Successful preparation of Ce-Zr-A1 oxide thin films and glassy products by an organic-free modification of the sol-gel technique is reported. TEM, XRD, FTIR, EPR, UV-Vis and XPS methods were used to investigate the effect of preparation technique on the structural composition and some properties of Ce-Zr-A1-O samples obtained by sol-gel method as compared to co-precipitated one. According to TEM data air-dried (50 degrees C) Ce-Zr-A1-O samples prepared by both methods show no visible structural difference while the further thermal treatment reveals the significant distinction in the samples properties. In particular, the conversion of the precipitate into colloidal state was proved to increase the efficiency of defect formation under thermal treatment of Ce-Zr-A1-O samples. (c) 2005 Elsevier B.V. All rights reserved.