Structural and Spectroscopic Characterization of ZrO2:Eu3+ Nanoparticles

2008 ◽  
Vol 8 (12) ◽  
pp. 6431-6436 ◽  
Author(s):  
P. Salas ◽  
N. Nava ◽  
C. Ángeles-Chavez ◽  
E. De la Rosa ◽  
L. A. Díaz-Torres
Keyword(s):  
Raman Spectroscopy ◽  
Crystalline Structure ◽  
Sol Gel ◽  
Tetragonal Zirconia ◽  
Fluorescence Emission ◽  
Spectroscopic Characterization ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Xrd Patterns

ZrO2:Eu3+ nanocrystals were prepared by the sol–gel technique. The structural and luminescence properties of europium doped zirconia with 0.5 to 2 mol% were studied by Mössbauer spectroscopy, Raman spectroscopy, X-ray diffraction (XRD), High Resolution Transmission Electron Microscopy (HRTEM) and photoluminescence (PL) under UV excitation. Structural characterization shows a crystallite size between 16 to 55 nm and monoclinic and tetragonal zirconia phases as the main crystalline structure. XRD patterns shown that the content of the active ions stabilizes the tetragonal structure of ZrO2 at 1000 °C, being 100% for 2 mol% Eu2O3 doped sample. Such results are in agreement with HRTEM and Raman spectroscopy. The Mössbauer spectra of the ZrO2:Eu3+ samples show a single peak near zero velocity which is attributed to Eu+3. Luminescence characterization shows the typical emission band centered at 595 and 611 nm. Change in the structure of such band was observed and explained in terms of crystalline phase change. The dependence between the fluorescence emission and the crystalline structure is discussed.

Microstructure Characterization of Metal Mixed Oxides

MRS Advances ◽  
2017 ◽  
Vol 2 (64) ◽  
pp. 4025-4030 ◽  
Author(s):  
T. Kryshtab ◽  
H. A. Calderon ◽  
A. Kryvko
Keyword(s):  
Mixed Oxides ◽  
Profile Analysis ◽  
Atomic Resolution ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Reconstruction Procedure ◽  
Transmission Electron ◽  
Xrd Patterns ◽  
Co Precipitation

ABSTRACTThe microstructure of Ni-Mg-Al mixed oxides obtained by thermal decomposition of hydrotalcite-like compounds synthesized by a co-precipitation method has been studied by using X-ray diffraction (XRD) and atomic resolution transmission electron microscopy (TEM). XRD patterns revealed the formation of NixMg1-xO (x=0÷1), α-Al2O3 and traces of MgAl2O4 and NiAl2O4 phases. The peaks profile analysis indicated a small grain size, microdeformations and partial overlapping of peaks due to phases with different, but similar interplanar spacings. The microdeformations point out the presence of dislocations and the peaks shift associated with the presence of excess vacancies. The use of atomic resolution TEM made it possible to identify the phases, directly observe dislocations and demonstrate the vacancies excess. Atomic resolution TEM is achieved by applying an Exit Wave Reconstruction procedure with 40 low dose images taken at different defocus. The current results suggest that vacancies of metals are predominant in MgO (NiO) crystals and that vacancies of Oxygen are predominant in Al2O3 crystals.

The effect of silver concentration and calcination temperature on structural and optical properties of ZnO:Ag nanoparticles

2015 ◽  
Vol 29 (01) ◽  
pp. 1450254 ◽  
Author(s):  
M. Shayani Rad ◽  
A. Kompany ◽  
A. Khorsand Zak ◽  
M. E. Abrishami
Keyword(s):  
Calcination Temperature ◽  
Sol Gel ◽  
Visible Emission ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
Zno Nps ◽  
Calcination Temperatures ◽  
Transmission Electron ◽  
Xrd Patterns ◽  
Average Size

Pure and silver added zinc oxide nanoparticles ( ZnO -NPs and ZnO : Ag -NPs) were synthesized through a modified sol–gel method. The prepared samples were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. In the XRD patterns, silver diffracted peaks were also observed for the samples synthesized at different calcination temperatures of 500°C, 700°C, 900°C except 1100°C, in addition to ZnO . TEM images indicated that the average size of ZnO : Ag -NPs increases with the amount of Ag concentration. The PL spectra of the samples revealed that the increase of Ag concentration results in the increase of the visible emission intensity, whereas by increasing the calcination temperature the intensity of visible emission of the samples decreases.

