JOURNAL OF NANOSTRUCTURES
Year:2019 | Volume:9 | Issue:1|Papers Count:20

Organic-inorganic hybrid mesoporous materials such as amino functionalized silica (SBA-Pr-NH2) have received considerable attention due to their basic catalytic applications and adsorption functions. In this work, we investigated the efficient role of SBA-Pr-NH2 as a heterogeneous nano catalyst in the synthesis of 9, 10-diaryl-7H-benzo[d, e]imidazo[2, 1-a] isoquinolin-7-one derivatives. Application of SBA-Pr-NH2 as an ecofriendly and reusable catalyst resulted in reducing reaction time and temperature in this method. The preparation method was developed using a green one-pot three-component reaction of acenaphthoquinone, benzils and ammonium acetate under solvent-free condition. Besides, the synthesis of benzil derivatives as starting material was carried out. The new compounds were characterized by IR, mass, and NMR spectroscopy. The significant merits of this protocol are its simplicity, short reaction times, low reaction temperature, catalyst reusability, and non-chromatographic purification of products. Also, imidazole and benzimidazole moieties represent significant substructures of a wide variety of bioactive compounds and also significant structural motifs in biological systems, natural products, and drugs.

[Pb(gly)2]n (1) (gly is the abbreviation of Glycine) have been synthesized and characterized by elemental analyses, IR, 1 H NMR and 13 C NMR spectroscopy. The single crystal structure of 1 show the complex is 2D coordination polymer with octahedral environment that is formed into 3D supramolecule through hydrogen bond. Structural determination of compound 1 reveals the Pb(II) ion is four coordinated, bonded to a nitrogen, oxygen and two carbon atoms from the Glycine ligand. PbO nanoparticles were synthesized by calcinations of compound 1 at 500, 550 and 600 ° C under air atmosphere. The PbO nanostructure was characterized by scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). The thermal stability of compound 1 was studied by thermal gravimetric (TG) and differential thermal analyses (DTA).

In the present work, stable ferrofluids containing oleic acid capped magnetite nanoparticles were synthesized via low temperature hydrothermal method. The physical and chemical properties of the synthesized particles were studied using TEM, XRD, AFM, VSM and PCS techniques. Mean particles size of the samples was between 4. 5 and 10 nanometers, depending on experimental conditions. Effect of precursor’ s medium alkalinity was investigated on particle size. Cell culture experiments performed via MTT assay demonstrated that this product was biocompatible. In addition, cellular uptakes were investigated by Prussian blue staining and also measuring Fe concentration by inductively coupled plasma spectroscopy. Finally, the synthesized particles were dispersed in the Ethiodol and the obtained suspension was used as a potential MRI contrast agent. To the best of our knowledge, the mentioned procedure of using a non-aqueous based MRI contrast agent has been done for the first time in the present work and provides good capabilities as opposed to aqueous ones including reduced synthesis process time and increased magnetic properties of the obtained contrast agent.

In the present work, MoS2 decorated graphene nano composite powders were synthesized by laser scribing method. The obtained flexible light-scribed graphene/MoS2 composites are very suitable as microsuper capacitors and thus their performance was evaluated at different concentrations. The effect of laser scribing process to reduce graphene oxide (GO) was investigated. The GO/MoS2 composite was synthesized using a chemical mixing of GO solution withMoS2/Dim ethyl formamide (DMF) solution. The mixtures with various concentrations of MoS2 were then coated on a Light Scribe DVD disk and laser scribed to reduce GO and create aMoS2/laser-scribed graphene (LSG) composite. Four different concentrations of MoS2/LSG composites (pristine rGO, 1: 100, 1: 75 and 1: 50 MoS2/LSG) were utilized as supercapacitor electrode and the electrode with the best performance was selected for flexible micro-supercapacitor applications. The present findings demonstrate that MoS2/LSG microsupercapacitor has high specific capacitance per area. The sample with MoS2/LSG volume ratio of 1: 50 shows the highest specific capacitance (~ 8 Fcm-3 ) and its cyclic stability is favorable over 1000 cycles.

