Growth and shape control of orthorhombic Fe_5(PO_4)_4(OH)_3 · 2H_2O single crystalline dendrites

摘要

Orthorhombic Fe_5(PO_4)_4(0H)_3·2H_2O single crystalline dendritic nanostructures have been synthesized by a facile and reproducible hydrothermal method without the aid of any surfactants. The influences of synthetic parameters, such as reaction time, temperature, the amount of H_2O_2 solution, pH values, and types of iron precursors, on the crystal structures and morphologies of the resulting products have been investigated. The formation process of Fe_5(PO_4)_4(OH)_3·2H_2O dendritic nanostructures is time dependent: amorphous FePO_4·H_2O nanoparticles are formed firstly, and then Fe_5(PO_4)4(OH)_3·2H_2O dendrites are assembled via a crystallization-orientation attachment process, accompanying a color change from yellow to green. The shapes and sizes of Fe_5(PO_4)_4(OH)_3 · 2H_2O products can be controlled by adjusting the amount of H_2O_2 solution, pH values, and types of iron precursors in the reaction system.