ABSTRACT
Photodegradation of organic and inorganic pollutants on semiconductors is a current topic of research. The TiO2 has the advantages of its high chemical stability, nontoxicity, and relatively low-price, but a serious disadvantage would be that only UV light can be used for photocatalytic reactions. Therefore, it is of great interest to find ways to extend the absorption wavelength range of TiO2 to visible region without the decrease of photocatalytic activity [1]. Asahi et al. reported that N-doped TiO2 shows a significant shift of the absorption edge to the visible light region[2]. There are many reports for the successful preparation of nitrogen doped titania, [3, 4] The sol-gel method or a variation thereof, is the most commonly used chemical method in the literature [5].
