X-ray structure determination of the rare earth oxides (Er1−uGdu)2O3applying the Rietveld method

2002 ◽  
Vol 35 (5) ◽  
pp. 577-580 ◽  
Author(s):  
Zein Heiba ◽  
Hasan Okuyucu ◽  
Y. S. Hascicek
Keyword(s):  
Rare Earth ◽  
Rietveld Method ◽  
Sol Gel ◽  
Average Crystallite Size ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gel Technique ◽  
Average Size

Nanosized polycrystalline samples of (Er1−uGdu)2O3(0 ≤u≤ 1.0) were synthesized by a sol–gel technique. X-ray diffraction data were collected and the crystal structures were refined by the Rietveld method. All samples are found to have the same crystal system and formed solid solutions over the whole range ofu. The Er3+and Gd3+ions were randomly distributed over two cationic sites, 8band 24d, in the space groupIa\bar{3} (206) in all refined structures. The lattice parameter was found to vary non-linearly with the composition (u). The average microstrain and average crystallite size have been calculated from the Williamson–Hall plots for each sample. The average size ranges from 50 to 70 nm, and the microstrain from 0.4 to 1.7%.

Synthesis and Characterization of CeO2 Doped ZrO2 Ceramics by a Simple Sol-Gel Route

2017 ◽  
Vol 907 ◽  
pp. 56-60
Author(s):  
Ummuhanı Hilal Özer ◽  
Kerim Emre Öksüz ◽  
Ali Özer
Keyword(s):  
Tetragonal Phase ◽  
Sol Gel ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Ceramic Powders ◽  
Zirconia Ceramics ◽  
Simple Method ◽  
X Ray ◽  
Gel Technique

It is well known that sol-gel technique is a simple method to produce nano sized ceramic powders. In this study, cerium oxide doped zirconia samples, with 10 mol%-12mol% and14mol% CeO2, were synthesized by sol-gel technique and characterized. The surface morphology, elemental composition, microstructure, and phase analysis, of the sintered CeO2 doped ZrO2 ceramics were characterized by field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDS) analysis, and X-ray diffraction (XRD) respectively. X-ray diffraction for samples sintered at 1550 °C for 4h revealed that the zirconia ceramics have a tetragonal phase structure. The addition of CeO2 can raise the content of the tetragonal phase, but the minor monoclinic phase exists even at the CeO2 content of 10 mol%. The effect of dopant concentration on the lattice parameter, average primary crystallite size and micro-strain was studied. Relative densities for CeO2 doped ZrO2 bulk ceramics varied between 95% and 99 %, depending on the CeO2 addition.

scholarly journals Enhancement of Photocatalytic Activity by Mg2+ Doped Ceria Quantum Dots

2017 ◽  
Vol 2 (1) ◽  
Keyword(s):  
Quantum Dots ◽  
Photocatalytic Activity ◽  
Quantum Dot ◽  
Sol Gel ◽  
Lattice Parameter ◽  
Doped Ceria ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gel Technique ◽  
Cubic Structure

The pure and Mg2+ doped CeO2 quantum dot were synthesized by sol-gel technique. The prepared quantum dots were characterized using X-ray diffraction pattern (XRD), Scanning electron microscope (SEM-EDX). The XRD results show cubic structure of the CeO2 quantum dots. The crystalline size (D), microstrain (ε), dislocation density (δ) and lattice parameter (α) were calculated and analyzed. SEM-EDX analysis shows the morphology and the presence of elements. The photocatalytic activity of the synthesized quantum dot was evaluated based on the photodegradation of methylene blue (MB) by UV-Vis spectrometry.

