Syntheses of Mesoporous ZnO and SnO2 Microspheres by Spray Reaction Process

2012 ◽  
Vol 519 ◽  
pp. 74-78 ◽  
Author(s):  
Hui Zhang ◽  
Chen Chen ◽  
Xiao Long Xu ◽  
Rong Wu ◽  
Fan Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Spherical Particles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zno Particles ◽  
Mesoporous Zno ◽  
Average Size ◽  
Synthesized Materials ◽  
First Time ◽  
Scanning Electron

For the first time, mesoporous ZnO and SnO2 spherical particles were synthesized by spray reaction (SR) process. The synthesized materials were characterized by thermo-gravimetry/differential thermal analysis (TG/DTA), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Results reveal that few ZnO microspheres were formed after calcined at 700 °C while large quantity of non-spherical ZnO particles was produced. And the predominant hexagonal ZnO (h-ZnO) is attained when heated at 700 °C. Mesoporous SnO2 microspheres prepared at 800 °C possess an average size ~2.22 μm and a major tetragonal phase (t- SnO2) with crystallite size 7.8 nm.

Electrochemical Synthesis and Photocatalytic Activity of Differently Shaped CuOx Particles

2017 ◽  
Vol 13 ◽  
pp. 330-333
Author(s):  
Anna Ulyankina ◽  
Igor Leontyev ◽  
Nina Smirnova
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Electrochemical Method ◽  
Spherical Particles ◽  
Photocatalytic Efficiency ◽  
X Ray Diffraction ◽  
X Ray ◽  
Polyhedral Particles ◽  
Copper Electrodes ◽  
Scanning Electron

CuOx powders with diff erently shaped particles were firstly prepared via an electrochemical method by oxidation and dispersion of copper electrodes in an electrolyte solution under pulse alternating current (PAC). By means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) the current density is found to have an influence on the morphology and composition of CuOx particles. Photocatalytic efficiency of CuOx towards methyl orange (MO) degradation under visible light was investigated. The prepared polyhedral particles show the best photocatalytic activity of 81 % towards MO comparing to octahedral and spherical particles with 70 and 61 %, respectively.

scholarly journals Formation of ZnO/Zn0.5Cd0.5Se Alloy Quantum Dots in the Presence of High Oleylamine Contents

Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 999
Author(s):  
Yi-An Chen ◽  
Kuo-Hsien Chou ◽  
Yi-Yang Kuo ◽  
Cheng-Ye Wu ◽  
Po-Wen Hsiao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Quantum Dots ◽  
Particle Size ◽  
X Ray Diffraction ◽  
One Pot ◽  
X Ray ◽  
Transmission Electron ◽  
Average Size ◽  
Alloy Quantum Dots ◽  
First Time

To the best of our knowledge, this report presents, for the first time, the schematic of the possible chemical reaction for a one-pot synthesis of Zn0.5Cd0.5Se alloy quantum dots (QDs) in the presence of low/high oleylamine (OLA) contents. For high OLA contents, high-resolution transmission electron microscopy (HRTEM) results showed that the average size of Zn0.5Cd0.5Se increases significantly from 4 to 9 nm with an increasing OLA content from 4 to 10 mL. First, [Zn(OAc)2]–OLA complex can be formed by a reaction between Zn(OAc)2 and OLA. Then, Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) data confirmed that ZnO is formed by thermal decomposition of the [Zn(OAc)2]–OLA complex. The results indicated that ZnO grew on the Zn0.5Cd0.5Se surface, thus increasing the particle size. For low OLA contents, HRTEM images were used to estimate the average sizes of the Zn0.5Cd0.5Se alloy QDs, which were approximately 8, 6, and 4 nm with OLA loadings of 0, 2, and 4 mL, respectively. We found that Zn(OAc)2 and OLA could form a [Zn(OAc)2]–OLA complex, which inhibited the growth of the Zn0.5Cd0.5Se alloy QDs, due to the decreasing reaction between Zn(oleic acid)2 and Se2−, which led to a decrease in particle size.

