Journal of Nanostructures

Phytosynthesis and Biological Activities of Fluorescent CuO Nanoparticles Using Acanthospermum hispidum L. Extract

Shreyas Pansambal — 2017-10-31

Copper oxide nanoparticles (CuO-NPs) synthesized by an implicitly environmentally benign process using Acanthospermum hispidum L. aqueous plant extract as an effective bio-oxidizing/bio-reducing agent. Phytochemical screening of the fresh aqueous leaves extract showed the presence of coumarins, tannins, saponins, phenols, flavonoids, sterols and volatile oils. Fourier transform infrared spectroscopy confirmed the possible biomolecules responsible for the formation of copper oxide nanoparticles. X-ray diffraction patterns revealed the monoclinic phase of the synthesized copper oxide nanoparticles. The average size, shape and the crystalline nature of the nanoparticles were determined by field emission scanning electron microscopy and transmission electron microscopy analysis. Energy-dispersive X-ray spectroscopy analysis confirmed the presence of elements in the synthesized nanoparticles. Photoluminescence and fluorescence life-time spectroscopy showed luminescence properties of copper oxide nanoparticles. Furthermore, Copper oxide nanoparticles evinced highly robust antimicrobial, antimalarial and antimycobacterial activity against Pseudomonas aeruginosa, Streptococcus pyogenes, Staphylococcus aureus, Escherichia coli, Plasmodium falciparum and Micobacterium tuberculosis H₃₇RV. The current study demonstrates convenient utilization of Acanthospermum hispidum L. extract as a fuel for the efficient synthesis of copper oxide nanoparticles through a green synthesis method to obtain significantly biologically active material.

Green Synthesis of Iron Oxide-Palladium Nanocomposites by Pepper extract and Its Application in Removing of Colored Pollutants from Water

Shahab Khaghani — 2017-10-31

Fe₃O₄ nanoparticles were synthesized in the presence of pepper extract as a capping agent via a hydrothermal method. Then palladium nanoparticles and Fe₃O₄-Pd nanocomposites were synthesized with the aid of pepper extract as a reducing agent. Vibrating Sample magnetometer illustrated that Fe₃O₄nanoparticles have super paramagnetic behaviour. The photo catalytic behaviour of Fe₃O₄-Pd nanocomposites was investigated using the degradation of two azo dyes under ultraviolet light irradiation. The results show that nanocomposites have feasible magnetic and photo catalytic properties. The prepared products were characterized by X-ray diffraction pattern, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy.

Structural, Magnetic and Photocatalytic Properties of BiFeO3 Nanoparticles

Seyyed Morteza Masoudpanah — 2017-10-31

Single phase BiFeO₃ nanoparticles as a visible light photocatalyst were successfully synthesized by thermal decomposition of the glyoxylate precursor. The glyoxylate precursors were formed by the redox reaction between ethylene glycol and nitrate ions. The phase evolution, structure and optical properties of BiFeO₃ nanoparticles were characterized by X-ray diffraction, electron microscopy and UV–Vis spectroscopy methods. The BiFeO₃ nanoparticles showed the quasi spherical shape. The BiFeO₃ nanoparticles synthesized at 500 °C showed the weak ferromagnetism behavior, due to the size confinement effect, in spite of the antiferromagnetic behavior of the BiFeO₃ nanoparticles synthesized at 600 °C. The BiFeO₃ nanoparticles exhibited strong absorption in the visible region with the optical band gap calculated from Tauc’s plot. The optical band gap decreased from 2.10 to 2.08 eV by the increasing of thermal decomposition temperature. Moreover, the BiFeO₃ nanoparticles were used for the degradation of methylene blue as a typical dye pollutant under direct sunlight irradiation.

