Study of the preparation and properties of CeO2single/multiwall hollow microspheres

2007 ◽  
Vol 22 (6) ◽  
pp. 1472-1478 ◽  
Author(s):  
Youjin Zhang ◽  
Tao Cheng ◽  
Qixiu Hu ◽  
Zhiyong Fang ◽  
Kaidong Han
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Reaction Time ◽  
Reaction Temperature ◽  
Hollow Microspheres ◽  
X Ray ◽  
Molar Ratios ◽  
Preparation Conditions ◽  
Transmission Electron ◽  
Absorption Edges

Novel slight yellow CeO2single/multiwall hollow microspheres were synthesized by the hydrothermal method without any surfactant and characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), field-emission scanning electron microscopy (FESEM), and x-ray photoelectron spectra (XPS). The results showed that the products were CeO2single/multiwall hollow microspheres, the shells of which were composed of CeO2nanoparticles with a mean size of 70 nm. The effect of the preparation conditions, the reaction temperature, the reaction time, and the molar ratios of urea to Ce(NO3)3·6H2O on the morphology of the products, was investigated. The optimal preparation conditions are determined as follows: the reaction temperature of 230 °C, the reaction time of 6 to 10 h, and the molar ratios of urea to Ce(NO3)3·6H2O of 3:1 to 6:1. The formation mechanism of CeO2single/multiwall hollow microspheres was proposed. The ultraviolet-visible (UV-VIS) diffuse reflectance spectra of the samples were measured. The results showed that the absorption edges of the samples were red-shifted compared with that of bulk CeO2, and that the red-shift of the absorption edges and the yellow of the samples enhanced with increasing the yield of CeO2single/multiwall hollow microspheres. The catalytic activity and the recycling performance of the sample on CO oxidation were tested and theT100%(the temperature at which CO 100% conversion) was 230 °C in the first run and decreased by 270 and 205 °C compared with that of bulk CeO2and CeO2nanocrystal, respectively.

Synthesis and Tribological Properties of TiSe2 Nanoparticles

2017 ◽  
Vol 45 ◽  
pp. 34-41 ◽  
Author(s):  
Qin Shi ◽  
Jing Xu ◽  
Li Feng Dang ◽  
Jun Chen ◽  
Guo Gang Tang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Reaction Time ◽  
Reaction Temperature ◽  
Tribological Properties ◽  
Raw Materials ◽  
Homogeneous Distribution ◽  
Formation Mechanisms ◽  
Base Oil ◽  
Transmission Electron

TiSe2 nanobelts/nanoplates have been successfully fabricated through a facile and environment-friendly pressureless sintered process using micro-sized Ti and Se elements as raw materials. The morphology and structure of the as-prepared TiSe2 products were investigated by X-ray diffractometer, scanning electron microscopy, transmission electron microscopy and high resolution transmission electron microscopy. The experimental results indicated that the morphology of TiSe2 products were strongly dependent on the reaction temperature and reaction time. As the reaction temperature was set at 600°C and 800°C, long belts-like and plates-like structures of as-prepared TiSe2 products could be observed, respectively. However, a mixture of nanobelts and nanoplates could be obtained at a reaction temperature of 700°C. It was also found that the reaction time played a crucial role in obtaining the homogeneous distribution nanoparticles, therefore, reasonable reaction process and formation mechanisms of as-prepared TiSe2 nanoparticles were proposed. Moreover, the tribological properties of the TiSe2 nanobelts/nanoplates were investigated. The test results showed that the addition of TiSe2 nanoparticles could improve the tribological properties of base oil. Furthermore, the friction coefficient of base oil containing TiSe2 nanoplates was lower and more stable than those of TiSe2 nanobelts and pure base oil.