Synthesis of bis sulfamic acid-grafted on silica-coated nano-Fe3O4 particles (MNPs-TBSA) as a novel core/shell hybrid organic-inorganic magnetic nanostructures, and their performance as a retrievable heterogeneous acidic catalyst is disclosed. The catalytic performance of this novel material was studied for the green synthesis of pharmaceutically valuable polyhydroquinoline and tetrahydrobenzopyran derivatives via onepot multi-component condensation of aryl aldehydes, dimedone, ethyl acetoacetate, malononitrile and ammonium actate in ethanol as a solvent and at 70 º C. Eco-friendly method, high yield and purity of the desired products, short reaction time along with the ease of the workup procedure outlines the advantages of these new methodologies over the earlier ones. Surface and magnetic properties of the core/shell hybrid nanoparticles were characterized via field emission scanning electron microscopy (FESEM), X-ray diffraction measurements (XRD), the energy dispersive X-ray spectroscopy (EDS), FT-IR spectroscopy and vibrating sample magnetometer (VSM). The crystallite size of the magnetic nanoparticle is calculated to be 15. 5 nm.

Hematite (α-Fe2O3) nanorods were synthesized by hydrothermal method using Cetyltrimethylammonium bromide (CTAB) as a surfactant agent. To study optical, nanostructural properties, and to control the morphology and shape of nanorods, 0. 025 mol L-1, 0. 05 mol L-1 and 0. 1 mol L-1 concentration of CTAB were used. Moreover, the effect of interaction between bovine serum albumin (BSA) A9418-5G protein solution and hematite nanorods was investigated. Fourier transform infrared spectroscopy (FTIR), transmitting electron microscopy (TEM), X-Ray Diffraction (XRD), Energy Dispersive X-Ray Spectroscopy (EDS) and UV-vis spectroscopy were used to characterize α-Fe2O3 nanorods. The samples prepared by the interaction of BSA protein and hematite nanorods did not representa rod shape because the electrostatic interaction between CTAB and BSA would cause the nanorods to have a limited capacity for carrying protein. Hematite nanorods obtained from 0. 025 mol L-1 of CTAB showed a maximum length of 25-30 nm. However, BSA protein solution falsification of rod shape particles increased. The results showed that BSA protein could affect the shape of hematite nanorods and their aggregation, and formspherical structures as well.

Nanosheets of MFI zeolite were successfully synthesized by hydrothermal method and were properly characterized by XRD, FE-SEM, EDX-dot mapping, TEM, FT-IR, N2 adsorption/desorption, NH3-TPD, ICP-AES and TGA techniques. The characterizations of MFI zeolite nanosheets suitably confirmed well synthesized MFI nanostructure, superior specific surface area (695. 96m 2. g-1 ) and great mesopores volume. Currently, the major concern in commercialized technologies of methanol to propylene (MTP) process is to discover the best operational conditions for maximizing propylene selectivity. Therefore, in present investigation the effectiveness of more significant operational conditions such as reaction temperature, methanol molar percent in feedstock and methanol WHSV on propylene selectivity was considered. For first time, conventional response surface methodology and an artificial neural network model coupled with genetic algorithm were appropriately employed to optimize MTP operational conditions. For providing the data bank of optimization, MTP reaction was carried out over the synthesized MFI zeolite nanosheets at various operational conditions. It was concluded that neuro-genetic method showed more reliable performance in optimizing MTP operational conditions with R 2 value of 0. 9998. Furthermore, time on stream examination was conducted over MFI zeolite nanosheets at optimal operational conditions which were suggested by neuro-genetic approach. At optimal operational conditions the catalytic life-time was sufficiently enhanced (101h).

