Synthesis of Anatase-Based Titania Nanostructures Using Extreme Hydrothermal Conditions

2012 ◽  
Vol 463-464 ◽  
pp. 1493-1496
Author(s):  
Vorrada Loryuenyong ◽  
Pat Sooksaen ◽  
Phiphatphong Sanitchai
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Phase Transformation ◽  
Anatase Phase ◽  
Particle Morphology ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Calcination Temperatures ◽  
Transmission Electron ◽  
Titania Nanostructures

TiO2nanostructures with a pure anatase phase were successfully synthesized using hydrothermal treatment of P25-TiO2nanoparticles. These nanostructures were characterized using transmission electron microscopy (TEM) and x-ray powder diffraction measurements. The dependences of reaction temperature and calcination temperature on titanate-anatase phase transformation and the morphology of TiO2nanostructures were also discussed. The results demonstrated that phase composition and particle morphology can be controlled by both the reaction and calcination temperatures.

Characterization of Highly Luminescent LaPO4:Eu3+/LaPO4 One-Dimensional Core/Shell Heterostructures

2008 ◽  
Vol 8 (3) ◽  
pp. 1266-1271 ◽  
Author(s):  
Wenbo Bu ◽  
Jianlin Shi
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Core Shell ◽  
Trap States ◽  
Hydrothermal Conditions ◽  
One Dimensional ◽  
X Ray ◽  
Luminescence Efficiency ◽  
Transmission Electron

Highly luminescent LaPO4:Eu3+/LaPO4 one-dimensional (1D) core/shell heterostructures were successfully synthesized by a mild and simple self-aggregation process under refluxing or hydrothermal conditions. The resulting 1D core/shell heterostructures were characterized using a variety of techniques including X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), and X-ray photoelectron spectroscopy (XPS) to demonstrate successful coating by the crystalline LaPO4. In addition, a possible formation mechanism for this core/shell heterostructure was proposed. Finally, the photoluminescence property of the LaPO4:Eu3+/LaPO4 1D core/shell heterostructures was investigated in detail, which illustrates that the core/shell heterostructures remarkably increase the luminescence efficiency because the LaPO4 shells effectively eliminate surface trap-states and suppress the energy quenching in the energy-transfer processes.

STUDY OF HYDROTHERMAL SYNTHESIS AND PROPERTIES OF Bi2Fe4O9

2010 ◽  
Vol 03 (03) ◽  
pp. 173-176 ◽  
Author(s):  
YIBO WANG ◽  
HUAJUN SUN ◽  
JING ZHOU ◽  
BO LI ◽  
CHENGYONG ZHANG ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Phase Transformation ◽  
Dielectric Properties ◽  
X Ray Diffraction ◽  
Impedance Analyzer ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Highly oriented Bi2Fe4O9 nanosheets can be fabricated with Fe(NO3)3 ⋅ 9H2O and Bi(NO3)3 ⋅ 5H2O using the low-temperature hydrothermal method. The as-prepared powders are characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM), which exhibit an excellent orientation along the (00l) planes. The leakage current density and dielectric properties of the nanosheet samples are measured by Radiant Precision Workstation and HP4291B Impedance Analyzer, respectively. The effects of NaOH concentration on the phase transformation, sheet size and morphologies of the Bi2Fe4O9 crystallites are studied in this paper.

scholarly journals Structures of AlN/VN Superlattices with Different AlN Layer Thicknesses

2002 ◽  
Vol 17 (5) ◽  
pp. 1224-1231 ◽  
Author(s):  
Quan Li ◽  
I. W. Kim ◽  
S. A. Barnett ◽  
L. D. Marks
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Phase Transformation ◽  
Structural Model ◽  
Hexagonal Wurtzite Structure ◽  
X Ray Diffraction ◽  
Rock Salt Structure ◽  
X Ray ◽  
Transmission Electron ◽  
Salt Structure

AlN/VN superlattices with different periods were studied using x-ray diffraction and transmission electron microscopy (TEM). A phase transformation of the AlN from an epitaxially stabilized rock-salt structure to a hexagonal wurtzite structure was observed for an AlN layer thickness greater than 4 nm. A structural model is proposed on the basis of TEM results for the orientation of the transformed phase. The VN layer grown on top of the hexagonal AlN was observed to be reoriented compared to that in the stabilized B1-AlN/VN. The VN nucleated by taking the w-AlN(002) plane as its (111) plane instead of the (002) plane.

