Hydrothermal Synthesis of GdVO4:Eu 3+ Phosphors by Optimizing its Preparation Conditions

2011 ◽  
Vol 287-290 ◽  
pp. 1360-1364
Author(s):  
Ying Lin Yan ◽  
Yun Hua Xu ◽  
Juan Wang ◽  
Zhen Xing Luan
Keyword(s):  
Ph Value ◽  
Photo Luminescence ◽  
Luminescence Spectroscopy ◽  
Temperature Reaction ◽  
Hydrothermal Temperature ◽  
Red Emission ◽  
X Ray ◽  
Preparation Conditions ◽  
Optimal Reaction Condition ◽  
Optimal Reaction

Eu3+ -doped GdVO4 powders have been synthesized via a novel hydrothermal method using commercially available Gd2O3, NH4VO3 and Eu2O3 as the reacting precursors. The influences of several important parameters, such as hydrothermal temperature, reaction time and pH value, of the experiment were investigated. The obtained samples were characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), and photo-luminescence spectroscopy (PL). The experimental results showed that the optimal reaction condition was processed at 180°C for 12 h and adjusted pH value to 4. The morphology of products was uniform pseudo-octahedron with a little conglomeration. All the phosphors exhibit the characteristic dominant red emission of Eu3+ ion (5D0 → 7F2) at 618nm.

scholarly journals Hydrothermal Synthesis of Various Shape-Controlled Europium Hydroxides

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 529
Author(s):  
Hongjuan Zheng ◽  
Kongjun Zhu ◽  
Ayumu Onda ◽  
Kazumichi Yanagisawa
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Ph Value ◽  
Hydrothermal Temperature ◽  
X Ray ◽  
Hydrothermal Reactions ◽  
Starting Solution ◽  
Initial Ph ◽  
Shape Controlled ◽  
Scanning Electron

Eu(OH)3 with various shape-controlled morphologies and size, such as plate, rod, tube, prism and nanoparticles was successfully synthesized through simple hydrothermal reactions. The products were characterized by XRD (X-Ray Powder Diffraction), FE-SEM (Field Emission- Scanning Electron Microscopy) and TG (Thermogravimetry). The influence of the initial pH value of the starting solution and reaction temperature on the crystalline phase and morphology of the hydrothermal products was investigated. A possible formation process to control morphologies and size of europium products by changing the hydrothermal temperature and initial pH value of the starting solution was proposed.

Characterization of (4,4)- and (5,3)-Type Stacking-Faults in 4deg.-Off 4H-SiC Epitaxial Wafers by Synchrotron X-Ray Topography and by Photo-Luminescence Spectroscopy

2013 ◽  
Vol 740-742 ◽  
pp. 585-588 ◽  
Author(s):  
T. Yamashita ◽  
H. Matsuhata ◽  
Y. Miyasaka ◽  
M. Odawara ◽  
K. Momose ◽  
...  
Keyword(s):  
Strain Field ◽  
Room Temperature ◽  
Stacking Faults ◽  
Photo Luminescence ◽  
Epitaxial Films ◽  
Luminescence Spectroscopy ◽  
X Ray ◽  
Different Types

Experimentally,the grazing-incident X-ray topography at different diffraction conditions, and room temperature photo-luminescence spectroscopy, various different types of stacking-faults in epitaxial films on 4-degrees-off 4H-SiC wafers were identified precisely without wafer cutting. Their types and the numbers were investigated statistically. It became clear that (4,4) type stacking-faults were the most common ones and two different types were identified. Still 34% of the stacking-faults were unknown types in the present investigation.Several different kinds of stacking-faults formed on the surface of 4-degrees-off 4H-SiC epitaxial wafers were investigated. Their types could be identified and type distribution in a wafer could be obtained using X-ray topography and room temperature Photo-Luminescence without wafer cutting. Type determination of 8H(4,4)- stacking fault ; with or without strain field, could also be decideddemonstrated using this method.

