Local Structures of Solid Solutions Sr1–xYxF2+x (x = 0...0.5) with Fluorite Structure Prepared by Sol–Gel and Mechanochemical Syntheses

2016 ◽  
Vol 120 (16) ◽  
pp. 8992-8999 ◽  
Author(s):  
Benjamin Ritter ◽  
Thoralf Krahl ◽  
Gudrun Scholz ◽  
Erhard Kemnitz
Keyword(s):  
Solid Solutions ◽  
Sol Gel ◽  
Fluorite Structure ◽  
Local Structures

Solid solubility and transport properties of Ce1−xNdxO2−δ nanocrystalline solid solutions by a sol-gel route

2001 ◽  
Vol 16 (11) ◽  
pp. 3207-3213 ◽  
Author(s):  
Liping Li ◽  
Xiaomin Lin ◽  
Guangshe Li ◽  
Hiroshi Inomata
Keyword(s):  
Activation Energy ◽  
Solid Solutions ◽  
Solid Solubility ◽  
Oxygen Vacancies ◽  
Sol Gel ◽  
Broad Band ◽  
Sample Surface ◽  
Fluorite Structure ◽  
Lattice Parameter ◽  
Dopant Content

Ce1−xNdxO2−δ (x = 0.05 to 0.55) nanocrystalline solid solutions were prepared by a sol-gel route. X-ray diffraction analysis showed that Ce1−xNdxO2−δ crystallized in a cubic fluorite structure. The lattice parameter for the solid solutions increased linearly with the dopant content. The solid solubility of Nd3+ in ceria lattice was determined to be about x = 0.40 in terms of the nearly constant lattice parameters at a dopant level larger than x = 0.40. First-order Raman spectra for Ce1−xNdxO2−δ at a lower dopant content exhibited one band associated with the F2g mode. At higher dopant contents, F2g mode became broadened and asymmetric, and a new broad band appeared at the higher frequency side of the F2g mode. This new band was assigned to the oxygen vacancies. The electron paramagnetic resonance spectrum for x = 0.05 showed the presence of O2− adsorbed on sample surface at g = 2.02 and 2.00 and of Ce3+ with a lower symmetry at g = 1.97 and 1.94. Further increasing dopant content led to the disappearance of the signals for O2−. Impedance spectra showed the bulk and grain boundary conduction in the solid solutions. The bulk conduction exhibited a conductivity maximum and an activation energy minimum with increasing dopant content. Ce0.80Nd0.20O2−δ was determined to give promising conduction properties such as a relatively high conductivity of σ700 °C = 2.44 × 10−2 S cm−1 and moderate activation energy of Ea = 0.802 eV. The variations of conductivity and activation energy were explained in terms of relative content of oxygen vacancies Vö and defect associations {CeCe ′Vö}/{NdCe ′Vö}.

scholarly journals Spray‐dried sol‐gel glass‐ceramic powders based on the tunable thermal expansion of quartz and keatite solid solutions

2021 ◽  
Author(s):  
Alessio Zandona ◽  
Gundula Helsch ◽  
Aurina Martínez Arias ◽  
Alfred P. Weber ◽  
Joachim Deubener
Keyword(s):  
Thermal Expansion ◽  
Solid Solutions ◽  
Glass Ceramic ◽  
Sol Gel ◽  
Ceramic Powders ◽  
Spray Dried

scholarly journals FABRICATION AND PROPERTIES OF Co DOPED Bi0.5K0.5TiO3 – BiFeO3 SOLID SOLUTION

2018 ◽  
Vol 56 (1A) ◽  
pp. 197
Author(s):  
Nguyen Hoang Tuan
Keyword(s):  
Solid Solution ◽  
Raman Spectroscopy ◽  
Magnetic Properties ◽  
Crystal Structures ◽  
Solid Solutions ◽  
Sol Gel ◽  
Structure And Properties ◽  
Antiferromagnetic Ordering ◽  
Co Doped ◽  
Good Agreement

In this study, we present some results on the structure and properties of the solid solution of Bi0.5K0.5TiO3– BiFeCoO3 (BKT – BFCO) by Sol-gel method. Crystal structures of BKT – BFCO solid solutions were studies by XRD and Raman spectroscopy. The results were in good agreement with the previous reports of Bi0.5K0.5TiO3– BiFeO3 (BKT – BFO) and Bi0.5K0.5TiO3 – BiCoO3 (BKT – BCO) solid solutions. The magnetic properties were investigated via unsaturated M-H loop, which showed the competition of paramagnetic and antiferromagnetic ordering in BKT – BFCO. However, differing from the BKT – BFO and BKT – BCO solid solutions, the unclear values of saturated magnetism in BKT – BFCO raised the unexplained question, which needed further studies.

ChemInform Abstract: CeO2-Based Solid Solutions with the Fluorite Structure as Novel and Effective Catalysts for Methane Combustion.