X-ray structure and microstructure determination of the mixed sesquioxides (Eu1−xYbx)2O3prepared by a sol–gel process

2003 ◽  
Vol 36 (6) ◽  
pp. 1411-1416 ◽  
Author(s):  
Z. K. Heiba ◽  
Y. Akin ◽  
W. Sigmund ◽  
Y. S. Hascicek
Keyword(s):  
Crystallite Size ◽  
Rietveld Method ◽  
Sol Gel ◽  
Average Crystallite Size ◽  
X Ray Diffraction ◽  
X Ray ◽  
Profile Fitting ◽  
Cationic Distribution ◽  
Sol Gel Process ◽  
Multiple Orders

Polycrystalline samples of (Eu1−xYbx)2O3(x= 0.0, 0.1, 0.2, 0.5, 0.8, 0.9 and 1.0) were synthesized by a sol–gel process. X-ray diffraction data were collected and the crystal structures were refined by the Rietveld method. All samples are found to have the same crystal system and formed solid solutions over the whole range ofx. The lattice parameters are found to vary linearly with the compositionx. The cationic distribution over the two non-equivalent sites 8band 24dof the space group Ia{\bar 3} is found to be random in the range 0.0 <x≤ 0.5 and preferential in the range 0.5 <x≤ 1.0. Replacing Eu3+and Yb3+by each other introduces slight changes in the atomic coordinates. Crystallite size and microstrain analysis are performed on single and multiple orders for each sample using profile fitting and the Warren–Averbach method. The obtained values of microstrain are correlated with the distribution of the rare earth (RE) ions over the two cationic sites of the structure. The average crystallite size ranges from 35 to 96 nm and the mean-square strain from 0.052 to 0.225 × 10−2.

Structure Analysis of Nanocrystalline MgO Aerogel Prepared by Sol-Gel Method

2007 ◽  
Vol 130 ◽  
pp. 203-206 ◽  
Author(s):  
Grzegorz Dercz ◽  
Lucjan Pająk ◽  
Krystian Prusik ◽  
Roman Pielaszek ◽  
Janusz J. Malinowski ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Magnesium Oxide ◽  
Sol Gel ◽  
Average Crystallite Size ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Gel Technique ◽  
Microscopy Images ◽  
Nanocrystalline Mgo

Wet gel obtained by sol-gel technique was dried in supercritical CO2 to prepare hydrated form of magnesium oxide. Calcination at 723 K under vacuum yielded nanocrystalline MgO aerogel. Structure studies were performed by X-ray diffraction, scanning and transmission electron microcopies. Electron microscopy images reveal rough, unfolded and ramified structure of solid skeleton. Specific surface area SBET was equal to 238 m2/g. X-ray pattern reveals the broadened diffraction lines of periclase, the only crystalline form of magnesium oxide. The gamma crystallite size distribution was determined using FW 5 4 / 5 1 M method proposed by R. Pielaszek. The obtained values of <R> and σ (measure of polydispersity) of particle size parameters are equal to 6.5 nm and 1.8 nm, respectively, whereas the average crystallite size estimated by Williamson-Hall procedure was equal to 6.0 nm. The obtained at Rietveld refinement Rwp, and S fitting parameters equal to 6.62% and 1.77, respectively, seem to be satisfactory due to the nanosize of MgO crystallites and because of the presence of amorphous phase.

scholarly journals Calcination Effect on Structural Trasformation of Barium Titanite Ferroelectric Ceramic by Sol-Gel Method

2019 ◽  
Vol 9 (1) ◽  
pp. 5893-5896
Keyword(s):  
Glacial Acetic Acid ◽  
Sol Gel ◽  
Ferroelectric Ceramic ◽  
Tetrabutyl Titanate ◽  
Chemical Modifier ◽  
Barium Acetate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gel Technique ◽  
Scanning Electron

High purity barium titanate BaTiO3 was successfully synthesized by using the sol-gel technique. Barium acetate Ba(CH3COO)2 and tetrabutyl titanate, Ti(C4H9O)4 was dissolved moderately in the solvent of glacial acetic acid and ethanol was added as the chemical modifier. The synthesized BaTiO3 nanoparticle was calcined at the temperature range of 700 ºC to 1100 ºC. The powders were further characterized by X-ray diffraction and scanning electron microscopy (SEM). Fined BaTiO3 powders result indicates the phase of tetragonal structures and high crystallites of BaTiO3. It was observed that the crystallinity and particle size of BaTiO3 is greatly influenced by the calcination temperature.

