Phase formation and evolution of Cu:Zn partials in binary metal pyrophosphates Cu(2-x)Zn(x)P2O7; x approximate to 1

摘要

Binary metal pyrophosphate powders were prepared by the solid state reaction method and subsequently calcined at 400, 500, 600, 700, and 800 degrees C in order to study Cu:Zn partial evolution to the final CuZnP2O7 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 center dot 2P(2)O(5)center dot 0.3NH(3)center dot 0.2H(2)O, Cu2P2O7, Zn2P2O7, and Zn2P2O7 center dot 3H(2)O intermediates. Decreasing percentage of 3CuO center dot 2P(2)O(5)center dot 0.3NH(3)center dot 0.2H(2)O intermediates was related directly to an increasing final product. Cu:Zn contents changed in Cu(2-x)Zn(x)P2O7 in the temperature range of 400-600 degrees C, when x approximate to 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 CuZnP2O7 structure, and it indicated environment around metal atoms. (C) 2014 Elsevier B.V. All rights reserved.