engleski

Formation of porous alpha-Fe2O3 microstructure by thermal decomposition of Fe(IO3)3

Formation of porous alpha-Fe2O3 microstructure by thermal decomposition of Fe(IO3)3 was monitored using 57Fe Mössbauer spectroscopy, FT-IR spectroscopy and field emission scanning electron microscopy. Spherical Fe(IO3)3 particles were built of close-packed hexagonal rods. Both, Fe(IO3)3 as prepared and Fe(IO3)3 thermally treated at 300 oC showed single line in the corresponding Mössbauer spectra recorded at room temperature. At 350 oC and higher temperatures, the microporous network appeared. DTA curve of Fe(IO3)3 showed a very strong and broad endothermic peak between 440 and 535 oC, centered at 515 oC due to complete crystallization of alpha-Fe2O3. Upon heating at 800 oC there is recrystallization of microporous alpha-Fe2O3 network, whereas porous microstructure almost disappeared upon heating at 900 oC and close-packed hexagonal alpha-Fe2O3 subunits were formed. Spherical shape of the particles was preserved from room temperature to 900 oC.

Mossbauer; FT-IR; alpha-Fe2O3; porous oxides; thermal decomposition

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