Ultrathin β-FeOOH and ɛ-Fe2O3 nanowires

We report the facile synthesis of ultrathin β-FeOOH and ɛ-Fe2O3 nanowires with diameter of 2–3 nm. The β-FeOOH nanowires show the unique optical properties attributed to the size- and shape-related quantum confinement effect. Upon heat treatment, they are transformed into ɛ-Fe2O3 nanowires, which exhibit the different magnetic properties compared with the previously reported ɛ-Fe2O3 nanostructures synthesized in silica matrices. The ɛ-Fe2O3 nanowires also exhibit high catalytic efficiency and hold potential for environmental-remediation applications.