A novel hierachically-nanostructured Pt/SiO₂/Fe₃O₄ catalyst with high activity and recyclability towards hydrosilylation

Recycling of noble-metal-based catalysts remains difficult and limits their applications towards catalysis in organic synthesis reactions with high viscosity. This work demonstrates a magnetically responsive hydrosilylation catalyst with novel core-shell nanostructure, which can be recycled from highly viscous reaction solutions. The supporting material, with core-shell structure, incorporates a Fe₃O₄ nanoparticle as the core coated with silica shell through reverse microemulsion approach to form SiO₂/Fe₃O₄ nanoparticles which show superparamagnetic behavior. Ultrafine Pt NPs are facilely prepared and loaded on SiO₂ shell via a simple hydrothermal protocol, forming Pt/SiO₂/Fe₃O₄ catalyst. As-synthesized catalysts exhibit high catalytic activity towards the hydrosilylation of allyl polyether with low-hydro silicone oil. Despite the high viscosity of the reaction system, the catalyst dispersed in reaction solution shows superparamagnetic response upon the application of magnetic field and can be recycled up to 7 times without appreciable loss in the catalytic activity. This work demonstrates a highly efficient and recyclable catalyst to catalyze hydrosilylation reaction with high viscosity and proposes a new philosophy to design reusable catalyst for organic reaction.