Low temperature solution-based synthesis of porous flower-like α-Fe2O3 superstructures and their excellent gas-sensing properties

A facile solution approach was employed to synthesize flower-like alpha-FeOOH precursors by using FeSO4 center dot 7H(2)O and CO(NH2)(2) as raw materials at 80 degrees C for 6h without any template and surfactant. After annealing in air at 500 degrees C for 2h, the porous flower-like alpha-Fe2O3 superstructures were successfully obtained, whose morphological feature is characterized as self-assembled by porous nanorods with an average length of 0.1-1.0 mu m and diameter of 50-150 nm. Transmission electron microscopy (TEM) images show that there are many porous walls with a pore size of about 10 nm on the surface. As a demonstration of potential application for gas-sensing materials, the porous flower-like superstructures exhibited short response/recovery time within 6/3s. and presented a much higher gas response than alpha-Fe2O3 nanoparticles aggregations towards different concentrations of ethanol, methanol and acetone. (C) 2011 Elsevier B.V. All rights reserved.