Effect of Synthesis Parameters on the Structure and Magnetic Properties of Magnetic Manganese Ferrite/Silver Composite Nanoparticles Synthesized by Wet Chemistry Method

In the present work, magnetic manganese ferrite/silver (MnFe₂O₄-Ag) composite nanoparticles were synthesized by wet chemistry method. This synthesis process consists of two steps: first, the seed of manganese ferrite nanoparticles (MnFe₂O₄ NPs) was prepared by a coprecipitationmethod; second, growth of silver nanoparticles (AgNPs) on the MnFe₂O₄ seed by modified photochemical reaction. We have conducted systematically the effects of synthesis parameters such as pH value, synthesis time, precursor salts concentration, mass ratio and stabilizing agents on the structure and magnetic properties of nanocomposites. In an optimized condition of synthesis parameters, the high quality MnFe₂O₄ NPs are obtained at pH value = 13, Mn²⁺ cation concentration= 0.4 M and synthesis time about 105 min; and the use of PVP stabilizing agent is found to optimize the formation of Ag-NPs on the surface of MnFe2O4 NPs. The as-prepared MnFe₂O₄-Ag magnetic nanocomposites display excellent properties of high crystallinity, long-term aggregation stability in aqueous medium, large saturation magnetization in the range of 15-20 emu/g, and small sizes of Ag-NPs similar to 20 nm. These exhibited properties made the MnFe₂O₄-Ag nanocomposites attractive candidate for various technological applications in biomedicine, catalyst and environmental monitoring.