scholarly journals Crystal structure analysis of Nd-doped ceria solid solutions

2008 ◽  
Vol 40 (1) ◽  
pp. 63-68
Author(s):  
B. Matovic ◽  
J. Dukic ◽  
A. Devecerski ◽  
S. Boskovic ◽  
M. Ninic ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid Solutions ◽  
Structural Information ◽  
Crystal Structure Analysis ◽  
Ion Concentration ◽  
Doped Ceria ◽  
Cell Parameters ◽  
Ceria Solid Solutions ◽  
Fluorite Type ◽  
Powder Particles

This paper deals with Nd-doped ceria solid solutions: Ce1-xNdxO2-d with "x" ranging from 0 to 0.25. Six different powders were synthesized by applying the method based on selfpropagating room temperature reaction (SPRT) between metallic nitrates and sodium hydroxide. The method is known to assure very precise stoichiometry of the final product in comparison with a tailored composition. Rietveld refinement was employed to get structural information on the synthesized powder. An increase of Nd ion concentration increases the unit cell parameters and average bond distances. We have shown that all obtained powders were solid solutions with a fluorite-type crystal structure and all powder particles were of nanometric size (about 3 nm).

scholarly journals Crystal structure analysis of Nd-doped ceria solid solutions

2008 ◽  
Vol 40 (1) ◽  
pp. 63-68 ◽  
Author(s):  
B. Matovic ◽  
J. Dukic ◽  
A. Devecerski ◽  
S. Boskovic ◽  
M. Ninic ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid Solutions ◽  
Structural Information ◽  
Crystal Structure Analysis ◽  
Ion Concentration ◽  
Doped Ceria ◽  
Cell Parameters ◽  
Ceria Solid Solutions ◽  
Fluorite Type ◽  
Powder Particles

This paper deals with Nd-doped ceria solid solutions: Ce1-xNdxO2-d with "x" ranging from 0 to 0.25. Six different powders were synthesized by applying the method based on selfpropagating room temperature reaction (SPRT) between metallic nitrates and sodium hydroxide. The method is known to assure very precise stoichiometry of the final product in comparison with a tailored composition. Rietveld refinement was employed to get structural information on the synthesized powder. An increase of Nd ion concentration increases the unit cell parameters and average bond distances. We have shown that all obtained powders were solid solutions with a fluorite-type crystal structure and all powder particles were of nanometric size (about 3 nm).

scholarly journals Influence of mg doping on structural, optical and photocatalytic performances of ceria nanopowders

2017 ◽  
Vol 11 (4) ◽  
pp. 304-310
Author(s):  
Branko Matovic ◽  
Jelena Lukovic ◽  
Bojan Stojadinovic ◽  
Sonja Askrabic ◽  
Aleksandra Zarubica ◽  
...  
Keyword(s):  
Solid Solutions ◽  
Oxygen Vacancies ◽  
Uv Light ◽  
Doped Ceria ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ceria Solid Solutions ◽  
Fluorite Type ◽  
Photocatalytic Performances ◽  
Mg Doped

Nanosized Mg-doped ceria powders were obtained by self-propagating room temperature reaction without using surfactants or templates. X-ray diffraction analysis and field emission scanning microscopy results showed that the doped samples are solid solutions with fluorite-type structure and spherical morphology. Raman spectra revealed an increase in the amount of oxygen vacancies with the increase of Mg concentration. This increasing results in a narrowing of the bandgap of CeO2. The photocatalytic performances of the Mg-doped ceria solid solutions were evaluated by decomposing an organic dye, crystal violet under UV irradiation. The Mg-doped ceria solid solutions exhibit significantly better photocatalytic activity than the pure CeO2 and commercial TiO2. The higher first rate constant of the Mg-doped samples demonstrated that they are much more efficient than TiO2 and CeO2 under UV light. Mg2+ dopant ions and oxygen vacancies play a significant role in the enhancement of photocatalytic performances of the Mg-doped ceria.

