One-step synthesis of robust amine- and vinyl-capped magnetic iron oxide nanoparticles for polymer grafting, dye adsorption, and catalysis.

Magnetic iron oxide nanoparticles (MIONs) bearing amine and vinyl groups are fabricated straightforwardly using vinyl-based tertiary amine molecules as both alkaline source and ligands based on the coprecipitation of iron ions in aqueous solution. The as-prepared MIONs present amphiphilic performance that can be well-dispersed both in aqueous solution and common organic solvents (e.g., ethanol, dichloromethane and tetrahydrofuran). Transmission electron microscopy (TEM), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM) measurements reveal that the MIONs are superparamagnetic Fe3O4 nanoparticles with a mean diameter below 10 nm. The presence of ligands on the surface of MIONs was confirmed by thermogravimetric analysis (TGA), Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS) characterizations. Benefiting from the surface vinyl groups, the MIONs are able to graft polyvinyl-based polymers by in situ polymerization of the corresponding vinyl monomers as confirmed by grafting poly(methyl methacrylate) (PMMA) in this paper. On the basis of their surface amine groups, the MIONs show high adsorption capacity (ca. 0.42 mmol/g) for congo red dye and excellent performance for in situ growth of Pt nanocatalyst. Moreover, the MIONs possess high stability and can be reused several times without obvious decrease of their adsorption capacity and catalytic efficiency. Considering the facile fabrication process and versatile performance of the obtained MIONs, this work may open up new opportunities for the large-scale applications of MIONs.