Microwave-Assisted Hydrothermal Preparation of YVO4:Eu3+ Phosphor

2010 ◽  
Vol 663-665 ◽  
pp. 417-420
Author(s):  
En Guo Wang
Keyword(s):  
Electron Microscope ◽  
Ph Value ◽  
Doping Amount ◽  
Hydrothermal Preparation ◽  
X Ray ◽  
Microwave Assisted ◽  
Preparation Conditions ◽  
Microwave Hydrothermal ◽  
Microwave Hydrothermal Method ◽  
Scanning Electron

YVO4:Eu3+ phosphors were prepared by microwave hydrothermal method in this work. YVO4:Eu3+ phosphors were probed by photoluminescence (PL), X-ray powder diffraction (XRD) and scanning electron microscope (SEM). The effects of different preparation conditions on the photoluminescence, the structure and the morphology of YVO4:Eu3+ phosphors were studied. The experiment results show that the pH value and the Eu3+ doping amount have some important effect on the photoluminescence and the morphology of YVO4:Eu3+phosphors.

scholarly journals Study on Remediation of Hexachlorobenzene Contaminated Soil by Mechanochemical Method

2021 ◽  
Vol 233 ◽  
pp. 01118
Author(s):  
Li Xue ◽  
Chen Huichao ◽  
Liang Xiao
Keyword(s):  
Contaminated Soil ◽  
Photoelectron Spectroscopy ◽  
Research Work ◽  
Mechanism Study ◽  
Mechanochemical Method ◽  
X Ray ◽  
Natural Minerals ◽  
Low Energy Consumption ◽  
Optimal Reaction Condition ◽  
Optimal Reaction

The mechanochemical method is a potential way to destroy pollutants such as heavy metals and organic compounds due to its advantages such as complete reaction, adaptation of various pollutants and low energy consumption, etc. Research work was conducted to investigate the feasibility of remediating the persistent organic pollutants (POPs) contaminated soil and how the parameters influence the destruction of the pollutants. In the study, hexachlorobenzene (HCB) was used as a presentative of the POPs in soil. Natural minerals such as albite and magnetite were selected as additives to treat HCB contaminated soil with the application of mechanochemical method. The reasonable operation parameters as well as the soil properties on the destruction of HCB were determined. Analysis such as Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffractometer (XRD), X-ray Photoelectron Spectroscopy (XPS) and Raman Spectrometer were conducted for the supplement of mechanism study. A degradation rate of 92.5% for HCB was achieved under the optimal reaction condition. According to the XPS analysis results, the transformed valence state of iron, provided electrons for the destruction of HCB, on the basis of specific structure of albite. The amorphous carbon and graphite carbon were the final products of the destruction of HCB in the process of ball milling. The selected reagents with albite and magnetite would be viable for the damage of other POPs by mechanochemical method.

scholarly journals Preparation and Photocatalytic Properties of a Bagasse Cellulose-Supported Nano-TiO2 Photocatalytic-Coupled Microbial Carrier

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1645 ◽  
Author(s):  
Jianhua Xiong ◽  
Yinna Liang ◽  
Hao Cheng ◽  
Shuocheng Guo ◽  
Chunlin Jiao ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Mass Fraction ◽  
Photocatalytic Performance ◽  
Ph Value ◽  
Optimum Conditions ◽  
Nano Tio2 ◽  
X Ray ◽  
Preparation Conditions ◽  
Initial Ph ◽  
Composite Carrier

Intimate coupling of photocatalysis and biodegradation (ICPB) has shown promise in removing unwanted organic compounds from water. In this study, bagasse cellulose titanium dioxide composite carrier (SBC-TiO2) was prepared by low-temperature foaming methods. The optimum preparation conditions, material characterization and photocatalytic performance of the composite carrier were then explored. By conducting a single factor test, we found that bagasse cellulose with a mass fraction of 4%, a polyvinyl alcohol solution (PVA) with a mass fraction of 5% and 20 g of a pore-forming agent were optimum conditions for the composite carrier. Under these conditions, good wet density, porosity, water absorption and retention could be realized. Scanning electron microscopy (SEM) results showed that the composite carrier exhibited good biologic adhesion. X-ray spectroscopy (EDS) results confirmed the successful incorporation of nano-TiO2 dioxide into the composite carrier. When the mass concentration of methylene blue (MB) was 10 mg L−1 at 200 mL, 2 g of the composite carrier was added and the initial pH value of the reaction was maintained at 6, the catalytic effect was best under these conditions and the degradation rate reached 78.91% after 6 h. The method of preparing the composite carrier can aid in the degradation of hard-to-degrade organic compounds via ICPB. These results provide a solid platform for technical research and development in the field of wastewater treatment.

