Enhancement of TiO₂ NPs Activity by Fe₃O₄ Nano-Seeds for Removal of Organic Pollutants in Water.

The enhancement of the photocatalytic activity of TiO₂ nanoparticles (NPs), synthesized in the presence of a very small amount of magnetite (Fe₃O₄) nanoparticles, is here presented and discussed. From X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analyses, the crystallinity of TiO₂ nanoparticles (NPs) seems to be affected by Fe₃O₄, acting as nano-seeds to improve the tetragonal TiO₂ anatase structure with respect to the amorphous one. Photocatalytic activity data, i.e., the degradation of methylene blue and the Ofloxacin fluoroquinolone emerging pollutant, give evidence that the increased crystalline structure of the NPs, even if correlated to a reduced surface to mass ratio (with respect to commercial TiO₂ NPs), enhances the performance of this type of catalyst. The achievement of a relatively well-defined crystal structure at low temperatures ( = 150 °C), preventing the sintering of the TiO₂ NPs and, thus, preserving the high density of active sites, seems to be the keystone to understand the obtained results.