Synthesis of hexagonal pyramidal columnar hematite particles by a two-step solution route and their characterization

Hexagonal pyramidal columnar hematite (α-Fe2O3) particles have been synthesized by a hydrolysis method using iron sheets and nitric acid of mildly acidic pH at 90 °C. The morphologies and structures of the resulting products have been characterized by transmission electron microscopy (TEM) and field-emission scanning electron microscopy (FESEM), X-ray powder diffraction (XRD), and Fourier-transform IR spectroscopy (FTIR). An aggregation growth mechanism is proposed to rationalize the formation of α-Fe2O3. The influence of pH on the structure and morphology of the as-prepared α-Fe2O3 has been investigated. Additionally, magnetic investigations have shown that the hexagonal pyramidal columnar α-Fe2O3 exhibited weak ferromagnetism at room temperature.