The photoelectrochemical degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) at a Pt doped TiO2/Ti electrode was investigated. The electrode was prepared by first oxidizing the surface of a titanium sheet to form TiO2 and then doping platinum in H2PtCl6 solution. The degradation efficiency of 2,4-D in the solution with 51 mg/l concentration was, respectively, 16% for electrochemical process and 27% for photochemical process after 5 It reaction. It became 53% when photo- and electrochemical processes were integrated. The 10% higher 2,4-D degradation efficiency by the integrated method than the sum of the two individual processes demonstrates an obvious synergetic effect between the photo- and electrochemical catalysis. Besides, a decrease in current density was observed with reaction time. The degradation efficiency increased with the increase of potential bias. The degradation of 2,4-D was also dependent on pH and concentration of sodium sulfate acting as a supporting electrolyte. (C) 2003 Elsevier B.V. All rights reserved.