Photocatalytic Efficiency of Zeolite-Based TiO 2 Composites for Reduction of Cu (II): Kinetic Models Anca Peter,* Leonard Mihaly-Cozmuta, Anca Mihaly-Cozmuta, and Camelia Nicula Department of Chemistry and Biology, North University Center of Baia Mare, Technical University Cluj Napoca, Victor Babes 76, 430122 Baia Mare, Romania Lucian Barbu Tudoran Faculty of Biology and Geology, Babes-Bolyai University, Clinicilor 5-7, 400006 Cluj-Napoca, Romania Adriana Vulpoi and Lucian Baia Faculty of Physics and Institute for Interdisciplinarity Research on Bio-Nano-Sciences, Babes-Bolyai University, M. Kogalniceanu 1, 400084 Cluj-Napoca, Romania This study evaluates the photoactivity of novel zeolite-based TiO 2 composites modified with metal particles for the pho- toreduction of Cu 2+ , depending on the zeolite and metal particles (Ag or Fe) content and to establish the photoreduction mechanism. The composites have been prepared by incorporating zeolite particles in the sols during the sol-gel preparation of the TiO 2 , followed by impregnation of the gels in solutions containing metal ions. The zeolite-based TiO 2 composites have been characterized using X-ray diffraction, Raman and FTIR spectroscopy techniques and TEM microscopy. The role of zeo- lite particles in the photoreduction process was demonstrated by using different kinetic models. The apparent constant rate for photoreduction increases in direct proportion with the content of zeolite and is higher for the composites modified with Fe than for those modified with Ag nanoparticles. The results demonstrate that composites have a higher photocatalytic *peteranca@yahoo.com © 2013 The American Ceramic Society Int. J. Appl. Ceram. Technol., 1–14 (2013) DOI:10.1111/ijac.12046