An efficient heterogeneous nanocatalyst consisting of silica microsphere core decorated with Au nanoparticles shell encapsulated with a porous silica shell was successfully synthesized. The resulting core-shell- shell nanocatalyst catalyzed styrene epoxidation in toluene in the presence of a radical initiator and an oxidant tert-butyl hydroperoxide (TBHP) under inert atmosphere, giving ~100 % reactant conversion and 61 % selectivity towards the corresponding epoxide product at 80 °C. The maximum turnover frequency (TOF) of the catalyst was found to be 10400 h -1 at 80 °C under nitrogen atmosphere. The material also catalyzed trans-stilbene under similar condition, affording 52 % reactant conversion and 55 % selectivity towards trans-stilbene oxide product in 6 h. The catalyst was shown to be recycled and reused multiple times without losing its catalytic activity. Moreover, the Au nanoparticles in the catalyst did not undergo any significant leaching during the catalytic reactions.
All Science Journal Classification (ASJC) codes
- Catalytic oxidation
- Core-shell-shell nanomaterials
- Gold nanoparticles
- Heterogeneous nanocatalyst
- Styrene epoxidation