Iron oxide nanopropellers prepared by a low-temperature solution approach.

The α-Fe 2 O 3 (hematite) nanopropellers were synthesized via a low-temperature solution-based method using FeCl 2 as a precursor in the presence of urea and glycine hydrochloride. The formation of α-Fe 2 O 3 nanopropellers is strongly depended on the addition of glycine hydrochloride, which serves as a pH modulator and affects the oxidation rate of Fe 2+ . The structural evolution of the propeller-structured hematite was found to follow dissolution and recrystallization processes. For the structural conformation, each nanopropeller presents a hexagonal central column closed by six equivalent surfaces of {1100} and the six arrays of the nanopropeller structure are a result of growth along ±[1100], ±[1010], and ±[0110]. Preliminary results show that the magnetic maghemite (γ-Fe 2 O 3 ) nanopropellers could also be prepared by a reduction and reoxidation process from the α-Fe 2 O 3 (hematite) nanopropeller precursors.