Naslov
Formation of iron oxides in a highly alkaline medium in the presence of rhodium ions
(Formation of iron oxides in a highly alkaline medium in the presence of rhodium ionsNS)

Autori
Krehula, Stjepko ; Musić, Svetozar

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
International Conference on the Applications of the Mössbauer Effect, ICAME 2009, Programme and Abstracts / Müller, H. - Beč : Technische Universität Wien, 2009, 243-243

Skup
International Conference on the Applications of the Mössbauer Effect

Mjesto i datum
Beč, Austrija, 19.07.2009. - 24.07.2009

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
iron oxides ; rhodium ; Mössbauer spectroscopy ; XRD ; FE-SEM

Sažetak
The effect of the presence of rhodium ions on the formation of iron oxides in a highly alkaline precipitation system was investigated using X-ray powder diffraction (XRPD), Mössbauer and FT-IR spectroscopies, field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDS). Acicular α-FeOOH particles precipitated in a highly alkaline medium with the addition of tetramethylammonium hydroxide (TMAH) were used as reference material. The initial addition of rhodium ions to that precipitation system had a significant effect on the formation of iron oxide phases and their properties. Characterization of α-FeOOH samples formed in the presence of rhodium ions showed thinner particles, smaller mean crystallite size, decreased average hyperfine magnetic field and a shift in the position of IR absorption bands in comparison with the reference sample. In the presence of higher concentrations of rhodium ions a small fraction of α-Fe2O3 was also formed. By additional autoclaving at 160 °C of the precipitation system, α-FeOOH precipitated in the presence of rhodium ions was transformed to α-Fe2O3 crystals in the form of hexagonal bipyramids via a dissolution-reprecipitation mechanism with a simultaneous formation of metallic rhodium nanoparticles. These rhodium nanoparticles acted as a catalyst for the reductive dissolution of α-Fe2O3 particles and the formation of Fe3O4 crystals in the form of octahedrons

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA