Synthesis and Characterization of Sr3MgSi2O8:Eu2+, Dy3+ Phosphor Prepared by a Chemical Solution Method

2011 ◽  
Vol 675-677 ◽  
pp. 1089-1092 ◽  
Author(s):  
Wen Pan ◽  
Ning Hui Wang ◽  
Guo Feng Li ◽  
Gui Ling Ning
Keyword(s):  
Solution Method ◽  
Intermediate Phase ◽  
Precursor Solution ◽  
X Ray Diffraction ◽  
Calcination Process ◽  
Chemical Solution Method ◽  
Transmission Electron ◽  
Dispersion Media ◽  
Better Than

A novel synthesis route for the production of Sr3MgSi2O8:Eu2+,Dy3+ sub-micron quasisphere phosphor powder is reported. Both the host and activator cations were co-precipitated in water-ethanol mixed solutions and precipitation was performed with analytical grade ammonium citratetribasic. As the dispersion media, optimum concentration for PEG in the precursor solution is determined to be 0.08 g/mL. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and fluorescence spectrophotometer were employed to characterize the phosphor. The effect of the calcining temperature on the crystalline particle and luminescence properties of Sr3MgSi2O8:Eu2+,Dy3+ is systematically discussed. Sr3MgSi2O8:Eu2+,Dy3+ single phased quasi-sphere phosphor was achieved by calcining the asprecipitated precursor at 1100°C. Sr2SiO4 was identified as the intermediate phase during the calcination process. Despite the small particle size, the emission intensities were higher by the present method. However, the afterglow characteristic was not better than that prepared by solidstate reaction in the comparable condition.

CeO2/TiO2 Nanotubes Composites: Synthesis, Characterization, and Photocatalytic Properties

2012 ◽  
Vol 583 ◽  
pp. 86-90 ◽  
Author(s):  
Hai Bin Li ◽  
Xin Yong Li ◽  
Yan De Song ◽  
Shu Guang Chen ◽  
Ying Wang ◽  
...  
Keyword(s):  
Diffuse Reflectance Spectroscopy ◽  
Atomic Ratio ◽  
X Ray Diffraction ◽  
Hydrothermal Route ◽  
Electron Hole ◽  
Calcination Process ◽  
X Ray ◽  
Transmission Electron ◽  
Hole Recombination

TiO2nanotubes were prepared via a hydrothermal route. CeO2nanoparticles with diameters around 5nm were loaded onto the surface of TiO2nanotubes via a deposition approach followed by a calcination process. Transmission electron microscopy (TEM), X-ray diffraction (XRD), and UV-vis diffuse reflectance spectroscopy (UV-vis) were applied for the characterization of the as-prepared CeO2/TiO2nanotubes composites. The results show that CeO2particles are highly dispersed on the surface of TiO2nanotubes. The TiO2 nanotubes are modified to response to the visible light due to the combination with CeO2. The CeO2/TiO2nanotubes composites with a CeO2/TiO2atomic ratio of 2.5% show a further improvement on the photocatalytic activity for degradation of Rhodamine B in water. The presence of CeO2improves the light absorption of TiO2nanotubes and inhibits the electron-hole recombination.

SYNTHESIS AND CHARACTERIZATION OF ZnO NANORODS AND NANOWIRES USING PVP AS CAPPING

2009 ◽  
Vol 08 (03) ◽  
pp. 285-287 ◽  
Author(s):  
M. ESKANDARI ◽  
V. AHMADI ◽  
Sh. AHMADI
Keyword(s):  
Solution Method ◽  
Zno Nanorods ◽  
Green Emission ◽  
Zno Nanowires ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chemical Solution Method ◽  
Air Atmosphere ◽  
20 Nm

In this study, ZnO nanowires are synthesized via ZnO nanorods at low temperature by using zinc acetate dehydrate and polyvinylpyrrolidone as precursor and capping, respectively. We use chemical solution method for synthesis of ZnO nanowires. Samples are characterized by means of scanning electron microscopy and X-ray diffraction. First, the nanorods are prepared at 300°C temperature, and then they are put into the furnace under air atmosphere at 450°C for 2 h. It is observed that nanowires with 20 nm diameter are produced. Photoluminescence spectra of nanorods and nanowires are compared. It shows that intensity of ultraviolet peak in the nanowires decreases but in contrast the intensity of green emission part increases. This is because, the surface effects such as oxygen vacancies increase in the structures of ZnO .

