جستجوی مقالات مرتبط با کلیدواژه "solid state" در نشریات گروه "شیمی"

A Bi2O3 nanomaterial was fabricated by a facile and low temperature solid state method using a basic bismuth nitrate raw compound at 400 ˚C and 14 h. Rietveld analysis data indicated that α-Bi2O3 was crystallized well in monoclinic crystal system with the space group of P121/c1. The morphology of the synthesized material was studied by field emission scanning electron microscope (FESEM). The direct band gap energy (Eg) value was calculated by ultraviolet – visible (UV-Vis) spectroscopy. The peaks at 400 – 550 cm-1 are assigned to oxygen – metal – oxygen (O-M-O) vibrations. The data showed that the Eg of the synthesized material was about 2.2 eV. In addition, the vibrating-sample magnetometer (VSM) analysis data confirmed that the synthesized sample had ferromagnetic behavior. Further, gas sensing property of the synthesized Bi2O3 nanomaterial for carbon monoxide gas was studied, and the data confirmed the good sensitivity of the prepared sensor at low CO concentrations.

Nanostructured Bi2Sn2O7 and Bi2MxSn2O7 (M = Y3+, Eu3+, Gd3+ and Yb3+)nanomaterials were synthesized by conventional one-step solid state crystalgrowth reactions among Bi(NO3)3, SnCl2 and M2O3 raw materials at 800 ̊C for 10 and 15 h. The doped nanomaterials were synthesized to study the capacity of the crystal system to locate each of the dopant ions into the crystal system cavities. The synthesized nanomaterials were characterized by powder X-ray diffraction (PXRD) technique. Rietveld analysis showed that the obtained materials were crystallized well in orthorhombic crystal structure with the space group Aba2. The PXRD data revealed that dopant ion type had a considerable influence on the crystal phase purity of the obtained targets. The morphologies of the synthesized materials were studied by field emission scanning electron microscopy (FESEM) technique. Ultraviolet-visible spectra analysis showed that the synthesized nanomaterials had strong light absorption in the ultraviolet light region. Photocatalytic performance of the synthesized nanomaterials was investigated for the degradation of pollutant Malachite Green under solar light condition. The optimum conditions were modeled and obtained by design expert software for Bi2Sn2O7 that was synthesized at 800 ̊C for 10 h which were 0.06 mL H2O2, 12 mg catalyst and 40 min for the removal of 50 mL of 40 ppm MG solution. The degradation yield in these conditions was 100 %. The photocatalytic degradation fitted to the Langmuir–Hinshelwood kinetic model. As a result of the model, the kinetic of degradation followed a pseudo-zero-order kinetic model.

Nanostructured Ni1-xLnxSb2O6 (Ln = Eu, Gd, Ho and Yb) powders were synthesized via stoichiometric 1:2 Ni:Sb molar ratio by solid state reaction at 800 ºC for 8 h using Ni(NO3)2, Sb2O3, Eu2O3, Gd2O3 and Ho2O3 raw materials. The synthesized materials were characterized by X-ray diffraction (XRD) technique. Structural analyses were done by FullProf program employing profile matching with constant scale factor. The results showed that the patterns had a main orthorhombic NiSb2O6 crystal structure with P42/mbc space group. The morphologies of the synthesized materials were studied by field emission scanning electron microscope (FESEM) which showed that the synthesized samples had sponge morphology. Ultraviolet – Visible (UV-Vis) spectroscopy showed that the smallest direct optical band gap energies were in the ranges of 1.6 to 1.8 eV suggesting a high efficient photocatalytic activity. Photocatalytic performance of the synthesized nanomaterials was investigated for the degradation of pollutant Malachite Green (MG) in aqueous solution under visible light condition. It was found that the optimum conditions were 0.04 mL H2O2, 30 mg catalyst, and 35 min reaction time. It was found that the synthesized NiSb2O6 nanocatalyst had very good efficiency in aqueous solution under the optimized conditions at the presence of visible light irradiation. The degradation yield at the optimized conditions was 96 %. The optimum photocatalytic condition was used to study the performance of the other synthesized materials in the photocatalytic degradation process.

In this research, pure-phased Ni0.5Cu0.5Cr2O4 synthesis via solid-state method successfully. In the other part, the photocatalytic activity of synthesized Ni0.5Cu0.5Cr2O4 was investigated in various aspects by using Malachite green as a pollutant and compared with the number of previous photocatalysts. The Photocatalysis process is a promising technique for solving many current environmental and energy issues. The environmental pollutant, especially water contaminates, can influence human health, animals, and the ecosystem. Dye as one of the most important pollutants has investigated in this study. In this study, purification and crystal structure of material have been determined by X-Ray powder Diffraction (XRD) method. The results showed that the synthesized Ni0.5Cu0.5Cr2O4 was crystallized in tetragonal structure with space group I 41/AMD. The morphology of obtained materials was modified by Field Emission Scanning Electron Microscope (FESEM). Also, the material was characterized by Fourier-Transform InfraRed (FT-IR) spectroscopy and Thermo Gravimetric Analysis (TGA).

Nanostructures of magnesium oxide is one of the most attractive materials which have shown various applications in many aspects of industries. So, finding a controllable and inexpensive technique to produce desirable nanostructures of MgO is valuable. In this work, magnesium oxide (MgO) with different morphologies was successfully prepared via a simple solid-state method. The molar ratio of sodium hydroxide to magnesium salt precursor was obtained 1 to 8. Furthermore, the effect of different magnesium precursors (magnesium chloride and magnesium acetate) on the morphology of MgO was investigated. It was shown that adding halide salts (NaX) to the solid-state reaction media, in spite of the noteworthy influence on the product morphology, facilitate the formation of MgO phase from Mg(OH)2. The synthesized magnesium oxide particles were characterized by Fourier transform infrared (FTIR) spectrometer, scanning electron microscope (SEM) and X-ray diffraction (XRD). Synthesized magnesium oxide particles were used to remove congored dye from waste water.

LiMn2O4 spinel cathode materials have been successfully synthesized by solid-state reaction. Surface of these particles were modified by nanostructured LiFePO4 via sol gel dip coating method. Synthesized products were characterized by thermally analyzed by Thermogravimetric and Differential Thermal Analysis(TG/DTA), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray (EDX) spectroscopy. The results of electrochemical tests showed that the charge/discharge capacities improved up to 120 mAh/g and charge retention of battery enhanced over %95. This improved electrochemical performance is caused by LiFePO4 phosphate layer on surfaces of LiMn2O4cathode particles.

CaCO3 nanoparticles have been synthesized via heat-treatment of a new precursor and solid state reaction. Effect of calcinations temperature and quantity of surfactant on particle size has been investigated. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared (FT–IR) spectroscopy.