The Effect of Synthetic Method and Annealing Temperature on Metal Site Preference in Al1–xGaxFeO3

Walker, James D.S.; Grosvenor, Andrew P.

doi:10.1021/ic4007636

Cited by 10 publications

(4 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It was established that XANES is sensitive to oxygen vacancies and bond covalency in several pyrochlore systems. [24][25][26] It was generally found that Zr and Hf cation coordination number (CN) increases with increasing size of the Ln cation as the pyrochlore approaches the phase boundary. The change in the CN tends to reflect an increase in local disorder across the pyrochlore series.…”

Section: Introductionmentioning

confidence: 99%

Investigating the order–disorder phase transition in Nd2−xYxZr2O7via diffraction and spectroscopy

et al. 2013

View full text Add to dashboard Cite

The pyrochlore-defect fluorite phase transition in the mixed-metal zirconate Nd2-xYxZr2O7 (0 ≤ x ≤ 2) solid solution was investigated using synchrotron X-ray and neutron diffraction, as well as X-ray absorption spectroscopy. Diffraction analysis revealed a two-phase region between 1.0 ≤ x ≤ 1.2. In the pyrochlore phase, Zr L3-edge XANES analysis demonstrated a gradual change in the local coordination environment of the B site with increasing Y content that was consistent with an increase in disorder. Although Y L3-edge XANES analysis suggested that the Y cations remained in an ordered coordination environment in the pyrochlore phase, disorder did gradually increase once the fluorite phase formed. It was found that Y cations prefer an ordered coordination environment near the phase boundary whereas Zr cations prefer a disordered coordination environment.

show abstract

Section: Introductionmentioning

confidence: 99%

Investigating the order–disorder phase transition in Nd2−xYxZr2O7via diffraction and spectroscopy

et al. 2013

View full text Add to dashboard Cite

show abstract

“…The starting binary oxides used in the ceramic route had defined crystal structures, which likely acted as a template, increasing the ordering between the metal-oxygen polyhedra. 56 In contrast, the starting precipitate materials that were formed in the co-precipitation method lacked this inherent structure. This explains why the lattice constants of the materials made via the ceramic method were greater than those of the materials made via the co-precipitation route.…”

Section: Powder Xrdmentioning

confidence: 99%

Investigation of Nd_xY_0.25–_xZr_0.75O_1.88 inert matrix fuel materials made by a co-precipitation synthetic route

Hayes

Grosvenor

2016

Can. J. Chem.

Self Cite

View full text Add to dashboard Cite

Yttria-stabilized zirconia (YSZ) is a material that is being considered for use as an inert matrix fuel in nuclear reactors, but a complete characterization of these materials is required for them to be licensed for use. A series of Nd x Y 0.25-x Zr 0.75 O 1.88 materials have been synthesized using a co-precipitation method, and the thermal stability of these materials has been studied by annealing them at 1400 and 1500°C. (Nd was used as surrogate for Am.) The long-range and local structures of the materials were characterized via powder X-ray diffraction, scanning electron microscopy, wavelength dispersive spectroscopy, and X-ray absorption spectroscopy at the Zr K-and Y K-edges. These results were compared with the previous characterization of Nd-YSZ materials synthesized using a ceramic method. The results indicated that the ordering in the local metal-oxygen polyhedral remains relatively unaffected by the synthetic method, but there was increased long-range disorder in the materials prepared by the co-precipitation method. Further, it was found that the materials produced by the co-precipitation method were unexpectedly unstable when annealed at high temperature. This study highlights the importance of determining the effect of synthetic method on material properties and demonstrates how the co-precipitation route could be used to produce inert matrix fuels.Key words: XAS, ceramics, stabilized zirconia, nuclear energy, XRD.Résumé : La zircone stabilisée par oxyde d'yttrium (YSZ) constitue un matériau dont l'utilisation est envisagée comme combustible à matrice inerte dans les réacteurs nucléaires, mais une caractérisation complète de tels matériaux est nécessaire pour que leur utilisation puisse être autorisée. Nous avons synthétisé une série de matériaux de formule Nd x Y 0,25-x Zr 0,75 O 1,88 par une méthode de coprécipitation et étudié la stabilité thermique de ces matériaux en les soumettant à un recuit à 1 400 et 1 500°C. (Le Nd a été employé comme substitut de l'Am.) Par la suite, nous avons caractérisé les matériaux en effectuant des analyses structurales d'ordre à longue et à courte distance au moyen de techniques de diffraction des rayons X sur poudre, de microscopie électronique à balayage, de spectroscopie de dispersion des longueurs d'onde et de spectroscopie d'absorption des rayons X au seuil K du Zr et de l'Y. Nous avons comparé ces résultats avec les analyses antérieures de caractérisation de matériaux de Nd-YSZ préparés à l'aide d'une méthode de synthèse de céramiques. Les résultats ont montré que la méthode de synthèse a relativement peu d'influence sur l'ordre à courte distance dans le polyèdre métal-oxygène, tandis qu'une augmentation du désordre à longue distance a été observée dans les matériaux synthétisés par la méthode de coprécipitation. De plus, nous avons observé que les matériaux produits par la méthode de coprécipitation présentaient une instabilité imprévue lorsqu'ils étaient soumis au recuit à haute température. La présente étude souligne l'importance de déterminer l...

