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Author: search.filters.author.Baitahe, RattanaiSubject: search.filters.subject.X-ray absorption spectroscopy

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    Phase formation and evolution of Cu:Zn partials in binary metal pyrophosphates Cu(2-x)Zn(x)P2O7; X ≈ 1
    (2014-11-20)
    Baitahe, Rattanai
    ;
    Vittayakorn, Naratip
    Binary metal pyrophosphate powders were prepared by the solid state reaction method and subsequently calcined at 400, 500, 600, 700, and 800 °C in order to study Cu:Zn partial evolution to the final CuZnP<inf>2</inf>O<inf>7</inf> product. Synchrotron X-ray absorption, X-ray diffraction, Raman, FT-IR spectroscopy, and thermogravimetric analysis were used in this investigation. Phase evolution of the reaction products was investigated systemically. The results showed that complicated mixtures contributed to the reaction of synthesis temperature. The reaction comprised 3CuO·2P<inf>2</inf>O<inf>5</inf>·0.3NH<inf>3</inf>·0.2H<inf>2</inf>O, Cu<inf>2</inf>P<inf>2</inf>O<inf>7</inf>, Zn<inf>2</inf>P<inf>2</inf>O<inf>7</inf>, and Zn<inf>2</inf>P<inf>2</inf>O<inf>7</inf>·3H<inf>2</inf>O intermediates. Decreasing percentage of 3CuO·2P<inf>2</inf>O<inf>5</inf>·0.3NH<inf>3</inf>·0.2H<inf>2</inf>O intermediates was related directly to an increasing final product. Cu:Zn contents changed in Cu<inf>(2-x)</inf>Zn<inf>(x)</inf>P<inf>2</inf>O<inf>7</inf> in the temperature range of 400-600 °C, when x ≈ 1 clearly was related linearly to the reaction temperature. The final product was confirmed by EXAFS fitting spectra as solid solution between the Cu and Zn atom in the CuZnP<inf>2</inf>O<inf>7</inf> structure, and it indicated environment around metal atoms.
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    Item type:Publication,
    X-ray absorption spectroscopy studies of Cu (2-x)Zn xP2O7 binary pyrophosphates
    (2013-01-01)
    Baitahe, Rattanai
    ;
    Kongmark, Chanapa
    ;
    Muanghlua, Rangson
    ;
    Seeharaj, Panpailin
    ;
    Vittayakorn, Naratip
    Binary metal pyrophosphates; Cu<inf>(2-x)</inf>Zn<inf>x</inf>P <inf>2</inf>O<inf>7</inf> (x = 0.0-2.0) compounds, were prepared via the solid solution method. The synthesize powders were characterized by X-ray diffraction (XRD). The local structure of Cu was analyzed by the mean of synchrotron X-ray absorption near the edge structure (XANES). The Cu<sup>2+</sup>-O1, Cu <sup>2+</sup>-O2 and Cu-Cu/Zn distances determined are extended X-ray absorption fine structure (EXAFS) measurements at the Cu K-edge, with a distance of about 1.52, 2.11, and 2.74 Å. The correlation between the structural changes and Cu content was analyzed and discussed. The analysis of the EXAFS spectra collected at the Cu K-edge indicates that the local structure around Cu atoms also is affected by the introduction of Zn atoms in the structure. © 2013 Copyright Taylor and Francis Group, LLC.