Synthesis and characterization of Ni nanoparticles incorporated into hyperbranched polyamidoamine–polyvinylamine/SBA-15 catalyst for simple reduction of nitro aromatic compounds

Abstract

In this study, hyperbranched polyamidoamine (PAMAM) was grown up onto the surface of polyvinyl amine-functionalized SBA-15 (PVAm/SBA-15) by a divergent method, without using organosilane precursors. Because of the surface modification of the PVAm/SBA-15 with the PAMAM hyperbranched polymer, the obtained hybrid material is able to trap water soluble metal ions such as Ni²⁺ via complex formation of PAMAM with metal ions. The reduction of trapped nickel ions in the hyperpolymeric shell of the PAMAM–PVAm/SBA-15 by sodium borohydride led to immobilized nickel nanoparticles in the structure of the composite. The obtained nanocomposite was effectively employed as a heterogeneous catalyst for the reduction of aromatic nitro compounds in the presence of NaBH₄ as a reducing agent. The physical and chemical properties of the Ni nanoparticle-PAMAM–PVAm/SBA-15 were investigated by XRD, FT-IR, BET, TEM and XPS. The catalyst showed excellent activity for the reduction of a number of aromatic nitro compounds in water at room temperature and could be reused ten times without any significant loss of activity.