Preparation and characterization of magnetic hollow Fe3O4/P(GMA-EGDMA)-SO3H/Au-PPy recyclable catalyst for catalytic reduction of 4-nitrophenol

A highly effective and stable hollow Fe 3 O 4 /P(GMA-EGDMA)-SO 3 H/Au-PPy catalyst was prepared. Monodisperse hollow Fe 3 O 4 microspheres were synthesized using a hydrothermal method. As the catalyst support, magnetic hollow Fe 3 O 4 /P(GMA-EGDMA) microspheres with core–shell structure were prepared by distillation precipitation polymerization. Then sulfonic acid groups (─SO 3 H) were introduced into the surface of the support by surface modification. Au 3+ could be adsorbed by coordination with ─SO 3 H and underwent redox reactions with added pyrrole monomers. Finally, an Au–polypyrrole (PPy) layer was formed on the surface of the Fe 3 O 4 /P(GMA-EGDMA)-SO 3 H microspheres. The synthesized material was characterized using various techniques. Results indicated that the as-prepared hollow Fe 3 O 4 /P(GMA-EGDMA)-SO 3 H/Au-PPy catalyst had excellent catalytic activity and exhibited reusability for the reduction reaction of 4-nitrophenol. In addition, the catalyst was reusable for at least ten successive cycles.