Cathodic electrosynthesis of TiO2, Nb2O5, PZT, composite RuO2-TiO2 and Al2O3-TiO2 films and powders was performed. In the proposed approach, TiO2, Nb2O5, PZT film formation on platinized silicon or/and Pt substrates was achieved via peroxoprecursors. . Obtained deposits were characterized by XRD, SEM, Auger and SIMS methods. The crystallization behaviour of the deposits has been studied. Possible cathodic reactions which underlie the deposition process and the role of hydrogen peroxide are discussed. (C) 1999 Published by Elsevier Science Limited. All rights reserved.