The influence of platinum(IV) ions on the formation of iron oxides in a highly alkaline medium (CROSBI ID 171322)
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Podaci o odgovornosti
Krehula, Stjepko ; Musić, Svetozar
engleski
The influence of platinum(IV) ions on the formation of iron oxides in a highly alkaline medium
The effect of the presence of platinum(IV) ions, in the form of [Pt(OH)6]2- at a high pH, on the formation of iron oxides in a highly alkaline precipitation system was investigated using X-ray powder diffraction (XRD), 57Fe Mössbauer and FT-IR spectroscopies, field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDS). Monodispersed lath-like α-FeOOH (goethite) particles precipitated by hydrothermal treatment in a highly alkaline medium with the addition of tetramethylammonium hydroxide (TMAH) were used as reference material. In the presence of 1 or 5 mol% of platinum ions in the precipitation system the lath-like α-FeOOH particles were formed as a single phase after a short hydrothermal treatment (2 h). No significant change in the size and shape of these particles in comparison to the reference sample was observed. After 6 h of autoclaving the formation of platinum nanoparticles at the surface of α-FeOOH particles via reduction by TMAH and/or its decomposition products became visible. These nanoparticles acted as a catalyst for the reduction of Fe(III) ions into Fe(II) and gradual transformation of α-FeOOH into a mixed Fe(II)–Fe(III) oxide (Fe3O4, magnetite) by the dissolution–recrystallization mechanism. The presence of a higher concentration of platinum ions accelerates the process of α-FeOOH → Fe3O4 transformation with the appearance of α-Fe2O3 (hematite) particles as an intermediate product.
iron oxides ; platinum ; XRD ; 57Fe Mössbauer spectroscopy ; FT-IR ; FE-SEM
Rad je prezentiran na skupu XXXth European Congress on Molecular Spectroscopy, održanom od 29.08.-03.09.2010., Firenca, Italija.
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Podaci o izdanju
993 (1/3)
2011.
382-389
objavljeno
0022-2860
1872-8014
10.1016/j.molstruc.2010.09.037