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Título : | Heat Induced Charge Transfer in the Solid Solution Co3–xTx[Fe(CN)6]2 yH2O with T = Mn, Ni, Cu, Zn and Cd |
Palabras clave : | Chemical Synthesis. Precipitation X-ray Diffraction Crystal Structure Thermal Analysis |
Fecha de publicación : | 16-ene-2013 |
Editorial : | Z. Phys. Chem. |
Descripción : | Cobalt hexacyanoferrates have a relatively low energy barrier for the charge transfer between cobalt and iron atoms. That energy barrier can be overcome by irradiation with light in the ultravioletblue region or through the sample heating. Such feature for that charge transfer process is determined by structural and compositional factors. In this contribution the role of a second metal partially substituting to Co in the material composition on the heat induced charge transfer is studied. Samples of the solid solution Co3–xTx[Fe(CN)6]2yH2O with T = Mn, Ni, Cu, Zn and Cd, were prepared by a simple synthetic route and their behavior on moderate heating, from 80 to 160 °C, was evaluated. The behavior of the solid solution on heating was followed by infrared, X-ray diffraction andMössbauer data. The heat induced charge transfer appears to be favored once the crystal water is removed, when the metal-metal interaction, through the CN bridges, reaches its maximum strength. From this fact, when a metal like Cu, Zn and Cd, with a relatively weak interaction with the coordinated water molecules and, as a consequence, with a low dehydration temperature, is present in the material structure, a lower activation energy is required to be able the heat induced charge transfer. Even in the presence of a second divalent transition metal occupying a fraction of the structural sites for Co, the charge transfer was observed, which is particularly pronounced in the 120–140 °C temperature range. The heat-induced charge transfer was also evaluated from the photo-induced inverse process in the heated samples using photo-acoustic spectroscopy. |
URI : | http://www.repositoriodigital.ipn.mx/handle/123456789/11137 |
Otros identificadores : | Z. Phys. Chem. 222 (2008) 1661–1678 http://hdl.handle.net/123456789/648 |
Aparece en las colecciones: | Doctorado |
Ficheros en este ítem:
Fichero | Descripción | Tamaño | Formato | |
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2008ZPChMVS 1.pdf | 36.46 kB | Adobe PDF | Visualizar/Abrir |
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