Structural features of copper ferrite-chromites
| Autor: | T. P. Minyukova, I. Yu. Molina, N. V. Shtertser, Tamara M. Yurieva, L. M. Plyasova, Vladimir I. Zaikovskii, G. N. Kustova |
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| Rok vydání: | 2015 |
| Předmět: |
Materials science
Inorganic chemistry Spinel Thermal decomposition chemistry.chemical_element Thermal treatment engineering.material Copper Catalysis Inorganic Chemistry Tetragonal crystal system Chromium Crystallography chemistry Materials Chemistry engineering Ferrite (magnet) Physical and Theoretical Chemistry |
| Zdroj: | Journal of Structural Chemistry. 56:642-649 |
| ISSN: | 1573-8779 0022-4766 |
| DOI: | 10.1134/s0022476615040058 |
| Popis: | The structural features and the distribution of cations over crystallographic sites of copperchromite, copper ferrite, and mixed chromite-ferrites with the spinel structure obtained by thermal decomposition at 600°C and 900°C of mixed hydroxy compounds of copper, iron, and chromium with the composition Cu2+/(Fe3++Cr3+) = 1/2 and different Fe3+/Cr3+ ratios are studied using a set of physicochemical methods. It is shown that the spinel-structure phases formed exist in two modifications: cubic and tetragonal, depending on the Fe3+/Cr3 ratio. The crystallographic relationship between the cubic and tetragonally distorted phases of spinel is analyzed. The distribution of cations over crystallographic sites, the character and degree of tetragonal distortion of Cu–Fe–Cr spinel depend on the Fe3+/Cr3+ ratio: when Fe3+/Cr3+ > 1, the ratio of unit cell parameters c*/а* > 1; when Fe3+/Cr3+ < 1, the ratio c*/а* < 1; when Fe3+/Cr3+ = 1, the spinel is cubic irrespective of the temperature of thermal treatment. The oxygen coordination of copper ions in the spinel structure has a significant effect on the catalytic properties of the samples in the low-temperature water gas shift reaction. |
| Databáze: | OpenAIRE |
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