Synthesis and application of rare-earth elements (Gd, Sm, and Nd) doped ceria-based solid solutions for methyl mercaptan catalytic decomposition

Relevance of the work caused by necessity of expanding the database of the mutual solubility of salts of rare earth elements to create technologies for producing them in pure form for high-tech industries. The main aim of the study: was to investigate reciprocal solubility of lanthanum and erbium bromates and trichloroacetates in the water and the and to determine the conditions of solid solutions formation and the possibility of obtaining concentrates of lanthanum and erbium.

Download Full-text

Synthesis and sintering of rare-earth-doped ceria powder by the oxalate coprecipitation method

Journal of Materials Research ◽

10.1557/jmr.1999.0127 ◽

1999 ◽

Vol 14 (3) ◽

pp. 957-967 ◽

Cited By ~ 125

Author(s):

Kenji Higashi ◽

Kazutoshi Sonoda ◽

Hiroshi Ono ◽

Soichiro Sameshima ◽

Yoshihiro Hirata

Keyword(s):

Electron Microscopy ◽

Rare Earth ◽

Oxalic Acid ◽

Solid Solutions ◽

Nitrate Solution ◽

Doped Ceria ◽

Powder Preparation ◽

Oxide Powders ◽

Aspect Ratios ◽

Rare Earth Doped

Doped ceria, which has a higher oxygen ion conductivity than yttria-stabilized zirconia, is one of the possible electrolytes for solid oxide fuel cell at low temperatures. This study concerns powder preparation and densification of rare-earth-doped ceria. Rare-earth-doped ceria powders with a composition of Ce0.8R0.2O1.9(R = Yb, Y, Gd, Sm, Nd, and La) were prepared by heating the oxalate coprecipitate when a mixed rare earth/cerium nitrate solution was added to an oxalic solution. The oxalate and derived-oxide powders were characterized by x-ray diffraction (XRD), thermogravimetry differential thermal analysis (TG-DTA), particle size analyzer with laser diffraction, inductively coupled plasma (ICP), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). This method provided the oxalate solid solutions containing Ce and R, which were calcined to form the oxide solid solutions at 600 °C in air. The lattice parameter of oxide powders increased linearly with increasing ionic radius of doped rare earth. The size of platelike particles of oxalates and oxides depended on the concentration of oxalic acid and showed a minimum at 0.4 M oxalic acid. Dry milling of oxide powder with α–Al2O3ball was effective in reducing the size and aspect ratios of particles with little contamination of Al2O3. These rare-earth-doped ceria powders with various sizes were formed by uniaxial pressing (49 MPa) followed by cold isostatic pressing (294 MPa), and sintered at 900–1600 °C in air for 4 h. The micrometer-sized-doped CeO2 powders were densified above 95% of the theoretical density at 1200 °C. The grain size of rare-earth-doped ceria after sintering at 1600 °C was larger in the samples with the larger rare-earth element.

Download Full-text

Transition (Mn, Fe) and rare earth (La, Pr) metal doped ceria solid solutions for high performance photocatalysis: Effect of metal doping on catalytic activity

Research on Chemical Intermediates ◽

10.1007/s11164-017-3244-5 ◽

2017 ◽

Vol 44 (4) ◽

pp. 2523-2543 ◽

Cited By ~ 15

Author(s):

Perala Venkataswamy ◽

Deshetti Jampaiah ◽

Ahmad Esmaielzadeh Kandjani ◽

Ylias M. Sabri ◽

Benjaram M. Reddy ◽

...

Keyword(s):

Catalytic Activity ◽

Rare Earth ◽

Solid Solutions ◽

High Performance ◽

Doped Ceria ◽

Metal Doping ◽

Ceria Solid Solutions ◽

Metal Doped ◽

Rare Earth La

Download Full-text

Zirconia – A Ceramic for Excess weapons Plutonium Wastes

MRS Proceedings ◽

10.1557/proc-556-63 ◽

1999 ◽

Vol 556 ◽

Cited By ~ 9

Author(s):

W. L. Gong ◽

W. Lutze ◽

R. C. Ewing

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Metal Oxides ◽

Solid Solutions ◽

Binary Systems ◽

Single Phase ◽

Sol Gel ◽

Neutron Absorber ◽

Cubic Zirconia

AbstractWe synthesized a ceramic containing simulated excess weapons plutonium waste in solidsolution with zirconia (ZrO2)ss. ZrO2 has a large solubility for other metal oxides. More thantwenty binary systems AxOy- ZrO2 have been reported in the literature, including PuG2, rare earth elements, and oxides of metals contained in weapons plutonium wastes. We show that significant amounts of gadolinium (neutron absorber) and yttrium (stabilizer of the cubic modification) can be dissolved in ZrO2, together with plutonium (simulated by Th4+, Ce4+, or U4+) and impurities (e.g., Ca Mg, Fe, Si). Sol-gel and powder methods were applied to make homogeneous, single phase zirconia solid solutions. Pu waste impurities were completely dissolved in the solid solutions. In contrast to other phases, e.g., zirconolite and pyrochlore, yttrium stabilized cubic zirconia does not undergo amorphization upon irradiation.

