APSUSC 338-2015-75

Direct in situ activation of Ag0nanoparticles in synthesis of Ag/TiO2and its photoactivity

Metallic Ag nanoparticles (Ag0) were successfully activated using a direct in situ electrochemical methodbefore being supported on TiO2. Catalytic testing showed that 5 wt% Ag–TiO2gave the highest photodegra-dation (94%) of 50 mg L−12-chlorophenol (2-CP) at pH 5 using 0.375 g L−1catalyst within 6 h, while undersimilar conditions, 1 wt% and 10 wt% Ag–TiO2only gave 75% and 78% degradation, respectively. Character-ization results illustrated that the photoactivity was affected by the amount of Ag0and oxygen vacancieswhich act as an electrons trap to enhance the electron–hole separation. While, the Ag O Ti bonds forma-tion reduced the photoactivity. The degradation followed a pseudo-first order Langmuir–Hinshelwoodmodel where adsorption was the controlling step. Study on the effect of scavengers showed that thehole (H+) and hydroxyl radical (OH•) play important roles in the photodegradation. The regeneratedphotocatalyst was still stable after five cycling runs.