A simple and general approach for the decoration of interior surfaces of silica hollow microspheres with noble metal nanoparticles and their application in catalysis

Precise control of the size, composition, and assembly process of each component is expected to play a key role in the construction of integrated functional nanostructures. Herein we report a unique sacrificial template method for the fabrication of noble metal@silica hollow microspheres with noble metal (Au, Pt, and Pd) nanoparticles uniformly immobilized on the inner surfaces of silica hollow microspheres. A polystyrene microsphere as a sacrificial template is used to play dual roles, creating a cavity inside the silica microsphere and introducing noble metal nanoparticles into the silica microsphere. Distinct from the reported sacrificial template methods, this method takes advantage of a thermodynamic effect to easily deposit the noble metal nanoparticles with different sizes and compositions onto the template microspheres. In addition, taking Au@silica hollow microspheres for example, they exhibit excellent catalytic activity and recyclability for the reduction of p-nitrophenol (4-NP) by NaBH₄.