Chemical Synthesis of Magnetic Fe3O4 Nanoparticles

2005 ◽  
Vol 475-479 ◽  
pp. 2275-2278 ◽  
Author(s):  
Rui Feng Yang ◽  
Yu Zhen Lv ◽  
Yahui Zhang ◽  
Chen Min Liu ◽  
Lin Guo
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fe3o4 Nanoparticles ◽  
Solution Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chemical Solution Method ◽  
Transmission Electron ◽  
Wet Chemical ◽  
Surface Modified

Fe3O4 nanoparticles were simply prepared by a wet chemical solution method. In this method, poly (N-vinyl-2-pyrrolidone) (PVP) was used as surface modified reagent to control the shape of the product. Transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD) were used to characterize the asprepared Fe3O4 nanoparticles. Furthermore, the magnetic properties of the sample were investigated by a VSM (vibrating sample magnetometer) technique.

Preparation, Characterization and Application in Electromagnetic Wave Absorption of Core-Shell C/Fe3O4 Nanocomposites

2011 ◽  
Vol 239-242 ◽  
pp. 1725-1730 ◽  
Author(s):  
Qiang Chun Liu ◽  
Jian Ming Dai ◽  
Zhen Fa Zi ◽  
Da Jun Wu ◽  
Yu Ping Sun
Keyword(s):  
Electron Microscopy ◽  
Solution Method ◽  
Wide Frequency Range ◽  
Core Shell ◽  
Carbon Sphere ◽  
Carbon Spheres ◽  
X Ray Diffraction ◽  
Microwave Absorption Properties ◽  
Transmission Electron ◽  
Better Than

Large-quantity core-shell carbon spheres/Fe3O4nanocomposites were synthesized via a simple solution method. The phase structures and morphologies of the composite had been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the carbon spheres were covered by a layer of Fe3O4nanoparticles with a diameter of about 25 nm. Measurements of the electromagnetic parameters of the samples showed that microwave absorption properties of the carbon sphere-Fe3O4nanocomposites were much better than that of the pure Fe3O4or the mixtures of carbon spheres and Fe3O4microspheres. The optimal reflection loss (RL) reached −37.8 dB at 14.8 GHz for a layer thickness of 2.0 mm, which is favorable for application of our samples in a wide frequency range.

Synthesis and Characterization of Surface-Grafted Magnesium Oxide Whiskers with poly(L-lactide)

2013 ◽  
Vol 820 ◽  
pp. 41-44
Author(s):  
Wei Wen ◽  
Bing Hong Luo ◽  
Cai Rong Li ◽  
Wan Xu ◽  
Chang Ren Zhou
Keyword(s):  
Electron Microscope ◽  
Magnesium Oxide ◽  
Solution Method ◽  
Magnesium Carbonate ◽  
X Ray Diffraction ◽  
Vibration Absorption ◽  
Transmission Electron ◽  
Stretching Vibration ◽  
Vibration Absorption Peak

Firstly, Magnesium oxide (MgO) whiskers were prepared by calcination of magnesium carbonate (MgCO3)whiskers which were obtained by solution method. Then, surface-grafted MgO whiskers with poly (L-lactide) were synthesized by bulk ring-opening polymerization ofL-lactide onto the surface of MgO whiskers. The MgO whiskers and surface-grafted MgO whiskers were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), x-ray diffraction (XRD) and fourier transformation infrared (FTIR). Results showed that MgO whiskers diameter in the range of 0.02-0.5μm, the length is between 10-80μm and well dispersed. A new characteristic stretching vibration absorption peak of C=O apppeared in the IR spectrum of the surface-grafted MgO whiskers, which suggested that poly (L-lactide) chains were successfully grafted on the surface of MgO whiskers.

Synthesis and Characterization of Nano-Hexaferrites SrFe12O19 by Aqueous Solution Method

2011 ◽  
Vol 306-307 ◽  
pp. 404-409 ◽  
Author(s):  
Jian An Liu ◽  
Mei Mei Zhang ◽  
Yan Fei Zhang ◽  
Shu Jiang Liu
Keyword(s):  
Aqueous Solution ◽  
Magnetic Properties ◽  
Solution Method ◽  
Nano Particles ◽  
X Ray Diffraction ◽  
Nanometer Materials ◽  
Transmission Electron ◽  
Fast Synthesis ◽  
Aqueous Solution Method

