engleski

Modification of α-Fe2O3 nanotubes with divalent and trivalent metal cations

Jia et al. (2005) showed that phosphate anions could induce the preferential dissolution of the hematite spindle precursor to yield single-crystalline iron oxide nanotubes. Recently the same authors (2008) introduced sulphate anions into the system in order to achieve better control of its morphology and this double anion mediation resulted in the synthesis of iron oxide nanorings. In a previous work we successfully controlled the morphology of iron oxide nanotubes by adding divalent metal cations M2+ (M = Mn, Cu, Zn, Ni). The divalent metal cations gradually modify the spindle to a pseudosphere and the nanotube to nanoring particle morphologies. The Mössbauer and XRD of these nanoparticles showed the presence of α-Fe2O3 ; however, the Mössbauer lines were broadened in relation to referent α-Fe2O3 nanoparticles. Such broadening of spectral lines can be related to the addition of the divalent metal cations at the beginning of the precipitation process. It should be noted that in the modified α-Fe2O3 nanoparticles no presence of the divalent cations was detected with EDS and PIXE. In this work we extended the modification of iron oxide nanotubes by Co2+ and Cd2+ divalent cations as well as some trivalent metal cations, such as Ce3+ and Gd3+.

nanoring; α-Fe2O3; divalent cations; Mössbauer spectroscopy; gadolinium; cerium

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