Synthesis and characterization of substitutional and interstitial nitrogen-doped titanium dioxides with visible light photocatalytic activity

Both substitutional and interstitial nitrogen-doped titanium dioxides (N-TiO₂) were prepared. Their surface states were clarified by XPS spectra of N 1s, O 1s and Ti 2p. The results of photocatalysis show that both substitutional and interstitial N impurities greatly enhance the photoactivity of TiO₂ in visible light. Moreover, the visible light activity of interstitial N-doped TiO₂ is higher than that of substitutional N-doped TiO₂. The microwave synthesis presented in this paper is a promising and practical method to produce interstitial nitrogen-doped photocatalysts with high visible light activity.