Synthesis and characterization of core-shell-shell magnetic (CoFe2O4-SiO2-TiO2) nanocomposites and TiO2 nanoparticles for the evaluation of photocatalytic activity under UV and visible irradiation

Magnetic TiO2-SiO2-CoFe2O4 (TSC) composite photocatalytic particles with a core-shell structure and a high crystalline anatase TiO2 shell were synthesized via controlled hydrolysis and condensation of titanium isopropoxide. Nano-sized TiO2 powders were synthesized by a sol-gel/hydrothermal route. The prepared TiO2 and its composites were characterized by XRD, SEM, TEM, FT-IR, VSM, and UV-Vis. The results show that the obtained TSC composite particles were composed of spherical nanoparticles, about 5-8 nm in diameter, with several CoFe2O4 fine particles as cores and silica as coatings and barrier layers between the magnetic cores and anatase titania shells. The average crystallite size of TiO2 nanoparticles with an anatase structure is 6 nm. The photocatalytic activities of the samples were evaluated by the photocatalytic degradation of dichlorophenol-indophenol (DCPIP) dye. The maximum level reached for the degradation of the dye molecule was 95.32 and 87.27% for 3 minutes under UV and visible light respectively for mesoporous TiO2 nanoparticles.