Characterization of iron oxide in Fe2O3/SiO2 catalyst

Iron oxide–silica nanocomposites via sol–gel processing

“…Similar results were achieved using Si(OC 2 H 5 ) 4 and iron (III) acetylacetonate [8]. Sol -gel composites have also been prepared from Si(OC 2 H 5 ) 4 and iron (III) nitrate in ethylene glycol which when sintered formed g-Fe 2 O 3 particles, which converted to a-Fe 2 O 3 at >650 jC [9]. Fe 2 O 3 -SiO 2 composites prepared using Si(OC 2 H 5 ) 4 and Fe(NO 3 ) 3 as starting materials gave g-Fe 2 O 3 <900 jC and a-Fe 2 O 3 at higher temperatures [5].…”

Nanocrystalline Maghemite (γ‐Fe2O3) in Silica by Mechanical Activation of Precursors

“…The central doublet observed in the spectrum measured at room temperature is attributed to iron oxide particles behaving superparamagnetically, whereas the magnetically split sextuplet observed at 78 K is caused by the presence of iron oxide particles exhibiting ferrimagnetic properties. 21 Figure 7 shows the magnetization as a function of applied magnetic field, measured at room temperature, for the composition mechanically activated for 10, 20, 30, and 40 h, respectively. The initial susceptibilities observed for all four compositions show no hysteresis at room temperature, i.e., both the retentivity and coercivity are zero, which is consistent with the superparamagnetic behavior expected from the Mössbauer results.…”

“…M AGHEMITE (␥-Fe 2 O 3 ) is a technologically important magnetic material that has a wide range of applications in information storage 1,2 and catalysis. 3 There has been a dramatic increase of interest in nanocrystalline ␥-Fe 2 O 3 for its magnetic properties that are strongly dependent on the particle and crystallite sizes. This is especially so when the particle size reaches the nanometer scale.…”

Structural and magnetic properties of γ- and ε-Fe2O3 nanoparticles dispersed in silica matrix

“…Among magnetic nanoparticles, iron oxides (cFe 2 O 3 and Fe 3 O 4 ) have attracted technological interest due to their potential application in magnetic, magneto-optic, electronic, catalysis and biomedical fields [4][5][6][7][8]. Most of the applications in these fields require well-dispersed chemically stable iron oxide nanoparticles of uniform size and shape.…”