The TiO2 thin film photoanodes for hydrogen generation by water photolysis have been prepared by dc reactive magnetron sputtering. Optical monitoring of the plasma emission with the feedback signal I/I-0 controlling the reactive gas admission and reflecting the target oxidation state has been used. X-ray diffraction GID and AFM studies have revealed the systematic evolution of the microstructure with I/I-0, from that of well-crystallized mixture of anatase and rutile at the lowest I/I-0 (oxidized target) to that of amorphous state with finely dispersed rutile grains at the highest I/I-0 (metallic target). It has been demonstrated that the microstructure of TiO2 affects to a large extent the optical and photoelectrochernical properties of the photoanodes. Optical band gap E-opt and the photocurrent response have been found to increase systematically with a decreasing feedback signal I/I-0. The best efficiency, i.e. the highest IPCE (incident photon-to-current conversion efficiency) has been obtained for the TiO2 photoanodes sputtered at I/I-0 = 0.09 from the oxidized target. (c) 2007 Elsevier B.V. All rights reserved.