Titanium-mordenites catalysts prepared by impregnation (TiMin), solid-solid interaction (TiMimp) and in situ incorporation during synthesis (TiMin); using ortho-phenylenediamine as a new templating agent under hydrothermal conditions (TiCl4, 160 degrees C, 6 days), were thoroughly characterized by TG/DTA, N-2 adsorption, XRD, FTIR, UV-vis and pyridine-FTIR. They were tested; in comparison with TiO2 Degussa, for degradation of meta-chlorophenol (MCP) in the presence of UV-Iight irradiation. It was possible to correlate the results obtained for MCP degradation over various catalysts with their structural and acidic properties. The photocatalytic degradation of MCP has been modeled to Langmuir-Hinshelwood rate law. TiMss showed the highest degradation rate (0.060 min(-1)) followed by those of TiMimp (0.050 min(-1)), TiMin (0.025 min(-1)) and TiO2 Degussa (0.0 18 min(-1)), respectively. The marked higher rate observed for the former catalyst was due to the larger pore radius (29 angstrom), acidity and the extra-framework TiO2 anatase species (of absorption at 340 nm). Very strong emphasize to the state of titania within the three samples (TiM) was demonstrated and most importantly Si-O-Ti linkages (950-940 cm(-1)) were observed and correlated with photoactivities of all samples. Degradation products of MCP, including both aromatic and aliphatic intermediates, were monitored by HPLC. Chloride ions, on the other hand, were followed up during the degradation processes. Formic acid (formate) was identified as a final intermediate in the solution before it further mineralized to CO2. Reasonable degradation pathway for MCP molecule is proposed on the basis of structural identification of several by-products. (C) 2007 Elsevier B.V. All rights reserved.