Effect of Fe3O4 substrate preparation method for Fe3O4/Ag composite on methyl orange and 4-nitrophenol catalytic reduction

We present a straightforward method for creating reusable magnetic Fe 3 O 4 /Ag catalysts. Three distinct Fe 3 O 4 varieties were synthesized using different methods, and Ag nanoparticles were deposited onto the Fe 3 O 4 matrix via a hydrothermal process. The resulting Fe 3 O 4 and Fe 3 O 4 /Ag materials were characterized by XRD, XPS, FT-IR, Raman, DLS, FE-SEM, TEM, EDX, VSM, and UV-Vis spectroscopy. XRD analysis of the Fe 3 O 4 particles synthesized using the solvothermal reduction process (S2) revealed firm diffraction peaks, indicating high crystallinity. After hydrothermal treatment, S2/Ag retained a hollow spherical morphology and magnetic properties similar to Fe 3 O 4 . The synthesized Fe 3 O 4 /Ag catalytic performance was evaluated for the reduction of 4-nitrophenol (4-NP) and methyl orange (MO) dye in the presence of NaBH 4 . All catalysts effectively reduced both dyes and could be magnetically separated from the aqueous solution. The P1/Ag catalyst achieved over 95 % reduction of MO and 4-NP within 2 minutes. S2/Ag exhibited superior stability, preventing Ag leaching during the reaction. Furthermore, its high saturation magnetization allows easy magnetic extraction from the solution. These findings strongly suggest S2/Ag as a promising catalyst due to its selectivity and advantageous properties.