scholarly journals Transparent Sol-Gel Oxyfluoride Glass-Ceramics with High Crystalline Fraction and Study of RE Incorporation

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 530 ◽  
Author(s):  
Giulio Gorni ◽  
Jose Velázquez ◽  
Jadra Mosa ◽  
Glenn Mather ◽  
Aida Serrano ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Rare Earth Ions ◽  
Oxyfluoride Glass ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Synthesis Strategy ◽  
Wide Range ◽  
X Ray Absorption

Transparent oxyfluoride glass-ceramic films and self-supported layers with composition 80SiO2-20LaF3 doped with Er3+ have been successfully synthesized by sol-gel process for the first time. Crack-free films and self-supported layer with a maximum thickness up to 1.4 µm were obtained after heat treatment at the low temperature of 550 °C for 1 min, resulting in a LaF3 crystal fraction of 18 wt%, as confirmed by quantitative Rietveld refinement. This is the highest value reported up to now for transparent oxyfluoride glass-ceramics prepared by sol-gel. This work provides a new synthesis strategy and opens the way to a wide range of potential applications of oxyfluoride glass-ceramics. The characterization by a wide range of techniques revealed the homogeneous precipitation of LaF3 nanocrystals into the glass matrix. X-ray absorption spectroscopy and electron paramagnetic resonance confirmed that the Er3+ ions are preferentially embedded in the low phonon-energy LaF3 nanocrystals. Moreover, photoluminescence (PL) measurements confirmed the incorporation of dopants in the LaF3 nanocrystals. The effective concentration of rare-earth ions in the LaF3 nanocrystals is also estimated by X-ray absorption spectroscopy.

scholarly journals Determination of the relative concentrations of rare earth ions by x-ray absorption spectroscopy: Application to terbium mixed oxides

1986 ◽  
Vol 47 (4) ◽  
pp. 413-416 ◽  
Author(s):  
G. van der Laan ◽  
J.C. fuggle ◽  
M.P. van Dijk ◽  
A.J. Burggraaf ◽  
J.-M. Esteva ◽  
...  
Keyword(s):  
Rare Earth ◽  
Absorption Spectroscopy ◽  
Mixed Oxides ◽  
Rare Earth Ions ◽  
X Ray ◽  
X Ray Absorption

Effects of Lattice Defects on Cathode Properties of LiMn2O4 Synthesized at Low Temperatures for Lithium Ion Secondary Battery

2008 ◽  
Vol 388 ◽  
pp. 41-44 ◽  
Author(s):  
Hiroyuki Kaiya ◽  
Shinya Suzuki ◽  
Masaru Miyayama
Keyword(s):  
Absorption Spectroscopy ◽  
Low Temperatures ◽  
Heating Temperature ◽  
Sol Gel ◽  
Lithium Ion ◽  
Lattice Defects ◽  
X Ray ◽  
Secondary Battery ◽  
Cation Mixing ◽  
X Ray Absorption

Effects of lattice defects on cathode properties of LiMn2O4 synthesized at low temperatures were investigated. LiMn2O4 powders were synthesized by a sol-gel method. The specific capacities of LiMn2O4 decreased from 134 to 81 mAh g-1 with decreasing heating temperature from 750 to 200°C. X-ray absorption spectroscopy showed that a large amount of lattice defects such as cation vacancies existed and cation mixing occurred in LiMn2O4 calcined at low temperatures. It was found that the low specific capacities of LiMn2O4 calcined at low temperatures were attributed to these lattice defects.

X-ray Diffraction and X-ray Absorption Spectroscopy Studies of Sol−Gel-Processed Zirconium Titanates

2000 ◽  
Vol 12 (11) ◽  
pp. 3347-3355 ◽  
Author(s):  
J. Xu ◽  
C. Lind ◽  
A. P. Wilkinson ◽  
S. Pattanaik
Keyword(s):  
Absorption Spectroscopy ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Spectroscopy Studies ◽  
X Ray Absorption

Analysis of the distribution of Tm3+ ions in LaF3 containing transparent glass-ceramics through X-ray absorption spectroscopy

2014 ◽  
Vol 384 ◽  
pp. 83-87 ◽  
Author(s):  
A. de Pablos-Martín ◽  
M.A. García ◽  
A. Muñoz-Noval ◽  
G.R. Castro ◽  
M.J. Pascual ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Glass Ceramics ◽  
Transparent Glass ◽  
X Ray ◽  
X Ray Absorption

scholarly journals [FeFe]-Hydrogenase Maturation: H-Cluster Assembly Intermediates Tracked by Electron Paramagnetic Resonance, Infrared, and X-Ray Absorption Spectroscopy

2020 ◽  
Author(s):  
Brigitta Németh ◽  
Moritz Senger ◽  
Holly J. Redman ◽  
Pierre Ceccaldi ◽  
Joan Broderick ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Absorption Spectroscopy ◽  
Cluster Assembly ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Hydrogenase Maturation ◽  
Catalytically Active ◽  
X Ray Absorption ◽  
Electron Paramagnetic

[FeFe]-hydrogenase enzymes employ a unique organometallic cofactor for efficient and reversible hydrogen conversion. This so-called H-cluster consists of a [4Fe-4S] cubane cysteine-linked to a diiron complex coordinated by carbon monoxide and cyanide ligands and an azadithiolate ligand (adt = NH(CH2S)2). [FeFe]-hydrogenase apo-protein binding only the [4Fe-4S] sub-complex can be fully activated in vitro by the addition of a synthetic diiron site precursor complex ([2Fe]adt,). Elucidation of the mechanism of cofactor assembly will aid in the design of improved hydrogen processing synthetic catalysts. We combined in situ electron paramagnetic resonance, Fourier-transform infrared, and X-ray absorption spectroscopy to characterize intermediates of H-cluster assembly as initiated by mixing of the apo-protein (HydA1) from the green alga Chlamydomonas reinhardtii with [2Fe]adt. The three methods consistently show rapid formation of a complete H-cluster in the oxidized, CO-inhibited state (Hox-CO) already within seconds after the mixing. Moreover, FTIR spectroscopy support a model in which Hox-CO formation is preceded by a short-lived Hred´-CO like intermediate. Accumulation of Hox-CO was followed by CO release resulting in the slower conversion to the catalytically active state (Hox) as well as formation of reduced states of the H-cluster.

Structure of Titania Sol−Gel Films:  A Study by X-Ray Absorption Spectroscopy

2002 ◽  
Vol 106 (6) ◽  
pp. 1153-1160 ◽  
Author(s):  
Tracey L. Hanley ◽  
Victor Luca ◽  
Ingrid Pickering ◽  
Russell F. Howe
Keyword(s):  
Absorption Spectroscopy ◽  
Sol Gel ◽  
X Ray ◽  
Titania Sol ◽  
Sol Gel Films ◽  
X Ray Absorption
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