The aim of this study is to determine some phytochemical contents, to synthesize silver nanoparticles AgNPs using Cuminum cyminum (C. cyminum) leaf extract, to study the effects of different conditions on the rate of synthesis, and to evaluate their antibaterial and antifungal activities. AgNPs were synthesized using C. cyminum leaf extract as bioreducer agent and aqueous silver nitrate solution (AgNO3) as precursor at different conditions. The synthesized AgNPs were characterized using Ultraviolet-visible absorption spectroscopy (UV-vis), Scaning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). In addition, the synthesized AgNPs were evaluated for their antibacterial and antifungal activities against 4 positive and negative bacteria using agar disc diffusion method and the fungus Fusarium oxysporum cultivated in Potatoes Dextrose Agar (PDA) medium, respectively. Results showed that the bioreduction process was quite fast and the synthesized AgNPs were nearly spherical in shape and the size range of 3-20 nm. The AgNPs formation was affected by different parameters including concentration of AgNO3 solution and the extract, temperature and the time of reaction. The best condition for AgNPs biosynthesis was achieved by 1-3 mM AgNO3 at 40 ° C after 4 h. In addition, the leaf extract and AgNPs showed efficient antibacterial activites against Gram positive and negative bacteria, respectively.

In this paper, meso-Tetraphenylporphyrin iron(III) chloride complex, Fe(TPP)Cl, supported on magnetic nanoparticles (PCMNPs) was synthesized and characterized by HRTEM, SEM, TGA, and FT-IR and VSM. The value of saturation magnetic moments of MNPs and PCMNPs are 68. 5 and 60. 3 emu/g, respectively. The SEM and HRTEM image were shown the uniformity and spherical-like morphology of nanoparticles with an average diameter from ∼ 55 to 65 and and15 ± _5 nm, respectively. The synthesized catalyst was successfully applied as a magnetically recoverable heterogeneous catalyst in oxidation of sulfides to related sulfoxides in water/ethanol as green solvents by meta-Chloro peroxy benzoic acid (m-CPBA). The selectivity and chemoselectivity of this clean system were attracted so much attention. No surfactants, additives, toxic reagents or organic solvents and by-product were involved. The maximum conversion and selectivity were attained at around neutral pH, which is advantageous for full-scale application. Ten successive cycles of catalyst was shown that the catalyst was most strongly anchored to the magnetic nanoparticles.

In this study, carbon nanotubes (CNTs) reinforced aluminum matrix was synthesized by DPDS for the first time. Planetary ball mill has been used to disperse of CNTs in Al matrix. The effects of the CNTs content and secondary pressing-sintering on properties of the nano-composites were investigated. Mechanical properties of aluminum metal matrix nanocomposites samples were characterized using compression and microhardness measurements. Enhancements of about 52% in compressive strength and 64% in hardness were observed as compared to pure aluminum (matrix) fabricated under the similar condition by conventional sintering process. The morphology and phase analysis of composites have been studied by SEM, and XRD. This research work shows feasibility of manufacturing CNT reinforced metal composites by DPDS.

Various antireflection thin films are often used to cover glass to increase solar cell electrical parameters. In the recent years many efforts have been done to develop and improve of solar cell films with high electrical output. One of the most important challenges of obtaining of high-efficiency thin films of solar cells is creation an effective light trapping system. The new polymeric protecting materials are called polyhedral oligomeric silsesquioxanes (POSS) that can improve the solar cells properties. In the present work, firstly Tetraglycidyloxypropyl tetramethyl POSS was synthesized via sol-gel method and used to prepare TGTM POSS-silica nanocomposite, then it was applied on solar cell slides. The structural, morphological, thermal, optical and electrical properties were investigated by TEM, FTIR, NMR, FE-SEM, TGA, UV-VIS spectroscopy and solar simulator. Evaluation of the obtained results showed that the efficiency of solar cells was improved twice or more (50%) compared with that without POSS coating. The coatings transmittances were equal 100% that are ideal for solar cell films. The solar cells stability to solar light with POSS coating was also evaluated. The obtained results showed that the degradation of solar cell transmission.

CdS nanoparticles are II-VI group semiconductors in nature with suitable band gap for photoluminescence and photo-catalyst applications. CdS nanostructures were synthesized via a facile precipitation method in the presence of green capping agents such as starch, glucose, gelatin, salicylic acid in the green solvent of water. The influence of concentration, surfactant, precipitating agent on the particle size and shape of the products were examined. Then for preparation of polymer based nanocomposites, cadmium sulphide nanoparticles were added to poly styrene, poly vinyl alcohol, cellulose acetate and acrylonitrile-butadiene-styrene polymers. The prepared samples were characterized by X-ray diffraction pattern (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) spectroscopy. The photocatalytic behaviour of cadmium sulfide was evaluated using the degradation of three azo dyes (methyl orang, acid violet 49 and acid black 1) under ultraviolet and visible light irradiation. Our results confirm preparation of pure semiconductor nanoparticles and polymer-based thin film nanocomposite with both appropriate photo-luminescence and photocatalytic performance simultaneously. Interestingly outcomes show photocatalysts can photo-degrade toxic dyes in less than 15 min.