Download Full-text

Structural/surface characterization and catalytic evaluation of rare-earth (Y, Sm and La) doped ceria composite oxides for CH3SH catalytic decomposition

Applied Surface Science ◽

10.1016/j.apsusc.2016.08.129 ◽

2016 ◽

Vol 390 ◽

pp. 959-967 ◽

Cited By ~ 37

Author(s):

Dedong He ◽

Dingkai Chen ◽

Husheng Hao ◽

Jie Yu ◽

Jiangping Liu ◽

...

Keyword(s):

Rare Earth ◽

Surface Characterization ◽

Catalytic Decomposition ◽

Doped Ceria ◽

Composite Oxides ◽

Structural Surface ◽

La Doped

Download Full-text

Promotion effect of rare-earth elements on the catalytic decomposition of ammonia over Ni/Al2O3 catalyst

Applied Catalysis A General ◽

10.1016/j.apcata.2015.07.020 ◽

2015 ◽

Vol 505 ◽

pp. 77-85 ◽

Cited By ~ 37

Author(s):

Kaname Okura ◽

Takeou Okanishi ◽

Hiroki Muroyama ◽

Toshiaki Matsui ◽

Koichi Eguchi

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Catalytic Decomposition ◽

Promotion Effect ◽

Al2o3 Catalyst

Download Full-text

Compositional Variability of Monazite–Cheralite–Huttonite Solid Solutions, Xenotime, and Uraninite in Geochemically Distinct Granites with Special Emphasis to the Strongly Fractionated Peraluminous Li–F–P-Rich Podlesí Granite System (Erzgebirge/Krušné Hory Mts., Central Europe)

Minerals ◽

10.3390/min11020127 ◽

2021 ◽

Vol 11 (2) ◽

pp. 127

Author(s):

Karel Breiter ◽

Hans-Jürgen Förster

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Solid Solutions ◽

Heavy Rare Earth Elements ◽

Compositional Variability ◽

Variscan Granites ◽

Almost All ◽

Ree Pattern ◽

Highly Evolved ◽

Comprehensive Study

A comprehensive study of monazite–cheralite–huttonite solid solutions (s.s.) and xenotime from the highly evolved, strongly peraluminous P–F–Li-rich Podlesí granite stock in the Krušné Hory Mts., Czech Republic, indicates that, with the increasing degree of magmatic and high-T early post-magmatic evolution, the content of the cheralite component in monazite increases and the relative dominance of middle rare earth elements (MREE) in xenotime becomes larger. Considering the overall compositional signatures of these two accessory minerals in the late Variscan granites of the Erzgebirge/Krušné Hory Mts., three types of granites can be distinguished: (i) chemically less evolved F-poor S(I)- and A-type granites contain monazite with a smooth, mostly symmetric chondrite-normalized (CN) rare-earth elements (REE) pattern gradually declining from La to Gd; associated xenotime is Y-rich (˃0.8 apfu Y) with a flat MREE–HREE (heavy rare earth elements) pattern; (ii) fractionated A-type granites typically contain La-depleted monazite with Th accommodated as the huttonite component, combined with usually Y-poor (0.4–0.6 apfu Y) xenotime characterized by a smoothly inclining, Yb–Lu-dominant CN-REE pattern; (iii) fractionated peraluminous Li-mica granites host monazite with a flat, asymmetric (kinked at La and Nd) CN-LREE pattern, with associated xenotime distinctly MREE (Gd–Tb–Dy)-dominant. Monazite and xenotime account for the bulk of the REE budgets in all types of granite. In peraluminous S(I)-type granites, which do not bear thorite, almost all Th is accommodated in monazite–cheralite s.s. In contrast, Th budgets in A-type granites are accounted for by monazite–huttonite s.s. together with thorite. The largest portion of U is accommodated in uraninite, if present.

Download Full-text