Rutile and anatase TiO2 films have been grown on Ti plates by thermal (500-800degreesC) and anodic oxidation followed by thermal annealing (w400-500degreesC), respectively. The photoelectrochemical efficiency of these photoanodes, evaluated by current density measurements in the photooxidation of 4-methoxybenzyl alcohol in deaerated CH3CN; has been determined. The photocurrent efficiency increases with the thickness of the TiO2 rutile film up to 1 mum (the most efficient thickness). At the wavelengths furnished by the irradiation apparatus similar thicknesses of anatase and rutile films show nearly the same efficiencies. Anodic bias produces similar relative increases of current intensity in both crystalline forms. (C) 2002 Elsevier Science B.V. All rights reserved.