TiO2 and SnO2 Magnetic Nanocomposites: Influence of Semiconductors and Synthetic Methods on Photoactivity

A number of reports have been published on use of TiO(2) in thin films, magnetic nanocomposites, or heterostructures such as TiO(2)/Ag and TiO(2)/SnO(2), as catalysts for water decontamination. Hence, semiconductor materials such as SnO(2), associated with TiO(2) in such nanocomposites, should be assessed in depth for such applications, especially those involving complex structures, such as magnetic photocatalytic nanocomposites. The present study describes the synthesis, characterization and testing of the photocatalytic potential of TiO(2) or SnO(2) magnetic nanocomposites obtained by the polymeric precursor and the hydrolytic sol gel methods. The nanocomposites TiO(2)/CoFe(2)O(4) and SnO(2)/CoFe(2)O(4) were synthesized from polymeric precursors while TiO(2)/Fe(3)O(4) and SnO(2)/Fe(3)O(4) were synthesized by the hydrolytic sol gel method. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (FEG/SEM) and transmission electron microscopy (TEM). The photocatalytic potentials were evaluated by rhodamine B dye photodegradation under UV-C radiation. Compared to SnO(2), the nanocomposites with a coating of TiO(2) were found to show better photocatalytic activity, but the SnO(2) magnetic nanocomposites showed some photocatalytic activity, even though SnO(2) is reported to be inactive for these purposes. As for the synthesis method, the nanocomposites obtained from polymeric precursors had smaller surface areas, but higher photocatalytic activity, than those obtained by the hydrolytic sol gel method. This observation was attributed to the higher crystallinity and a more active surface resulting from calcination of the polymeric precursor material.