A simple and low-temperature hydrothermal route for the synthesis of tubular α-FeOOH

Tubular α-FeOOH was synthesized via hydrothermal reaction at 120 °C. X-ray diffraction (XRD) pattern indicates that the as-prepared sample is the pure orthorhombic phase α-FeOOH. Fourier transform infrared (FT-IR) analysis further confirms the formation of orthorhombic phase α-FeOOH. The morphology and structure of the as-obtained product were characterized by transmission electron microscopy (TEM) techniques. TEM images show a high degree of contrast between the bright central part and the darker edges, demonstrating the hollow core of the product. The obtained tubular α-FeOOH was ∼ 10 nm in outer diameter and ∼ 6 nm in inner diameter, respectively. High-resolution TEM image of one single nanotube shows the clearly resolved interplanar spacing of about 4.18 Å, which corresponds to the spacing between (110) planes of the orthorhombic-type α-FeOOH crystal. The room-temperature UV-Vis absorption spectrum of the tubular α-FeOOH nanostructures is presented.