Fabrication of Rutile TiO2−Sn/Anatase TiO2−N Heterostructure and Its Application in Visible-Light Photocatalysis

A new type of composite film (heterostructure) with optoelectronic properties have been prepared by coupling Sn-doped rutile TiO 2 (R-TiO 2 −Sn) and N-doped anatase TiO 2 (A-TiO 2 −N) with use of a sol−gel method. Under visible and UV light irradiation, it exhibits a higher photocatalytic activity than both R-TiO 2 −Sn and A-TiO 2 −N films due to the formation of a heterojunction at the interface, as well as the increase of total amount of photogenerated charge carriers and introduction of doping states. If R-TiO 2 −Sn is the outmost layer, moreover, the composite film shows a much higher photodegradation capability of HCHO than that when A-TiO 2 −N is the outmost layer. Our results offer a paradigm for developing optoelectronic functional materials that can be used in many fields, such as solar cells, photocatalysis, and photosynthesis.