Convenient Route to Cu-Ag Bimetallic Nanoleaflets with High Content of Cu and their Electrochemical Properties

2017 ◽  
Vol 727 ◽  
pp. 395-402
Author(s):  
Zi Run Wang ◽  
Xin Liu ◽  
Gui Qi Xie ◽  
Yi Wu ◽  
Ming Nie ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Reduction Method ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molar Ratios ◽  
Phase Reduction ◽  
Transmission Electron ◽  
Convenient Route

Cu-Ag alloy nanoparticles were synthesized by a liquid phase reduction method. Using sodium formaldehyde sulfoxylate (SFS) as reducing agents, copper-silver bimetallic nanoleaflets with high content of Cu were prepared. The obtained Cu-Ag bimetallic nanocrystal were characterized by powder X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), field emission scanning electron microscope (FESEM), high resolution transmission electron microscopy (HRTEM) and transmission electron microscopy (TEM). Different molar ratio of Cu-Ag bimetallic nanomaterials could produce different morphologies. The surfactant β-CD plays a crucial role on the structure of the products. The different molar ratios of Cu-Ag were also investigated. The electrochemical activity was evaluated using cyclic voltammetry (CV), electrochemical hydrogen evolution reaction (HER) in a 0.5M Na2SO4 electrolyte.

scholarly journals Facile synthesis of nanoscaled α-Fe2O3, CuO and CuO/Fe2O3 hybrid oxides and their electrocatalytic and photocatalytic properties

2013 ◽  
Vol 11 (5) ◽  
pp. 763-773 ◽  
Author(s):  
Lu Pan ◽  
Jing Tang ◽  
Fengwu Wang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Basic Solution ◽  
X Ray Diffraction ◽  
Methyl Orange Degradation ◽  
X Ray ◽  
Molar Ratios ◽  
Transmission Electron ◽  
Nitrophenol Reduction

AbstractA facile and easily controlled route was designed to synthesize nano-structured Fe2O3, CuO, and CuO/Fe2O3 hybrid oxides with different Cu/Fe molar ratios via a hydrothermal procedure. The samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM) and field-emission scanning electron microscopy (FE-SEM). The results showed that the morphologies of the samples changed with different Cu/Fe ratios. The electrocatalytic properties of the samples modified on a glassy carbon electrode for p-nitrophenol reduction in a basic solution were investigated. The results indicated that CuO/Fe2O3 hybrids with lower Cu/Fe ratio exhibited higher electrocatalytic activity. The photocatalytic performances of the samples for methyl orange degradation with assistance of oxydol under irradiation of visible light were studied. The results revealed that CuO/Fe2O3 hybrids with higher Cu/Fe ratio showed efficient photocatalytic activity.

Synthesis and Hydrogen Absorption Capacity of Multilayered SnO2 Hollow Microspheres

2014 ◽  
Vol 924 ◽  
pp. 57-60
Author(s):  
Zhi Yuan Wang ◽  
Feng Ping Wang ◽  
Ming Yan Li ◽  
M. Zubair Iqbal ◽  
Qurat Ul Ain Javed ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Hydrogen Absorption ◽  
Multilayered Structure ◽  
Absorption Capacity ◽  
Hollow Microspheres ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Water As Solvent

Multilayered SnO2hollow microspheres (MHS-SnO2) have been successfully synthesized via a solvothermal method by using glycol-water as solvent. The morphology, composition and structure of the product have been characterized by field-emission scanning electron microscopy (FESEM) with an energy dispersive X-ray (EDX) spectroscopy, transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) with selected area electron diffraction (SAED) and X-ray diffraction (XRD). The FESEM, TEM and HRTEM images indicate that the as-prepared microspheres show multilayered structure and the wall of the hollow microspheres is composed of single crystalline nanoparticles. Study on hydrogen absorption characteristics of MHS-SnO2performed at 373 K shows a good absorption capacity of 0.85 wt.%.

