Web Release Date: October 20,
Synthesis of Ferromagnetic Core-Shell Nanofibers
Department of Chemistry and Kanbar Laboratory for Nanomaterials at the Bar-Ilan University Center for Advanced Materials and Nanotechnology, Bar-Ilan University, Ramat-Gan, 52900, Israel
Received: August 13, 2007
In Final Form: September 11, 2007
Abstract:
A rapid, solvent-less RAPET (reactions under autogenic pressure at elevated temperature) approach is described
for the fabrication of 1-D core-shell nanostructures. Ferromagnetic FeS and FeSe nanomaterials are covered
in situ in a multiwalled carbon shell by the one-step thermolysis of Fe(CO)5 in the presence of either S or Se
powders in a closed reactor at 700 
C for 30 min under autogenic pressure in an inert atmosphere. SEM
measurements revealed the 1-D morphology of FeS or FeSe wires coated with carbon as having a 80-100
nm diameter with a micrometer length. XRD measurements were consistent with a hexagonal phase of FeS
and a tetragonal crystal structure of FeSe. HR-TEM images confirmed the 1-D core-shell morphologies of
FeS or FeSe with carbon (MX/C; MX = metal chalcogenide) as the shell. The ferromagnetic characteristics
of these MX/C samples were investigated using a vibrating sample magnetometer. Nitrogen gas adsorption
on the surface of MX/C nanostructures was determined by BET surface area analysis. A plausible mechanism
for the formation of magnetic cores (FeS or FeSe) with a carbon shell is suggested.
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