Silica aerogel–iron oxide nanocomposites: structural and magnetic properties

Silicon oxide in an iron(III) oxide matrix: the sol–gel synthesis and characterization of Fe–Si mixed oxide nanocomposites that contain iron oxide as the major phase

“…All of the materials have high surface areas between 350 and 450 m 2 /g. A direct comparison with previously reported Fe-Si mixed oxide materials is difficult since all previously reported materials contain silica as the major phase and the surface areas of these materials vary greatly depending on the method of preparation [12,16,29]. A better comparison is to pure iron(III) oxide aerogels prepared by the epoxide addition 24 20 method.…”

“…The literature on Fe-Si mixed oxide composite materials has thus far been limited to the isolation of iron oxides in silica matrices or coating of particles of one component with the other [8][9][10][11][12]32,33]. Most of these composites had well defined domains of silica and iron oxide.…”

“…Iron oxide/silica composites synthesized from novel iron containing silsequioxane precursors containing up to 11 wt% Fe have been studied for ammonia oxidation and N 2 O decomposition as well [8]. Magnetic behavior of 20-35 wt% Fe 2 O 3 in amorphous SiO 2 matrices has been evaluated for a variety of materials [9][10][11][12][13][14]. Finally, others have used silica matrices to support iron metal nanoparticles which have been prepared by reduction of iron oxide particles in Fe 2 O 3 -SiO 2 composites [14].…”

Nanocluster iron oxide-silica aerogel catalysts for methanol partial oxidation

“…Other phase assignments to amorphous iron oxide nanoclusters or some crystallites were also not excluded. Possible factors for a discrepancy between all reported versions involve the selection of iron precursor and the progressive transformation of g-to a-forms with heat treatment [22][23][24][25][26]. Empirically, iron oxide made from an alkoxide precursor similar in nature to the one we used exhibits a hematite phase at 500 8C as determined by XRD analysis [27].…”

Cu2O/nano-CuFe2O4: A novel and recyclable magnetic catalyst for three-component coupling of carbonyl compounds–alkynes–amines under solvent-free condition

“…Among them, the iron oxides are usually applied as simplest magnetically recoverable catalysts, as they are nontoxic, cheap in preparation, amenable to functionalization and easy to handle [2]. They have been extensively used in some organic reactions such as, C-C and C-X couplings [3,4], reduction [5], oxidation [6] and multi-component reactions [7].…”