N-doped TiO2 coatings grown by atmospheric pressure MOCVD for visible light-induced photocatalytic activity

N-doped TiO2 films were deposited by atmospheric pressure CVD from titanium tetra-isopropoxide (TTIP) and N2H4 as reactive gas in the temperature range 400-500 degrees C on various substrates. The films grown at 400 degrees C are amorphous and exhibit a compact structure and a smooth surface morphology. Increasing the deposition temperature first leads to the crystallization in the anatase structure (temperature range 410-450 degrees C) and then to the formation of rutile, so that an anatase-rutile mixture is observed in the temperature range 450-500 degrees C. Correlation between the structure, the morphology, optical properties, hydrophilicity and photocatalytic activity of the thin films both under UV and VIS light are presented and discussed in relation with deposition conditions. (C) 2007 Elsevier B.V. All rights reserved.