In this study, we report that nitrogen doped TiO2 could be achieved via thermal treatment of Degussa P25 TiO2 in NO atmosphere directly (P25-NO). The samples were characterized with XRD, XPS, and FT-IR. The characterization results suggested that nitrogen species were interstitially doped in P25-NO during the NO thermal treatment process. In comparison with P25, the P25-NO exhibited significantly enhanced photocatalytic activities under visible light irradiation (lambda > 420 nm) for gaseous NO removal. On the basis of electronic band structure theory, we proposed a possible mechanism for the enhanced visible light driven photocatalytic oxidation process over the interstitial N doping P25-NO samples. This work could not only deepen understanding of the enhanced photoactivity originated from interstitial N doping in TiO2, but also provide a facile route to prepare nitrogen doped TiO2 for environmental and energy applications. (C) 2011 Elsevier B.V. All rights reserved.