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The preparation of iron oxide nanoparticles in the mesopore of silicate MCM-41 and
MCM-48 materials is demonstrated. The encapsulation of iron oxy-hydroxides was
carried out at room temperature by incipient wetness method and the corresponding
oxides were obtained by calcination. This process not only resulted in entrapment
of iron oxy-hydroxides / oxides in the mesopores but also led to isomorphous
substitution of trivalent iron in the silicate framework. The encapsulted
nanoparticles exhibit superparamagnetism while the substituted iron shows
paramagnetic behavior. The above is ascertained by using various techinques viz.,
X-ray diffraction (XRD), diffuse reflectance ultraviolet-visible (DRUV-VIS),
electron paramagnetic resonance (EPR), Mossbauer, and magnetic susceptibility
measuremnets.
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