Magnetic recyclable Ag catalysts with a hierarchical nanostructure

This study reports the fabrication of a novel hierarchically structured nanocatalyst system possessing a well-defined nickel silicate (NS) protected Fe3O4 core and a layer of uniform Ag nanoparticles on the NS shell by using a multi-step approach. The multifunctional microparticles show high performance in the reduction of 4-nitrophenol and the rate of the catalytic reaction can be controlled by changing the concentration of nanocatalysts. In particular, there was no visible decrease in the catalytic activity of the reused catalysts even after being recycled five times. Thus the hierarchically structured Fe3O4@NS particles are very suitable as a catalyst support for catalyst separation and redispersion.