Silica/ultrasmall Ag composite microspheres: facile synthesis, characterization and antibacterial and catalytic performance

Abstract

Uniform silica/ultrasmall silver composite microspheres have been prepared from [Ag(NH₃)₂]⁺ in the presence of silica microspheres via a hydrothermal process. The reaction temperature plays a critical role in the formation of the as-prepared SiO₂/ultrasmall Ag composite microspheres. The as-prepared product was investigated by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM, JEOL-6700F) and transmission electron microscopy (TEM, JEOL 3010). The silica/ultrasmall silver composite microspheres are 200 nm in diameter and the silica microspheres decorated with ultrasmall Ag nanoparticles have an average diameter of 4 nm. As expected, the as-prepared silica/ultrasmall silver composite microspheres exhibit superior bacteriostatic and bactericidal activities and excellent photodecomposition towards Rhodamine 6G (R6G) dyes.