Journal of Nano Structures
Volume:5 Issue: 1, Winter 2015

BiOCl microflowers were synthesized using bismuth nitrate pentahydrate and sodium chloride by microwave (MW) assisted synthesis method for 23 minutes at 180 W. Scanning electron microscopy (SEM) studies revealed a unique morphology of flower-like assemblies comprised of nanosheets. The X-ray diffraction (XRD) pattern showed that a highly pure and crystalline phase has been obtained. The energy dispersive X-ray (EDS) and photoluminescence (PL) and Fourier transform infrared (FTIR) spectroscopies were also used to evaluate the composition and structure of the product. The UV-vis diffuse reflectance spectroscopy (DRS) studies revealed the indirect band gap value of about 3.33 eV for the fabricated semiconductor.Photocatalytic studies confirmed that the BiOCl nanostructure could remove Rhodamine B (RhB) and Natural Red 4 (N-Red) dyes from the aqueous solutions by dye-photosensitized degradation mechanism under visible light illumination.

In this research nickel zinc ferrite nanoparticles with composition of Ni1-xZnxFe2O4 (where x=0, 0.3, 0.7, 1) were synthesized by a sol-gel method at 600 °C for 5 hours. The structure of nanoparticles was studied using X-ray diffraction pattern. The lattice parameter of ferrite nanoparticles was calculated and indicates lattice constant of nanoparticles depend on zinc concentration. The crystallite size of nickel zinc nanoparticles was calculated by Debye–Scherrer equation and the crystallite sizes of nanoparticles decreased by increasing in x contents. Morphology of nanoparticles was observed and investigated using the scanning electron microscopy. The grain size of nickel zinc ferrite nanoparticles were in suitable agreement with the crystalline size calculated by X-ray diffraction results. Magnetic properties of nanoparticles were examined with vibration sample magnetometer. Hysteresis loops of nanoparticles reveal the super-paramagnetic behavior.

NiCr2O4 normal spinel nanostructures were prepared via hydrothermal treatment at 180 °C for 12 h in the presence of cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulphate (SDS) and poly vinylpyrrolidone-25000 (PVP-25000) as capping agents and subsequent calcination process at 500 °C for 3 h. In this method, [Ni(en)2(H2O)2](NO3)2 and [Cr(en)3]Cl3.3H2O used as precursors and not utilized any alkaline or precipitating agent. Detailed characterization of the as-prepared nanostructures were carried out by Fourier transform infrared (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), UV-Vis diffuse reflectance spectroscopy (DRS). XRD revealed the formation of pure nickel chromite spinel phase and SEM showed the formation of uniform sphere-like nanoparticles. Furthermore, the photocatalytic degradation of acid black 1 as diazo dye used in textile and dyeing water pollutants was Investigated.

In this work at the first step calcium hydroxide nano-particles were synthesized via sono-chemical method at room temperature. At the second step aminated multi-walled carbon nano-tubes was prepared via chemical modification of surfaces of CNT. Finally modified-MWCNT and Ca(OH)2 were added to paraloid matrix by aid of ultrasonic irradiation. Paraloid-modified-MWCNT-Ca(OH)2 nanocomposite was used as a protection agent applicable in cultural heritage preservation. This nanocomposite can be used against acid rain that is destructive agent in historic monuments. One of the main advantages of paraloid as a consolidant is that it is stronger and harder than polyvinyl acetate without being extremely brittle. Nanostructures were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Thermal stability behavior of paraloid filled with calcium hydroxide was investigated by thermogravimetric analysis (TGA). Our results show that the MWCNT-Ca(OH)2 nanostructure can enhance thermal stability property of the paraloid matrix. Nano-additives like a barrier slow down volatilization of paraloid chains against heat.

Surface and small scale effects on free transverse vibration of a single-walled carbon nanotube (SWCNT) fitted with Y-junction at downstream end conveying viscose fluid is investigated in this article based on Euler-Bernoulli beam (EBB) model. Nonlocal elasticity theory is employed to consider small scale effects due to its simplicity and efficiency. The energy method and Hamilton’s principle are used to establish the corresponding motion equation. To discretize and solve the governing equation of motion the Galerkin method is applied. Moreover, the small-size effect, angle of Y-junction, surface layer and Pasternak elastic foundation are studied in detail. Regarding fluid flow effects, it has been concluded that the fluid flow is an effective factor on increasing the instability of Y-SWCNT. Results show that increasing the angle of Y-junction enhances the flutter fluid velocity where the first and second modes are merged. This work could be used in medical application and design of nano-electromechanical devices such as measuring the density of blood flowing through such nanotubes.

This study reports the fabrication of n-TiO2/p-Si hetrojunction by deposition of TiO2nanowires on p-Si substrate. The effect of system pressure and the current-voltage (I-V) characteristics of n-TiO2/p-si hetrojunction were studied. The morphology of the samples was investigated by Field Emission Scanning Electron Microscopy (FESEM) which confirms formation of TiO2 nanowires that their diameters increase with increasing the pressure of system. The I-V characteristics were measured to investigate the hetrojunction effects of under forward and reverse biases at different system pressure by sweeping in the voltage from 0 to +6 V, then to -6 V, and finally reaching 0 V. TiO2/Si diodes in the system pressure 60 mbar and 30 mbar indicated that a p-n junction formed in the n-TiO2/p-Si hetrojunction. But as the system pressure increased to 1000 mbar, the I-V characteristics became inversed. This treatment can be scribed by the change of the energy band structure of TiO2.

In this paper, tin dioxide nanoparticles were synthesized by a fast and simple co-precipitation method. For SnO2 preparation, we used ammonia as precipitation agent and bis (acetylacetone) ethylene diamineas as capping agent. By changing in SnCl4, acacen mole-ratio different morphologies were obtained. This semiconductor nanostructure has photo-catalyst activities and can degrade organic dyes as water pollution. The synthesized materials were characterized by X-ray diffraction (XRD) pattern, scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. In situ poly vinyl alcohol-tin dioxide nanocomposite was prepared and results show that the SnO2 nanostructure can improve flame retardant property of the PVA matrix.

In order to fabricate transparent TiO2 nanotube dye-sensitized solar cells, anodically growth nanotube membranes are detached from Ti substrate by a re-anodization method. The membranes are transferred on FTO glass by two different methods. At the first one, 100mM Ti-isopropoxide is used to make TiO2 nanoparticles for adhering TiO2 nanotube membranes to FTO and in the second one a commercial TiO2 nanoparticle paste is used as connector material. In order to investigate the effect of annealing temperature on the crystallinity of the photoanodes, they were annealed in temperatures from 350 to 650°C. All of the annealed photoanodes show high crystallinty and pure anatase phase in both cases. However nanoprticles with large diameter about 500nm and no homogeneity of dispersion of them at the first method leads to week interconnection between membranes and FTO glasses but good interconnection at the second method leads to high power conversion efficiency of 6.13% under 1 sun illumination without any extra treatment.

NiCu alloy nanowires arrays were embedded into the anodic aluminum oxide (AAO) template by ac-pulse electrodeposition. Different off-time were used in electrolyte with constant concentration of Ni and Cu and acidity of 3. The effect of deposition parameters on alloy contents was investigated by studying the microstructure and magnetic properties of as-deposited NiCu alloy nanowires. Atomic force microscopy, x-ray analysis were employed to investigate the morphology and microstructure of prepared sample. Vibrating sample magnetometer was also used in order to study the magnetic properties of nanowires array. The obtained results revealed, with increase in off-time, Cu non-magnetic element content increases through electroless process.