Growth of TiO2 thin films by AP-MOCVD on stainless steel substrates for photocatalytic applications

TiO2 thin films were deposited under atmospheric pressure by MOCVD in the temperature range 400-600 degrees C on stainless steel and Si(100) substrates. Titanium tetraisopropoxide (TTIP) was used as Ti and O source. Single-phased anatase and bi-phased (anatase/rutile) coatings with controlled composition have been deposited depending on the temperature and the TTIP mole fraction. The films grown on stainless steel at low temperature (<420 degrees C) and low TTIP mole fraction (< 10(-4)) are constituted of pure anatase and they exhibit a high photocatalytic activity under UV light and a high hydrophilicity. In the temperature range 430-600 degrees C the rutile starts growing leading to anatase/rutile mixtures and subsequently to a progressive decrease of both photocatalytic activity and wettability. Correlations between functional properties and microstructure of the films are discussed. (c) 2007 Elsevier B.V. All rights reserved.