Glycerin-assisted solvothermal synthesis of Fe3(PO4)2(OH)2 microspheres

Iron hydroxyl phosphate (Fe3(PO4)2(OH)2) microspheres with diameters of several micrometers have been successfully prepared using Fe(NO3)3·9H2O and NaH2PO4·2H2O in a mixed solvent of deionized water and glycerin by a facile one-step solvothermal method. The crystal phase of the product changes from poorly crystallized FePO4·2H2O nanoparticles into well-crystallized Fe3(PO4)2(OH)2 microspheres as the amount of glycerin increases. The as-prepared Fe3(PO4)2(OH)2 microspheres can transform into FePO4 through thermal treatment at 800 °C in air. The cytotoxicity tests show that the as-prepared Fe3(PO4)2(OH)2 microspheres have good biocompatibility. We expect that the as-prepared Fe3(PO4)2(OH)2 microspheres are promising for the applications in various fields.