Synthesis of Nano-Hydroxyapatite Surface-Grafting Poly(L-Lactide) under Microwave Irradiation

2011 ◽  
Vol 204-210 ◽  
pp. 1929-1933 ◽  
Author(s):  
Bing Hong Luo ◽  
Chung En Hsu ◽  
Jing Yang ◽  
Jian Hao Zhao ◽  
Chang Ren Zhou
Keyword(s):  
Microwave Irradiation ◽  
Ring Opening ◽  
Irradiation Time ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Surface Grafting ◽  
X Ray ◽  
X Ray Scattering ◽  
Optimal Reaction Condition ◽  
Optimal Reaction

Nano-hydroxyapatite (n-HAP) surface-grafting poly(L-lactide) (g-HAP) was synthesized by ring-opening polymerization ofL-lactide (L-LA) using stannous octoate as initiator andn-HAP as co-initiator under microwave irradiation. An optimal reaction condition was obtained as follows: temperature of 140 °C, irradiation time of 45 min and microwave power of 50 W. The products were characterized by FTIR, TGA, x-ray scattering and particle size analysis. Results showed that the feeding ratio ofnn-HAP：nL-LAhad a significant influence on the grafting percentage ofg-HAP. With increasing thenn-HAP:nL-LAfeeding ratio from 1:50 to 1:400, the grafting percentage ofg-HAP increased correspondingly from 14.91% to 35.88%. Theg-HAP particles showed a smaller size than that of pristinen-HAP, suggesting that the grafted poly(L-lactide) segment facilitated to prevent theg-HAP particles from aggregating.

Controllable Shape Evolution of Cu2O Flowers and Their Morphologies-Dependent Selective CO Oxidation

Nano LIFE ◽  
2014 ◽  
Vol 04 (03) ◽  
pp. 1441004
Author(s):  
Daoli Zhao ◽  
Xuefei Guo ◽  
Yuchuan Zheng ◽  
Linlin Wang ◽  
Qing Yang
Keyword(s):  
Electron Microscope ◽  
Shape Evolution ◽  
Temperature Reaction ◽  
Hydrothermal Temperature ◽  
X Ray ◽  
Selective Co Oxidation ◽  
Synthesis Parameters ◽  
Co Catalytic Oxidation ◽  
Different Shapes ◽  
Scanning Electron

The flower-like Cu 2 O nanostructures were hydrothermally synthesized without using any template or surfactant. The influences of hydrothermal temperature, reaction time and reactants concentrations on the growth of nanostructures were investigated in detail. The samples were characterized by scanning electron microscope (SEM) and X-ray powder diffraction (XRD). Cu 2 O crystals with different shapes, i.e., flower-like (F-product) cubic box (CB-product) and cubic box with holes in each face (CBH-product), were synthesized by controlling the synthesis parameters and explored for CO catalytic oxidation. It was found that F-product showed higher catalytic than others.

The 3-Dimensional Molecular Structure of the Actin Filament Revisited

1985 ◽  
Vol 43 ◽  
pp. 480-481
Author(s):  
U. Aebi ◽  
R. Millonig ◽  
H. Salvo
Keyword(s):  
Actin Filament ◽  
Supramolecular Assembly ◽  
Specimen Preparation ◽  
X Ray Diffraction ◽  
Single Filament ◽  
X Ray ◽  
3 Dimensional ◽  
Filament Diameter ◽  
Preparation Conditions ◽  
Apparent Diameter

To date, most 3-D reconstructions of undecorated actin filaments have been obtained from actin filament paracrystal data (for refs, see 1,2). However, due to the fact that (a) the paracrystals may be several filament layers thick, and (b) adjacent filaments may sustantially interdigitate, these reconstructions may be subject to significant artifacts. None of these reconstructions has permitted unambiguous tracing or orientation of the actin subunits within the filament. Furthermore, measured values for the maximal filament diameter both determined by EM and by X-ray diffraction analysis, vary between 6 and 10 nm. Obviously, the apparent diameter of the actin filament revealed in the EM will critically depend on specimen preparation, since it is a rather flexible supramolecular assembly which can easily be bent or distorted. To resolve some of these ambiguities, we have explored specimen preparation conditions which may preserve single filaments sufficiently straight and helically ordered to be suitable for single filament 3-D reconstructions, possibly revealing molecular detail.

