Reverse microemulsion-mediated synthesis of Au@SiO2 hybrid nanoparticles with different morphologies

In this study, we report a simple synthesis of multiple Au nanodots core-silica shell nanoparticles (multi-Au@SiO2 NPs). The Au@SiO2 hybrid nanoparticles were synthesized in a water-in-oil microemulsion with a composition of polyoxyethylene(10) tertoctylphenyl ether (Triton X-100)/1-hexanol/cyclohexane/H2O and have been fully characterized by transmission electron microscopy (TEM), high-resolution TEM (HR-TEM) observations, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), UV-vis measurements, and thermogravimetric analysis (TGA). The morphologies of the hybrid nanoparticles of Au@SiO2 can be easily tuned by the molar ratio of HAuCl4 to NaBH4 and the volume ratio of HAuCl4 aqueous solution to TEOS. As the morphologies of Au@SiO2 nanoparticles varied, the optical properties also changed as revealed by UV absorption spectrum. These Au@SiO2 hybrid nanoparticles which possess these properties make them fascinating candidates for a variety of applications such as catalysis and life science.