Efeito da incorporação de íons de ferro nas propriedades estruturais, morfológicas, magnéticas e fotocatalíticas de nanocristais de óxido de zinco

Abstract

In this work, pure zinc oxide (ZnO) nanocrystals and those with varying concentrations of iron (Fe) were synthesized using a controlled synthesis method to investigate the influence of iron ion ncorporation/saturation on the structural, morphological, magnetic, and photocatalytic properties of ZnO. Structural characterization was carried out using X-ray diffraction (XRD), revealing the formation of a hexagonal wurtzite crystal structure in all samples, with alterations in lattice parameters corresponding to increased iron concentrations, confirming the incorporation of Fe ions into the ZnO crystal lattice. Moreover, at concentrations above 1.0%, the formation of iron oxide nanocrystals was observed, resulting in the creation of a nanocomposite. Morphological analysis, performed using scanning electron microscopy (SEM), confirmed that the incorporation of iron ions into the ZnO structure promotes an increase in the length of ZnO rods. Magnetic properties were evaluated through vibrating sample magnetometry (VSM), where a transition from diamagnetic behavior, typical of pure ZnO, to ferromagnetic behavior was observed in iron-doped samples, especially at higher concentrations. Furthermore, the photocatalytic properties of the nanocrystals were tested in the degradation of organic dyes under ultraviolet (UV) light irradiation. The results indicated that, in this methodology, iron doping diminished the photocatalytic efficiency of ZnO. This study underscores the importance of investigating the effect of iron concentration for the modification and enhancement of ZnO nanocrystal properties, highlighting their potential for applications in spintronic and magnetic devices. The results presented provide a solid foundation for future research on the optimization of the functional properties of Fe-doped ZnO nanocrystals, demonstrating the concentration range in which only doping occurs and the range that favors the formation of a nanocomposite containing iron oxide.