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

Abstract

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 N2 absorption–desorption study. The results show that the well-designed composite spheres featured thin and spherical silica shell (~10 nm), large surface area (>240 m2 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.