PMHS-reduced fabrication of hollow Ag-SiO2 composite spheres with developed porosity

A one-pot method was introduced to fabricate Ag-SiO2 hollow composite spheres with developed porosity by employing monodisperse carboxylic-capped polystyrene (PS-COOH) spheres as a hard template. During the synthetic process, Ag+ ions were immediately anchored on the surface of the PS-COOH spheres via electrostatic interaction and readily reduced by employing polymethylhydrosiloxane (PMHS) as a reducing agent. At the same time, silica oligomers derived from the hydrolysis of PMHS and TEOS were slowly deposited on the PS-COOH spheres to form solid silica shells. Subsequent decomposition of the PS-COOH spheres in air induced the formation of Ag-SiO2 hollow spheres. The as-prepared products were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and N-2 absorption-desorption study. The results show that the well-designed composite spheres featured thin and spherical silica shell (similar to 10 nm), large surface area (> 240 m(2) g(-1)) and mesopore (6.0-9.0 nm). In addition, the Ag-SiO2 hollow composite spheres exhibited high catalytic performance toward the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). A one-pot method was reported to prepare Ag-SiO2 hollow spheres with well-developed porosity, which exhibited high catalytic performance and durable activity for the reaction of 4-NP to 4-AP.