Nanostructured CaWO4, CaWO4:Eu3+ and CaWO4:Tb3+ Particles: Sonochemical Synthesis and Luminescent Properties

2008 ◽  
Vol 8 (3) ◽  
pp. 1183-1190 ◽  
Author(s):  
Chunxia Li ◽  
Cuikun Lin ◽  
Xiaoming Liu ◽  
Jun Lin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Field Emission ◽  
Spherical Particles ◽  
X Ray Diffraction ◽  
Blue Emission Band ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Nanostructured CaWO4, CaWO4:Eu3+, and CaWO4:Tb3+ phosphor particles were synthesized via a facile sonochemical route. X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, photoluminescence, low voltage cathodoluminescence spectra, and photoluminescence lifetimes were used to characterize the as-obtained samples. The X-ray diffraction results indicate that the samples are well crystallized with the scheelite structure of CaWO4. The transmission electron microscopy and field emission scanning electron microscopy images illustrate that the powders consist of spherical particles with sizes from 120 to 160 nm, which are the aggregates of even smaller nanoparticles ranging from 10 to 20 nm. Under UV light or electron beam excitation, the CaWO4 powder exhibited a blue emission band with a maximum at 430 nm originating from the WO2−4 groups, while the CaWO4:Eu3+ powder showed red emission dominated by 613 nm ascribed to the 5D0 → 7F2 of Eu3+, and the CaWO4:Tb3+ powders showed emission at 544 nm, ascribed to the 5D4 → 7F5 transition of Tb3+. The PL excitation and emission spectra suggest that the energy is transferred from WO2−4 to Eu3+CaWO4:Eu3+ and to Tb3+ in CaWO4:Tb3+. Moreover, the energy transfer from WO2−4 to Tb3+ in CaWO4:Tb3+ is more efficient than that from WO2−4 to Eu3+ in CaWO4:Eu3+. This novel and efficient pathway could open new opportunities for further investigating the novel properties of tungstate materials.

Combustion Synthesis of V(CN) Powders

2012 ◽  
Vol 452-453 ◽  
pp. 278-281
Author(s):  
Yun Сhao Mu ◽  
Bao Yan Liang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Combustion Synthesis ◽  
Titanium Carbonitride ◽  
Scanning Electron Microscopy Image ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microscopy Image ◽  
Average Size ◽  
Scanning Electron

Titanium carbonitride, V(C, N) has been prepared by combustion synthesis from V powders and a carbon-nitrogen precursor. The phase composition of the sample was investigated by X-ray diffraction. The scanning electron microscopy image indicates that the average size of the obtained V(C, N) grains was 1µm.

Study of the Reproducibility of Ni-Zn Nanoferrite Obtained by Combustion Reaction

2014 ◽  
Vol 775-776 ◽  
pp. 415-420 ◽  
Author(s):  
Débora Albuquerque Vieira ◽  
Verônica Cristina Souza Diniz ◽  
Daniel R. Cornejo ◽  
Ana Cristina Figueiredo de Melo Costa ◽  
Ruth Herta Goldsmith Aliaga Kiminami
Keyword(s):  
Electron Microscopy ◽  
Combustion Synthesis ◽  
Soft Magnetic Materials ◽  
Spherical Particles ◽  
Magnetic Characteristics ◽  
X Ray Diffraction ◽  
Soft Magnetic ◽  
X Ray ◽  
Crystallite Sizes ◽  
Scanning Electron

This work involved a study of the reproducibility of the process of combustion synthesis to produce Ni-Zn ferrites. The structural, morphological and magnetic characteristics of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and magnetometry using an alternating gradient magnetometer (AGM). The XRD diffractograms of the samples indicated that they are monophasic, crystalline, with crystallite sizes ranging from 21 to 38 nm, and have a homogeneous morphology consisting of agglomerates of spherical particles. The samples behaved as soft magnetic materials, with magnetization levels ranging from 37 to 47 emug-1. The combustion synthesis was found to be efficient in producing Ni-Zn nanoferrites, yielding reproducible results.

Synthesis of Powders Nanometer Al2O3 Method by Sol-Gel

2012 ◽  
Vol 727-728 ◽  
pp. 9-13
Author(s):  
Suzana Arleno S. Santos ◽  
Eduardo Sousa Lima ◽  
Luis Henrique Leme Louro ◽  
Célio Albano da Costa
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Thermogravimetric Analysis ◽  
Calcination Temperature ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Average Size ◽  
Scanning Electron

This study aimed to produce nanometric powders of alumina by sol-gel route. Six samples were produced by varying the amount of water for dilution of aluminum nitrate and the calcination temperature. The final products were evaluated by thermogravimetric analysis, scanning electron microscopy, X-ray diffraction and particle size. It could be noticed that, beyond the time of gelation and calcination temperature, the addition of water also influenced the average size of the clusters.

scholarly journals Effect of “cobalt–carbon nanotubes” catalysts on anthracene coking

2019 ◽  
Vol 484 (4) ◽  
pp. 451-454
Author(s):  
V. V. Chesnokov ◽  
A. S. Chichkan ◽  
V. N. Parmon
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Carbon Coating ◽  
Cobalt Catalyst ◽  
Coke Formation ◽  
Spherical Particles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coking Products ◽  
First Time

Coking of anthracene at 400–600°C in the presence or in the absence of a cobalt catalyst supported on carbon nanotubes (CNTs) was studied for the first time. The coking products were examined by X-ray diffraction and electron microscopy. The CoO-CNTs catalyst considerably (by 50°C) decreased the temperature of the onset of coking and accelerated the coke formation. The presence of CoO-CNTs changed the coke morphology. Whereas coking of pure anthracene affords ~1 micron spherical particles of poorly crystallized carbon, in the presence of the catalyst, a carbon “coating” covering the CNT surface is formed.

