Synthesis and Properties of Bifunctional Fe O /Ag Nanoparticles

LANDA, ROMINA A.; JORGE, GUILLERMO A.; MOLINA, FERNANDO V.; ANTONEL, PAULA S.

Buenos Aires

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

Comisión Nacional de Energía Atómica

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, Fe304 nanoparticles have been comprehensively studied for a range of biomedical applications, owing to their unique magnetic properties and biocompa-tibility. 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 Fe304/Ag nanoparticles was developed. In the first step, an aqueous dispersion of Fe304 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 difierent molar ratios with respect to Fe304 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 Fe304/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 hasshown to be partial, as the Fe-304 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 Fe304, resulting in a partial dissolution of the magnetic nanoparticles. From EDS measurements it was possible to obtain the proportion of Ag in the Fe304/Ag nanoparticles. From DC magnetization measurements it was found that allthe Fe304/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)/Fe304 ratio = 2.5 was needed in order to observe electrical conductivity in the metallic regime. As a conclusion, magnetic and electrical Fe304 nanoparticles were successfully synthesized.