Synthesis of crystalline and amorphous iron phosphate nanoparticles by simple low-temperature method

Abstract

A simple and well-designed route for controlled synthesis of crystalline iron phosphate (FePhcry) and amorphous iron phosphate (FePhamph) with simple reflux-based method at 90 °C is introduced. The method allows for mass production at low cost. The crystalline is formed at initial pH of 0.38 to final pH = 1.0 and the amorphous form is obtained at initial pH of 1.3 to final pH (after completed reflux) of 8.0. Characterization techniques such as FT-IR spectroscopy, energy dispersive x-ray analysis (EDS), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD) and BET surface area determination are used for the investigation of the phase structure and morphological properties of the FePhcry and FePhamph nanomaterials. The average values of particle size are ∼50–100 nm and ∼5–15 nm with surface area of 16.013 m2 g−1 and 154 m2 g−1 for FePhcry and FePhamph, respectively. Based on the XRD pattern, the obtained phase structure of the FePhcry is FePO4.2H2O (80%) and Fe12 (OH)7.3 (PO4)8.4.7H2O (20%) with a monoclinic and orthorhombic crystallographic form, respectively. For the FePhamph sample the phase structure is completely amorphous with chemical structure of FePO4.