Ag/Au-decorated Fe3O4/SiO2 composite nanospheres for catalytic applications

Noble metal particles in nanoscale (Au, Ag, Pt, etc.) have attracted intensive research interest due to their promising catalysis properties. However, the practical applications of these nanoparticle catalysts are always jeopardized by two problems. One is the difficulty in recovering the used nanoparticles and the other arises from the low catalytic efficiency due to the aggregation of the nanoparticles. In this work, Ag/Au nanoparticles were distributed onto spherical superparamagnetic carriers (SSCNs), which were fabricated through a facile oil-in-DEG emulsion route. The Ag/Au nanoparticles were attached onto the SSCNs by two steps. The Au seeds were attached onto the silica surface through electrostatic attraction first, and the Ag nanoparticles were grown on the basis of the Au seeds. The obtained Ag/Au–SSCN composite nanospheres demonstrated promising catalytic properties, which could also be recycled very easily by using a magnet.