Controllable synthesis of fluorapatite microcrystals decorated with silver nanoparticles and their optical properties

An EDTA-assisted hydrothermal method is developed for the controlled preparation of fluorapatite microcrystals (FHAp MPs) decorated with silver nanoparticles (Ag NPs). The synthesis process involves the use of EDTA as both a chelating agent and a reducing agent, allowing the one-pot formation of Ag/FHAp composites. The resultant product was characterized by X-ray diffraction patterns (XRD), field emission scanning electron micrographs (FESEM), transmission electron microscopy (TEM), and UV-vis diffuse reflection spectroscopy (UV-DRS). The Ag NPs prepared via this method exhibit a monodispersed size distribution and essentially uniform dispersion on FHAp MPs supports. It was demonstrated that the morphology of FHAp MPs can be tuned by varying the concentration of silver nitrate in the starting reaction solution, or by varying the pH value of the reaction solution. A possible growth mechanism was discussed for the formation of Ag/FHAp composites. Additionally we also demonstrated that the resulting Ag/FHAp composites with different Ag loadings possess tunable optical properties.