CINDECA   05422
CENTRO DE INVESTIGACION Y DESARROLLO EN CIENCIAS APLICADAS "DR. JORGE J. RONCO"
Unidad Ejecutora - UE
artículos
Título:
"Loading channels of SiO2 mesoporous matrices with Fe oxides"
Autor/es:
N. A. FELLENZ; L. A. CANO; J. F. BENGOA; I. DE SOUZA AZEVEDO; R. C. MERCADER; S. G. MARCHETTI
Revista:
HYPERFINE INTERACTIONS
Editorial:
Springer
Referencias:
Año: 2011 vol. 202 p. 17 - 24
ISSN:
0304-3843
Resumen:
After embedding hematite nanowires (15 wt% Fe) into a MCM-41 hard
template, we have explored alternative routes to induce the structural
transformations that lead from hematite to maghemite and magnetite embedded
nanowires. The impregnation media (ethanol or water) and the calcination
atmosphere (air and NO/He) on the hematite nanowires production play a
significant role at the time of reducing and re-oxidizing the embedded hematite
nanoparticles. The solids were characterized by X-ray diffraction, nitrogen
adsorption, and Mössbauer spectroscopy. The results indicate that the effect of
the solvent on the structural properties of the iron species is more important
than the calcination atmosphere. The best conditions for iron magnetic
nanowires not to get outside of the MCM-41 channels over the treatments are
reached using water as the solvent and air as the calcination atmosphere. When
ethanol is the solvent used over the preparation step, the end iron oxides are
in the form of nanotubes spread out on the amorphous silica walls of the
matrix.