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1.
In the present paper, novel t-Se microspheres with holes were successfully prepared via a facile solution-phase approach at 150 °C for 20 h, employing SeO2 and glucose as reagents, poly(vinylpyrrolidone) (PVP) as the surfactant. The phase and morphology of the product were characterized by means of powder X-ray diffraction (XRD), energy dispersive spectrometry (EDS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The conversion from α-Se to t-Se was investigated by a series of experiments and a possible formation process was suggested based on the experimental results. 相似文献
2.
[Bis(2-hydroxy-1-naphthaldehydato)copper(II)] complex, as a novel precursor, was employed in thermal decomposition process to synthesize metallic copper nanoparticles using oleylamine (C18H37N) as capping agent. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible (UV-vis) spectroscopy. The synthesized copper nanoparticles have a fcc structure with average size 20-35 nm. 相似文献
3.
Luminescence properties of hierarchical CaMoO4 microspheres derived by ionic liquid-assisted process
Chao Xu 《Journal of luminescence》2009,129(5):474-5219
Hierarchical calcium molybdate (CaMoO4) nanostructured microspheres were synthesized via a facile room-temperature route assisted by an ionic liquid, 1-n-butyl-3-methylimidazolium chloride. The product was characterized by means of X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that micro-scaled CaMoO4 powders were assembled by nanoparticles with diameters ranging from 10 to 20 nm. The optical absorbance, photoluminescence emission (PL), and luminescence excitation (PLE) were investigated. The PL spectra excited at 273 nm have a strong green emission band maximum at 511 nm, which is attributed to the charge-transfer transitions within the MoO42− complex, and the luminescence intensity indicated a good luminescence quality of the CaMoO4 materials. By varying the amount of this assisted agent, we found that the ionic liquid played a crucial role as a surfactant in the formation of CaMoO4 materials with uniform hierarchical structure, which may be beneficial to the luminescence performance. This study presented a promising preparation strategy towards other luminescent materials. 相似文献
4.
Nanosized zinc oxide has been synthesized through a novel single step solution combustion route using citric acid as fuel. The X-ray diffraction (XRD) analysis revealed that the synthesized ZnO nanopowder has the pure wurtzite structure. The phase purity of the nanopowder has been confirmed using differential thermal analysis (DTA), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR). The morphology and crystalline size of the as-prepared nanopowder characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that the powder consisted of a mixture of nanoparticles and nanorods. The nanocrystalline ZnO could be sintered to ∼97% of the theoretical density at 1200 °C in 4 h. The dielectric constant (εr) and dielectric loss (εi) of sintered ZnO pellets at 5 MHz were 1.38 and 9×10−2, respectively, at room temperature. 相似文献
5.
Gaoke Zhang Fan Lü Junling Yang Baibiao Huang 《Journal of Physics and Chemistry of Solids》2010,71(4):579-159
Nanometer Bi2WO6 catalyst with visible-light responsive was prepared by a sol-gel method in the presence of EDTA. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectrum, Fourier transform infrared (FTIR) spectrum, Brunauer-Emmet-Teller (BET). The UV-vis diffuse reflectance spectrum of the as-prepared sample shows a markedly blue-shift as compared to that of the sample obtained by a solid-state reaction. The as-prepared samples exhibited higher activities than that synthesized by the solid-state reaction for 4BS photodegradation under visible-light irradiation (λ>400 nm) and the sample prepared at 450 °C exhibited the highest photocatalytic activity. 相似文献
6.
Nanoparticles of Zn1−xCuxS with various dopant contents (0 ≤ x ≤ 0.15) were prepared in water by refluxing for 90 min at about 95 °C. Powder X-ray diffraction (XRD) patterns of the nanoparticles demonstrate that loading of Cu2+ ions does not change the crystal structure of ZnS. Scanning electron microscopy (SEM) images demonstrate that size of the nanoparticles decreases with increasing Cu2+ ions. UV-Vis diffuse reflectance spectra (DRS) of the nanoparticles show significant absorption in visible light region. Adsorption capacity of the nanoparticles for methylene blue (MB) increases with mole fraction of copper ions. Photocatalytic activity of the nanoparticles toward photodegradation of MB was evaluated under visible light irradiation. The results indicate that Zn0.85Cu0.15S nanoparticles exhibit highest photocatalytic activity among the prepared samples. Moreover, effects of refluxing time applied for preparation of the nanoparticles and calcination temperature were investigated. 相似文献
7.
Synthesis process of nanowired Al/CuO thermite 总被引:1,自引:0,他引:1
M. Petrantoni C. Rossi V. Conédéra D. Bourrier P. Alphonse 《Journal of Physics and Chemistry of Solids》2010,71(2):80-85
Al/CuO nanothermites were fabricated by thermal oxidation of copper layer at 450 °C for 5 h and by aluminum thermal evaporation: thermal evaporation allows producing thin layer less than 2 μm in size. The copper has been deposited by electroplating or thermal evaporation depending on the required thickness. The obtained diameter of Al/CuO nanowires is 150-250 nm. Al/CuO nanowires composite were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and differential thermal analysis (DTA). Two distinct exothermic reactions occurred at 515 and 667 °C and total energy release of this thermite is 10 kJ/cm3. 相似文献
8.
