Designing Magnetic Catalyst Based on Au Nanoparticles Supported by EDTA Functionalized Amino‐Modified PNIPAM for Reduction of Nitro Compounds in Water

Abstract

A novel smart catalyst was developed with amino‐modified thermo‐responsive poly (N‐isopropyl acrylamide) (PNIPAM) grafts on silica‐coated MNPs using the conventional free radical polymerization process. By this methodology, the polymer was successfully grafted mainly onto the silica modified iron oxide nanoparticles (Fe₃O₄@Si). The PNIPAM‐grafted Fe₃O₄@Si was then subjected to ethylenediamine treatment to produce the amino‐functionalized support (Fe₃O₄@Si@PNIPAM‐NH₂), which was subsequently modified with carboxyl functional groups by using EDTA (ethylenediaminetetraacetic acid) to create Fe₃O₄@Si@PNIPAM‐NH₂‐EDTA. Au nanoparticles were then decorated on this support through its two amines and four carboxylates Different methods were used to study this novel catalyst, including ICP, FT‐IR, TGA, DLS, SEM, EDX, VSM, XRD, and CHN. The reduction of several aryl‐nitro derivatives demonstrated a significant catalytic activity for the as‐synthesized gold catalyst (Fe₃O₄@Si‐PNIPAM‐NH₂‐EDTA‐Au). The Au catalyst can be successfully removed from the reaction components using magnetic fields and used again in 8 successive reduction reactions without significant gold leaching and loss of catalytic activity.

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