Controlled Fabrication and Properties of Ce0.5Zr0.5O 2 Solid Solutions

2011 ◽  
Vol 295-297 ◽  
pp. 1414-1417
Author(s):  
Zhi Fang Zhang ◽  
Fang Yan Du ◽  
Xiang Rong Ma
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Solid Solutions ◽  
Sol Gel ◽  
Size Distributions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calcination Temperatures ◽  
Transmission Electron ◽  
Pore Size Distributions

The nanocrystals Ce0.5Zr0.5O2 solid solutions with various morphologies and crystal structures have been synthesized via a modified sol-gel method assisted with a template. Aerosol OT and/or ionic liquids ([MMIM]Cl] and [BMIM]Cl]) was used as a template. The characterization results of the X-ray diffraction, transmission electron microscopy and N2 adsorption at 77 K indicate that the physical properties of the solid solutions were significantly affected by the templates used and the calcination temperatures. The Ce0.5Zr0.5O2 calcined at 773 K possessed bimodal mesopores, narrow pore size distributions, and tetragonal phase.

Structure and Magnetic Properties of Fe-Doped TiO2 Nano-Crystals by Nonaqueous Synthesis

2010 ◽  
Vol 663-665 ◽  
pp. 883-889
Author(s):  
Chu Feng Li ◽  
Ling Yue ◽  
Wen Jin ◽  
Ting Zhang ◽  
Huan Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Anatase Phase ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
X Ray ◽  
Transmission Electron ◽  
Crystallite Sizes ◽  
Nonaqueous Synthesis

Ti1-xFexO2 nanocrystals with x = 0.01, 0.02, 0.03 were prepared via a nonaqueous synthesis route. X-ray diffraction, transmission electron microscopy and high resolution transmission electron microscopy characterization confirmed the formation of anatase-phase nanocrystals with the average crystallite sizes of around 10 nm. The lattice constants alternate with the increase of the Fe content and no iron clusters were generated. X-ray photoelectron spectroscopy measurements showed that the substitutional Fe ions present mainly the valence of +3. The magnetic hysteresis loops measured at room temperature (RT) 300K showed that all the doped samples are atypically ferromagnetic, and the coercivity (Hc) of all the Fe-doping samples is around 0.1 T. An interpretation for the intrinsic RT ferromagnetism is put up based on the free carriers and defects induced interaction between Fe3+ ions.

Microstructure Evolution of a Metastable CrMnN Austenitic Stainless Steel during Compression Deformation

2010 ◽  
Vol 146-147 ◽  
pp. 26-33 ◽  
Author(s):  
Ming Zhou Xu ◽  
Jian Jun Wang ◽  
Li Jun Wang ◽  
Wen Fang Cui ◽  
Chun Ming Liu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Stainless Steel ◽  
Phase Transformation ◽  
Austenitic Stainless Steel ◽  
Deformation Twin ◽  
X Ray Diffraction ◽  
X Ray ◽  
Compression Deformation ◽  
Transmission Electron

Microstructural evolution of a metastable 18Cr12Mn0.55N austenitic stainless steel during compression deformation was investigated by transmission electron microscopy (TEM) and X-ray diffraction (XRD). TEM observation showed the occurrence of deformation-induced phase transformation and atypical deformation twin, the deformation-induced phase cannot be identified as austenite or martensite. XRD test showed that the amount of deformation-induced phase is less than the detectable limit of XRD.

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