Abstract: In this work, choline was employed as both a catalyst and a reducing agent to catalyze the hydrolysis/condensation of tetraethyl orthosilicate and reduce chloroauric acid tetrahydrate. Through a one-step concerted reaction process, successfully prepared Au/mesoporous silica composite particles. Transmission electron microscopy (TEM) and nitrogen desorption characterization revealed that thickness of the mesoporous shell increased from 30 nm to 20 and 8 nm when the pre-treatment time after the addition of choline was delayed from 4 min to 8 and 15 min, respectively. Additionally, when the concentration of cetyltrimethylammonium bromide in the reaction medium increased from 2.0 to 8.0 mmol/L, mesoporous pore diameter of the silica shell increased from 2.0 nm to 2.8 nm. Finally, as the volume ratio of water to ethanol decreased from 15:1 to 13:3, number of the Au particles encapsulated within the mesoporous silica shells could be further adjusted, transitioning from single-core to multi-core encapsulation, and the catalytic results showed that the multi-core encapsulated Au/mesoporous silica composite particles exhibited higher catalytic activity.

Key words: Silica; Au particles, Mesoporous, Composite particles, Catalytic performance