Metallic Ag nanoparticles (Ag-0) were successfully activated using a direct in situ electrochemical method before being supported on TiO2. Catalytic testing showed that 5 wt%Ag-TiO2 gave the highest photodegradation (94%) of 50 mg L-1 2-chlorophenol (2-CP) at pH 5 using 0.375 g L-1 catalyst within 6 h, while under similar conditions, 1 wt% and 10 wt%Ag-TiO2 only gave 75% and 78% degradation, respectively. Characterization results illustrated that the photoactivity was affected by the amount of Ag-0 and oxygen vacancies which act as an electrons trap to enhance the electron-hole separation. While, the Ag-O-Ti bonds formation reduced the photoactivity. The degradation followed a pseudo-first order Langmuir-Hinshelwood model where adsorption was the controlling step. Study on the effect of scavengers showed that the hole (H+) and hydroxyl radical (OH center dot) play important roles in the photodegradation. The regenerated photocatalyst was still stable after five cycling runs. (C) 2015 Elsevier B.V. All rights reserved.