Study of Synthesis and Crystal Structure of Barium Cerate at High Temperatures

2017 ◽  
Vol 891 ◽  
pp. 473-477
Author(s):  
Renáta Verbová ◽  
Viktor Kavečanský ◽  
Pavel Diko ◽  
Samuel Piovarči
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Barium Cerate ◽  
X Ray Diffraction ◽  
Oxalate Precursor ◽  
X Ray ◽  
Different Temperatures ◽  
Average Size ◽  
Scanning Electron

Crystalline barium cerate was synthesized by oxalate coprecipitation from nitrates of barium and cerium [1]. The oxalate precursor prepared by chemical methods was calcined at different temperatures up to 950°C. The barium cerate was studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). X-ray diffraction investigation enables the determination of the phases that originate at different stages of synthesis and the crystal structure of final barium cerate, as well. From XRD patterns the average size of coherent regions was estimated by using Halder-Wagner method [2]. Both size and shape of crystallites were also studied by scanning electron microscopy. It was found that crystallites of barium cerate arise within the initial particles of the oxalate precursor.

Synthesis of Nanostructured PZT Ceramics with Powder Obtained from Coprecipitate Method

2014 ◽  
Vol 798-799 ◽  
pp. 110-115
Author(s):  
Alexandre Costa Lanza ◽  
Daniel Thomazini ◽  
Maria Virgínia Gelfuso
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Grain Morphology ◽  
Microwave Oven ◽  
Spherical Particles ◽  
X Ray Diffraction ◽  
Pzt Ceramics ◽  
X Ray ◽  
Piezoelectric Devices ◽  
Scanning Electron

Ceramics of Pb1.02(Zr0.53Ti0.47)O3(PZT) comprise the majority of piezoelectric devices in use today. In general, these ceramics are obtained by solid-state reaction, which favors the formation of micrometric grains. Recent studies have shown that reducing the particle size from micro to nanoscale, it generates PZT ceramics with superior dielectric properties. In this way, this study aimed to obtain nanostructured PZT ceramics from the coprecipitate method, using precursor materials as oxides reagents. From the Differential Thermal Analysis (DTA) was observed that the formation of PZT through the proposed methodology is initiated at 550oC. However, the full phase crystallization was observed at 850oC confirmed by X-Ray Diffraction (XRD). Spherical particles near 200nm were observed using scanning electron microscopy (SEM). This powder was sintered in conventional and microwave oven. The ceramics obtained from both sintering methods showed substantial differences in microstructure such as presence of piroclore phase and grain morphology.

Influence of Cyclodextrin in the Synthesis of Magnetite

2009 ◽  
Vol 1243 ◽  
Author(s):  
L. A. Cobos Cruz ◽  
C. A. Martínez Perez ◽  
A Martínez Villafañe ◽  
J. A. Matutes Aquino ◽  
J. R. Farias Macilla ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Inorganic Material ◽  
Inorganic Nanoparticles ◽  
Spherical Particles ◽  
X Ray Diffraction ◽  
Guest Molecules ◽  
X Ray ◽  
Ft Ir ◽  
Scanning Electron ◽  
Made In

ABSTRACTCyclodextrin (CD) has been studied intensively due to its ability to form inclusion complexes with a variety of guest molecules in the solid state. A few studies have paid attention to the use of CD to facilitate the synthesis of inorganic nanoparticles. In this work the synthesis of magnetite (M) is made in the presence of CD. The particle size of the inorganic material is controlled by the presence of CD, in which spherical particles of few nanometers are grown. The synthesis of Fe3O4 (M) in the presence of α-cyclodextrin (α-CD) and β-cyclodextrin (βCD) is described. The formation of an M-CD complex is studied in both cases by Fourier transform infrared spectroscopy (FT-IR) in order to elucidate the chemical bonding of the complex. The morphology and size of the particles are determined by Field Emission Scanning Electron Microscopy (FESEM) and software. X-ray diffraction (XRD) is used to confirm the formation of magnetite.

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