The electronic coupling and photocatalytic activity of Ag2CO3-TiO2 nanocomposite can be optimized by the fine-tuning of the band position of titanium oxide with nitrogen doping. The increase of the valence band energy of TiO2 by N-doping leads not only to the enhanced absorption of visible light but also to the promoted hole transfer from Ag2CO3 to TiO2, resulting in the efficient spatial separation of photo-generated electrons and holes. While the undoped Ag2CO3-TiO2 nanocomposite shows an inferior photocatalytic activity to the pure Ag2CO3, the photocatalyst performance of N-doped nanocomposite is better than those of Ag2CO3 and undoped Ag2CO3-TiO2 nanocomposite. This observation underscores a significant enhancement of the photocatalytic activity of nanocomposite upon N-doping, a result of enhanced electronic coupling between the hybridized species. The present results clearly demonstrate the importance of the fine-tuning of band position in optimizing the photocatalytic activity of hybridtype photocatalysts. (C) 2015 Elsevier Inc. All rights reserved.