جستجوی مقالات مرتبط با کلیدواژه « نانولوله » در نشریات گروه « شیمی »

Magnesium ion rechargeable batteries are useful for storing electrical energy because the abundance and energy density of magnesium is higher than lithium. In this research, the primary structures of the (4, 4), (5, 5) and (6, 6) single-walled carbon nanotubes were optimized using the M06-2X method and the 6-31g(d,p) basis set using Gaussian 09 program package. Then, the interaction of magnesium ion with these structures was studied to evaluate their ability to make magnesium batteries. The results show that the complexes created from these structures have good binding energies and the larger the outer diameter of the nanotubes, the more favorable the binding energy. In fact, the energy gap of these nanotubes decreases with the increase of the diameter of the nanotubes and affects their binding strength to magnesium ions. On the other hand, boron nitride nanotubes corresponding to carbon type were also optimized with a similar method and the interaction of magnesium ion with these structures was also investigated. The results show that boron nitride nanotubes with smaller outer diameters form complexes with higher binding energies with magnesium ions. In general, both types of these nanotubes are good options for preparing the anode material in magnesium ion batteries. Finally, increasing the binding energy of their complexes with magnesium ions is associated with increasing battery voltage.

In this paper, the optical properties of nanosheet and (6,6) armchair As2GeSe nanotube (the real and imaginary part of dielectric function, spectrum of energy loss, refractive index, extinction coefficient, and absorption coefficient) are investigated based on the density functional theory. The results obtained from the optical properties of the nanosheet show the anisotropy of this compound, especially at low and middle energies. The behavior of the dielectric function of this material is like a semiconductor material. The main peaks of the imaginary part of dielectric function for in-plane and nanotube growth directions start from low energies up to about 6 eV. The optical transmissions below the Fermi level are associated with the p-orbitals for the As, Ge, and S atoms and above the Fermi level to the p-orbitals of the Se and As atoms. Our results show that the highest reflectance for both in-plane-direction at the energy of 5.66 eV is 46%.

To monitor air quality and medical use, metal-oxide semiconductor are highly-sensitive and a good option for detecting small amounts of gases. In this paper, we study the analytical characteristics of the ethanol gas sensor made of ZnO nanotubes. For this purpose, ZnO nanotube were synthesized using a rapid electrochemical method in 40 minutes and used to make a sensor. The response of the gas sensor which based on the ratio of the electrical resistance of the sensor in the presence of gas samples to its electrical resistance in the air, was investigated. The sensor's analytical characteristics with a detection limit of 6.5 ppm and a good correlation coefficient of 0.9998 for the calibration curve, a relative standard deviation of 0.52 and a high recovery speed of 20 seconds, indicating that the sensor is sensitive, repeatable and have fast response.

In this study, since alkaloids are the main substance of many bitter drugs, so structural, electron, reactivity, aromaticity and thermochemical properties of alkaloid purine in the presence of a nanotube and in the absence of nanotubes are investigated. Therefore, the non-bonded interaction of single-wall boron nitride (8.8) with a length of 5 angstroms with theophylline has been studied theoretically. The effects of electron unconsideration, dipole-dipole interactions and spatial suppression on structural and electron properties and the reactivity of the theophylline structure in the presence of single-wall boron nitride nanotubes (8,8), using quantum mechanical calculations of density functional theory at B3LYP and 6-31G * basis set have been reviewed. Frequency calculations were performed to determine the thermodynamic functions and vibration frequencies in the gas phase. Also, NMR isotropic parameters are calculated using the GIAO method to obtain structural information, dynamic behavior and inter-molecular interactions, and the results obtained from NMR spectra are discussed and concluded.

Today, pollution of water resources by petroleum compounds and its presence in the food chain is one of the environmental problems. Therefore, the removal of these compounds during the water purification process is very important. The aim of this study was to investigate the removal of benzene and toluene monoaromatic compounds by functionalized chitosan biopolymer. First, chitosan hydrogels were prepared. It was then functionalized with carbon nanotubes at three levels (zero, 10 and 20%). The influence of concentration and type of hydrogel, pH, contact time and different concentrations of BT on adsorption was investigated. The experiments have shown that nano-hydrogels prepared to remove BT from aqueous solutions. Chit /CNTS hydrogel with 20% nanotube is able to remove 500 mg/ 100 ml of the contaminant at a concentration of 200 mg/ l in 40 minutes at the inherent pH of the solution with the highest percentage.

In this study the synthesis of nano Titanium oxide / zinc oxide based on single wall carbon nanotubes was evaluated that were prepared by co-precipitation method. Using zinc choloride and titanium choloride in benzyl alchol and the obtained powders were calcinated at 4000c. It was functionalized using 3-aminopropyl riethoxysilane and further anchored on carboxylated carbon nano tubes via the formation of an Amide bond to give the TiO2/ZnO nanocomposites. The structure and morphology of the resulting particles were characterized by XRD and FT IR analysis.

The purpose of this research is preparation of titanium dioxide nanotubes modified with nickel nanoparticles as a photocatalyst sensitive to visible light. For this purpose, at first, titanium dioxide nanotubes was synthesized on the surface of titanium using electrochemical anodizing; then by immersion of prepared nanotubes in an aqueous solution of nickel nitrate, film of nickel nanoparticles on the surface of the nanotubes were produced. Morphology and crystal structure of the resulting films were studied using scanning electron microscopy and X-ray diffraction. To determine the composition and confirmation the presence of nickel nanoparticles, we used from energy dispersive X-ray spectroscopy (EDX). Then, photocatalysts efficiency of obtained nano-catalysts for the removal of methylene blue dye was performed. Photocatalytic test results showed that produced nanocatalysts have good activity.