show abstract

“…For example, Walker and Grosvenor investigated the Al 1−x Ga x FeO 3 (0 ≤ x ≤ 1) system synthesized through sol−gel, coprecipitation, and ceramic methods. 13 They observed through X-ray absorption near-edge spectroscopy measurements that samples synthesized by the coprecipitation method revealed the largest variability in the metal coordination number depending on the composition and annealing temperature. The coordination number changes were also observed with the sol−gel and ceramic methods but to a much smaller extent.…”

mentioning

confidence: 99%

“…In other words, does changing how a material is made change its properties? For example, Walker and Grosvenor investigated the Al 1– x Ga x FeO 3 (0 ≤ x ≤ 1) system synthesized through sol–gel, coprecipitation, and ceramic methods . They observed through X-ray absorption near-edge spectroscopy measurements that samples synthesized by the coprecipitation method revealed the largest variability in the metal coordination number depending on the composition and annealing temperature.…”

mentioning

confidence: 99%

Editorial for the ACS Select Collection on Solid-State Chemistry

Halasyamani¹

2014

Inorg. Chem.

View full text Add to dashboard Cite

New materials are the lifeblood of solid-state materials research and device technology. Simply put, new materials are discovered by chemists. Thus, the synthetic chemist especially if s/he develops a proficiency in relating structure, bonding, and other chemical−physical considerations to properties of interestis in a key position in determining the direction and success of solid-state research, and ultimately, technology." These statements, paraphrased from Dr. Robert Laudise of Bell Laboratories, succinctly summarize the relevance of solid-state materials, which provide the foundation for a variety of commonplace applications. From the batteries in our cellular phones and computers 1 to blue-ray DVD players 2 and sensors and detectors in alarms, 3 as well as medical 4 and oil and gas technologies, 5 solid-state materials are ubiquitous in our daily lives.This ACS Select collection is focused on the accomplishments in solid-state materials chemistry of 13 emerging investigators whose work has been selected from ACS Select collection involve, in one manner or another, the synthesis of new solid-state materials in combination with advanced characterization techniques. Progress has occurred not only in the synthesis and functional property characterization of materials but also in theoretical calculations to better understand the complex bonding and interactions observed in many of the reported structure types. Topics covered in this ACS Select collection include battery research, magnetic behavior in intermetallics and oxide materials, broad-band white-light emitters, superconductivity, thermoelectricity, and use of density functional theory (DFT) to predict and understand solid-state materials, noncentrosymmetric (NCS) materials, and open-framework compounds. The above list is by no means comprehensive with respect to the current research in solid-state materials chemistry but rather represents the research interests of the authors selected for this ACS Select collection.One of the research themes in this virtual issue involves photoelectrochemical water oxidation. This work, done by Professor Bart Bartlett and co-workers at the University of Michigan (http://www.umich.edu/~bmbgroup/) involves a visibl e-l ight-abso rbing semi co nductor o xy nitride Ti 1−(5x/4) Nb x O 2−y−d N y , 6 as well as an earth-abundant molecular catalyst, Fe(tebppmcm)Cl 2 , with a semiconducting photoelectrode, WO 3 . 7 The former material was impregnated with RuO 2 , which resulted in polycrystalline cocatalyst compounds. The RuO 2 cocatalyst is needed to evolve oxygen, and Bartlett and co-workers demonstrated that the water oxidation activity depends on the cocatalyst weight percent loading. With the iron molecular catalyst, in combination with the semiconducting photoelectrode, WO 3 , they noted a dramatic increase in the rate and selectivity of photoelectrochemical water oxidation. In addition, they removed the need for any sacrificial chemical oxidant, e.g., Ce 4+ .

show abstract

The Effect of Synthetic Method and Annealing Temperature on Metal Site Preference in Al_1–xGa_xFeO₃

Cited by 10 publications

References 45 publications

Investigating the order–disorder phase transition in Nd2−xYxZr2O7via diffraction and spectroscopy

Investigating the order–disorder phase transition in Nd2−xYxZr2O7via diffraction and spectroscopy

Investigation of Nd_xY_0.25–_xZr_0.75O_1.88 inert matrix fuel materials made by a co-precipitation synthetic route

Editorial for the ACS Select Collection on Solid-State Chemistry

Contact Info

Product

Resources

About

The Effect of Synthetic Method and Annealing Temperature on Metal Site Preference in Al1–xGaxFeO3

Cited by 10 publications

References 45 publications

Investigating the order–disorder phase transition in Nd2−xYxZr2O7via diffraction and spectroscopy

Investigating the order–disorder phase transition in Nd2−xYxZr2O7via diffraction and spectroscopy

Investigation of NdxY0.25–xZr0.75O1.88 inert matrix fuel materials made by a co-precipitation synthetic route

Editorial for the ACS Select Collection on Solid-State Chemistry

Contact Info

Product

Resources

About

The Effect of Synthetic Method and Annealing Temperature on Metal Site Preference in Al_1–xGa_xFeO₃

Investigation of Nd_xY_0.25–_xZr_0.75O_1.88 inert matrix fuel materials made by a co-precipitation synthetic route