CONTROLLED SYNTHESIS AND CHARACTERIZATION OF TiO2 NANOPARTICLES VIA A SOL–GEL METHOD

2004 ◽  
Vol 03 (06) ◽  
pp. 749-755 ◽  
Author(s):  
YING LI ◽  
SUO HON LIM ◽  
TIM WHITE
Keyword(s):  
Sol Gel ◽  
Critical Role ◽  
Rietveld Analysis ◽  
Nanocrystalline Powders ◽  
X Ray Diffraction ◽  
Gelation Temperature ◽  
Gel Method ◽  
Sol Gel Method ◽  
Transmission Electron

The properties influencing the photocatalytic activity of TiO 2 particles have been suggested to include the surface area, crystallinity, crystallite size and crystal structure. Therefore, manipulation of the microstructure of titania, especially of nanocrystalline powders, is very important in the preparative process. In this study, nanocrystalline TiO 2 powders with controlled particle size and phase composition were synthesized at low temperature (<80°C) by a modified sol–gel method. The effects of gelation temperature were systematically investigated. It was found that this parameter played a critical role in determining the crystallinity of single phase anatase. With increasing gelation temperature, the crystallinity of anatase improved initially and then decreased if the temperature was raised to 80°C. These nanomaterials were characterized comprehensively by powder X-ray diffraction (including Rietveld analysis), high-resolution transmission electron microscopy, DSC/TGA thermal analysis and UV–Vis spectrometry.

Synthesis and Characterization of Cadmium with Titanium Oxide (Cd-TiO2) Nanocomposite: Testing its Antibacterial Effect

2021 ◽  
Vol 12 (4) ◽  
pp. 2523-2529
Author(s):  
Daniel Sam N ◽  
Anish C I ◽  
Sabeena G ◽  
Rajaduraipandian S ◽  
Manobala ◽  
...  
Keyword(s):  
Sol Gel ◽  
Gram Negative Bacteria ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Gram Negative ◽  
X Ray ◽  
Weight Percentage ◽  
Inhibition Concentration ◽  
Xrd Patterns

Sol gel methods were used for the study of the antimicrobial activity of Cd-TiO2 against gram-negative and positive bacteria. These Cd-TiO2 have been characterized by various optical and techniques. They have been exhibited by X-ray diffraction, scanning electron microscopy, ultraviolet spectroscopy, and infrared spectroscopy. The structures of the various XRD patterns indicate that the product has a structure. The particle size of Cd-TiO2 is 35nm. The SEM images confirm the spherical appearance of the sample. The energy X-ray spectra have been confirmed as well and then C, O, Ti, Cd, Pt element are present in Cd-TiO2. The weight percentage of Cadmium is 5.8%, Ti is 51.03%, C is 5.13% and O is 31.75% in Cd-TiO2. BET image shows that the major pore size distribution of Cd-TiO2 is ranged from 2.24 nm. The Cd-TiO2 that the antibacterial activity when tested against the pathogens only gram-negative bacteria such as Pseudomonas. The zone of minimum inhibition concentration was measured in a range of 20mm in 25μl and 30mm in 100μl.

Sol-Gel Synthesis and Characterization of Nanocrystalline Bi4Ti3O12 Powders

2014 ◽  
Vol 997 ◽  
pp. 359-362 ◽  
Author(s):  
Chun Hong Ma ◽  
Xue Lin ◽  
Liang Wang ◽  
Yong Sheng Yan
Keyword(s):  
Phase Inversion ◽  
Bismuth Titanate ◽  
Sol Gel ◽  
Tetrabutyl Titanate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Sol Gel Synthesis ◽  
Source Materials

Nanocrystalline bismuth titanate (Bi4Ti3O12; BTO) powders were successfully prepared by the sol-gel method, using bismuth nitrate (Bi(NO3)3·5H2O) and tetrabutyl titanate (Ti(OC4H9)4) as source materials, acetic anhydride and ethanediol as solvents. The thermal decomposition and phase inversion process of the gel precursors were studied by using differential thermal analysis (DTA). The crystal structures and microstructures of BTO powders were investigated by using x-ray diffraction (XRD), and transmission electron microscope (TEM). The crystallization of amorphous bismuth titanate has been discussed. The effect of sintering temperature on the structure and morphology of BTO was investigated. At 644 oC and above, BTO powder undergoes a phase transformation from tetragonal to orthorhombic. At 900 oC, the purified orthorhombic BTO nanocrystals were obtained.

Photocatalytic Analysis and Characterization of Zn2SnO4 Nanoparticles Synthesized via Hydrothermal Method with Na2CO3 Mineralizer

2010 ◽  
Vol 97-101 ◽  
pp. 19-22 ◽  
Author(s):  
Yu Shiang Wu ◽  
Wen Ku Chang ◽  
Min Jou
Keyword(s):  
Photocatalytic Activity ◽  
Hydrothermal Process ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
Transmission Electron ◽  
Excellent Photocatalytic Activity ◽  
Face Centered ◽  
Xrd Patterns

Zinc stannate Zn2SnO4 (ZTO) nanoparticles were synthesized via a hydrothermal process utilizing sodium carbonate (Na2CO3) as a weak basic mineralizer. The samples were hydrothermally treated at 150, 200, and 250oC for 48 h. The X-ray diffraction (XRD) patterns show that the highly-crystalline ZTO nanostructure could be formed in a well-dispersed manner for the 250°C sample at a particle size of less than 50 nm. As determined from transmission electron microscopy (TEM) results, ZTO nanoparticles are face-centered cubic single crystals agglomerated together. The Raman spectra results showed that the ZTO nanocrystals have a spinel structure. Furthermore, photocatalytic activity was tested with methylene blue (MB) by UV irradiation. The ZTO synthesized by the 2 M Na2CO3 mineralizer at 250oC demonstrated excellent photocatalytic activity. The ZTO treated three different ways had three distinct UV-Visible absorption curves, which directly influences their corresponding photocatalytic activity.

