Síntese e caracterização estrutural de sistemas de óxidos metálicos: Fe3O4 e Fe3O4@Ag

Abstract

Coated magnetic nanoparticles (NPs) have shown great potential for applications in industrial and biomedical areas, mainly as drug delivery and contrast agents in medical images. In this work, iron oxide nanoparticles (magnetite), Fe3O4, were synthesized using the coprecipitation method, evaluating the synthesis parameters to optimize them and favor the method reproducibility, and then functionalize the NPs through doping with silver. The main objective was to qualitatively study structural, morphological details and physical properties by varying the size of NPs. To characterize them, we collected data from X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning (SEM) images - including chemical analysis by energy dispersion -, Raman spectroscopy and UV-Vis absorption. It was possible to confirm the face-centered cubic structure with space group F d−3m, estimate the particle size, and qualitatively suggest the presence of medium defects (microstrains). In particular, TEM images, although with very low resolution, allowed us to visualize the spherical morphology, average size and distribution of the particles. To test the concentrations in both doped and undoped samples (with silver), we analyzed the spectral map of concentrations by energy dispersion (EDS) under the SEM microscope; UV-Vis Absorption allowed qualitatively estimating optical properties as a function of average size. This work allows us to move on to more complex microstructure analyses, such as the characterization of defects.