Adsorption properties and catalytic activity of Fe3O4-Ag nanostructures

https://doi.org/10.1016/j.apsusc.2024.160236

The morphology and magnetic properties as well as adsorption capacity and catalytic activity of Fe₃O₄-Ag nanoparticles synthesized by the solvothermal method were studied in dependence on the duration of the thermolysis process (3, 6, and 8 h). X-ray diffraction, transmission electron microscopy, and energy-dispersive spectroscopy measurements showed that the morphology of nanoparticles changed strongly as the duration of thermolysis increased. At 6 and 8 h duration, Fe₃O₄ nanocrystals grow and assemble into porous spherical globules with an Ag core (samples 2 and 3). These samples demonstrate high magnetization value and very low coercivity. The adsorption capacity of nanoparticles was studied with respect to two organic dyes: cationic methylene blue (MB) and anionic Congo red (CR). The particles showed preferential adsorption of the cationic dye. High catalytic activity towards four dyes: MB, methyl orange (MO), CR, and Rhodamine C (RhC) at the presence of NaBH₄ is the remarkable property of these samples. The rate constant of the catalytic reaction was 1.4 min⁻¹. Simultaneous exposure of CR and MO dyes to nanoparticles and NaBH₄ caused their irreversible 100 % degradation while in the case of MB and RhC, a transition to their leuco form occurred.