Synthesis of FePO<sub>4</sub> Hollow Microspheres with Bilayer Shell by a Biotemplate

Abstract

Monodispersed iron phosphate hollow microspheres with high uniformity were synthesized by using the rape pollen grains as biotemplate. The as-prepared microspheres were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, energy disperses spectroscopy and scanning electron microscopy. The shell of the microspheres was found to be a bilayer structure composed with a compact inner layer and rough outer layer. Through the investigation of the adsorption behavior of the pollen grains, the formation of the bilayer structure was attributed to the selective permeation of the pollen wall. The inner layer was formed by the ion passed through the pollen wall and adsorbed on the pollen core; while the outer layer was formed by the coating of the particles could not permeate the pollen wall. When the pollen grains were removed by the calcinations, both of the precipitate in the pollen and on the pollen wall were condensed to from the hollow microspheres with a shell of bilayer. This process provides us with a new insight on the preparation of the hollow microspheres with special structure using the pollen grains as biotemplate. The microspheres with core/shell or multilayer structure should be achieved by utilization of the selective permeation of the pollen wall.