Synthesis of CuInSe2 and CuInGaSe2 Nanoparticles by Solvothermal Route

2004 ◽  
Vol 449-452 ◽  
pp. 273-276 ◽  
Author(s):  
Ki Hyun Kim ◽  
Young Gab Chun ◽  
Byung Ok Park ◽  
Kyung Hoon Yoon
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Reaction Time ◽  
Spherical Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Cigs Nanoparticles ◽  
Scanning Electron

Chalcopyrite CuInSe 2 (CIS) and CuInGaSe 2</sub(CIGS) nanoparticles were directly synthesized by a solvothemal route in an autoclave with alkylamine as a solvent. The rod-like CIS nanoparticles with widths of 5-10 nm and lengths of 10-30 nm were obtained at 180°C for 36 hour whereas spherical nanoparticles with diameter in the range of 10-80 nm were observed at 200- 250 °C for 36 hour. A morphology change from spherical to rod-like CIS nanoparticles was observed at 190 °C as reaction time increased from 36 to 60 hour. The formation of the rod-like nanoparticles in diethylamine, without double N-chelation, was explained by the SLS (Solution- Liquid-Solid) mechanism. Spherical CIGS nanoparticles with diameter in the range of 30-80 nm were obtained in ethylenediamine at 280 °C for 14 hour. The products were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM) and high-resolution scanning electron microscopy (HRSEM).

Preparation of Size Controllable BaTiO3 Nanoparticles in Microemulsion at Low Temperature

2014 ◽  
Vol 1004-1005 ◽  
pp. 63-68 ◽  
Author(s):  
Zhao Deng ◽  
Ying Dai ◽  
Hua Xiao ◽  
Meng Jun Zhou
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Low Temperature ◽  
Atmospheric Pressure ◽  
Tetrabutyl Titanate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molar Ratios ◽  
Transmission Electron ◽  
Barium Titanate Nanoparticles

Size controllable Barium titanate nanoparticles were synthesized in microemulsion consisting of water, OP-10, hexanol and cyclohexane under atmospheric pressure and low temperature, with Ba (OH)2·8H2O and tetrabutyl titanate used as starting reactants. Products were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX). The results show that 65°C is the proper temperature for the synthesis. The particle size can be controlled by varying the reactants’ concentration, ω value (molar ratios of water to surfactant) and aging time.

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

A High Resolution Study of G.P. Zones in Aluminum - 4.2 at % Silver

1982 ◽  
Vol 40 ◽  
pp. 722-723 ◽  
Author(s):  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Computer Simulations ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Study

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.

Magnesium and sulfur in mast cell and basophil granules of lower vertebrates in relation with histamine

1992 ◽  
Vol 50 (2) ◽  
pp. 1596-1597
Author(s):  
Kenichi Takaya
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Mast Cell ◽  
Mast Cells ◽  
Tree Frog ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Fresh Frozen ◽  
Ultrathin Sections

Mast cell and basophil granules of the vertebrate contain heparin or related sulfated proteoglycans. Histamine is also present in mammalian mast cells and basophils. However, no histamine is detected in mast cell granules of the amphibian or fish, while it is shown in those of reptiles and birds A quantitative x-ray microanalysis of mast cell granules of fresh frozen dried ultrathin sections of the tongue of Wistar rats and tree frogs disclosed high concentrations of sulfur in rat mast cell granules and those of sulfur and magnesium in the tree frog granules. Their concentrations in tree frog mast cell granules were closely correlated (r=0.94).Fresh frozen dried ultrathin sections and fresh air-dried prints of the tree frog tongue and spleen and young red-eared turtle (ca. 6 g) spleen and heart blood were examined by a quantitative energy-dispersive x-ray microanalysis (X-650, Kevex-7000) for the element constituents of the granules of mast cells and basophils. The specimens were observed by transmission electron microscopy (TEM) (80-200 kV) and followed by scanning transmission electron microscopy (STEM) under an analytical electron microscope (X-650) at an acceleration voltage of 40 kV and a specimen current of 0.2 nA. A spot analysis was performed in a STEM mode for 100 s at a specimen current of 2 nA on the mast cell and basophil granules and other areas of the cells. Histamine was examined by the o-phthalaldehyde method.

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