Lattice Parameters of Gd-Doped Ceria Electrolytes

2005 ◽  
Vol 494 ◽  
pp. 175-180 ◽  
Author(s):  
B. Matović ◽  
Snezana Bošković ◽  
Ljiljana Živković ◽  
M.D. Vlajić ◽  
Vladimir D. Krstić
Keyword(s):  
Solid Solutions ◽  
Lattice Parameter ◽  
Lattice Parameters ◽  
Doped Ceria ◽  
Ceria Solid Solutions ◽  
Fluorite Type ◽  
Parameter Versus ◽  
Average Size ◽  
20 Nm ◽  
Type Crystal

This paper deals with Gd-doped ceria solid solutions: Ce1−XGdXO2−d with "x" ranging from 0 to 0.2. Four different powders were synthesized by modified glycine nitrate procedure with very precise stoichiometry according to tailored composition. The method was modified by decreasing glycine/nitrate ratio to 0.5. All obtained solid solutions exhibit a fluorite-type crystal structure with composition dependent lattice parameters. The variation of the lattice parameter was studied and correlated with the equation describing the ion-packing model. It has been found that the change of lattice parameter versus Gd concentration obeys Vegard's rule very well. Results also show that all powders are nanometric in size. The average size of Ce1−XGdXO2−d particles is about 20 nm.

Elaboration and characterization of europium doped ceria solid solutions

2005 ◽  
Vol 123 ◽  
pp. 35-39
Author(s):  
L. Aneflous ◽  
S. Villain ◽  
J. R. Gavarri ◽  
J. Musso ◽  
H. Benyaich ◽  
...  
Keyword(s):  
Solid Solutions ◽  
Doped Ceria ◽  
Ceria Solid Solutions

Sintering Analysis of Undoped and Cobalt Oxide Doped Ceria Solid Solutions

2005 ◽  
Vol 88 (11) ◽  
pp. 3013-3019 ◽  
Author(s):  
Eva Jud ◽  
Christoph B. Huwiler ◽  
Ludwig J. Gauckler
Keyword(s):  
Cobalt Oxide ◽  
Solid Solutions ◽  
Doped Ceria ◽  
Ceria Solid Solutions

Ionic conductivity of high-purity Gd-doped ceria solid solutions

2006 ◽  
Vol 41 (3) ◽  
pp. 563-568 ◽  
Author(s):  
T.S. Zhang ◽  
J. Ma ◽  
H. Cheng ◽  
S.H. Chan
Keyword(s):  
Ionic Conductivity ◽  
Solid Solutions ◽  
High Purity ◽  
Doped Ceria ◽  
Ceria Solid Solutions

scholarly journals Synthesis and Ionic Conductivity of Mechanically Synthesized Yttrium-doped Ceria Solid Solutions

2011 ◽  
Vol 11 (8) ◽  
pp. 1285-1290 ◽  
Author(s):  
O.P. Shing ◽  
T.Y. Ping ◽  
Taufiq-Yap Y.Hin ◽  
Z. Zainal
Keyword(s):  
Ionic Conductivity ◽  
Solid Solutions ◽  
Doped Ceria ◽  
Ceria Solid Solutions

The new P-chalcopyrite compound Cu2FeIn2Se5; synthesis, thermal analysis (DTA), and crystal structure analysis by X-ray powder diffraction (XRPD)

2021 ◽  
Vol 67 (1 Jan-Feb) ◽  
pp. 18
Author(s):  
G. E. Delgado ◽  
P. Grima-Gallardo ◽  
J. A. Aitken ◽  
A. Cárdenas ◽  
I. Brito
Keyword(s):  
Crystal Structure ◽  
Thermal Analysis ◽  
Three Dimensional ◽  
Crystal Structure Analysis ◽  
Chalcopyrite Structure ◽  
Distribution Analysis ◽  
X Ray Diffraction ◽  
Quaternary Compound ◽  
X Ray ◽  
Cell Parameters

The Cu2FeIn2Se5 alloy, belonging to the system (CuInSe2)1-x(FeSe)x with x= ⅓, was synthesized by the melt and annealing technique. The differential thermal analysis (DTA) indicates that this compound melts at 1017 K. The crystal structure of this new quaternary compound was established using powder X-ray diffraction. Cation distribution analysis indicates that this material crystallizes in a P-chalcopyrite structure, space group P2c (Nº 112), with unit cell parameters a = 6.1852(2) Å, c = 12.3633(9) Å, V = 472.98(4) Å3. Cu2FeIn2Se5 is a new adamantane type compound derivative of the sphalerite structure, and consists of a three-dimensional arrangement of distorted CuSe4, FeSe4, and InSe4 tetrahedral connected by common faces.