Low Temperature Synthesis and Characterization of CaO and MgO- Stabilized Nanocrystalline Tetragonal Zirconia by Citrate Gel Process

2008 ◽  
Vol 368-372 ◽  
pp. 754-757
Author(s):  
Hasan Gocmez ◽  
Hirotaka Fujimori
Keyword(s):  
Single Phase ◽  
Tetragonal Zirconia ◽  
Xrd Analysis ◽  
Complex Method ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Heat Treated ◽  
Crystallite Sizes ◽  
Citrate Gel Process

The citrate gel method, similar to the polymerized complex method, was used to synthesize homogenous tetragonal zirconia at 800oC and 1000oC. Nanocrystalline tetragonal single phase has been fully stabilized with 3, 7, 10 mol% CaO and 10, 15 mol% MgO at 800oC, respectively. In addition, the XRD analysis showed the absence of monoclinic phase after addition of 7 and 10 mol% CaO into zirconia-based solid solutions, which have been fully stabilized both 800oC and 1000oC. The crystallite sizes of the t-ZrO2 with 3, 7 and 10 mol% CaO at 1000oC were 32, 28 and 29nm, respectively. For ZrO2- x mol% MgO (x=3, 10, 15) solid solution, the crystallite sizes of samples at 800oC were less than 29nm, however it was increased up to 69nm at 1000oC. The prepared gel and subsequent heat-treated powders were characterized by X-ray diffraction (XRD), Raman spectroscopy and transmission electron microscopy (TEM) to get detail information regarding to differentiation of polymorphs of zirconia as well as formation of powders.

Sol-gel processing of nanocrystalline haematite thin films

1997 ◽  
Vol 12 (6) ◽  
pp. 1441-1444 ◽  
Author(s):  
L. Armelao ◽  
A. Armigliato ◽  
R. Bozio ◽  
P. Colombo
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Raman Spectroscopy ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Single Particles ◽  
X Ray ◽  
Transmission Electron ◽  
Gel Processing

The microstructure of Fe2O3 sol-gel thin films, obtained from Fe(OCH2CH3)3, was investigated by x-ray diffraction (XRD), transmission electron microscopy (TEM), and Raman spectroscopy. Samples were nanocrystalline from 400 °C to 1000 °C, and the crystallized phase was haematite. In the coatings, the α–Fe2O3 clusters were dispersed as single particles in a network of amorphous ferric oxide.

Synthesis and Characterization of Mesoporous Silica Nanoparticles Embedded Gadolinium Oxide

2011 ◽  
Vol 306-307 ◽  
pp. 1275-1279 ◽  
Author(s):  
Ning Qi Luo ◽  
Zhan Yun Huang ◽  
Ping Luo ◽  
Yuan Zhi Shao ◽  
Di Hu Chen
Keyword(s):  
Mesoporous Silica ◽  
Self Assembly ◽  
Mesoporous Silica Nanoparticles ◽  
Sol Gel ◽  
Mesoporous Structure ◽  
Gadolinium Oxide ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
The Mean

We first synthesized gadolinium oxide (Gd2O3) by a modified “polyol” strategy and then embedded it into mesoporous silica by a simple self-assembly sol-gel reaction. Scanning electron microscope (SEM) results show that the samples have good sphericity and good dispersibility. The structure of mesoporous silica was characterized by transmission electron microscopy (TEM) and small-angle X-ray diffraction (SAXRD). Results show that the mesoporous structure has not been destroyed after gadolinium oxide imbedding. The ratio of gadolinium and silica was determined by the mean of energy dispersive spectroscopy (EDS).

Sol-gel derived Ba(Mg1/3Ta2/3)O3 thin films: Preparation and structure

1997 ◽  
Vol 12 (3) ◽  
pp. 596-599 ◽  
Author(s):  
Ji Zhou ◽  
Qing-Xin Su ◽  
K. M. Moulding ◽  
D. J. Barber
Keyword(s):  
Thin Films ◽  
Annealing Temperature ◽  
Volume Fraction ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Small Grains

Ba(Mg1/3Ta2/3)O3 thin films were prepared by a sol-gel process involving the reaction of barium isopropoxide, tantalum ethoxide, and magnesium acetate in 2-methoxyethanol and subsequently hydrolysis, spin-coating, and heat treatment. Transmission electron microscopy, x-ray diffraction, and Raman spectroscopy were used for the characterization of the thin films. It was shown that the thin films tend to crystallize with small grains sized below 100 nm. Crystalline phase with cubic (disordered) perovskite structure was formed in the samples annealed at a very low temperature (below 500 °C), and well-crystallized thin films were obtained at 700 °C. Although disordered perovskite is dominant in the thin films annealed below 1000 °C, a low volume fraction of 1 : 2 ordering domains was found in the samples and grows with an increase of annealing temperature.

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