy techniques, X-ray diffraction, vibrating sample magnetometry and atomic absorption spectroscopy. Copyright © 2017 John Wiley & Sons, Ltd  

Palladium(II) have been immobilized into the nano magnetic Fe3O4 which was functionalized with glucose in order to achieve a one-pot synthesis of 2-substituted benzoxazole derivatives with high yields in the diverse range of organic solvents. The nano catalyst is highly dispersive in polar solvents and can be easily recovered and reused for 6 runs without significant loss of its activity. Finally, the catalyst was fully characterized by FT-IR, TGA, CHN, SEM, EDX and atomic absorption spectroscopy. Copyright © 2018 John Wiley & Sons, Ltd  

Using a combined hydrothermal and sol-gel route, TiO 2 -capped ZnO nanoparticles with an average size of 60 nm were prepared. The titania shell was amorphous with a thickness of ∼10 nm. Formation of Zn 2TiO 4 phase at higher calcination temperature was noticed. Effects of Ti/Zn molar ratio and coating time on the thickness of TiO 2 shell and the photoactivity of the particles for decolorization of Methylene Blue (MB) under UV lamp irradiation (3 mW/cm 2) were investigated. The nanoparticles were characterized by X-ray diffraction, transmission electron microscopy, fourier-transform infrared spectrometry (FTIR), diffuse reflectance spectroscopy (DLS), and atomic absorption spectroscopy.... 

The aim of this paper is to study the influence of frequency in pulse electrodeposition, on the current efficiency, Ni content and surface morphology of deposits from a novel cyanide-citrate electrolyte with 20 mM gold as KAu(CN) 2 and 7 mM NiSO 4, with the aim of design of experiment by respond surface method (RSM). Frequency was in the range of 1-200 Hz in constant average current density, temperature, and duty cycle of 7 mA/cm 2, 59 °C and 55% respectively. Composition of the deposits was determined by atomic absorption spectroscopy (AAS). Additionally, deposits were characterized by scanning electron microscopy (SEM), and Energy-dispersive X-ray spectroscopy (EDS). It was shown that from... 

A manganese porphyrin, meso-tetrakis(pentafluorophenyl)porphyrinato manganese(iii) acetate, Mn(TPFPP)OAc, was immobilized on silica-coated magnetic Fe3O4 nanoparticles functionalized with 3-aminopropyltriethoxysilane (APTS) through the amino propyl linkage using a grafting process in toluene solvent. This enabled the covalent immobilization of Mn(iii) porphyrin via an aromatic nucleophilic substitution reaction, to afford the Fe3O4@SiO2-NH2@MnPor catalyst. The resulting nanoparticles were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), FT-IR spectroscopy, UV-Vis spectroscopy, elemental analysis (CHN), atomic absorption spectroscopy (AAS), and vibrating... 

This article reports the synthesis of a magnetic heterogeneous catalyst through the decoration of gold ions onto the cross-linked polymeric nanocomposite from 2,6-diaminopyridine. The activity of the resulting catalyst was then evaluated in the bromination of aromatic compounds. The nitrogen rich support showed a high affinity to gold ions, and the measured content of Au was 0.76 mmol g-1. The structure of the catalyst was fully characterized by using Fourier-transform infrared spectroscopy, thermogravimetric analysis, atomic absorption spectroscopy, transmission electron microscopy, scanning electron microscope, energy-dispersive X-ray spectroscopy, Brunauer-Emmett-Teller surface area... 

We report a novel strategy for the synthesis of magnetic nanocomposite for highly efficient catalysis. Poly(glycidyl methacrylate) (PGMA) chains were grafted to the surface of magnetic nanoparticles (MNPs) through surface-initiated reversible addition-fragmentation chain transfer polymerization. Then, the oxirane rings in the PGMA chains were opened with 2,6-diamino pyridine (DAP) molecules as ligands to prepare the solid support. Finally, this magnetic nanocomposite was used for the immobilization of gold nanoparticles. Fourier-transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, transmission electron microscopy, scanning electron microscopy, gel permeation... 

Mn-doped ZnO nanoparticles, Zn1−xMnxO, were synthesised by a polyethylene glycol (PEG) sol–gel method and the physicochemical properties of compounds were characterised by atomic absorption spectroscopy (AAS), energy-dispersive X-ray analysis, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The catalytic degradation of an organic dye, methylene blue (MB), in the presence of Zn1−xMnxO as the catalyst and hydrogen peroxide (H2O2) as the oxidant at room temperature in water has been studied. Effects of oxidant, catalyst amount, catalyst composition, pH value of the solution and an OH-radical...