Synthesis and properties of bifunctional Fe3O4/Ag nanoparticles

LANDA, R. A.; JORGE, G. A.; MOLINA, F. V.; ANTONEL, P. S.

Buenos Aires

Congreso; X Latin American Workshop on Magnetism, Magnetic Materials and their Applications; 2013

Bifunctional precious metal-iron oxide nanoparticles have attracted great attention due to their potential applications in novel electrical, optical, magnetic, catalytic, and sensing technologies. Especially, Fe3O4 nanoparticles have been comprehensively studied for a range of biomedical applications, owing to their unique magnetic properties and biocompatibility. More interesting, magnetic nanoparticles covered with a thin gold or silver shell would exhibit both electrical and magnetic functions simultaneously. In this work, a successful facile synthesis of Fe3O4/Ag nanoparticles was developed. In the first step, an aqueous dispersion of Fe3O4 nanoparticles and poly(vinylpyrrolidone) (PVP) (used as protecting agent) was prepared under ultrasound treatment. In the second step, Ag(I) ions were incorporated into the dispersion, in different molar ratios with respect to Fe3O4 nanoparticles (0.5, 1, 2.5 and 5). The chemical reduction of Ag(I) was performed using D-glucose as an environmentally benign agent and NaOH as a base reaction catalyst. The obtained Fe3O4/Ag nanoparticles were characterized by XRD studies, SEM and TEM observation, Energy Dispersive X-Ray Spectroscopy (EDS), conductivity measurements and DC magnetization measurements. From TEM and SEM observation it was found that the PVP protection has shown to be partial, as the Fe3O4 nanoparticles have a lower diameter after the reduction treatment in basic media. It is possible that the D-glucose also reduces the Fe(III) ions of the Fe3O4, resulting in a partial dissolution of the magnetic nanoparticles. From EDS measurements it was possible to obtain the proportion of Ag in the Fe3O4/Ag nanoparticles. FromDC magnetization measurements it was found that all the Fe3O4/Ag nanoparticles are superparamagnetic at room temperature, and the magnetization of saturation decreases as the Ag content increases. Finally, from conductivity measurements, a Ag(I)/Fe3O4 ratio = 2.5 was needed in order to observe electrical conductivity in the metallic regime. As a conclusion, magnetic and electrical Fe3O4 nanoparticles were successfully synthesized.