Facile Preparation of Uniform Nanocomposite Spheres with Loading Silver Nanoparticles on Polystyrene-methyl Acrylic Acid Spheres for Catalytic Reduction of 4-Nitrophenol

A simple, mild and green route is developed for the preparation of uniform polystyrene-methyl acrylic acid/silver (PSMAA/Ag) nanocomposite spheres with high catalytic activities. In this approach, monodisperse polystyrene-methyl acrylic acid (PSMAA) spheres are used as polymeric matrixes; silver precursor-[Ag(NH3)2]+ ions are then adsorbed onto the surfaces of PSMAA spheres due to the strong electrostatic attraction between carboxyl groups (electronegative) and [Ag(NH3)2]+ ions (electropositive). Meanwhile, [Ag(NH3)2]+ ions are reduced to Ag nanoparticles and simultaneously protected by PVP on the surface of PSMAA spheres. In this way, the PSMAA/Ag nanocomposite spheres with loading Ag nanoparticles on PSMAA spheres are prepared in aqueous media without any toxic reagents used during the preparation process. Ag nanoparticles uniformly distribute on the surfaces of PSMAA spheres with its size ranging from 8 to 24 nm. Moreover, the coverage degree of Ag nanoparticles on PSMAA spheres increases with the increasing of concentration of silver precursor-[Ag(NH3)2]+ ions. In addition, thermal analysis results show that the prepared PSMAA/Ag nanocomposite spheres exhibit improved thermal stabilities and glass translation temperature when compared to the related neat PSMAA spheres. Catalytic studies indicate that the prepared PSMAA/Ag nanocomposite spheres exhibit high catalytic activities and good recyclability for the reduction of 4-nitrophenol, rendering a potential use in the fields of catalytic reduction of 4-nitrophenol to 4-aminophenol.