Crystal-structure analysis of four mineral samples of anhydrite, CaSO4, using synchrotron high-resolution powder X-ray diffraction data

2011 ◽  
Vol 26 (4) ◽  
pp. 326-330 ◽  
Author(s):  
Sytle M. Antao
Keyword(s):  
Crystal Structure ◽  
High Resolution ◽  
Unit Cell Volume ◽  
Crystal Structure Analysis ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Rietveld Refinements ◽  
X Ray ◽  
Cell Parameters

The crystal structures of four samples of anhydrite, CaSO4, were obtained by Rietveld refinements using synchrotron high-resolution powder X-ray diffraction (HRPXRD) data and space group Amma. As an example, for one sample of anhydrite from Hants County, Nova Scotia, the unit-cell parameters are a = 7.00032(2), b = 6.99234(1), c = 6.24097(1) Å, and V = 305.487(1) Å3 with a > b. The eight-coordinated Ca atom has an average <Ca-O> distance of 2.4667(4) Å. The tetrahedral SO4 group has two independent S-O distances of 1.484(1) to O1 and 1.478(1) Å to O2 and an average <S-O> distance of 1.4810(5) Å. The three independent O-S-O angles [108.99(8) × 1, 110.38(3) × 4, 106.34(9)° × 1; average <O-S-O> [6] = 109.47(2)°] and S-O distances indicate that the geometry of the SO4 group is quite distorted in anhydrite. The four anhydrite samples have structural trends where the a, b, and c unit-cell parameters increase linearly with increasing unit-cell volume, V, and their average <Ca-O> and <S-O> distances are nearly constant. The grand mean <Ca-O> = 2.4660(2) Å, and grand mean <S-O> = 1.4848(3) Å, the latter is longer than 1.480(1) Å in celestite, SrSO4, as expected.

Crystal structure of low-cristobalite-type Al0.5Ga0.5PO4: A combined Rietveld refinement of neutron and X-ray diffraction data

2005 ◽  
Vol 20 (3) ◽  
pp. 207-211 ◽  
Author(s):  
S. N. Achary ◽  
A. K. Tyagi ◽  
S. K. Kulshreshtha ◽  
O. D. Jayakumar ◽  
P. S. R. Krishna ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Diffraction Data ◽  
Three Dimensional ◽  
Crystal Structure Analysis ◽  
Tetrahedral Coordination ◽  
X Ray Diffraction ◽  
Rietveld Refinements ◽  
X Ray ◽  
Cell Parameters ◽  
Bond Lengths

The low-cristobalite-type modification of Al0.5Ga0.5PO4 is prepared by annealing the amorphous precipitate of stoichiometric phosphate at 1300 °C. The phase purity of the sample is ascertained by powder X-ray diffraction. The crystal structure is refined by Rietveld refinements of the neutron and X-ray diffraction data of the polycrystalline powder. This compound crystallizes in an orthorhombic lattice with unit cell parameters, a=7.0295(8), b=7.0132(8), and c=6.9187(4) Å, V=341.08(6) Å3, Z=4 (Space group C 2221, No. 20). The crystal structure analysis reveals the random distribution of the Al3+ and Ga3+ having tetrahedral coordination with typical M–O (M=Al3+:Ga3+) bond lengths as 1.74 Å. Similarly, the P5+ have tetrahedral coordination with typical P–O bond lengths 1.52–1.54 Å. The Mo4 and PO4 tetraheda are linked by common corners forming a three-dimensional framework lattice. The details of the crystal structure are presented in this paper.

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