Synthesis, characterization and photocatalytic activity of Au/SiO₂@TiO₂ core-shell microspheres

By using HAuCl₄ as the gold precursor, spherical Au@SiO₂/TiO₂ core-shell nanostructures were prepared with the sol-gel method and ethanol reflux. The preparation process was convenient and fast. The obtained samples were characterized by UV-Vis, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. The results suggested that these spherical particles were in uniform distribution of particle size and with excellent monodispersity. Gold nanoparticles were successfully loaded on the core-shell structure, and TiO₂ nanoparticles were functionalized. With the functionalization of gold nanoparticles, Au@SiO₂/TiO₂ nanoparticles showed excellent photocatalysis activity for the degradation of methyl orange. The possible mechanism of catalytic degradation was discussed in the paper. (author)