Naslov
Tailoring the morphology of goethite nanorods by incorporating Bi in the structure

Autori
Gajović, Andreja ; Šturm, Sašo ; Jančar, Boštjan, Čeh, Miran

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

Izvornik
Hot nano topics 2008, Abstract book / Mihajlović, Dragan ; Kobe, Spomenka ; Scoles, Giacinto ; Remškar, Maja ; Jamnik, Janez ; Čopič, Martin ; Drobne, Damjana ; Vericat, Joan Albert ; Hoeck, Juergen - Ljubljana : IJS, 2008, 115-115

Skup
Hot nano topics

Mjesto i datum
Portorož, Slovenija, 23.05.2009. - 30.05.2009

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
goethite ; nanorods ; HRTEM ; tailoring

Sažetak
Goethite ( -FeOOH) is an antiferromagnetic iron oxyhydroxide with nominally spherical nanoparticles to submicrometer, acicular particles. Goethite nanostructures are suitable for the production of pseudomorph magnetic iron or iron oxide particles for magnetic-recording media [1]. We synthesized the goethite nanorods in a hydrothermal reaction of precipitates prepared by two different precipitation procedures and with the addition of various molar fractions of bismuth ions. In the first procedure the solutions containing both iron and bismuth ions (starting compounds Fe(NO3)3• 9H2O and Bi(NO3)3) were co-precipitated with tetraethyl ammonium hydroxide (TMAH), while in the second procedure the precipitation of the iron and bismuth ions was carried out separately, prior to mixing in an autoclave. Before the precipitation the Bi(NO3)3 was dissolved in HNO3 by vigorous stirring. The hydrothermal treatments were performed in the Teflon-lined autoclave at pH 13.54 at 200°C for 6 h. The crystal structures of the prepared samples were analyzed using X-ray powder diffraction (XRD) and Raman spectroscopy (RS), while the morphologies and nanostructures were determined using high-resolution transmission electron microscopy (HRTEM) and/or scanning electron microscopy (SEM). The chemical compositions were examined by energy-dispersive X-ray analysis (EDXS). Tailoring the goethite’ s morphology in both series of precipitations was possible, although with a higher fraction of bismuth other phases ( - Fe2O3, BiFeO3, Bi2O3) were also produced. It was observed, for example, that the aspect ratio of goethite nanorods increased with an increase in the number of Bi3+ ions in the reaction. The change of the goethite’ s morphology and the appearance of the additional phases in the reaction occurred with the addition of a 5% fraction of bismuth for the co-precipitation procedure ; however, for the case of separate precipitation, these phases only appeared when more than 10% of bismuth was added. In the goethite nanorods synthesized by separate precipitation the content of Bi+3 inbuilt into the structure was larger (1.5– 3.5 at %) than in goethite prepared after co-precipitation (0.3– 1.5 at %). The influence of the bismuth addition on the goethite morphology and the appearance of other phases will be discussed in terms of the condition of hydrothermal reactions and the ionic radius of bismuth. [1] D. J. Burleson, R. L. Penn, Langmuir 22 (2006) 402 and references there in.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

POVEZANOST RADA