In the present work, a one pot, rapid and room temperature photochemical Synthesis of transition metal (TM; Cu, Mn, Cr)-doped ZnSe/ZnS core/shell nanocrystals (NCs) was reported. FT-IR spectrum confirmed the capping of ZnSe by thioglycolic acid. XRD and TEM analysis demonstrated zinc blende phase NCs with an average size of around 3 and 5 nm for TM: ZnSe and TM: ZnSe/ZnS NCs, respectively. PL spectra of ZnSe NCs showed a broad emission with two peaks located at 380 and 490 nm related to exitonic and trap states emission, respectively. For ZnSe: Cu NCs, exitonic emission disappeared completely and PL intensity of trap states emission increased. For ZnSe: Mn and ZnSe: Cr NCs, the exitonic emission decreased gradually with the increase in the impurity concentration whereas trap state emission increased. Moreover a peak about 580 nm was appeared from 4T1-6A1 transition of the Mn impurity. ZnS Shell increased photoluminescence and stability of all of TM-doped ZnSe NCs.

Si2N2O is considered as a new great potential structural/functional candidate in place of Si3N4. The amorphous Si3N4 nanopowder was incorporated into silica sol by adding of MgO and Y2O3 as sintering aid. Synthesized powders were heated by spark plasma sintering at a heating rate of 100 o C/min yielded fully dense compacts at 1550 and 1750 o C for 40 min. The phase formation of samples was characterized by X-ray diffraction technique and Raman spectroscopy. The microstructure was studied by field emission scanning electron microscopy equipped by energy dispersive X-ray spectroscopy. Optical emissivity of Si2N2O phase was investigated by photoluminescence spectroscopy. The obtained results confirm that employing MgO in compare to the Y2O3 could promote the fabrication of a fully dense pure Si2N2O specimen by SPS at much shorter time than conventional sintering. Si2N2O have a strong, stable blue emission band centered at 455 nm with excitation wavelengths of 240 nm.

A simple, time effective and cost effective, method was reported for synthesis of nickel oxide nanostructure. The NiO nanostructure was synthesized by gamma-irradiation method from NiSO4 precursor. The solution was irradiated by 60 Co gamma-ray source at the dose rate of 40 Gy/min for determined time. The synthesized powders are characterized by means of X-ray powder diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX), Scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR) spectroscopy. The XRD and FTIR results confirmed the formation of high pure phase of NiO nanostructure. Results of scanning electron microscope (SEM) images showed that product has flowe-like nanostructure morphology with average particle size of 60 nm. The mechanism of product formation through water radiolysis was discussed. Three main stages can be considered for the radiolytic reactions of water in different time scales. (a) The physical stage (1 fs after the initial radiation interaction), (b) Physico-chemical stage (10 − 15 – 10 − 12 s), (c) The chemical stage (10 − 12 – 10 − 6 s).

In this study, highly ordered mesoporous silica material (SBA-15) functionalized with Diethyl 2-(9-fluorenyl) malonate as a flourophore is reported. The anchoring of flourophores to the hydroxyl group on SBA-15 surface was done with post synthesis method. The obtained materials were characterized by small and wide angle X-ray diffraction, N2 adsorption– desorption, Fourier transform infrared spectroscopy and thermogravimetric analysis that indicate the successful immobilization of Diethyl 2-(9-fluorenyl) malonate on the surface of mesoporous silica. This organic– inorganic hybrid displayed highly selective and sensitive to Fe 3+ ion over other cations such as Mg 2+, Cr 3+, Co 2+, Ni 2+, Cu 2+, Hg 2+ and Zn 2+. Turn-off photoluminescence of this material was remarkably observed for iron ions in comparing of the other cations. A good linearity between the fluorescence intensity of the prepared material and the concentration of Fe 3+ ion is constructed, which enables this martial as a fluorescence chemo sensor for detecting the Fe 3+ ion with a suitable detection limit.

