Valence Variation of Yb Encapsulated in the Supercage of Y-Type Zeolite

Yb/K-Y exhibits various catalytic reactivities by evacuation at various temperatures. By evacuation with elevating temperature, successive desorption of hydrogen, ammmonia, and hydrogen was observed. Yb L 2 , edge XANES spectra showed that Yb is present as a mixture of Yb 2+ and Yb 3+ . The sample a...

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Published inJapanese Journal of Applied Physics Vol. 32; no. S2; p. 481
Main Authors Tanaka, Tsunehiro, Hanada, Tomoko, Yoshida, Satohiro, Baba, Toshihide, Ono, Yoshio
Format Journal Article
LanguageEnglish
Published 01.01.1993
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Summary:Yb/K-Y exhibits various catalytic reactivities by evacuation at various temperatures. By evacuation with elevating temperature, successive desorption of hydrogen, ammmonia, and hydrogen was observed. Yb L 2 , edge XANES spectra showed that Yb is present as a mixture of Yb 2+ and Yb 3+ . The sample as prepared consists of Yb 3+ species mainly. With elevating the evacuation temperature, the fraction of Yb 2+ increases and reaches a maximum in the vicinity of 500 K. Then, the fraction of Yb 2+ decreases and reaches a minimum at 873 K. The valence variation is in a good accordance with a catalytic variation. Desorption of hydrgen and ammonia corresponds to the chemical change of Yb species: amine → imine → nitride.
ISSN:0021-4922
1347-4065
DOI:10.7567/JJAPS.32S2.481