Facile synthesis of 3D flowerlike α-FeOOH architectures and their conversion into mesoporous α-Fe2O3 for gas-sensing application

We reported a facile and efficient solution-based route to prepare novel flowerlike α-FeOOH architectures without any template or surfactant. Scanning electron microscope (SEM) images reveal that leaf-like nanosheets with a thickness about 40 nm assembled into flowerlike superstructures. On the basis of time-dependent experiments, a multistage reaction mechanism for the formation of the flowerlike α-FeOOH was proposed. After heat treatment, the flowerlike α-FeOOH could be converted into corresponding mesoporous α-Fe2O3. Transmission electron microscopy (TEM) images and porosity analysis showed that the nanosheets have porous walls with a pore size of about 7 nm. As a demonstration of potential application for gas-sensing materials, the mesoporous α-Fe2O3 nanostructures exhibited short response/recovery time within 5/10 s, and low response concentration of 1 ppm toward acetone vapors. Large specific surface area and mesoporous structure should be beneficial for the sensing properties of α-Fe2O3.

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