Water Photooxidation by Smooth and Ultrathin α-Fe2O3 Nanotube Arrays

One-dimensional nanostructures exhibit quantum confinement that leads to unique electronic properties, making them attractive as the active elements for various applications. Iron oxide (alpha-Fe2O3 or hematite) nanotubes are of particular interest in catalysis, sensor devices, Li-ion battery, environmental remediation and photocatalysis. Here, we report a simple sonoelectrochemical anodization method to grow smooth and ultrathin (5-7 nm thick) Fe2O3 nanotube arrays (3-4 mu m long) on Fe foil in as little as 13 min. The prepared catalyst has shown tremendous potential to split water to generate hydrogen Under solar light illumination. A photocurrent density of 1.41 mA/cm(2) is observed for hematite nanotube arrays with more than 50%, being contributed by the visible light components of the solar spectrum.