Nano-hexaferrite SrFe12O19 has been prepared using the aqueous solution method. The structure and magnetic properties of SrFe12O19 have systematically been investigated by X-ray diffraction (XRD), Thermo gravimetric (TG), Fourier transform infrared spectroscopy (FTIR), Transmission Electron Microscopy (TEM), as well as Vibrating Sample Magnetometer (VSM). The XRD and TEM results showed that the samples are composed of SrFe12O19 nano-particles which are on average 70×50nm in dimensions when treated at 1200°C for 2 hours. The magnetic properties indicated that the saturation magnetization and the intrinsic coercivity were 48 Am2/kg and 506KA/m, respectively. The aqueous solution method is generally applicable to produce the nano-hexaferrite SrFe12O19 and is proved to be a promising method for fast synthesis of nanometer materials using nitrate.

Synthesis and Characterization of Polystyrene-Graphite Nanocomposites via Surface Raft-Mediated Polymerization

2012 ◽  
Vol 463-464 ◽  
pp. 527-532
Author(s):  
Hussein M. Etmimi ◽  
Ronald D. Sanderson
Keyword(s):  
Mechanical Properties ◽  
Miniemulsion Polymerization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Reversible Addition ◽  
Raft Agent ◽  
Polymerization Method ◽  
Better Than

The synthesis of polystyrene/GO (PS-GO) nanocomposites using the reversible addition-fragmentation chain transfer (RAFT) mediated polymerization method is described. The GO was synthesized and immobilized with a RAFT agent to afford RAFT-functionalized GO nanosheets. The RAFT-immobilized GO was used for the synthesis of PS nanocomposites in a controlled manner using miniemulsion polymerization. The moelcular weight and dispersity of the PS in the nanocomposites depended on the amount of RAFT-grafted GO in the system, in accordance with the features of the RAFT-mediated polymerization. X-ray diffraction and transmission electron microscopy analyses revealed that the nanocomposites had exfoliated morphology, even at relatively high GO content. The thermal stability and mechanical properties of the PS-GO nanocomposites were better than those of the neat PS polymer. Furthermore, the mechanical properties of the nanocomposites were dependent on the RAFT grafted GO content.

Synthesis and Characterization of Ce1-xZrxO2 Nanopaticles

2011 ◽  
Vol 110-116 ◽  
pp. 1411-1416
Author(s):  
Elham Motyeian ◽  
Hamid Reza Aghabozorg ◽  
Hossein Aghabozorg
Keyword(s):  
Electron Microscopy ◽  
Precursor Solution ◽  
Average Diameter ◽  
Fluorite Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxide Powders ◽  
Transmission Electron ◽  
Size Of Particles

A series of crystalline Ce1-xZrxO2 nanoparticles (where x = 0, 0.25, 0.5, 0.75 and 1.0) have been prepared by (i) hydrothermal (ii) polymer based metal-complex precursor solution reactions. Hydrothermal method was performed with diethanol amine as hydrolysis catalyst. The effect of reaction conditions on the size of particles and their morphology were investigated. In the polymer based method, by calcination of suitable polymer precursor solutions at a temperature range between 300 and 450 °C along with variation in the period of time, the metal oxide powders were subsequently obtained. The prepared powders have been characterized by powder X-ray diffraction (XRD), X-ray Fluorescence (XRF) .These studies reveled that zirconium is a good host for insertion into Cerium oxide in fluorite structure. The as-prepared samples were further characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The average diameter of the nanoparticles were calculated from line broadening of XRD peaks and confirmed by SEM and TEM studies.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Detonation Synthesis of Nano-Size Materials

1995 ◽  
Vol 418 ◽  
Author(s):  
J. Forbes ◽  
J. Davis ◽  
C. Wong
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Nucleation And Growth ◽  
Detonation Synthesis ◽  
X Ray Diffraction ◽  
Crystalline Materials ◽  
X Ray ◽  
Transmission Electron ◽  
Nano Size

AbstractThe detonation of explosives typically creates 100's of kbar pressures and 1000's K temperatures. These pressures and temperatures last for only a fraction of a microsecond as the products expand. Nucleation and growth of crystalline materials can occur under these conditions. Recovery of these materials is difficult but can occur in some circumstances. This paper describes the detonation synthesis facility, recovery of nano-size diamond, and plans to synthesize other nano-size materials by modifying the chemical composition of explosive compounds. The characterization of nano-size diamonds by transmission electron microscopy and electron diffraction, X-ray diffraction and Raman spectroscopy will also be reported.

Sign in / Sign up

Export Citation Format

Share Document