Crystal‐Phase‐ and Morphology‐Controlled Synthesis of Fe₂O₃ Nanomaterials

Abstract

Abstractα‐ and γ‐Fe2O3 nanorods have been prepared from a β‐FeOOH precursor that was obtained by aqueous‐phase precipitation of ferric chloride. The oxyhydroxide precursor had a rodlike shape with a diameter of 30–40 nm and a length of 400–500 nm. Calcination at 500 °C of the rod‐shaped oxyhydroxide in air yielded α‐Fe2O3 nanorods, whereas heating to reflux in polyethylene glycol (PEG) at 200 °C resulted in the formation of γ‐Fe2O3 nanorods. Both oxides inherited the rodlike morphology of the precursor but exposed different crystalline facets. When being used to catalyze NO reduction by CO, an environmentally important reaction in NO abatement, the γ‐Fe2O3 nanorods were much more active than the α‐Fe2O3 nanorods and showed an apparent crystal‐phase effect. This was because the γ‐Fe2O3 nanorods simultaneously exposed iron and oxygen ions on their surfaces, which facilitated the adsorption and activation of NO and CO molecules.

Selective Hydrogenation of Cinnamaldehyde Catalyzed by ZnO-Fe2O3 Mixed Oxide Supported Gold Nanocatalysts

“…As shown in Figure 2A, ZnO did not present reduction peaks, which was probably the result of complete dihydroxylation and high thermal stability [24,25]. There were three reduction peaks for the Fe 2 O 3 : the first reduction peak below 400 • C was due to the reduction of Fe 2 O 3 to Fe 3 O 4 , while the broad peaks above 400 • C represented the further reduction of Fe 3 O 4 to metallic iron, perhaps through FeO [26,27]. All the mixed oxides showed different reduction behavior.…”

Manganese oxides with different crystalline structures: Facile hydrothermal synthesis and catalytic activities

“…Recently, Mou et al [2] reported that nano Fe 2 O 3 showed apparent crystal-phase effect in the reaction of NO reduction, and g-Fe 2 O 3 nanorod was more active than a-Fe 2 O 3 . Bau et al [3] also reported that uniform octahedral Cu 2 O showed higher activity in CO oxidation than cubic Cu 2 O.…”

Evaluation of poly(ethylene glycol)-coated monodispersed magnetic poly(2-hydroxyethyl methacrylate) and poly(glycidyl methacrylate) microspheres by PCR

“…In the latter spectrum, a new broad asymmetric band at ca. 560 cm À1 appears because of Fe-O stretching vibrations [53] which confirms the formation of c-Fe 2 O 3 inside the microspheres [54,55]. Moreover, there is a strong asymmetrical stretching band of carboxyl anion at 1585 cm À1 , which originates from the asymmetrical NH 3 + bending accompanied with a weak symmetrical 1533 cm À1 band of NH 3 + bending.…”