ChemInform ◽  
2010 ◽  
Vol 26 (38) ◽  
pp. no-no
Author(s):  
F. ZAMAR ◽  
A. TROVARELLI ◽  
C. DE LEITENBURG ◽  
G. DOLCETTI
Keyword(s):  
Solid Solutions ◽  
Methane Combustion ◽  
Fluorite Structure

Low Temperature Combustion Synthesis and Characterization of Pr-CeO2 Doped with Zr Red Ceramic Pigments

2011 ◽  
Vol 399-401 ◽  
pp. 514-518
Author(s):  
Li Dan Yang ◽  
Ming Quan Ye ◽  
Ai Jun Han
Keyword(s):  
Low Temperature ◽  
Combustion Synthesis ◽  
Solid Solutions ◽  
Charge Transfer Band ◽  
Blue Shift ◽  
Fluorite Structure ◽  
Electronic Energy ◽  
Low Temperature Combustion ◽  
Visible Absorption ◽  
Temperature Combustion

New inorganic pigments Ce0.95ZrxPr0.05-xO2(x = 0, 0.01, 0.02, 0.03, 0.04, 0.05) based on CeO2-ZrO2-Pr6O11solid solutions were synthesized by low-temperature combustion synthesis (LCS) method using citric acid as a reductant and metal nitrate as an oxidant. The pigments are CeO2solid solutions doped with praseodymium and zirconium ions, and display colors ranging from dark brown via brick red to bright cream. The prepared pigments were characterized by X-ray powder diffraction, transmission electron microscopy, ultraviolet-visible absorption spectroscopy and colorimetrical measurements. Results show that cubic fluorite structure solid solution of 100 nm Ce0.95ZrxPr0.05-xO2particles can be obtained at 1000 °C. There was an effective absorption of visible blue and green in 600 nm, which is originated from the shift of charge transfer band in CeO2by doping of zirconium and praseodymium ions. Effective red hue was obtained for Ce0.95Zr0.02Pr0.03O2composition, which exhibited better L*, a*,and b* values (57.64, 23.83 and 23.78). The coloring mechanism is based on the introduction of an additional electronic energy level of unpaired 4f electron of the lanthanide ion into the cerianite forbidden band. Furthermore, the doping of Zr in Pr-CeO2system raises the slope of the absorption edge with a blue shift resulting in enhanced lightness. The prepared pigments were prospective to be alternatives for toxic pigments used in coloration of plastics.

Physicochemical characterization of Pt and Ir particles deposited on Ce(1-x)Ru(x)O2 solid-solutions for CO oxidation

MRS Advances ◽  
2019 ◽  
Vol 4 (61-62) ◽  
pp. 3433-3440
Author(s):  
E. Gonzalez-A ◽  
R. Rangel ◽  
J. Lara ◽  
J. J. Alvarado ◽  
P. Bartolo
Keyword(s):  
Solid Solutions ◽  
Crystal Size ◽  
Sol Gel ◽  
Physicochemical Characterization ◽  
Metallic State ◽  
Wet Impregnation ◽  
Iridium Nanoparticles ◽  
Gel Technique ◽  
Near Future

AbstractPt/Ce1-xRuxO2 and Ir/Ce1-xRuxO2 catalysts were prepared through the sol-gel technique, under microwave heating. In a first step, the Ce1-xRuxO2 solid solutions were prepared. Subsequently, an incipient wet impregnation process was carried out to homogeneously achieve the dispersion, either of platinum or iridium nanoparticles. The Pt/Ce1-xRuxO2 and Ir/Ce1-xRuxO2 catalysts were characterized by means of SEM, XRD, XPS, TEM, and specific surface area measurements. Crystal size and shifting into the CeO2 structure were detected after ruthenium doping producing the Ce1-xRuxO2 solid-solutions. Trough XPS technique Pt and Ir nanoparticles were found evenly dispersed in a metallic state. Those features allow us to foresee that, in the near future, these materials could be used efficiently as catalysts for oxidation process.

Luminescence Properties of Sol–Gel Derived Ceramic GdNbхTa1 –хO4 and YNbхTa1 –хO4 Solid Solutions

2020 ◽  
Vol 56 (4) ◽  
pp. 437-442
Author(s):  
M. N. Palatnikov ◽  
M. V. Smirnov ◽  
S. M. Masloboeva ◽  
O. B. Shcherbina ◽  
N. V. Sidorov ◽  
...  
Keyword(s):  
Solid Solutions ◽  
Sol Gel ◽  
Luminescence Properties

scholarly journals Studies on Structural and Morphological Properties of Multidoped Ceria Ce0.8Nd0.0025Sm0.0025Gd0.005Dy0.095Y0.095O2-δ(x=0.2) as Solid Solutions

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Marija Stojmenović ◽  
Maja C. Pagnacco ◽  
Vladimir Dodevski ◽  
Jelena Gulicovski ◽  
Milan Žunić ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Solid Solutions ◽  
Room Temperature ◽  
Oxygen Vacancies ◽  
Room Temperature Ferromagnetism ◽  
Fluorite Structure ◽  
Lattice Parameter ◽  
Morphological Properties ◽  
Fluorite Type ◽  
Potential Improvement

The nanopowdery solid solutions of multidoped ceria Ce0.8Nd0.0025Sm0.0025Gd0.005Dy0.095Y0.095O2-δ(x=0.2) with the fluorite type crystal structure of CeO2were synthesized for the first time. Two synthesis procedures were applied: the modified glycine-nitrate procedure (MGNP method) and room temperature self-propagating reaction (SPRT method). All nanopowders were characterized by XRPD analysis, Raman spectroscopy, low temperature nitrogen physisorption, TEM, and SEM methods. According to the XRPD and Raman spectroscopy results, single phase solid solutions of fluorite structure were evidenced regardless of the number of dopants and synthesis procedure. Both XRPD and TEM were analyses evidenced nanometer particle dimensions. The SPRT method results in obtaining sample with higher specific surface area, smaller crystallite and particles sizes, and the same values of the lattice parameter in comparison to pure CeO2. Raman spectroscopy was confirmed to the oxygen vacancies introduced into the ceria lattice when Ce4+ions were replaced with cations (dopants) of lower valence state (3+), which may indicate the potential improvement of ionic conductivity. Additionally, the presence of oxygen vacancies in the lattice ceria, as well as very developed grain boundaries, gives a new possibility for potential application of obtained nanopowders in the area of room temperature ferromagnetism as spintronics.

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