Studies on Synthesis and Characterization of Fe 3 O 4 @SiO 2 @Ru Hybrid Magnetic Composites for Reusable Photocatalytic Application

Degradation of dye pollutants by the photocatalytic process has been regarded as the most efficient green method for removal organic dyes from contaminated water. The current research work describes the synthesis of Fe 3 O 4 @SiO 2 @Ru hybrid magnetic composites (HMCs) and their photocatalytic degradation of two azo dye pollutants, methyl orange (MO) and methyl red (MR), under irradiation of visible light. The synthesis of Fe 3 O 4 @SiO 2 @Ru HMCs involves three stages, including synthesis of Fe 3 O 4 magnetic microspheres (MMSs), followed by silica (SiO 2 ) coating to get Fe 3 O 4 @SiO 2 MMSs, and then incorporation of presynthesized Ru nanoparticles (~3 nm) onto the surface of Fe 3 O 4 @SiO 2 HMCs. The synthesized HMCs were characterized by XRD, FTIR, TEM, EDS, XPS, BET analysis, UV-DRS, PL spectroscopy, and VSM to study the physical and chemical properties. Furthermore, the narrow band gap energy of the HMC photocatalyst is a significant parameter that provides high photocatalytic properties due to the high light adsorption. The photocatalytic activity of synthesized Fe 3 O 4 @SiO 2 @Ru HMCs was assessed by researching their ability to degrade the aqueous solution of MO and MR dyes under visible radiation, and the influence of various functional parameters on photocatalytic degradation has also been studied. The results indicate that the photocatalytic degradation of MO and MR dyes is more than 90%, and acid media favors better degradation. The probable mechanism of photodegradation of azo dyes by Fe 3 O 4 @SiO 2 @Ru HMC catalysts has been proposed. Furthermore, due to the strong ferromagnetic Fe 3 O 4 core, HMCs were easily separated from the solution after the photocatalytic degradation process for reuse. Also, the photocatalytic activity after six cycles of use is greater than 90%, suggesting the stability of the synthesized Fe 3 O 4 @SiO 2 @Ru HMCs.