Facile Template-Free Synthesis and Characterization of Elliptic α-Fe2O3 Superstructures

In this work, elliptic single-crystal line alpha-Fe2O3 superstructures are prepared successfully by a facile hydrothermal method independent of surfactants or templates. The as-obtained products were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). The elliptic superstructures are composed of nanorods with a mean diameter of ca. 40 nm and an average length of ca. 200 nm. By properly monitoring the component of the reaction system, the morphology of the alpha-Fe2O3 superstructures can also be tuned to be. spherical (consist of nanosheets) and quasi spindle-like (consist of integrated irregular blocks). On the basis of a series of contrast experiments over time, the probable growth mechanism and fabrication process of the products were proposed. The magnetic and electrochemical properties of the as obtained alpha-Fe2O3 superstructures with different morphologies are investigated systematically. The results show that these properties are greatly influenced by the special structures of the products. This work provides an additional strategy to prepared self-assembled superstructures with tailored morphologies (both for the building units and the overall products) and properties.