Sb2O3 nanowires with diameters of ∼233 nm and microspheres assembled by these nanowires were successfully synthesized by a simple poly-(vinylpyrrolidone) (PVP) assisted hydrothermal method. The morphologies, nano/microstructures and optical properties of the as-grown nanowires and microspheres were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-vis diffuse reflection spectrum. It has been found that the experimental parameters, such as mineralizers, played crucial roles in the morphological control of Sb2O3 nanowires. The possible growth mechanism of microspheres has been proposed. 相似文献
9.
Nanometer-scale TiO2 particles have been synthesized by sol-gel method. It was incorporated in a glass-based silica aerogel. The composite was characterized by various techniques such as particle size analysis, scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray diffraction (XRD), infrared spectroscopy (IR) and photoluminescence (PL). The bulk glass presents a strong luminescence at wavelengths ranging from 750 to 950 nm. This PL was attributed to various non-bridging oxygen hole centers (NBOHCs) defects resulting from thermal treatment and crystallization of TiO2 at the interface between titania nanoparticles and silica host matrix. 相似文献
10.
Graphene encapsulated metallic copper nanoparticle composite was prepared by reduction of stage-2 CuCl2-graphite intercalation compounds, using both metallic potassium and potassium borohydride/ethylenediamine matrix as reducing reagents. X-ray diffraction, high-resolution transmission electron microscopy and Raman spectroscopy were employed to characterize the reduction products. The results show that the copper nanoparticles in the graphite matrix are 30 to 70 nm in size. The copper concentration in the reduction product is experimental-condition dependant. A severe structure disorder of graphitic carbon occurs during the reduction procedure. The formation procedure of copper particles in the graphene sheets is discussed briefly. 相似文献
11.
Metastable VO2 nanobelts, designated as VO2 (B), were successfully fabricated by a facile hydrothermal route in the presence of V2O5 and glucose. The samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), transmission electron microscopy (TEM), selected area electronic diffraction (SAED), high-resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM) techniques. The main synthesis parameters such as temperature, reaction time and molar ratio of the starting materials have been also discussed. The results showed that pure B phase VO2 nanobelts with high crystallinity can be prepared easily at 180 °C in 24 h at the molar ratio of V2O5:glucose=1:1. Typically, the belt-like products were 0.6-1.2 μm long, 80-150 nm wide and 20-30 nm thick. It is noted that the whole process is free of any harmful reducing reagents and surfactants, and valuable gluconic acid can be formed as the main by-product. From an economic and environmental point of view, the present approach is particularly fit for the synthesis of VO2 (B) nanobelts on a large scale. 相似文献
12.
An ultrasonic-assisted and environmentally favorable method is proposed for preparation of CdS nanoparticles in the presence of a halide-free and low-cost room-temperature ionic liquid (RTIL), 1-ethyl-3-methylimidazolium ethyl sulfate, ([EMIM][EtSO4]). The prepared samples were characterized by powder X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM) and Fourier transform-infrared (FT-IR). Diffuse reflectance spectra (DRS) of the products reveal a blue shift of 1.45 eV relative to bulk CdS, which can be attributed to the quantum confinement effect of the prepared nanoparticles. Investigation of photocatalytic activity for the CdS nanoparticles towards photodegradation of methylene blue (MB) demonstrates that photodegradation of MB increases with RTIL content of the media using visible and UV irradiations. 相似文献
13.
Colloidal cupric oxide (CuO) nanoparticles were formed by using a colloid-thermal synthesis process. X-ray diffraction patterns, transmission electron microscopy (TEM) images, high-resolution TEM images, and X-ray energy dispersive spectrometry profiles showed that the colloidal CuO nanoparticles were formed. The optical band-gap energy of CuO nanoparticles at 300 K, as determined from the absorbance spectrum, was 3.63 eV. A photoluminescence spectrum at 300 K showed that a dominant emission peak appeared at the blue region. X-ray photoelectron spectroscopy profiles showed that the O 1s and the Cu 2p peaks corresponding to the CuO nanoparticles were observed. 相似文献
14.
Structural, optical and electrical characterization of antimony-substituted tin oxide nanoparticles 总被引:1,自引:0,他引:1
T. Krishnakumar Nicola Pinna M. Passacantando 《Journal of Physics and Chemistry of Solids》2009,70(6):993-850
Antimony-doped tin oxide (ATO) nanostructures were prepared using chemical precipitation technique starting from SnCl2, SbCl3 as precursor compounds. The antimony composition was varied from 5 to 20 wt%. The lower resistance was observed at composition of Sn:95 and Sb:05, when compared with undoped and higher doping concentration of antimony. The average crystalline size of undoped and doped tin oxide was calculated from the X-ray diffraction (XRD) pattern and found to be in the range of 30-11 nm and it was further confirmed from the transmission electron microscopy (TEM) studies. The scanning electron microscopy (SEM) analysis showed that the nanoparticles agglomerates forming spherical-shaped particles of few hundreds nanometers. The samples were further analyzed by energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and electrical resistance measurements. 相似文献
15.
