Transparent anatase TiO2-based multilayered photocatalytic films on porous alumina and glass substrates were synthesized via a sol-gel process. All films had a sponge-like microstructure and a mean crystallite dimension of ca. 8 nm. The simple anaerobic decomposition of acetic acid reaction was used as the standard test system for evaluating the photocatalytic activity of the films. Doping with iron(III) impeded the photocatalytic activity.