Dendrimer grafted core–shell Fe3O4–polymer magnetic nanocomposites stabilized with AuNPs for enhanced catalytic degradation of Rhodamine B – A kinetic study

Abstract

In this paper, three types of novel magnetically recoverable core–shell heterogeneous nanoparticle catalysts were prepared by individual grafting of poly(amidoamine) dendrimer with generation G(0), G(1) and G(2) on Fe3O4–Poly(4-MS-DVB-GMA) core–shell as a common matrix followed by stabilization of AuNPs. The SPR peak noticed at 547 nm in UV confirms the formation of AuNPs in each catalyst. The SEM supports the construction of core–shell magnetic nanocomposite in which an interior layer due to Fe3O4 core and the outer thick layer due to Poly(4-MS-DVB-GMA) shell grafted with PAMAM-G(0), G(1) and G(2) dendrimers and the XRD shows core size of Fe3O4 is 8 nm. From VSM analysis, the quantum of Fe3O4 NPs is estimated as 95.5%, 82.2%, 50.2%, 15.1% in OA-Fe3O4 and core–shelled Fe3O4–Poly(4-MS-DVB-GMA)–PAMAM-G(0), G(1) and G(2)-AuNPs. The XPS shows the presence of C(1s), N(1s), O(1s), Fe(2p) and Au(4f) elements. The reduction of Rhodamine B reveals that Fe3O4–Poly(4-MS-DVB-GMA)–PAMAM-G(2) is 6 times (kobs = 35.28 × 10−3 min−1) active than the G(0) dendrimer catalyst and its activity is maintained upto 5th cycle thus enlightening the recyclability and stability.