Diverse Nano Dimension of SDS, PEG and CTAB Roofed MgO Nano Powder Synthesized by Co-precipitation Method

Rajendran Varadharajan — 2017-10-31

The SDS, PEG and CTAB roofed MgO nano powders were synthesized by co-precipitation method. The sintered nano powders was shown Fm-3m space group with cubic phase obtained by the XRD pattern. The lattice strain was calculated to be used Williamson-Hall equations (W-H). The formation of Mg-O bond and hydroxyl radicals on the surface were confirmed by the FTIR analyses. The TEM revealed that the morphology of sintered nano powders has three different dimensions (0D, 1D, 2D) with average crystallites size was about ̴ 20-80 nm and length usually 200-500 nm. The UV-DRS spectra show that the ionic surfactants roofed MgO leads to band gap shrinkage. The evaluated optical band gap energy is Eg= 4.10eV, 3.41eV and 3.12eV for SDS, PEG and CTAB-MgO nano powder respectively. Also extending light absorption towards the visible region due to decrease in crystallite size of surfactants roofed MgO nano powders utilizing for photocatalytic purpose and opto electronic devices.

Preparation and Characterization of ZnO Thin Layers with Various Percentages of Gallium Impurities

Mohammad Hossein Manzari — 2017-11-01

In this study, thin films of pure ZnO and doped ZnO with different percentages of gallium (0.5, 1, 2 and 4vt. %) on the glass substrates were deposited by using sol-gel method via spin coating technique at 2500 rpm, and all layers were annealed at 200°C for 1h and then Were examined their electrical, optical and structural properties. Concentration of all solution was 0.1M. The results show that the optimized layer is 0.5% GZO. By examining the transmittance spectrums we find that by doping the transparency of samples were improved and all samples in the visible areas 400-800nm are transparent. The electrical conductivity of all samples has been measured by four-point probe technique. The electrical conductivitys of pure ZnO sample and 0.5% GZO are 910^-5 S/cm and 110^-4 S/cm respectively. It can be a good choice for optoelectronic applications. Also X-ray diffraction results showed that diffraction peaks of 0.5% GZO sample have a small changes towards lower angles compared to the diffraction peaks of ZnO.

Synthesis of Serrated GaN Nanowires for Hydrogen Gas Sensors Applications by Plasma-Assisted Vapor Phase Deposition Method

Mahdi Gholampour — 2017-11-01

Nowadays, the semiconductor nanowires (NWs) typically used in hydrogen gas sensors. Gallium nitride (GaN) with a wide band gap of 3.4 eV, is one of the best semiconductors for this function. NWs surface roughness have important role in gas sensors performance. In this research, GaN NWs have been synthesized on Si substrate by plasma-assisted vapor phase deposition at different deposition time, without using any catalyst. The precursors were gallium (Ga) metal and nitrogen (N) plasma. The GaN NWs were characterized by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy )FE-SEM(, photoluminescence (PL) and Raman Spectroscopy. The results indicate the serrated morphology for hexagonal structure of GaN NWs. The band gap energy of GaN NWs was obtained about 3.41 eV. The Raman results show two Raman active optical phonons at 563 cm^-1 and 720 cm^-1 due to E₂(high) and A₁(LO), respectively and indicates a good crystallinity of the NWs with the presence of defects in the crystal lattice.

Design, Optimization Process and Efficient Analysis for Preparation of Copolymer-Coated Superparamagnetic Nanoparticles

Mahnaz Mahdavi Shahri — 2017-11-01

Magnetic nanoparticles (MNPs) are very important systems with potential use in drug delivery systems, ferrofluids, and effluent treatment. In many situations, such as in biomedical applications, it is necessary to cover inorganic magnetic particles with an organic material, such as polymers. A superparamagnetic nanocomposite Fe₃O₄/poly(maleic anhydride-co-acrylic acid) P(MAH-co-AA) with a core/shell structure was successfully synthesized by a dispersion polymerization route. Iron oxide nanoparticles were used as a core, and P(MAH-co-AA) as a shell was covered on the surface of the Fe₃O₄magnetic nanoparticles. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that the Fe₃O₄/P(MAH-co-AA) magnetic nanocomposite were highly uniform in size and cubic shape with the average size about 17.06 nm. X-ray diffraction confirmed magnetite cores and also indicated that the binding process did not change the phase of Fe₃O₄. Vibrational sample magnetometer (VSM) revealed the nanoparticles were superparamagnetic and the saturation magnetization was 83.6 and 46.6 emu g^-1 for pure Fe₃O₄ and composite nanoparticles, respectively. Measurements by VSM also showed that the degree of saturation magnetization increased with increasing iron oxide concentration from 1% to 7 wt % of Fe₃O₄.

