Nanostructure, Band Gap, and Antibacterial Activity of Spinel Fe2MO4/OO Magnetic Fluids

Abstract

Abstract This research aimed at investigating Fe2MO4 ferrofluids nanostructure, with M was Fe, Ti and Cr. Fe2MO4 nanoparticles were synthesized through coprecipitation method, and the phase and crystallinity were analyzed using XRD instrument. The obtained results showed the Fe3O4 phase, but there was a shift in diffraction peak position contributed by the doping of Ti2+ and Cr3+ ions. Furthermore, a similar change occurred in the lattice parameter, crystal volume, and particle size. The particle sizes of Fe3O4, Fe2TiO4, and Fe2CrO4 particles were 10.2, 13.4, and 6.9 nm, respectively. The functional groups of the Fe2MO4/OO ferrofluids were characterized using FTIR and obtained the Fe-O stretching band shift due to the modification of structure. Furthermore, FTIR analysis was used as a reference to confirm functional groups of the ferrofluids. The absorbance data collection was performed through the characterization using UV-Vis instrument, and there was intervalence charge transfer at a wavelength near infra-red indicating there was Fe element and nanoparticle interface which raised an optimum absorption at the interval of 400-550 nm. Furthermore, through the obtained absorbance data, there was an energy gap of 2.2-2.24 eV. Interestingly, the results of antibacterial testing results through the dilution method showed a modification of structure could increase the antibacterial activity of the Fe2MO4/OO ferrofluids by minimizing the percentage of surviving colony number.