Exploring the characteristics of the nickel oxide nanoparticles via Sol - gel method

2020 ◽  
Vol 3 (3) ◽  
Author(s):  
Jothi M ◽  
Sowmiya K
Keyword(s):  
Nickel Oxide ◽  
Ph Value ◽  
Lattice Structure ◽  
Sol Gel ◽  
Systematic Change ◽  
Average Crystalline Size ◽  
Nio Nanoparticles ◽  
Nickel Oxide Nanoparticles ◽  
X Ray ◽  
Vis Spectroscopy

Nickel Oxide (NiO) is an important transition metal oxide with cubic lattice structure. NiO is thermally stable that is suitable for tremendous applications in the field of optic, ceramic,glass, electro-chromic coatings, plastics, textiles, nanowires, nanofibers, electronics,energy technology, bio-medicine, magnetism and so on. In this present study, NiO nanoparticles were successfully synthesized by sol-gel technique. Nano-sols were prepared by dissolving Nickel-Chloride [NiCl2.6H2O] in NaOH solvent and were converted into nano structured gel on precipitation. A systematic change in preparation parameters like calcination temperature, time, pH value has been noticed in order to predict the influence on crystallite size. Then the prepared samples were characterized by the X-ray Diffraction Spectroscopic (XRD), UV-VIS Spectroscopy, Fourier Transform Infra-Red Spectroscopy (FTIR), Energy Dispersive X-ray Spectroscopy (EDX), Scanning Electron Microscopy (SEM) and Particle Size Analyzer (PSA). From XRD, the average crystalline-size has been calculated by Debye-Scherrer Equation and it was found to be 12.17 nm and the band gap energy of Nickel oxide (NiO) from UV studies reveals around 3.85 eV. Further, EDX and FTIR studies, confirm the presences of NiO nanoparticles. The SEM study exhibits the spherical like morphology of Nickel oxide (NiO). Further from PSA, the mean value of NiO nanoparticles has been determined.

Structural/Texture Evolution During Facile Substitution of Ni into ZSM-5 Nanostructure vs. its Impregnation Dispersion Used in Selective Transformation of Methanol to Ethylene and Propylene

2020 ◽  
Vol 23 ◽  
Author(s):  
Parisa Sadeghpour ◽  
Mohammad Haghighi ◽  
Mehrdad Esmaeili
Keyword(s):  
High Temperature ◽  
Physicochemical Properties ◽  
Active Sites ◽  
Catalytic Performance ◽  
Fixed Bed Reactor ◽  
Light Olefins ◽  
Isomorphous Substitution ◽  
Impregnation Method ◽  
Hydrothermal Temperature ◽  
X Ray

Aim and Objective: Effect of two different modification methods for introducing Ni into ZSM-5 framework was investigated under high temperature synthesis conditions. The nickel successfully introduced into the MFI structures at different crystallization conditions to enhance the physicochemical properties and catalytic performance. Materials and Methods: A series of impregnated Ni/ZSM-5 and isomorphous substituted NiZSM-5 nanostructure catalysts were prepared hydrothermally at different high temperatures and within short times. X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Energy dispersive X-ray (EDX), Brunner, Emmett and Teller-Barrett, Joyner and Halenda (BET-BJH), Fourier transform infrared (FTIR) and Temperature-programmed desorption of ammonia (TPDNH3) were applied to investigate the physicochemical properties. Results: Although all the catalysts showed pure silica MFI–type nanosheets and coffin-like morphology, using the isomorphous substitution for Ni incorporation into the ZSM-5 framework led to the formation of materials with lower crystallinity, higher pore volume and stronger acidity compared to using impregnation method. Moreover, it was found that raising the hydrothermal temperature increased the crystallinity and enhanced more uniform incorporation of Ni atoms in the crystalline structure of catalysts. TPD-NH3 analysis demonstrated that high crystallization temperature and short crystallization time of NiZSM-5(350-0.5) resulted in fewer weak acid sites and medium acid strength. The MTO catalytic performance was tested in a fixed bed reactor at 460ºC and GHSV=10500 cm3 /gcat.h. A slightly different reaction pathway was proposed for the production of light olefins over impregnated Ni/ZSM-5 catalysts based on the role of NiO species. The enhanced methanol conversion for isomorphous substituted NiZSM-5 catalysts could be related to the most accessible active sites located inside the pores. Conclusion: The impregnated Ni/ZSM-5 catalyst prepared at low hydrothermal temperature showed the best catalytic performance, while the isomorphous substituted NiZSM-5 prepared at high temperature was found to be the active molecular sieve regarding the stability performance.

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