Synthesis and characterization of MnO2nanowires

2017 ◽  
Vol 31 (02) ◽  
pp. 1750006 ◽  
Author(s):  
Mohammad Hossein Ghorbani ◽  
Abdol Mahmood Davarpanah
Keyword(s):  
Lithium Batteries ◽  
Manganese Oxides ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Average Crystallite Size ◽  
X Ray Diffraction ◽  
X Ray ◽  
Xrd Method

Manganese oxides are of more interest to researchers because of their ability as catalysts and lithium batteries. In this research, MnO2nanowires with diameter about 45 nm were synthesized by sol–gel method at room temperature (RT). Effect of increasing the annealing temperature from 400[Formula: see text]C to 600[Formula: see text]C on crystalline structure of nanostructure were studied and average crystallite size was estimated about 22 nm. X-ray Diffraction (XRD) method, Energy-Dispersive X-ray Diffraction (EDXD), Scanning Electron Microscopy (SEM) and Vibrating Sample Magnetometer (VSM) were used to characterize the nanowires of MnO2.

scholarly journals Synthesis Photocatalytic and Antibacterial Activities of Nickle Doped Tio2 Nanoparticles

2018 ◽  
Vol 34 (6) ◽  
pp. 3140-3144
Author(s):  
Ritu Vershney ◽  
Komal Chelaramani ◽  
Arpan Bhardwaj ◽  
Nayma Siddiqui ◽  
Suresh Kumar Verma
Keyword(s):  
Photocatalytic Degradation ◽  
Tio2 Nanoparticles ◽  
Sol Gel ◽  
Antibacterial Activities ◽  
X Ray Diffraction ◽  
Zone Of Inhibition ◽  
Time Duration ◽  
X Ray ◽  
Gel Technique ◽  
Doped Titania

The synthesis of Ni doped titania (TiO2) nanoparticles were achieved via simple novel sol gel technique, in which Titanium-n-butoxide and NiCl2 were taken as precursors. Effect of different wt% of dopant in TiO2 was studied on photocatalytic degradation of Aniline blue and Toluidine Blue. The study suggested the increased photocatalytic degradation with increased time duration. The synthesized samples were analyzed by surface electron microscopy (SEM) and X-ray diffraction studies. The antibacterial activity was investigated against Gram-positive Staphylococcus aureus bacteriae. Studies revealed that on increasing the dopant concentration, the diameter of zone of inhibition also increased upto 1.5 wt%.

Fabrication of Porous LSCF-SDC Carbonates Composite Cathode for Solid Oxide Fuel Cell (SOFC) Applications

2011 ◽  
Vol 471-472 ◽  
pp. 179-184 ◽  
Author(s):  
Raharjo Jarot ◽  
Andanastuti Muchtar ◽  
Wan Ramli Wan Daud ◽  
Norhamidi Muhamad ◽  
Edy Herianto Majlan
Keyword(s):  
Thermal Expansion ◽  
Sol Gel ◽  
Composite Cathode ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Morphology ◽  
Composite Cathodes ◽  
Gel Technique ◽  
Optimum Porosity ◽  
Cold Pressed

Composite cathodes made of perovskite La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) and SDC carbonates (SDC-(Li/Na)2CO3) were investigated in relation to their structure, morphology, thermal expansion coefficient and porosity. As a first step, the LSCF powder was prepared by sol-gel technique. This was followed by the preparation of the LSCF-SDC carbonates composite cathode by mixing the LSCF with SDC-(Li/Na)2CO3 electrolyte via solid state reaction in various compositions, i.e. 30, 40 and 50 wt.%, namely 70LSCF-30SDC7030, 60LSCF-40SDC7030 and 50LSCF-50SDC7030, respectively. The powder mixtures were then calcined at 680oC. The resultant powder was fine with surface area of about 3.39-7.42 m2/g and particle size of 0.56-0.66µm. The powder consists of two distinct phases, i.e. LSCF and SDC-(Li/Na)2CO3 as confirmed with x-ray diffraction. The microstructures were observed under scanning electron microscopy (SEM). Increasing the amount of the SDC-(Li/Na)2CO3 electrolyte in the composite cathode was found to bring the thermal expansion of the cathode closer to that of the electrolyte. The cathode pellets were later compacted at different pressures (27, 32 and 37 MPa) and sintered at 600oC. The optimum porosity (20.99-24.98%) was achieved for samples with SDC-(Li/Na)2CO3 content of 30-50% sintered at 600oC and cold pressed at 37 MPa.

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