ChemInform Abstract: Formation of Sm2+ Ions in Sol‐Gel Derived Glasses of the System Na2O‐ Al2O3‐SiO2.

Nogami, Masayuki; Hayakawa, Naoya; Sugioka, Naoya; Abe, Yoshihiro

doi:10.1002/chin.199640240

Cited by 2 publications

(2 citation statements)

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“…One promising way to solve this problem is to codope silica-network-modifying oxides such as Na 2 O, CaO, P 2 O 5 , and Al 2 O 3 with RE ions. Among these oxides, Al 2 O 3 is effectively used to increase the FL intensity. − The charge of RE ions is compensated by oxygen surrounding the Al 3+ ions; this results in a homogeneous dispersion of RE ions in the glass structure. However, because of its high melting temperature for glasses, preparing a glass containing large amounts of Al 2 O 3 is difficult.…”

Section: Introductionmentioning

confidence: 99%

Reduction Mechanism for Eu Ions in Al₂O₃-Containing Glasses by Heat Treatment in H₂ Gas

Nogami

2015

J. Phys. Chem. B

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Superior functional glasses doped with rare-earth ions have been prepared by controlling the valence states of rare-earth ions. However, recent work has revealed unresolved questions about the controlling mechanism of rare-earth ions' valence states. To address these questions, oxide glasses with and without Al2O3 and doped with Eu(3+) ions were prepared by a melting process; then, the valence states of Eu(3+) ions were investigated during heating under a hydrogen environment. The Eu(3+) ions were reduced to Eu(2+) only in the glass containing Al(3+) ions; the reduction occurred in the center of the glass over a short heating period. It was discovered that the reduction of Eu(3+) ions concurrently occurred with the formation of OH bonds which were bound with Al(3+) ions. Considering this and the data for the H2 gas diffusion through the glass, we conclude that diffusing H2 gas molecules react with Al-O(-) bonds surrounding Eu(3+) ions to form AlOH bonds and reduce Eu(3+) ions to Eu(2+) via the extracted electrons. When H2 reacts with a glass structure, that hydrogen has transformed into -OH bonds and the hydrogen concentration in the glass decreases. In order to make up the lost hydrogen, more hydrogen molecules can enter into the glass, resulting in the fast reduction of Eu(3+) ions in the center of the glass.

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Section: Introductionmentioning

confidence: 99%

Reduction Mechanism for Eu Ions in Al₂O₃-Containing Glasses by Heat Treatment in H₂ Gas

Nogami

2015

J. Phys. Chem. B

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“…These alumina and rare earth‐containing glasses have shown unusual and interesting optical properties, such as the and high optical nonlinearity 8 . This easy reduction of rare‐earth ion oxidation state is only observed in Al 2 O 3 –SiO 2 glasses as the host matrix, but difficult in other ordinary oxide glasses such as Na 2 O–CaO–SiO 2 glasses 9 . This observation on the fast hydrogen reduction of the rare‐earth ions is favorable to understand the reaction between gas and glass and develop new functional glasses.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen Gas Reaction with Eu³⁺‐Doped Al₂O₃–SiO₂ Glasses

Nogami

Watanabe

Ito

et al. 2010

Journal of the American Ceramic Society

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In this paper, we report on fast permeation rate and reaction of hydrogen gas in alumino‐silicate glasses to provide new functional properties. Eu3+:Al2O3–SiO2 glass was prepared with high europium concentration and heat treated in hydrogen gas atmosphere. The approach involves the determination of diffusion coefficients by measuring both hydrogen gas permeation and the hydroxyl formation in addition to the reduction of Eu3+ into Eu2+. The diffusion coefficients, determined from the gas permeation experiment, were two orders of magnitude higher than those calculated from the formation of hydroxyl bonds. The high diffusion coefficient was discussed relating with the gas solubility and the number of reduction sites. It was also found that the present glass exhibits a permeation rate of hydrogen gas higher than that of SiO2 glass by 103 times.

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ChemInform Abstract: Formation of Sm2+ Ions in Sol‐Gel Derived Glasses of the System Na2O‐ Al2O3‐SiO2.

Cited by 2 publications

References 1 publication

Reduction Mechanism for Eu Ions in Al₂O₃-Containing Glasses by Heat Treatment in H₂ Gas

Reduction Mechanism for Eu Ions in Al₂O₃-Containing Glasses by Heat Treatment in H₂ Gas

Hydrogen Gas Reaction with Eu³⁺‐Doped Al₂O₃–SiO₂ Glasses

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ChemInform Abstract: Formation of Sm2+ Ions in Sol‐Gel Derived Glasses of the System Na2O‐ Al2O3‐SiO2.

Cited by 2 publications

References 1 publication

Reduction Mechanism for Eu Ions in Al2O3-Containing Glasses by Heat Treatment in H2 Gas

Reduction Mechanism for Eu Ions in Al2O3-Containing Glasses by Heat Treatment in H2 Gas

Hydrogen Gas Reaction with Eu3+‐Doped Al2O3–SiO2 Glasses

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Reduction Mechanism for Eu Ions in Al₂O₃-Containing Glasses by Heat Treatment in H₂ Gas

Reduction Mechanism for Eu Ions in Al₂O₃-Containing Glasses by Heat Treatment in H₂ Gas

Hydrogen Gas Reaction with Eu³⁺‐Doped Al₂O₃–SiO₂ Glasses