The morphology of titanium dioxide and titanium dioxide-tungsten trioxide nanocomposite films fabricated by anodizing in a glycerol solution containing 0. 13 M NH4F and different quantity of Na2WO4 was investigated as a function of sodium tungstate concentrations. The effects of sodium tungstate concentration on the surface morphology were observed by scanning electron microscopy (SEM). It was clearly seen that highly ordered titanium dioxide nanotube array films were formed in an anodizing solution free of tungsten. With a gradual increase in the sodium tungstate concentration, these nanotube structures changed to nanohoneycombs, nanoporous and compact films without porosity. These findings indicate that the composition of anodizing bath is very important factor in determining the surface and structure of anodized films. UV-Visible spectroscopy data show that the band gap decrease with increasing sodium tungstate from 3. 23 eV for bare titanium dioxide to 2. 78 eV for titanium dioxide-tungsten trioxide nanocomposites. Photo catalytic activity of samples was evaluated by measuring the degradation of methylene blue dye under visible light irradiation. Results revealed that nanocomposite films have excellent photo catalytic performance.

Copper oxide nanoparticle (CuO-NPs) has been widely utilized in biomedical application due to their antibacterial function. It is well known that antibacterial characteristics of materials could be controlled using the size, shape and composition of the particles. The aim of this paper is to green synthesis CuO-NPs with various morphologies, using Aloe Vera extract as reducing agent and investigate the effect of particle size and shape on the antibacterial properties. Results demonstrated the formation of pure CuO-NPs with crystallite size in range of 9-23 nm, depending on the precursor type and concentration as well as aging time. Furthermore, increasing the concentration of copper precursor from 6 mM to 1M altered the morphology from rod shape to spherical. We also examined the inhibitory effects of CuO-NPs toward the gram-negative bacterium, Escherichia coli and a gram-positive bacterium, Staphylococcus aureus cultures throughout a 24 hr period. Based on our data, while CuO-NPs had significant growth inhabitation, this property depended on the morphology and size of particles. Rod shape CuO-NPs with smooth surface were the most effective morphology due to the largest surface area contacting and highest reactivity in contact with bacteria. Results also demonstrated that St aureus was more resistant to CuO-NPs samples because it was a Gram positive bacteria and Gram-negative ones like E. coli were more susceptible, while all particles were toxic to both organisms. Together, these results suggest that the difference between the surface free energy may be a cause for their morphology-dependent antimicrobial activity.

La 3+ and Sm 3+ -doped Bi2Mn2O7 nanocatalysts were synthesized in 1 M NaOH aqueous solution, via a stoichiometric 1: 1 Bi: Mn molar ratio hydrothermal method at 180 ° C for 48 h. Bi(NO3)3, MnO2, La(NO3)3 and Sm2O3 were used as raw materials. The synthesized nanomaterials were characterized by powder X-ray diffraction (PXRD) technique. Both of the La 3+ and Sm 3+ -doped Bi2Mn2O7 nanomaterials were crystallized in a cubic crystal structure with space group. The morphologies of the synthesized materials were studied by field emission scanning electron microscope (FESEM). The optical properties of the as-synthesized nanomaterials were studied by ultraviolet visible (UV-Vis) diffuse reflectance spectra (DRS). It was found that the optical band gaps were increased with dopoing La 3+ and Sm 3+ into Bi2Mn2O7. Catalytic performance of the synthesized nanomaterials were investigated in Biginelli reactions which showed excellent efficiency. Correlation between the catalytic performance with the band gap and hard/soft proportion of the metal ions was shown.

SnCl4/nano-sawdust was prepared as a carbohydrate-based catalyst containing of tin bearing cellulose units. The catalyst was characterized by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDS). The catalyst was applied successfully as a readily available, inexpensive, biodegradable and environmentally benign heterogeneous bio-based solid acid for the one pot synthesis of 2-substituted benzimidazoles and benzothiazoles.