Naslov
Moessbauer, TEM, HREM and X-ray diffraction observations of iron doped TiO2 nanocomposites

Autori
Gotić, Marijan ; Tronc, E. ; Popović, Stanko ; Tonejc, Anđelka M. ; Ivanda, Mile ; Musić, Svetozar

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

Izvornik
Book of Abstracts ICAME-99 / - Garmisch-Partenkirchen : International Board on the Applications of Moessbauer Effect, 1999

Skup
Internationa Conference on the Applications of Moessbauer Effect, ICAME-99

Mjesto i datum
Garmisch-Partenkirchen, Njemačka, 29.08.1999. - 03.09.1999

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Sažetak
The iron doped TiO2 system has attracted much attention owing to its ability to activate a number of chemical reactions such as, the photoreduction of dinitrogen to ammonia, the splitting of water or hydrogen production as well as the photodegradation of perchloroethylene, oxalic acid and other organic pollutants. The improved photocatalytic efficiency of iron doped TiO2 has been attributed to the action of the iron ions within the TiO2 matrix inhibiting photogenerated charge pair recombination. The method of inserting iron ions into the TiO2 structure and the type of iron precursor strongly influences the homogeneity, microstructure, photocatalytic and other properties of the final material. In the present work, iron-doped TiO2 nanocomposite with the initial Ti/Fe ratio, Ti:Fe=1:0.15 was synthesized by a modified sol-gel method. Ti (IV) isopropoxide and iron(II) sulphate were dissolved in isopropoxide under inert (nitrogen) atmosphere and hydrolyzed with PEG (polyethylene glycol) dissolved in doubly distilled water. After 4 hours of hydrolysis the suspension was heated to evaporate the solvent and then the solid residue was thermally treated at 500oC for 2 h. Samples were analyzed by Mössbauer spectroscopy, vibrational spectroscopy, electron microscopy and XRD. Sulfate ions and PEG strongly influenced the hydrolysis and polycondensation processes during sol-gel synthesis as well as the dispersion of iron in the TiO2 matrix during the synthesis and thermal treatment. FT-IR results showed that sulfate ions were specifically adsorbed on TiO2 particles. PEG acted as a surfactant stabilizer, suppressed the rate of precipitation and aggregation, affected the pores and particle size distribution and improved the homogeneity of the final product. XRD and TEM analysis showed that for the given molar concentration of iron doped TiO2 (13 mol% of iron), samples consisted of at least two phases, with anatase as the dominant phase. The appearance of rutile at 500oC can be explained by a rather high level of doping TiO2 by iron. On the basis of Mössbauer spectroscopic measurements it was concluded that iron occupied substitutional and interstitial positions within anatase TiO2.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Kemija

POVEZANOST RADA