Synthesis of silver nanoshell-coated cationic polystyrene beads: A solid phase catalyst for the reduction of 4-nitrophenol

Silver nanoshell-coated cationic polystyrene beads have been synthesized at room temperature through immobilization of specific silver precursor ions, followed by wet chemical reduction. The electrostatic field force has been taken into consideration for the immobilization of precursor ions onto the resin beads. The as-synthesized particles were characterized by XRD, XPS, SEM, TEM, EDX, and FTIR studies and have been exploited as a solid phase catalyst for the reduction of 4-nitrophenol in the presence of sodium borohydride. The detailed kinetics of the reduction process was monitored under varied experimental conditions. At the end of the reaction, the catalyst particles remain active. They can thus be separated from the product, 4-aminophenol, and can be recycled a number of times after the quantitative reduction of 4-nitrophenol. The activity of the solid catalyst particles has also been examined to promote the reduction of other nitrophenols, e.g., 2-, 3-nitrophenol. The synthesis of the solid catalyst particles, their applications and detailed kinetic aspects of the reduction of 4-nitrophenol have been reported.