Andrew Ogden Jung-Il Hong James L. Gole 《Journal of Physics and Chemistry of Solids》2008,69(11):2898-2906
We study the temperature-dependent transformation of two distinctly synthesized TiO2 nanoparticles from the anatase to the rutile phase. These studies are carried out over the temperature range extending from room temperature to an excess of 800 °C where the anatase to rutile conversion is found to occur. Results obtained for both a sol-gel-generated nanocolloid (3-20 nm) and a sol-gel-generated micelle nanostructure (∼40 nm) are evaluated. While the TiO2 nanocolloid structures aggregate to form larger crystallites as a function of increasing temperature with sizes comparable to the sol-gel-generated micelle structures, the resulting anatase crystallites, which are of a diameter 40-50 nm, appear to transform to comparable or slightly smaller rutile structures at 800 °C. This is in contrast to the transformation to larger rutile structures, observed for larger anatase particles. The importance of kinetic effects is considered as it enhances the rate of anatase to rutile conversion. These characteristics are established using a combination of Raman spectroscopic, X-ray diffraction, and scanning electron microscopy. The relative playoffs of the Raman and X-ray diffraction techniques are considered as they are used for the analysis of particles at the nanoscale, especially when phase transformations are evaluated. 相似文献
16.
Preparation, conversion, and comparison of the photocatalytic property of Cd(OH)2, CdO, CdS and CdSe
In this paper, we report the hydrothermal preparation of Cd(OH)2 nanowires and further conversion to CdO nanobelts, CdS nanowires and CdSe nanoparticles through thermal treatment, solvothermal and mixed-solvothermal routes, respectively. The as-obtained products were characterized by means of powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and field emission scanning electron microscopy (FEMSEM). Research showed that four cadmium compounds were good photocatalysts for the degradation of organic dyes such as Safranine T and Pyronine B, under irradiation of 365 nm UV light. The order of catalytic activity of different materials was found to be Cd(OH)2<CdO<CdS<CdSe. 相似文献
17.
A facile hydrothermal reduction route based on a precipitate slow-release controlled process was developed to fabricate highly ordered dendritic cobalt microcrystals using cetyltrimethylammonium bromide (CTAB) in high alkali media. The shape, structure, and magnetic properties of the final products were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), electron diffraction (ED), and vibrating sample magnetometry (VSM). The results showed that the sample is hexagonal close-packed Co coexisting with cubic close-packed Co; the length of the main trunk is about 8 μm and diameter of the branches is 0.5-2 μm. Magnetic measurement at 300 K showed that these microstructures exhibited ferromagnetic character. The probable formation mechanism of the microcrystals was discussed on the basis of the experimental results. 相似文献
18.
Copper-doped titania with variable Cu/Ti ratios have been prepared via a simple aqueous-phase method at 85 °C. The obtained products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-vis absorption spectra analysis. The photocatalytic properties of the products were tested by photocatalytic degradation of aqueous brilliant red X-3B solution. The results showed that the sample with 2% copper doping has the best photocatalytic activity, which is 3 times that of undoped rutile titania. The effect of the doped copper on the structure and property of TiO2 has also been discussed. 相似文献
19.
Cobalt oxalate was used as a precursor to prepare Co3O4 nanorods by thermal decomposition. The combinations of triphenylphosphine and oleylamine were added as surfactants to control the morphology of the particles. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The diameters of Co3O4 nanorods are 20 nm and the average lengths are around 500 nm. The hysteresis loops of the obtained samples reveal the ferromagnetic behaviors, the enhanced coercivity (Hc) and decreased saturation magnetization (Ms) in contrast to their respective bulk materials. The study provides a simple and efficient route to synthesize Co3O4 nanorods at low temperature. 相似文献
20.
Célia M. Ronconi Nathalia Suvorova Eugene A. Irene 《Journal of Physics and Chemistry of Solids》2009,70(1):234-557
Thin Cd2Nb2O7 films were grown on single-crystal p-type SiO2/Si substrates by the metallo-organic decomposition (MOD) technique. The films were investigated by X-ray diffraction, X-ray energy-dispersive spectroscopy, and field emission scanning electron microscopy, and showed a single phase (cubic pyrochlore), a crack-free spherical grain structure, and nanoparticles with a mean size of about 68 nm. A Cauchy model was also used in order to obtain the thickness and index of refraction of the stack layers (transparent layer/SiO2/Si) by spectroscopic ellipsometry (SE). The dielectric constant (K) of the films was calculated to be about 25 from the capacitance-voltage (C-V) measurements. 相似文献