Photocatalyst Ag@N/TiO2 Nanoparticles: Fabrication, Characterization, and Investigation of the Effect of Coating on Methyl Orange Dye Degradation

Pourya Mehdizadeh — 2017-11-01

In this research, N-doped TiO₂ (N/TiO₂) nanoparticles have been synthesized by a sol-gel method. N/TiO₂ nanoparticle has been coated with Ag metal by photochemical method. Triethylamine, N(CH₃CH₂)₃, have been used as precursors of Nitrogen, titanium tetraiso-propoxide (TTIP), Ti[OCH(CH₃)₂]₄, used as precursors of titanium and Ag(NO₃)₂ used as precursors of Silver in synthesis of these nanoparticles. The photocatalytic activity has been perused for degradation of Methyl Orange (MO) as model of natural pollutants. Synthesized nanoparticles were analyzed by X-ray diffraction spectroscopy, Fourier transform spectroscopy, scanning electron microscopy, and energy dispersive of X-ray spectroscopy and diffuse-reflectance of Ultraviolet-visible spectroscopy. Results illustrated that under both visible and ultraviolet light, N/TiO₂ nanoparticles had medium activity but with coating, the activity in each area efficiently improved. The presence of 1.5% Ag coated on N/TiO₂ (with 2:1 mole ratio) resulted to the highest activity under visible and Ultraviolet irradiation in the catalyst.

Preparation of Nanocomposite Heteropoly Metalate Based Graphene Oxide: Insight into Cadmium Adsorption

Hanieh Fakhri — 2017-11-01

We developed a facile strategy for preparation of heteropoly metalate/graphene oxide nanocomposite as a new ion exchanger for cadmium ion removal from aqueous solution. The synthesized nanocomposite was characterized by X-ray powder diffraction (XRD), UV-Vis spectroscopy, FT-IR spectroscopy and Raman spectroscopy. Our findings indicated that the combination of heteropoly metalate nanoparticles with graphene oxide results in an excellent performance for cadmium ions removal of aqueous solution. The experimental data demonstrated that the adsorption isotherm fitted well by Langmuir model with maximum sorption capacity of 47.85 mg/g. The removal behavior of this compound was evaluated by various parameters such as contact time, concentration of metal ion, pH of solution and temperature. In addition, the effect of interfering cations on the cadmium adsorption is investigated. Dubinin–Radushkevich model represented physical sorption occurred as bold mechanism that is confirmed by thermodynamic parameters. Also, the obtained data of the recycling experiment presented excellent stability after 4 consecutive cycles. This study indicated heteropoly metalate supported graphene oxide with good performance for removal of cadmium can be used for treating polluted solution by other heavy metal.

Study of Composition and Optical Properties of Chemically Deposited Pd-xSb2S3 Thin Films

Patrick Akata Nwofe — 2017-11-01

The study reports on the effects of different concentration of palladium impurities on the compositional and optical properties of Palladium Doped Antimony Sulphide (Pd-xSb₂S₃) thin films grown by the chemical bath deposition method. The films were grown at room temperature and other deposition conditions such as the bath temperature, pH, complexing agents were kept constant. The concentration of the dopants were varied between 0.1 M to 0.3 M. The films were annealed at an annealing temperature of 200 ^oC for 1 hour. The films were characterised using the Rutherford Back Scattering (RBS) techniques and optical spectroscopy (transmittance versus wavelength, absorbance versus wavelength) to investigate the composition, and optical constants (optical absorption coefficient, energy band gap, and extinction coefficient) respectively. X-ray diffractometry and Scanning electron microscopy were also used to investigate the structural and morphological properties of the layers. The results show that the transmittances of the doped layers were higher compared to the as-deposited layers. The energy band gap was direct, and were found to be decreased for the doped layers, compared to the as-grown films. The values of the energy band gap were typically ≤ 2.30 eV for the former and 2.48 eV for the latter. These values strongly suggest the use of these films in optoelectronic applications especially in solar cell devices.