Titania-based nanoheterostructured microspheres for prolonged visible-light-driven photocatalysis.

Titanium dioxide is a widely used photocatalytic material possessing such advantages as safety, low cost, and high reactivity under the ultraviolet light illumination. However, its applicability in sunlight is limited due to the wide band gap and, as a consequence, the low quantum yield. Doping of titanium dioxide with metal or non-metal atoms and creating heterojunctions based on it are some of the most efficient ways to overcome this drawback. Herein we propose a new facile way of synthesis of nitrogen-doped TiO/MoO and TiO/WO microsphere-shaped nanocomposite photocatalysts, combining the advantages of these two methods. It is revealed that such structures are not only photo-active when exposed to visible light, but can also accumulate a photoinduced charge, thus allowing the catalytic reaction to be prolonged for a long time after the illumination is switched off (up to 48 h). With the help of EPR spectroscopy, paramagnetic defects in the samples were determined. The obtained results show good application prospects of the visible-light-driven TiO-based nanoheterostructured microspheres in the environmental purification.